Remove Lavaplayer and migrate to Lavalink

Replaced the bot's audio handling system by removing Lavaplayer dependencies and migrating to a Lavalink v4 node. Updated `MusicManager`, `TrackScheduler`, and related classes to utilize the `LavalinkClient`. Refactored playlist and track loading logic, task integrations, and event dispatch to integrate with the remote node. Deprecated the custom Udio source, preserving references for a future plugin port. Documented configuration and deployment details for the new audio architecture.

.env.example

@@ -1,5 +1,4 @@
 NETNEUTRALITY_TAG=latest
-
 NETNEUTRALITY_BOT_ENV=dev
 NETNEUTRALITY_BOT_TOKEN=
 NETNEUTRALITY_BOT_PREFIX=$
@@ -12,13 +11,17 @@ MYSQL_PORT=3306
 MYSQL_USER=java
 MYSQL_PASSWORD=password
 MYSQL_DATABASE=netneutrality
-MYSQL_ROOT_PASSWORD=password
-MARIADB_AUTO_UPGRADE=1
 
+NETNEUTRALITY_LAVALINK_URI=ws://lavalink:2333
+NETNEUTRALITY_LAVALINK_PASSWORD=youshallnotpass
+NETNEUTRALITY_LAVALINK_NAME=dev-player
 NETNEUTRALITY_PO_TOKEN=
 NETNEUTRALITY_VISITOR_DATA=
-NETNEUTRALITY_CIPHER_URL=http://localhost:8001
+NETNEUTRALITY_OAUTH_TOKEN=
+NETNEUTRALITY_CIPHER_URL=http://ejs-api:8001
 NETNEUTRALITY_CIPHER_PASSWORD=
+NETNEUTRALITY_WEBPO_URL=http://webpo:8080
+NETNEUTRALITY_WEBPO_PASSWORD=
 
 NETNEUTRALITY_SENTRY_DSN=
 GITLAB_HOST=

.junie/plans/improve-task-manager.md

@@ -0,0 +1,213 @@
+---
+sessionId: session-260919-132150-1vmv
+---
+
+# Requirements
+
+### Overview & Goals
+The `TaskManager` subsystem in Net Neutrality manages the in-memory registry, execution dispatch, locking, persistence, and lifecycle transitions for Discord interaction tasks (buttons, modals, reactions, step-by-step flows, and scheduled background tasks).
+
+This plan addresses several bugs, synchronization oversights, memory leak potentials, and architectural discrepancies between `docs/tasks.md` and `TaskManagerImpl.java`:
+1. **Fix Parent-Child Lifecycle Propagation**: Correctly handle `REMOVE_SELF_AND_CHILDREN` when triggered by child tasks (`WithParent`).
+2. **Synchronize DB Persistence on Removal**: Ensure `PersistableTask` entries are purged from the database via `TaskService.unpersistTask()` when removed.
+3. **Prevent Memory Leaks in Pending Tasks**: Unify `pendingTasks` tracking and ensure `TaskCleanup` cleans up expired pending step tasks.
+4. **Fix Concurrency & Lock Cleanup Hazards**: Eliminate race conditions where lock eviction during task execution allows duplicate concurrent runs.
+5. **Optimize Lookup Performance**: Replace eager full-collection queries with short-circuiting streams for partial ID lookups.
+6. **Improve Test Coverage**: Introduce thorough unit tests covering all task lifecycle paths, locking behavior, and persistence hooks.
+
+### Scope
+- **In Scope**:
+  - `me.bobert.netneutrality.core.tasks.TaskManager` interface.
+  - `me.bobert.netneutrality.core.tasks.TaskManagerImpl` implementation.
+  - `me.bobert.netneutrality.scheduled.cleanup.TaskCleanup` expiration handling.
+  - Interaction deletion error-handling callbacks on `InteractionHook`.
+  - Comprehensive unit test suite for `TaskManagerImpl`.
+- **Out of Scope**:
+  - Refactoring concrete task business logic (e.g., individual music or reaction commands).
+  - Schema changes to the `OTask` entity or database migrations.
+
+### Functional Requirements
+- **FR-1**: When any child task implementing `WithParent` returns `Lifecycle.REMOVE_SELF_AND_CHILDREN`, `TaskManager` must remove the parent task and all associated child tasks from the registry.
+- **FR-2**: When any `PersistableTask` is removed from `TaskManager` (via lifecycle completion, manual removal, or cancellation), `TaskManager` must call `taskService.unpersistTask()` so the task is deleted from persistent storage.
+- **FR-3**: Pending step tasks must be tracked reliably, exposed for expiration checks, and cleaned up by `TaskCleanup` if abandoned.
+- **FR-4**: Concurrent task invocations sharing the same `lockId` must be serialized safely without lock collisions or premature lock disposal.
+- **FR-5**: `findTaskByPartialId` must short-circuit upon finding the first match without allocating full intermediate lists.
+- **FR-6**: Interaction deletion via `Deletable` must gracefully handle expired hooks and Discord API errors asynchronously.
+
+# Technical Design
+
+### Current Implementation
+`TaskManagerImpl` (`me.bobert.netneutrality.core.tasks.TaskManagerImpl`) implements `TaskManager` and `Lifecycle`. It maintains:
+- `tasks`: `ConcurrentHashMap<String, Task>` for active tasks.
+- `pendingTasks`: `CopyOnWriteArrayList<Task>` for unassigned step tasks.
+- `deletableTasksContext`: `ConcurrentHashMap<String, CommandContext>` for tracking interaction hooks to delete.
+- `tasksLock`: `ConcurrentHashMap<String, ReentrantLock>` for per-task/per-parent synchronization.
+- `taskService`: `TaskService` for loading and persisting `PersistableTask` entities.
+
+### Key Issues & Decisions
+
+#### 1. Parent/Child Task Lifecycle Resolution
+- **Issue**: `handleTaskLifecycle` only checks `if (task instanceof WithChildren)` for `REMOVE_SELF_AND_CHILDREN`. When a button task (which implements `WithParent<P>`, such as `LoadTrackFromPlaylistTask`) returns `REMOVE_SELF_AND_CHILDREN`, the check evaluates to `false`, leaving the parent and sibling buttons active in memory.
+- **Decision**: In `handleTaskLifecycle`, check if the task implements `WithParent<?>`. If so, obtain the parent task (`taskWithParent.getParentTask()`) and remove the parent along with all of its child tasks (`parent.getChildTasks()`). If the task directly implements `WithChildren`, remove all its child tasks and itself.
+
+#### 2. Automatic Persistence Synchronization
+- **Issue**: `docs/tasks.md` specifies that persistable tasks removed after execution are deleted from the database. Currently `TaskManagerImpl.removeTask` only removes from `tasks` map and never calls `taskService.unpersistTask(persistableTask)`.
+- **Decision**: In `removeTask(Task task)`, check `if (task instanceof PersistableTask persistableTask)` and invoke `taskService.unpersistTask(persistableTask)`.
+
+#### 3. Pending Task Registry & Cleanup
+- **Issue**: `pendingTasks` is stored in a `CopyOnWriteArrayList<Task>`. `getTasks()` ignores it, preventing `TaskCleanup` from pruning expired step tasks. `removeTask()` also ignores `pendingTasks`.
+- **Decision**: Store `pendingTasks` in a `ConcurrentHashMap<String, Task>` (or unify with active tasks / pending lookup). Update `getTasks()` or provide a method to include pending tasks in cleanup routines. Update `removeTask(Task task)` to remove from `pendingTasks` as well as `tasks`.
+
+#### 4. Concurrency & Lock Management
+- **Issue**: `removeTask` calls `tasksLock.remove(task.getLockId())` immediately. If another thread is waiting or about to acquire the lock for a sibling task, it can get a new lock instance from `computeIfAbsent`, breaking mutual exclusion.
+- **Decision**: Maintain lock instances safely; do not remove locks eagerly while in the middle of executing handlers. Persistable tasks with state should also participate in locking if needed, or maintain clear locking semantics.
+
+#### 5. Lookup API Optimization
+- **Issue**: `findTaskByPartialId` calls `findTasksByPartialId`, instantiating and populating a full `ArrayList` before taking the first element.
+- **Decision**: Implement `findTaskByPartialId` with `.filter(...).findFirst()` directly on the stream.
+
+### Architecture & Component Interaction Diagram
+
+```mermaid
+graph TD
+    subgraph Discord Events
+        BE[ButtonInteractionEvent] --> EH[EventsHandler]
+        ME[ModalInteractionEvent] --> EH
+        RE[MessageReactionAddEvent] --> EH
+        MSG[MessageReceivedEvent] --> EH
+    end
+
+    subgraph TaskManager Subsystem
+        EH -->|TaskContext| TM[TaskManagerImpl]
+        TM -->|Acquire Lock| TL[tasksLock Map]
+        TM -->|Lookup Task| TR[tasks & pendingTasks Maps]
+        TM -->|Execute| T[Task.execute]
+        T -->|Return Lifecycle| TM
+        TM -->|Cascade Cleanup| LC[handleTaskLifecycle]
+        LC -->|WithParent / WithChildren| RM[removeTask]
+        RM -->|Unpersist| TS[TaskService]
+        TS -->|Delete| DB[(Database / OTask)]
+        RM -->|Deletable| DH[InteractionHook.deleteOriginal]
+    end
+
+    subgraph Background Maintenance
+        TC[TaskCleanup] -->|Periodic Poll| TM
+        TM -->|Prune Expired| RM
+    end
+```
+
+### Proposed Code Changes & Contracts
+
+#### `TaskManagerImpl.java`
+```java
+private void handleTaskLifecycle(Task task, Task.Lifecycle status) {
+    if (status == null) {
+        throw new IllegalArgumentException("Task lifecycle status cannot be null");
+    }
+
+    switch (status) {
+        case REMOVE_SELF -> removeTask(task);
+        case REMOVE_SELF_AND_CHILDREN -> {
+            if (task instanceof WithParent<?> taskWithParent) {
+                Task parent = taskWithParent.getParentTask();
+                if (parent instanceof WithChildren parentWithChildren) {
+                    for (Task child : parentWithChildren.getChildTasks()) {
+                        removeTask(child);
+                    }
+                }
+                removeTask(parent);
+            } else if (task instanceof WithChildren taskWithChildren) {
+                for (Task child : taskWithChildren.getChildTasks()) {
+                    removeTask(child);
+                }
+                removeTask(task);
+            } else {
+                removeTask(task);
+            }
+        }
+        case KEEP, PARENT, BUILTIN -> {
+            // Maintained in active registry
+        }
+    }
+}
+
+@Override
+public void removeTask(Task task) {
+    if (task == null) return;
+    String id = task.getId();
+    boolean removed = (tasks.remove(id) != null);
+    removed |= (pendingTasks.remove(task) != null);
+
+    if (removed) {
+        logger.debug("Removing task: {}", id);
+        if (task instanceof PersistableTask persistableTask) {
+            taskService.unpersistTask(persistableTask);
+        }
+    }
+}
+```
+
+### File Structure Changes
+- **Modified**: `src/main/java/me/bobert/netneutrality/core/tasks/TaskManagerImpl.java`
+- **Modified**: `src/main/java/me/bobert/netneutrality/scheduled/cleanup/TaskCleanup.java`
+- **Added**: `src/test/java/me/bobert/netneutrality/core/tasks/TaskManagerImplTest.java`
+
+# Testing
+
+### Validation Approach
+Automated unit tests will be created in `src/test/java/me/bobert/netneutrality/core/tasks/TaskManagerImplTest.java` utilizing JUnit 5, AssertJ, and Mockito to validate all functional requirements without requiring live Discord connections or database instances.
+
+### Key Scenarios
+1. **Task Registration & Lookup**:
+   - Insert standard `Task`, verify `getTask(id)` and `hasTask(id)` return `true`.
+   - Insert duplicate task ID, verify rejected with user notification.
+2. **Parent / Child Lifecycle (`REMOVE_SELF_AND_CHILDREN`)**:
+   - Create parent task implementing `WithChildren` and child task implementing `WithParent`.
+   - Execute child task returning `REMOVE_SELF_AND_CHILDREN`.
+   - Verify parent task and all sibling child tasks are removed from the registry.
+3. **Persistable Task DB Synchronization**:
+   - Insert `PersistableTask`, verify `TaskService.persistTask` is called.
+   - Remove `PersistableTask` via lifecycle completion or `removeTask()`, verify `TaskService.unpersistTask` is invoked.
+4. **Step Task Flow**:
+   - Insert `StepTask` into pending registry.
+   - Reassign ID via `activateTask(task, oldId)`, verify task moves from pending to active registry under new ID.
+5. **Partial ID Search**:
+   - Query `findTaskByPartialId` and verify it matches correct instance without scanning beyond first match.
+6. **Task Expiration & Cleanup**:
+   - Mock expired active and pending tasks, trigger `TaskCleanup.run()`, verify expired tasks are pruned from both collections.
+7. **Concurrency & Locking**:
+   - Simulate concurrent executions for tasks sharing a `lockId`, confirming mutual exclusion.
+
+# Delivery Steps
+
+### ✓ Step 1: Fix Task Lifecycle Hierarchy and DB Persistence Synchronization
+`TaskManagerImpl` correctly propagates parent-child lifecycle actions and synchronizes task deletions with `TaskService`.
+
+- Update `handleTaskLifecycle` in `TaskManagerImpl.java` to support `REMOVE_SELF_AND_CHILDREN` for tasks implementing `WithParent`, resolving the parent task and removing both the parent and all sibling child tasks.
+- Modify `removeTask(Task task)` in `TaskManagerImpl.java` to invoke `taskService.unpersistTask(persistableTask)` when `task instanceof PersistableTask`, ensuring persisted records in the database are purged when tasks finish.
+- Refactor `deleteInteraction(Task task)` in `TaskManagerImpl.java` to cleanly handle `Deletable` logic for both standalone and parented tasks, adding failure logging to `InteractionHook.deleteOriginal().queue()`.
+
+### ✓ Step 2: Refactor Pending Task Management and Concurrency Locking
+Pending tasks and active task locks are managed safely without race conditions or memory leaks.
+
+- Refactor `pendingTasks` in `TaskManagerImpl.java` to use a `ConcurrentHashMap<String, Task>` keyed by task ID for O(1) lookups and consistent state management.
+- Update `removeTask(Task task)`, `getTask(String id)`, and `getTasks()` in `TaskManagerImpl.java` to include pending tasks so they can be retrieved, removed, and cleaned up when expired.
+- Update `TaskCleanup.java` to ensure expired pending tasks are identified and cleaned up.
+- Improve lock management in `TaskManagerImpl.handle(TaskContext context)` so that lock eviction does not interfere with concurrently waiting threads acquiring new lock instances.
+
+### ✓ Step 3: Optimize Task Query Performance and Diagnostic Logging
+Task lookup methods use short-circuiting stream pipelines, and diagnostic logging is corrected.
+
+- Optimize `findTaskByPartialId` in `TaskManagerImpl.java` to use `.findFirst()` directly rather than allocating a full list via `findTasksByPartialId`.
+- Fix typos in log messages and warnings across `TaskManagerImpl.java` (e.g. `"Aquiring lock"`, `"childs"`).
+- Ensure consistent ephemeral fallback messages and handling when unacknowledged interactions or missing tasks are encountered.
+
+### ✓ Step 4: Add Comprehensive Unit Tests for Task Management
+A complete unit test suite validates `TaskManagerImpl` functionality across all task types, lifecycles, and concurrency scenarios.
+
+- Create `src/test/java/me/bobert/netneutrality/core/tasks/TaskManagerImplTest.java` using JUnit 5 and Mockito.
+- Implement tests for standard task registration (`insert`), lookup (`getTask`, `findTaskByPartialId`), and removal (`removeTask`).
+- Implement tests for parent-child tasks (`WithChildren`, `WithParent`), verifying lock inheritance and `REMOVE_SELF_AND_CHILDREN` cascading removals.
+- Implement tests for `StepTask` lifecycle (pending insertion, ID reassignment via `activateTask`, and expiration).
+- Implement tests for `PersistableTask` lifecycle, verifying automatic database persistence on insert and unpersisting on removal.
+- Implement tests verifying thread synchronization and lock acquisition during task execution.

.junie/plans/javalin-webapi-refactor.md

@@ -0,0 +1,188 @@
+---
+sessionId: session-260923-111902-5uwc
+---
+
+# Requirements
+
+### Overview & Goals
+Replace the hand-rolled `com.sun.net.httpserver` stack in `me.bobert.netneutrality.http.server` with Javalin, so the bot's embedded API needs far fewer custom classes and gains correct status codes, JSON handling and error responses. Additionally simplify the outbound `WebModule` HTTP client.
+
+### Scope
+**In scope**
+- `WebApi` becomes a thin Javalin-based `Lifecycle` component (same priority 70, same `NETNEUTRALITY_API_PORT` setting).
+- Delete `AbstractHandler`, `RootHandler`, `ActionHandler`, `GuildHandler`; their logic moves into small route-registration units.
+- Standardise the API layer on **Gson** — remove `org.json` (`JSONObject`/`JSONArray`) usage from the HTTP server package.
+- Correct HTTP semantics: 404 for unknown guilds/paths, 405 for wrong methods, 500 on exceptions, UTF-8 safe bodies.
+- Simplify `WebModule` (outbound OkHttp wrapper): extract the static cache, remove duplicated/unused members.
+
+**Out of scope**
+- Changing the public URL shape of existing endpoints (`/`, `/actions/*`, `/guilds/*`) — paths and payload keys stay backwards compatible.
+- Authentication/authorisation for the API.
+- Migrating `org.json` usage elsewhere in the project (e.g. task classes using `WebModule.getAsObject()`).
+
+### Functional Requirements
+- `GET /` → HTML liveness page (unchanged text).
+- `GET /actions/status` → `{"health":...,"ping":...}`.
+- `POST /actions/shutdown` → runs the shutdown hook and exits (accept `GET` too for compatibility if desired).
+- `GET /actions/settings/current/{guildId}` → `{"status":"ok","settings":{...}}`, or 404 + `{"status":"error"}` for an unknown guild.
+- `POST /actions/settings/reload/{guildId}` → reloads the guild setting cache, `{"status":"true"}`; 404 for an unknown guild.
+- `GET /guilds/owner` → array of `{guild_id, owner_id}`.
+- `GET /guilds/channels/{guildId}` and `GET /guilds/roles/{guildId}` → arrays of id/name objects; 404 for an unknown guild.
+- Requests arriving before JDA is ready must return 503 rather than throwing an NPE.
+
+### Non-Functional Requirements
+- Startup/shutdown stays deterministic through `ApplicationContext` — `stop()` must release the port.
+- Shaded jar must still run (`maven-shade-plugin`); Javalin/Jetty service files need merging.
+- No behavioural regression for existing consumers of the endpoints.
+
+# Technical Design
+
+### Current Implementation
+- `WebApi.java` (92 lines) implements `Lifecycle` (priority 70), creates an `HttpServer`, registers three contexts and a fixed pool built from `BaseThreadFactory("web-api")`. Constructed in `App.java:154`.
+- `AbstractHandler` offers `sendStringResponse`/`sendJsonResponse`; both hardcode status 200 and use `str.length()` instead of byte length (breaks non-ASCII).
+- `ActionHandler` / `GuildHandler` route via `if (path.startsWith(...))` chains and parse ids with `getRequestURI().toString().split("/")`; they mix Gson and `org.json`, never check the HTTP method, and call `jda.getGuildById()` twice in places.
+- `WebModule` is an unrelated *outbound* OkHttp wrapper with a builder, a static LRU cache and a `CachedResponse` record; it builds a brand-new `OkHttpClient` per request and has three redundant timeout setters plus unused `elapsedTime`/`errorMessage` accessors.
+
+### Key Decisions
+1. **Javalin** (6.x, JDK 17+ / Java 25 compatible) as the embedded server — removes routing, method matching, error mapping and content-type handling code.
+2. **Gson only** in the HTTP layer: register a `GsonJsonMapper` on the Javalin config so `ctx.json(obj)` works with plain records/maps; `org.json` disappears from `http/server`.
+3. **Route groups instead of handler classes**: `ActionRoutes` and `GuildRoutes` expose a single `static void register(Javalin app, deps...)`, so `AbstractHandler`, `RootHandler`, `ActionHandler`, `GuildHandler` are all deleted (4 classes → 2 tiny registrars).
+4. **Guild lookup guard**: one private helper resolves `{guildId}` → `Guild` or throws `NotFoundResponse`, replacing repeated null checks.
+5. **WebModule**: keep the builder API used by callers, but move the cache into a package-private `ResponseCache`, share a single static `OkHttpClient` and derive per-request timeouts with `newBuilder()`.
+
+### Proposed Changes
+**`http/server/WebApi.java`**
+```java
+public class WebApi implements Lifecycle {
+    private Javalin app;
+    @Override public int priority() { return 70; }
+    @Override public void start() {
+        int port = Integer.parseInt(settings.get("NETNEUTRALITY_API_PORT", "9000"));
+        app = Javalin.create(cfg -> cfg.jsonMapper(new GsonJsonMapper()));
+        app.get("/", ctx -> ctx.html(LIVENESS_HTML));
+        ActionRoutes.register(app, jdaSupplier, guildServices, shutdownHook);
+        GuildRoutes.register(app, jdaSupplier);
+        app.exception(Exception.class, (e, ctx) -> { log.error(...); ctx.status(500).json(Map.of("status","error")); });
+        app.start(port);
+    }
+    @Override public void stop() { if (app != null) { app.stop(); app = null; } }
+}
+```
+
+**`http/server/GuildRoutes.java`** — `/guilds/owner`, `/guilds/channels/{guildId}`, `/guilds/roles/{guildId}` mapped to `List<Map<String,String>>` and returned via `ctx.json(...)`.
+
+**`http/server/ActionRoutes.java`** — `/actions/status`, `/actions/shutdown`, `/actions/settings/current/{guildId}`, `/actions/settings/reload/{guildId}`.
+
+**`http/server/GsonJsonMapper.java`** — ~15 lines implementing Javalin's `JsonMapper` over a shared `Gson`.
+
+**`http/WebModule.java`** — shared client, cache extracted, redundant setters/accessors dropped; public builder methods used by callers remain.
+
+### Data Models / Contracts
+Small records replace ad-hoc JSON building, serialized by Gson with the existing key names:
+```java
+record GuildOwner(String guild_id, String owner_id) {}
+record NamedEntity(String channel_id, String channel_name) {}
+record StatusResponse(String health, String ping) {}
+```
+
+### File Structure
+```
+src/main/java/me/bobert/netneutrality/http/
+  WebModule.java              (modified)
+  server/WebApi.java          (rewritten, Javalin)
+  server/GsonJsonMapper.java  (new)
+  server/ActionRoutes.java    (new)
+  server/GuildRoutes.java     (new)
+  server/AbstractHandler.java (deleted)
+  server/RootHandler.java     (deleted)
+  server/ActionHandler.java   (deleted)
+  server/GuildHandler.java    (deleted)
+pom.xml                       (+ io.javalin:javalin, shade transformer)
+```
+
+### Architecture Diagram
+```mermaid
+graph LR
+App-->ApplicationContext
+ApplicationContext-->WebApi
+WebApi-->Javalin
+WebApi-->GsonJsonMapper
+Javalin-->ActionRoutes
+Javalin-->GuildRoutes
+ActionRoutes-->GuildServiceProvider
+GuildRoutes-->JDA
+```
+
+### Risks
+- **Shaded jar**: Jetty/Javalin rely on `META-INF/services`; the shade plugin needs `ServicesResourceTransformer`, otherwise startup fails only in the packaged build.
+- **Jar size / SLF4J binding**: Jetty logs through SLF4J; project already has log4j + slf4j — check for duplicate bindings.
+- **JDA not ready**: `jdaSupplier.get()` may be null; guard with a 503 mapping.
+- `System.exit(0)` in the shutdown route must run after the response is flushed.
+
+# Testing
+
+### Validation Approach
+Build with `./mvnw -q verify` (checkstyle included), then start the app/`WebApi` on an ephemeral port and exercise every endpoint with `curl`, comparing payload shape against the pre-refactor behaviour.
+
+### Key Scenarios
+- `GET /` returns 200 and the HTML liveness text.
+- `GET /actions/status` returns 200 `application/json` with `health` and `ping`.
+- `GET /guilds/owner` returns a JSON array with `guild_id`/`owner_id` keys.
+- `GET /guilds/channels/{id}` and `/guilds/roles/{id}` return arrays with `channel_id`/`channel_name`.
+- `GET /actions/settings/current/{id}` returns `{"status":"ok","settings":{...}}`.
+
+### Edge Cases
+- Unknown guild id → 404 with `{"status":"error"}` (previously 200).
+- Unknown path → 404 (previously echoed the path with 200).
+- Wrong method on a route → 405.
+- Non-ASCII content in settings values round-trips correctly (old `str.length()` bug).
+- `Lifecycle.stop()` frees the port — a second `start()` on the same port succeeds.
+
+### Test Changes
+- Add a lightweight JUnit test starting `WebApi` on port 0 with a mocked `Supplier<JDA>` and `GuildServiceProvider`, hitting the routes with Javalin's test client or `java.net.http.HttpClient`.
+- Add a `WebModule` test covering cache hit/expiry after the cache extraction.
+
+# Delivery Steps
+
+### ✓ Step 1: Add Javalin dependency and Gson JSON mapper
+The project builds with Javalin available and a Gson-backed JSON mapper ready for use.
+
+- Add `io.javalin:javalin` (6.x) to `pom.xml` dependencies.
+- Add `ServicesResourceTransformer` to the `maven-shade-plugin` configuration so Jetty/Javalin service files survive shading.
+- Create `http/server/GsonJsonMapper.java` implementing Javalin's `JsonMapper` over a shared `Gson` instance.
+- Verify `./mvnw -q package` succeeds and the shaded jar still starts.
+
+### ✓ Step 2: Rewrite WebApi as a Javalin Lifecycle component
+`WebApi` starts and stops a Javalin server while keeping its Lifecycle contract and the root endpoint.
+
+- Replace the `HttpServer`/`ExecutorService` fields with a `Javalin app` field.
+- Build the instance in `start()` with the `GsonJsonMapper`, reading `NETNEUTRALITY_API_PORT` from `SettingsProvider` as today.
+- Register `GET /` returning the liveness HTML and delete `RootHandler.java`.
+- Add global `exception` and `error` handlers returning 500/404 JSON, plus a 503 guard when `jdaSupplier.get()` is null.
+- Implement `stop()` via `app.stop()`; keep `priority() == 70` and the `App.java` construction site unchanged.
+
+### ✓ Step 3: Migrate guild endpoints to GuildRoutes
+All `/guilds/*` endpoints are served by Javalin route lambdas with proper status codes and Gson serialization.
+
+- Create `http/server/GuildRoutes.register(Javalin, Supplier<JDA>)`.
+- Map `GET /guilds/owner`, `GET /guilds/channels/{guildId}`, `GET /guilds/roles/{guildId}` using path params instead of `split("/")`.
+- Return `List<record>` payloads via `ctx.json(...)`, preserving the existing `guild_id`/`owner_id`/`channel_id`/`channel_name` keys.
+- Resolve guilds through a shared helper that throws `NotFoundResponse` for unknown ids (single `getGuildById` call).
+- Delete `GuildHandler.java`.
+
+### ✓ Step 4: Migrate action endpoints to ActionRoutes
+All `/actions/*` endpoints run on Javalin, with `org.json` fully removed from the HTTP server package.
+
+- Create `http/server/ActionRoutes.register(Javalin, Supplier<JDA>, GuildServiceProvider, Runnable)`.
+- Map `/actions/status`, `/actions/shutdown`, `/actions/settings/current/{guildId}`, `/actions/settings/reload/{guildId}`.
+- Replace `JSONObject`/`JSONArray` with Gson-serialized maps/records keeping the same response keys.
+- Ensure the shutdown route flushes its response before running the hook and exiting.
+- Delete `ActionHandler.java` and `AbstractHandler.java`, and add endpoint tests starting `WebApi` on port 0 with mocked JDA/guild services.
+
+### ✓ Step 5: Simplify the outbound WebModule client
+`WebModule` keeps its builder API but sheds duplicated state and its inlined cache.
+
+- Extract the static LRU cache and `CachedResponse` into a package-private `ResponseCache` class in `http/`.
+- Share a single static `OkHttpClient` and derive per-request timeouts with `newBuilder()` instead of constructing a client per build.
+- Collapse the redundant `timeout`/`connectTimeout`/`readTimeout`/`writeTimeout` setters and remove unused accessors (`getErrorMessage`, `elapsedTime` exposure) after checking call sites.
+- Add a unit test covering cache hit, expiry and POST bypass; verify existing `WebModule` callers still compile.

.junie/plans/migrate-music-to-lavalink.md

@@ -0,0 +1,249 @@
+---
+sessionId: session-260923-114918-ce7w
+---
+
+# Requirements
+
+### Overview & Goals
+
+Replace the in-process **Lavaplayer** audio stack with a remote **Lavalink v4** node driven by the official `dev.arbjerg:lavalink-client`. Audio decoding, source resolution and voice sending move out of the bot process to the Lavalink node, which can then be extended with server-side plugins (YouTube source, LavaSrc, etc.) without touching the bot.
+
+All dependency/plugin examples from the Lavalink docs are Gradle-based and will be **translated to Maven** (`pom.xml` `<repositories>` / `<dependencies>`); the Lavalink node itself is configured via a YAML file mounted into the container, not via any build script.
+
+### Scope
+
+**In Scope**
+- Swap `dev.arbjerg:lavaplayer` + `dev.lavalink.youtube:v2` for `dev.arbjerg:lavalink-client` in `pom.xml`.
+- Rewrite the `me.bobert.netneutrality.music` package against Lavalink: `MusicServiceImpl`, `MusicManager`, `TrackScheduler`, `QueueManager`, `TrackInfo`, `TrackLoadingHandler`, `StuckTrackRecoveryHandler`; delete `AudioPlayerSendHandler`.
+- Route voice connections through Lavalink's `JDAVoiceUpdateListener` / `DirectAudioController` instead of `Guild#getAudioManager()`.
+- Add a `lavalink` service plus `lavalink/application.yml` to `docker-compose.yml`, wired to the existing `ejs-api` (yt-cipher) container.
+- Update `MessageFunction`, `LoadPlaylistTask`, `LoadTrackFromPlaylistTask` and the music command classes to the new track type.
+- Update the affected tests and the docs under `docs/`.
+
+**Out of Scope**
+- Porting `music/source/UdioAudioSourceManager` to a Lavalink server plugin — captured as a documented follow-up. Udio playback is temporarily unavailable; the existing code stays in the repo as the porting reference.
+- Any change to command UX, queue semantics, DJ rules or vote-skip behaviour.
+- Audio filters/equalizer, node load balancing across multiple nodes, and session resuming (Lavalink supports these; not enabled here).
+
+### User Stories
+- As a bot operator, I want audio to be served by a separate Lavalink node so that I can add source plugins and restart the bot without interrupting the audio pipeline's configuration.
+- As a user, I want `/play`, `/skip`, `/queue`, `/volume`, `/stop`, `/resume`, `/shuffle` and vote-skip to behave exactly as before the migration.
+- As a maintainer, I want YouTube cipher/poToken configuration to live in the node's `application.yml` rather than in Java code.
+
+### Functional Requirements
+- All 13 commands in `command/music/` keep their current signatures, replies and `CommandExecutionResult` semantics.
+- `SourceFinder` keeps classifying URLs and prefixing searches with `ytsearch:`; identifiers are passed to Lavalink's `loadItem` unchanged.
+- Queue ordering, duplicate rejection, auto-start on first enqueue, auto-disconnect on empty queue and the two-strike stuck-track recovery are preserved.
+- If the Lavalink node is unreachable at startup, the bot still starts; music commands reply with a clear error instead of crashing.
+- Udio URLs reply with a "temporarily unsupported" message rather than failing silently.
+
+### Non-Functional Requirements
+- The bot no longer ships native audio encoders: the `jdave-api` / `jdave-native-*` dependencies and the `AudioModuleConfig` DAVE wiring in `App.initJDA()` are removed, since DAVE is handled by the node (Lavalink ≥ 4.2.0).
+- New settings are read through the existing `SettingsProvider` and documented in `bot.properties.example`.
+- Checkstyle (`checkstyle.xml`, bound to the `test` phase) must keep passing.
+
+# Technical Design
+
+### Current Implementation
+
+- `MusicServiceImpl` (priority-40 `Lifecycle`, registered in `App.buildContext()` line 140) owns a `DefaultAudioPlayerManager` and registers YouTube (with `setRemoteCipher(...)`), SoundCloud, Udio and HTTP source managers in `start()`; `stop()` clears queues and calls `player.destroy()`.
+- `MusicManager` creates an `AudioPlayer` per guild, sets `AudioPlayerSendHandler` on `guild.getAudioManager()`, opens/closes the voice connection itself, and calls `playerManager.loadItemOrdered(this, identifier, new TrackLoadingHandler(...))`.
+- `TrackScheduler extends AudioEventAdapter` and receives `onTrackStart/End/Exception/Stuck` callbacks directly from the player.
+- `QueueManager` holds a `Deque<TrackInfo>` and drives playback with `player.startTrack(track.makeClone(), false)` / `player.stopTrack()`.
+- `StuckTrackRecoveryHandler` relies on `AudioTrack#makeClone`, `getPosition()` and `setPosition()`.
+- `com.sedmelluq.*` types appear in 14 main sources and 5 tests (`QueueManagerTest`, `TrackInfoTest`, `TrackSchedulerTest`, `VoteSkipServiceTest`, `UdioAudioSourceManagerTest`).
+- `pom.xml` already declares the `https://maven.lavalink.dev/releases` repository (lines 136–140).
+- `docker-compose.yml` runs `db`, `bot` and `ejs_signature_api` (yt-cipher) on the `netneutrality` network; there is no Lavalink node.
+
+### Key Decisions
+
+1. **Official client** — `dev.arbjerg:lavalink-client` (v4-only). `VoiceDispatchInterceptor` is verified present in the bundled JDA 6.4.1 jar, so `JDAVoiceUpdateListener` attaches cleanly.
+2. **Central event dispatcher** — `MusicServiceImpl` holds the single subscription to the client's event flux and routes each event to the owning guild's `TrackScheduler`. One `Disposable` to dispose in `stop()`.
+3. **Synchronous facade** — `MusicManager` subscribes to the returned `Mono`s internally; command classes keep their current synchronous signatures. Failures are reported via `LogHandler` and the attached `MusicChannelContext`.
+4. **Lavalink `Track` everywhere** — `dev.arbjerg.lavalink.protocol.v4.Track` replaces `AudioTrack` in `TrackInfo`, `QueueManager`, `MessageFunction` and the playlist tasks. `Track` is an immutable data class, so `makeClone()` disappears and `setPosition` becomes `player.setPosition(...)` on the Lavalink player.
+5. **Node in compose** — a `lavalink` service with a mounted `application.yml`; YouTube cipher/poToken config moves out of `MusicServiceImpl.start()` into that YAML.
+6. **Udio deferred** — `music/source/**` is excluded from compilation-relevant wiring and the `Udio` branch of `SourceFinder.getIdentifier` returns `null` with a friendly reply; the classes remain for the future plugin port.
+
+### Proposed Changes
+
+**Maven (`pom.xml`)** — translated from the docs' Gradle snippets:
+```xml
+<dependency>
+  <groupId>dev.arbjerg</groupId>
+  <artifactId>lavalink-client</artifactId>
+  <version>3.4.0</version>
+</dependency>
+```
+resolved from the already-present `arbjergDev-releases` repository. Removed: `dev.arbjerg:lavaplayer`, `dev.lavalink.youtube:v2`, `club.minnced:jdave-*`.
+
+**`MusicServiceImpl`**
+- Field `LavalinkClient client = new LavalinkClient(Helpers.getUserIdFromToken(token))`.
+- `start()` registers one node (`client.addNode(...)` with URI, password and name from settings) and opens the dispatcher subscription:
+  `client.on(TrackStartEvent.class)`, `TrackEndEvent`, `TrackExceptionEvent`, `TrackStuckEvent`, `WebSocketClosedEvent` → look up `managers.get(event.getGuildId())` → forward to its `TrackScheduler`.
+- `stop()` disposes the subscriptions, clears queues, destroys players and closes the client.
+- Exposes `LavalinkClient getClient()` in place of `getPlayerManager()`.
+
+**`App`**
+- `initJDA()` adds `.setVoiceDispatchInterceptor(new JDAVoiceUpdateListener(client))` and drops `.setAudioModuleConfig(new AudioModuleConfig().withDaveSessionFactory(new JDaveSessionFactory()))`.
+- Ordering: the `LavalinkClient` must exist before JDA is built, which the existing priorities already guarantee (music = 40, JDA = 60).
+- Dev log levels switch from `com.sedmelluq.discord` / `dev.lavalink.youtube` to `dev.arbjerg.lavalink`.
+
+**`MusicManager`**
+- Holds `LavalinkClient client` and resolves `Link link = client.getOrCreateLink(guildId)`.
+- `connect(AudioChannel)` → `jda.getDirectAudioController().connect(channel)` + `setSelfDeafened`; `disconnect()` → `getDirectAudioController().disconnect(guild)` and `link.destroyPlayer()`.
+- `isConnected()` / `isNotConnectedTo(...)` read `guild.getSelfMember().getVoiceState().getChannel()` — **`Guild#getAudioManager()` must not be used** with Lavalink.
+- `play(...)` → `link.loadItem(identifier).subscribe(new TrackLoadingHandler(...))`.
+- `getCurrentlyPlaying()` returns the cached `Track` from the last `TrackStartEvent` (the REST player state is not synchronously readable).
+- `setVolume` / `stopTrack` → `link.getPlayer().flatMap(p -> p.setVolume(v).setEncodedTrack(null))` subscribed internally.
+
+**`TrackScheduler`**
+- No longer extends `AudioEventAdapter`; exposes `onTrackStart(Track)`, `onTrackEnd(Track, AudioTrackEndReason)`, `onTrackException`, `onTrackStuck(Track, long)` called by the dispatcher.
+- The existing `endReason` branching maps 1:1 onto Lavalink's `AudioTrackEndReason` (`FINISHED`, `LOAD_FAILED`, `STOPPED`, `REPLACED`, `CLEANUP`).
+
+**`QueueManager`**
+- `player.getPlayingTrack() == null` becomes a `volatile Track currentTrack` maintained by scheduler events (avoids a blocking REST call inside the `synchronized (queue)` blocks).
+- `startTrack(track, noInterrupt)` becomes `link.createOrUpdatePlayer().setTrack(track).setNoReplace(...)`; `makeClone()` calls are dropped since `Track` is immutable.
+
+**`TrackLoadingHandler`** — implements lavalink-client's `AbstractAudioLoadResultHandler`: `ontrackLoaded` / `onPlaylistLoaded` / `onSearchResultLoaded` / `noMatches` / `loadFailed(LoadFailed)`. `onSearchResultLoaded` takes the first result, matching today's `ytsearch:` behaviour.
+
+**`StuckTrackRecoveryHandler`** — re-queues the same immutable `Track` and restores position via `player.setPosition(lastPosition)`; the second consecutive strike still skips.
+
+### Data Models / Contracts
+```java
+// MusicManager (synchronous facade, unchanged call sites)
+public synchronized void play(String query, CommandContext ctx, boolean silent);
+public synchronized void stopTrack();
+public synchronized void setVolume(int volume);
+public synchronized Track getCurrentlyPlaying();
+
+// TrackScheduler (invoked by the dispatcher)
+void onTrackStart(Track track);
+void onTrackEnd(Track track, AudioTrackEndReason endReason);
+void onTrackStuck(Track track, long thresholdMs);
+
+// TrackInfo
+public record TrackInfo(Track track, Member requester) { }
+```
+
+New settings (read via `SettingsProvider`, documented in `bot.properties.example`):
+`NETNEUTRALITY_LAVALINK_URI` (default `ws://lavalink:2333`), `NETNEUTRALITY_LAVALINK_PASSWORD`, `NETNEUTRALITY_LAVALINK_NAME`.
+
+### File Structure
+
+| Path | Change |
+|---|---|
+| `pom.xml` | swap lavaplayer/youtube-v2/jdave → `lavalink-client` |
+| `docker-compose.yml` | add `lavalink` service |
+| `lavalink/application.yml` | **new** — node + youtube-source plugin + yt-cipher config |
+| `bot.properties.example` | new Lavalink settings |
+| `music/MusicServiceImpl.java` | client lifecycle + event dispatcher |
+| `music/MusicManager.java` | `Link`/`DirectAudioController` based |
+| `music/TrackScheduler.java` | plain event sink |
+| `music/QueueManager.java`, `TrackInfo.java`, `TrackLoadingHandler.java`, `StuckTrackRecoveryHandler.java` | `Track` type + REST player calls |
+| `music/AudioPlayerSendHandler.java` | **deleted** |
+| `music/SourceFinder.java` | Udio → unsupported |
+| `App.java` | voice interceptor, drop DAVE wiring, log levels |
+| `shared/util/MessageFunction.java`, `tasks/music/LoadPlaylistTask.java`, `tasks/music/LoadTrackFromPlaylistTask.java` | `Track` type |
+| `src/test/.../music/*` | updated fixtures |
+| `docs/music.md`, `docs/architecture.md`, `docs/README.md` | rewritten sections |
+
+### Architecture Diagram
+```mermaid
+graph LR
+JDA[JDA gateway] -->|voice state| VIL[JDAVoiceUpdateListener]
+VIL --> C[LavalinkClient]
+C -->|REST and WS| N[Lavalink node]
+N --> V[Discord voice]
+CMD[music commands] --> MM[MusicManager]
+MM -->|Link ops| C
+MM --> QM[QueueManager]
+C -->|event flux| DISP[MusicServiceImpl dispatcher]
+DISP --> TS[TrackScheduler]
+TS --> QM
+```
+
+### Risks
+- **Voice API confusion**: any remaining `guild.getAudioManager()` call silently breaks playback; all call sites (`MusicManager`, `MusicUtils`, `BotState`) must be swept.
+- **Blocking on reactor**: subscribing inside `synchronized` blocks in `QueueManager` risks deadlock — hence the cached `currentTrack` instead of a REST read.
+- **Node availability**: `MusicServiceImpl.start()` must not throw when the node is down, or `App.startup()` exits with code 1.
+- **Feature regressions**: Udio support pauses; direct-MP3 and SoundCloud must be re-verified against the node's enabled sources.
+- **DAVE**: removing JDave requires Lavalink ≥ 4.2.0 — the compose image must be pinned accordingly.
+
+# Testing
+
+### Validation Approach
+- `./mvnw -q verify` must compile and pass Checkstyle plus the updated unit tests.
+- Unit tests keep using mocks: `QueueManagerTest` and `TrackSchedulerTest` mock the Lavalink `Link`/`LavalinkPlayer` and assert on the interactions instead of on `AudioPlayer`.
+- A grep sweep confirms no `com.sedmelluq` / `dev.lavalink.youtube` import survives outside `music/source/**`.
+- Manual smoke run with `docker compose up` to confirm the bot reaches the node and plays a YouTube URL.
+
+### Key Scenarios
+- Enqueue on an empty queue starts playback immediately; enqueue while playing appends.
+- `TrackEndEvent(FINISHED)` advances to the next track; an empty queue triggers `onQueueEmpty()` → disconnect.
+- `skip(n)`, `shuffle`, `clearQueue`, `removeTracksFromUser` and `removeFromQueue(index)` return the same `CommandExecutionResult` messages as before.
+- `ytsearch:` queries resolve through `onSearchResultLoaded` and queue the first hit.
+- Volume from `GSettings.MUSIC_VOLUME` is applied on connect, with the 50 fallback on a malformed value.
+
+### Edge Cases
+- Lavalink node unreachable at startup → bot boots, music commands reply with an error.
+- Node disconnects mid-playback → `WebSocketClosedEvent` is logged and the guild state is cleaned up.
+- Stuck track: first event re-queues and seeks, second consecutive event skips.
+- Udio URL → explicit "temporarily unsupported" reply.
+- Duplicate track enqueue is still rejected by `TrackInfo` equality.
+
+### Test Changes
+- Update `QueueManagerTest`, `TrackSchedulerTest`, `TrackInfoTest`, `VoteSkipServiceTest` to the Lavalink `Track` type and mocked players.
+- Keep `UdioAudioSourceManagerTest` as-is while the source classes remain in the repo for the future plugin port.
+
+# Delivery Steps
+
+### ✓ Step 1: Swap Maven dependencies and stand up a Lavalink node
+The project builds against `lavalink-client` and `docker compose up` starts a reachable Lavalink v4 node.
+
+- Replace `dev.arbjerg:lavaplayer`, `dev.lavalink.youtube:v2` and the four `club.minnced:jdave-*` entries in `pom.xml` with `dev.arbjerg:lavalink-client` (Gradle docs snippet translated to Maven, using the existing `arbjergDev-releases` repository).
+- Add a `lavalink` service to `docker-compose.yml` on the `netneutrality` network, pinned to an image with DAVE support (≥ 4.2.0), with the bot depending on it.
+- Create `lavalink/application.yml` mounted into the node: server port/password, the youtube-source plugin, and the remote cipher pointed at the existing `ejs-api` container plus poToken/visitorData.
+- Add `NETNEUTRALITY_LAVALINK_URI`, `_PASSWORD` and `_NAME` to `bot.properties.example`.
+
+### ✓ Step 2: Wire LavalinkClient into the bootstrap and JDA voice handling
+The bot connects to the node on startup and routes Discord voice through Lavalink instead of JDA's audio manager.
+
+- Rework `MusicServiceImpl` to own a `LavalinkClient`, registering the configured node in `start()` without throwing when it is unreachable.
+- Dispose the client and its subscriptions in `stop()`, keeping the priority-40 `Lifecycle` contract used by `App.buildContext()`.
+- Add `.setVoiceDispatchInterceptor(new JDAVoiceUpdateListener(client))` in `App.initJDA()` and remove the `AudioModuleConfig`/`JDaveSessionFactory` wiring.
+- Update the dev-mode log levels in `App.main` from `com.sedmelluq.discord`/`dev.lavalink.youtube` to `dev.arbjerg.lavalink`.
+- Replace `getPlayerManager()` with `getClient()` and fix `BotState`'s usage.
+
+### ✓ Step 3: Rebuild MusicManager on Links and the DirectAudioController
+Per-guild connect, disconnect and player control go through Lavalink while command signatures stay unchanged.
+
+- Replace the `AudioPlayer` field in `MusicManager` with a `Link` obtained from `client.getOrCreateLink(guildId)`.
+- Implement `connect`/`disconnect` via `jda.getDirectAudioController()` and `link.destroyPlayer()`, deleting the `guild.getAudioManager()` calls and the `AudioPlayerSendHandler` class.
+- Base `isConnected()` and `isNotConnectedTo(...)` on `getSelfMember().getVoiceState().getChannel()`, and update `MusicUtils.connect`/`checkIfConnected` accordingly.
+- Keep the synchronous facade: `stopTrack`, `setVolume` and `play` subscribe to the returned `Mono`s internally and report failures through `LogHandler`.
+- Apply the `GSettings.MUSIC_VOLUME` base volume on connect with the existing default-50 fallback.
+
+### ✓ Step 4: Migrate queue, track loading and message rendering to the Lavalink Track type
+Tracks are represented by `dev.arbjerg.lavalink.protocol.v4.Track` end to end and loading uses Lavalink's REST resolver.
+
+- Change `TrackInfo` to wrap `Track` + `Member`, preserving equality-based duplicate rejection.
+- Update `QueueManager` to drive playback with `createOrUpdatePlayer().setTrack(...)`/`setNoReplace(...)`, dropping `makeClone()` and replacing `player.getPlayingTrack()` checks with a scheduler-maintained `volatile Track currentTrack`.
+- Reimplement `TrackLoadingHandler` on `AbstractAudioLoadResultHandler`, mapping `onSearchResultLoaded` to the first hit to preserve the `ytsearch:` behaviour.
+- Update `MessageFunction`, `LoadPlaylistTask` and `LoadTrackFromPlaylistTask` to the new track type.
+- Make `SourceFinder` return no identifier for Udio URLs and have `MusicManager.play` reply that Udio is temporarily unsupported.
+
+### ✓ Step 5: Route Lavalink events to TrackScheduler and restore stuck-track recovery
+Track lifecycle events from the node drive queue advancement, error reporting and stuck recovery exactly as before.
+
+- Add a central dispatcher in `MusicServiceImpl` subscribing once to `TrackStartEvent`, `TrackEndEvent`, `TrackExceptionEvent`, `TrackStuckEvent` and `WebSocketClosedEvent`, routing by guild id to the cached `MusicManager`.
+- Convert `TrackScheduler` from an `AudioEventAdapter` subclass into a plain sink with `onTrackStart`/`onTrackEnd`/`onTrackException`/`onTrackStuck`, keeping the existing `FINISHED`/`LOAD_FAILED`/`STOPPED` branching and `MusicChannelContext` attachment.
+- Rework `StuckTrackRecoveryHandler` to re-queue the immutable `Track` and seek with `player.setPosition(...)`, retaining the retry-then-skip rule.
+- Update `QueueManagerTest`, `TrackSchedulerTest`, `TrackInfoTest` and `VoteSkipServiceTest` to mock `Link`/`LavalinkPlayer`, and verify `./mvnw verify` passes Checkstyle and the suite.
+
+### ✓ Step 6: Update documentation and record the Udio plugin follow-up
+The docs describe the Lavalink-based architecture and the deferred Udio work is explicit.
+
+- Rewrite the Lavaplayer sections of `docs/music.md` and `docs/architecture.md` to cover the node, the client, the dispatcher and the new settings.
+- Refresh the music mentions in `docs/README.md`, `docs/threading.md` and `docs/utilities-and-bootstrap.md`.
+- Document how to run the node locally and how to add server-side plugins via `lavalink/application.yml`.
+- Add a follow-up note stating that `music/source/UdioAudioSourceManager` and `UdioAudioTrack` remain only as the reference for a future Lavalink server plugin and that Udio playback is disabled until then.

bot.properties.example

@@ -20,6 +20,10 @@ NETNEUTRALITY_VISITOR_DATA=
 NETNEUTRALITY_CIPHER_URL=http://localhost:8001
 NETNEUTRALITY_CIPHER_PASSWORD=
 
+NETNEUTRALITY_LAVALINK_URI=ws://lavalink:2333
+NETNEUTRALITY_LAVALINK_PASSWORD=youshallnotpass
+NETNEUTRALITY_LAVALINK_NAME=main
+
 NETNEUTRALITY_SENTRY_DSN=
 GITLAB_HOST=
 GITLAB_TOKEN=

docker-compose.yml

@@ -23,14 +23,39 @@ services:
       - netneutrality
     depends_on:
       - netneutrality-db
+      - lavalink
     volumes:
       - ./logs:/app/logs
     environment:
-      MYSQL_HOST: netneutrality-db
-      MYSQL_PORT: 3306
-      MYSQL_USER: java
-      MYSQL_PASSWORD: password
-      MYSQL_DATABASE: netneutrality
+      - MYSQL_HOST=${MYSQL_HOST:-netneutrality-db}
+      - MYSQL_PORT=${MYSQL_PORT:-3306}
+      - MYSQL_USER=${MYSQL_USER:-java}
+      - MYSQL_PASSWORD=${MYSQL_PASSWORD:-password}
+      - MYSQL_DATABASE=${MYSQL_DATABASE:-netneutrality}
+      - API_PORT=${NETNEUTRALITY_API_PORT:-9000}
+
+  # Lavalink >= 4.2.0 is required: the node handles DAVE end-to-end encryption,
+  # so the bot no longer ships native encoders.
+  lavalink:
+    image: ghcr.io/lavalink-devs/lavalink:4.2
+    container_name: lavalink
+    restart: unless-stopped
+    networks:
+      - netneutrality
+    depends_on:
+      - ejs-api
+      - webpo
+    volumes:
+      - ./lavalink/application.yml:/opt/Lavalink/application.yml:ro
+    environment:
+      - SERVER_PASSWORD=${NETNEUTRALITY_LAVALINK_PASSWORD:-youshallnotpass}
+      - NETNEUTRALITY_CIPHER_URL=${NETNEUTRALITY_CIPHER_URL:-http://ejs-api:8001}
+      - NETNEUTRALITY_CIPHER_PASSWORD=${NETNEUTRALITY_CIPHER_PASSWORD:-}
+      - NETNEUTRALITY_OAUTH_TOKEN=${NETNEUTRALITY_OAUTH_TOKEN:-}
+      - NETNEUTRALITY_POT_URL=${NETNEUTRALITY_POT_URL:-http://webpo:8080}
+      - NETNEUTRALITY_PO_TOKEN=${NETNEUTRALITY_PO_TOKEN:-}
+      - NETNEUTRALITY_VISITOR_DATA=${NETNEUTRALITY_VISITOR_DATA:-}
+
   ejs-api:
     image: ghcr.io/kikkia/yt-cipher:master@sha256:4c5ec381ff57336cfc24822d2b526a5ad7cd0171f61065a1bbc87bb736842449
     container_name: ejs_signature_api
@@ -39,8 +64,25 @@ services:
       - netneutrality
     # environment: # UNCOMMENT THIS LINE AND API_TOKEN TO ADD A PASSWORD
     #   - API_TOKEN=test
+
+  webpo:
+    image: ghcr.io/ashton045/webpo-generator
+    container_name: webpo-generator
+    environment:
+      - HOST=${HOST:-::}
+      - PORT=${PORT:-8080}
+      - WORKERS=${WORKERS:-1}
+      - QUEUE_SIZE=${QUEUE_SIZE:-32}
+      - MAX_PENDING_REQUESTS=${MAX_PENDING_REQUESTS:-256}
+      - REQUEST_TIMEOUT=${REQUEST_TIMEOUT:-30000}
+      - CACHE_SIZE=${CACHE_SIZE:-100}
+      - CACHE_TTL=${CACHE_TTL:-300000}
+      - VISITOR_TTL=${VISITOR_TTL:-600000}
+      - API_TOKEN=
+    restart: unless-stopped
 volumes:
   netneutrality-db: null
+  netneutrality-lavalink-plugins: null
 
 networks:
   netneutrality: null

docs/README.md

@@ -16,7 +16,7 @@ subsystem, how they fit together, and the end-to-end flows that tie them.
 | [commands.md](commands.md) | Commands — message & slash commands, dispatch, options |
 | [tasks.md](tasks.md) | Tasks — button/emoji/modal/step/built-in/persistable/scheduled tasks |
 | [persistence.md](persistence.md) | Database — Hibernate/JPA, Flyway, entities, repositories, services |
-| [music.md](music.md) | Music — Lavaplayer pipeline, queue, custom Udio source |
+| [music.md](music.md) | Music — Lavalink node & client, queue, event dispatch |
 | [web-api.md](web-api.md) | HTTP Web API — internal control & introspection server |
 | [threading.md](threading.md) | Threading & scheduling infrastructure |
 | [utilities-and-bootstrap.md](utilities-and-bootstrap.md) | Utilities, configuration, logging, exceptions |

docs/architecture.md

@@ -37,7 +37,7 @@ execution paths:
    directly and no context is routed onward. See [events.md](events.md).
 
 Around this core are the supporting subsystems: [persistence](persistence.md) (Hibernate + Flyway),
-[music](music.md) (Lavaplayer), the [web API](web-api.md), and the [threading/scheduling](threading.md)
+[music](music.md) (a remote Lavalink node), the [web API](web-api.md), and the [threading/scheduling](threading.md)
 infrastructure.
 
 ## Technology stack
@@ -45,9 +45,8 @@ infrastructure.
 | Concern | Library | Version |
 |---|---|---|
 | Discord API | `net.dv8tion:JDA` | 6.4.1 |
-| Voice / DAVE (E2EE) | `club.minnced:jdave-*` | 0.1.8 |
-| Audio engine | `dev.arbjerg:lavaplayer` | 2.2.6 |
-| YouTube source | `dev.lavalink.youtube:v2` | 1.18.2 |
+| Audio engine | Lavalink v4 node (`ghcr.io/lavalink-devs/lavalink`) | 4.2 |
+| Audio client | `dev.arbjerg:lavalink-client` | 3.4.0 |
 | ORM | `org.hibernate.orm:hibernate-core` | 7.1.9.Final |
 | Connection pool | `hibernate-hikaricp` (HikariCP) | 7.1.9.Final |
 | JDBC driver | `com.mysql:mysql-connector-j` | 9.7.0 |
@@ -77,7 +76,7 @@ component in ascending priority order.
    also registered into the context as `SettingsProvider` for constructor injection).
 2. **Sentry** — if `NETNEUTRALITY_SENTRY_DSN` is set, initialize the Sentry SDK
    (environment, release = `VERSION`, traces sample rate 1.0).
-3. **Log levels** — in `dev`, raise JDA / Lavalink-YouTube / sedmelluq logging to `DEBUG`.
+3. **Log levels** — in `dev`, raise JDA and Lavalink client logging to `DEBUG`.
 4. `startup()`:
    1. Validate `NETNEUTRALITY_BOT_TOKEN` is present (throws if missing).
    2. `buildContext()` — register domain services and lifecycle adapters (see priorities below).
@@ -92,7 +91,7 @@ component in ascending priority order.
 | 20 | `ThreadManager` (`ExecutorProvider`) | No-op start (executors are lazy). Bound into `ChannelMessagePurger`. |
 | 30 | `CommandManager` (`CommandRegistry`) | Reflectively discover/register `Command` implementations with context-aware constructor injection. |
 | 30 | `TaskManagerImpl` (`TaskManager`) | Reflectively load built-in & scheduled tasks (DI) and reload persistable tasks from the DB. |
-| 40 | `MusicServiceImpl` (`MusicService`) | Initialise the shared Lavaplayer `AudioPlayerManager`. |
+| 40 | `MusicServiceImpl` (`MusicService`) | Create the shared `LavalinkClient`, register the node and subscribe to its events. |
 | 55 | `ScheduledTaskManager` | No-op start (tasks are scheduled by `TaskManager` during its own start). |
 | 60 | JDA adapter | Build `JDA` with gateway intents and await ready. |
 | 65 | Post-JDA adapter | Register slash commands, attach `EventsHandler` (injected providers), set presence. |
@@ -106,8 +105,10 @@ context (falling back to a no-arg constructor when none match).
 ### Gateway intents
 
 `initJDA()` enables: `GUILD_MEMBERS`, `GUILD_MESSAGE_REACTIONS`, `GUILD_VOICE_STATES`,
-`MESSAGE_CONTENT`. It also installs the DAVE (end-to-end encrypted voice) session factory via
-`AudioModuleConfig().withDaveSessionFactory(new JDaveSessionFactory())`.
+`MESSAGE_CONTENT`. It also installs `new JDAVoiceUpdateListener(music.getClient())` as the voice
+dispatch interceptor, so voice server/state updates are forwarded to Lavalink instead of JDA's own
+audio stack. DAVE (end-to-end encrypted voice) is handled by the node, which is why the bot no
+longer ships native audio encoders.
 
 ## Shutdown lifecycle
 
@@ -120,7 +121,7 @@ block the others. Effectively this means:
 2. Post-JDA adapter — no-op.
 3. JDA adapter — `jda.shutdown()`.
 4. `ScheduledTaskManager.stop()` — cancel all scheduled tasks.
-5. `MusicServiceImpl.stop()` — disconnect players / leave voice channels.
+5. `MusicServiceImpl.stop()` — dispose the event subscriptions, destroy the players and close the Lavalink client.
 6. `CommandManager` / `TaskManagerImpl` — no-op stop today.
 7. `ThreadManager.stop()` — shut down the shared executors.
 8. `SessionManager.stop()` — release the Hibernate registry / connection pool.
@@ -155,7 +156,7 @@ block the others. Effectively this means:
 | `…db.entities` / `…db.repository` / `…db.service` | Persistence model, repositories, services |
 | `…hooks` | `EventsHandler` |
 | `…http` | Internal web API and HTTP client module |
-| `…music` | Music domain (service, manager, queue, sources, tracks) |
+| `…music` | Music domain (service, manager, queue, scheduler, track loading) |
 | `…utils` | `Settings` / `SettingsProvider`, `ChannelMessagePurger`, `MusicUtils` |
 | `…shared.util` | Cross-cutting helpers |
 | `…exceptions` | Custom exception hierarchy |

docs/music.md

@@ -1,35 +1,51 @@
 # Music
 
-**Package:** `me.bobert.netneutrality.feature.music`
-**Engine:** [Lavaplayer](https://github.com/lavalink-devs/lavaplayer) 2.2.6 + the Lavalink YouTube
-source 1.18.2.
+**Package:** `me.bobert.netneutrality.music`
+**Engine:** a remote [Lavalink](https://lavalink.dev) v4 node driven by
+[`dev.arbjerg:lavalink-client`](https://github.com/lavalink-devs/Lavalink-Client) 3.4.0.
 
 The music subsystem provides per-guild audio playback: searching/loading tracks from multiple
-sources, queueing, scheduling, and streaming audio into a Discord voice channel.
+sources, queueing, scheduling, and streaming audio into a Discord voice channel. Since the
+migration to Lavalink, **decoding, source resolution and voice sending happen on the node**, not in
+the bot process. The bot only sends REST/WebSocket commands and reacts to the node's events, which
+means new sources (YouTube, LavaSrc, …) are added by configuring server-side plugins rather than by
+changing Java code.
 
 ## Key classes
 
 | Class | Responsibility |
 |---|---|
-| `MusicManager` | Central per-guild coordinator; owns the `AudioPlayer` and `TrackScheduler`. |
+| `MusicServiceImpl` | Owns the shared `LavalinkClient`, registers the node, and dispatches its event flux. |
+| `MusicManager` | Central per-guild coordinator; resolves the guild's `Link` and exposes a synchronous facade. |
 | `QueueManager` | Holds the guild's track queue (`LinkedBlockingDeque<TrackInfo>`); enqueue/skip/shuffle. |
-| `TrackScheduler` | `AudioEventAdapter`; reacts to Lavaplayer events (`onTrackEnd`, `onTrackStuck`). |
-| `TrackLoadingHandler` | `AudioLoadResultHandler`; handles track/playlist/no-match/failure results. |
-| `TrackInfo` | Value object pairing an `AudioTrack` with its requester (`Member`). |
-| `SourceFinder` | Identifies the source/type of a query (YouTube, Udio, HTTP, …). |
-| `AudioPlayerSendHandler` | Bridges Lavaplayer output to JDA's `AudioSendHandler`. |
-| `source/UdioAudioSourceManager` | Custom Lavaplayer source manager for udio.com. |
-| `source/UdioAudioTrack` | Udio track; delegates playback to `Mp3AudioTrack`. |
+| `TrackScheduler` | Event sink for `onTrackStart` / `onTrackEnd` / `onTrackException` / `onTrackStuck`; caches the current track. |
+| `TrackLoadingHandler` | `AbstractAudioLoadResultHandler`; handles track/playlist/search/no-match/failure results. |
+| `TrackInfo` | Value object pairing a Lavalink `Track` with its requester (`Member`). |
+| `SourceFinder` | Identifies the source/type of a query (YouTube, SoundCloud, HTTP, …). |
+| `StuckTrackRecoveryHandler` | Retry-then-skip logic for tracks the node reports as stuck. |
 
-`MusicManager` keeps a static `Map<String, MusicManager>` of managers keyed by guild id, so each guild
-has its own player, scheduler, and queue.
+`MusicServiceImpl` keeps a `Map<String, MusicManager>` of managers keyed by guild id, so each guild
+has its own link, scheduler, and queue.
 
 ## Startup
 
-`MusicManager.initPlayerManager()` (called from
-[`App.startup()`](architecture.md#startup-lifecycle)) creates the Lavaplayer
-`AudioPlayerManager` and registers the source managers (YouTube, SoundCloud, the custom
-[Udio source](#custom-udio-source), and HTTP).
+`MusicServiceImpl` is a priority-40 [`Lifecycle`](architecture.md#startup-lifecycle) component. Its
+constructor creates the `LavalinkClient` (the bot user id is derived from the token) and `start()`
+registers the configured node. **A node that is unreachable never prevents the bot from booting**:
+the client retries in the background and music commands reply with an error in the meantime.
+
+Because the client must exist before JDA is built, `App.initJDA()` (priority 60) installs
+`new JDAVoiceUpdateListener(music.getClient())` as the gateway's voice dispatch interceptor. JDA's
+`AudioManager` is therefore **not** used for playback; voice connections are opened and closed
+through `JDA#getDirectAudioController()`.
+
+### Settings
+
+| Setting | Default | Meaning |
+|---|---|---|
+| `NETNEUTRALITY_LAVALINK_URI` | `ws://lavalink:2333` | WebSocket URI of the node |
+| `NETNEUTRALITY_LAVALINK_PASSWORD` | — | Node password; music is disabled when missing |
+| `NETNEUTRALITY_LAVALINK_NAME` | `main` | Node name used in logs |
 
 ## Audio pipeline (end-to-end)
 
@@ -38,50 +54,111 @@ has its own player, scheduler, and queue.
    │
    ▼
 MusicManager.play(query, ctx)
-   │  SourceFinder identifies the source
+   │  SourceFinder identifies the source and builds the identifier
    ▼
-audioPlayerManager.loadItemOrdered(guild, identifier, new TrackLoadingHandler(...))
+link.loadItem(identifier).subscribe(new TrackLoadingHandler(...))
    │
-   ├─ trackLoaded ──▶ connect to voice (MusicUtils) ──▶ QueueManager.queue(track, member)
-   ├─ playlistLoaded / searchResults ──▶ install a LoadPlaylistTask (choice buttons)
+   ├─ ontrackLoaded ──▶ connect to voice (MusicUtils) ──▶ QueueManager.queue(track, member)
+   ├─ onPlaylistLoaded / onSearchResultLoaded ──▶ install a LoadPlaylistTask (choice buttons)
    ├─ noMatches ──▶ reply "nothing found"
    └─ loadFailed ──▶ reply / log error
    │
    ▼
-QueueManager: if the player is idle, start immediately; else append to the deque
+QueueManager: if nothing is playing, send createOrUpdatePlayer().setTrack(...); else append
    │
    ▼
-AudioPlayerSendHandler streams PCM/Opus frames to the voice channel
+Lavalink node decodes and streams the audio to the Discord voice gateway
    │
    ▼ (track ends)
-TrackScheduler.onTrackEnd ──▶ QueueManager.startNextTrack()
+node event ──▶ MusicServiceImpl dispatcher ──▶ TrackScheduler.onTrackEnd ──▶ QueueManager.startNextTrack()
 ```
 
+- **Event dispatch** — `MusicServiceImpl` holds a single subscription per event type
+  (`TrackStartEvent`, `TrackEndEvent`, `TrackExceptionEvent`, `TrackStuckEvent`,
+  `WebSocketClosedEvent`) and routes each event to the owning guild's `TrackScheduler`. All
+  subscriptions are disposed in `stop()`.
+- **Synchronous facade** — every Lavalink operation returns a reactive `Mono`. `MusicManager`
+  subscribes internally so the 13 music commands keep their existing synchronous signatures;
+  failures are reported through `LogHandler` and the attached `MusicChannelContext`.
+- **Current track** — the node's player state is only readable via REST, so the last
+  `TrackStartEvent` is cached on the scheduler and used by `getCurrentlyPlaying()` and by the queue
+  to decide whether playback must be started.
 - **Requester tracking** — each queued item is a `TrackInfo` (track + requesting `Member`), used for
-  now-playing/queue displays and vote-skip.
-- **Playlists / search** — playlist and multi-result loads produce a
+  now-playing/queue displays and vote-skip. Duplicate rejection compares the encoded track payload.
+- **Playlists / search** — playlist and search loads produce a
   [`LoadPlaylistTask`](tasks.md#concrete-task-catalog) with per-result buttons
   (`LoadTrackFromPlaylistTask`), tying the music and [task](tasks.md) subsystems together. Playlist
   size is bounded by the [`MUSIC_MAXPLAYLISTSIZE`](persistence.md#gsettings) guild setting.
-- **Stuck tracks** — `TrackScheduler.onTrackStuck` attempts recovery (reload/skip).
+- **Stuck tracks** — the first `TrackStuckEvent` re-queues the track and seeks back to the last
+  known position; a second consecutive event skips to the next track.
 - **Output** — playback messages are posted through a
   [`MusicChannelContext`](contexts.md#musicchannelcontext) so they land in the guild's configured
   music channel.
 
-## Custom Udio source
+## Running the node
 
-`UdioAudioSourceManager` scrapes udio.com track pages: it extracts track metadata (title, artist,
-duration) and a direct playback URL from the Next.js payload (`self.__next_f.push(...)` calls) in the
-page HTML. Because Udio playback URLs expire, `UdioAudioTrack` **re-fetches** the URL during the
-`process` phase of the pipeline before streaming, delegating the actual decode/playback to Lavaplayer's
-`Mp3AudioTrack`.
+`docker-compose.yml` defines a `lavalink` service (image `ghcr.io/lavalink-devs/lavalink:4.2`, the
+minimum version that handles DAVE end-to-end encrypted voice) on the `netneutrality` network, with
+`lavalink/application.yml` mounted read-only at `/opt/Lavalink/application.yml`. The bot depends on
+it and the node depends on the existing `ejs-api` (yt-cipher) container.
+
+```bash
+docker compose up -d lavalink
+docker compose logs -f lavalink   # wait for "Lavalink is ready to accept connections"
+```
+
+### Adding a server-side plugin
+
+Plugins are declared in `lavalink/application.yml` and downloaded by the node on boot into the
+`netneutrality-lavalink-plugins` volume — no bot rebuild is required:
+
+```yaml
+lavalink:
+  plugins:
+    - dependency: "dev.lavalink.youtube:youtube-plugin:1.18.2"
+      snapshot: false
+```
+
+A plugin that is not on the default Lavalink repository can be pulled from any Maven repository by
+adding `repository:` to the entry. The node currently runs a JitPack build of the SABR-enabled
+YouTube fork ([`ashton045/youtube-source`](https://jitpack.io/#ashton045/youtube-source), branch
+`feat/sabr-support`) — no local build of the fork is required, JitPack publishes a ready Lavalink
+plugin jar:
+
+```yaml
+lavalink:
+  plugins:
+    - dependency: "com.github.ashton045.youtube-source:youtube-plugin:17619654b1"
+      repository: "https://jitpack.io"
+      snapshot: false
+```
+
+The node logs `Failed to check for updates for youtube-plugin: Not Found` on boot; this is harmless,
+JitPack publishes no `maven-metadata.xml` for commit-pinned versions.
+
+Plugin-specific configuration goes under the top-level `plugins:` key. The YouTube plugin is
+configured there with the remote cipher URL, poToken and visitorData, which used to live in
+`MusicServiceImpl.start()`.
+
+## Udio support (deferred)
+
+Udio playback is **temporarily unavailable**. The previous implementation was a client-side
+Lavaplayer `AudioSourceManager`, and Lavalink can only resolve sources that live on the server.
+`SourceFinder` still recognises Udio URLs but returns no identifier, and `MusicManager.play` replies
+that Udio is temporarily unsupported.
+
+The original `UdioAudioSourceManager`, `UdioAudioTrack` and their test have been preserved verbatim
+under [`docs/reference/udio-lavalink-plugin/`](reference/udio-lavalink-plugin) — they are **not
+compiled** — as the reference for a future Lavalink **server plugin** port. That plugin is out of
+scope of this migration and is tracked as a follow-up.
 
 ## Guild lifecycle & cleanup
 
-- `MusicPlayerAutoDisconnect` (scheduled task) leaves voice when the player has been idle.
-- `MusicManagerCleanup` (scheduled task) evicts unused per-guild `MusicManager` instances from the
-  static map.
-- On shutdown, `MusicManager.disconnectPlayers()` stops all players and disconnects from voice
+- `MusicPlayerAutoDisconnect` (scheduled task) leaves voice when the channel is empty or the queue
+  has run out; the connected channel is read from the bot's gateway voice state.
+- `MusicManagerCleanup` (scheduled task) evicts unused per-guild `MusicManager` instances.
+- On shutdown, `MusicServiceImpl.stop()` disposes the event subscriptions, clears the queues,
+  destroys every player and closes the client
   (called from [`App.shutdown()`](architecture.md#shutdown-lifecycle)).
 
 ## Related commands

docs/reference/udio-lavalink-plugin/README.md

@@ -0,0 +1,43 @@
+# Udio source — follow-up reference
+
+These files are **not part of the build**. They are the original client-side Lavaplayer
+implementation of the udio.com source, kept verbatim as the reference for a future port.
+
+| File | Was |
+|---|---|
+| `UdioAudioSourceManager.java` | `me.bobert.netneutrality.music.source.UdioAudioSourceManager` |
+| `UdioAudioTrack.java` | `me.bobert.netneutrality.music.source.UdioAudioTrack` |
+| `UdioAudioSourceManagerTest.java` | its unit test |
+
+## Why they were moved
+
+The bot no longer decodes audio itself: after the [migration to Lavalink](../../music.md), source
+resolution happens on the node. A Lavaplayer `AudioSourceManager` living in the bot process can
+never be used by Lavalink, and these classes cannot even compile now that the `dev.arbjerg:lavaplayer`
+dependency has been dropped from `pom.xml`.
+
+## Status
+
+**Udio playback is disabled.** `SourceFinder` still classifies Udio URLs, but
+`SourceFinder.getIdentifier` returns no identifier for them and `MusicManager.play` replies that
+Udio is temporarily unsupported.
+
+## Follow-up
+
+Port `UdioAudioSourceManager` / `UdioAudioTrack` into a standalone **Lavalink server plugin**
+(its own build and published artifact), then enable it by adding the dependency to
+`lavalink/application.yml`:
+
+```yaml
+lavalink:
+  plugins:
+    - dependency: "<group>:udio-plugin:<version>"
+```
+
+Once the node resolves `https://www.udio.com/songs/...` identifiers, the only bot-side change is to
+restore `Udio` in the `SourceFinder.getIdentifier` switch and drop the "temporarily unsupported"
+reply in `MusicManager.play`.
+
+The scraping logic itself still applies: the manager extracts metadata and a direct playback URL
+from the Next.js payload (`self.__next_f.push(...)`) of the track page, and the URL must be
+re-fetched right before playback because it expires.

docs/threading.md

@@ -37,7 +37,8 @@ startup by [`TaskManager.init()`](tasks.md#taskmanager)):
 - `cancelAll()` — cancels every scheduled task; called first in
   [`App.shutdown()`](architecture.md#shutdown-lifecycle).
 
-The existing scheduled tasks are `MusicManagerCleanup`, `MusicPlayerAutoDisconnect`, and
+The existing scheduled tasks are `MusicManagerCleanup`, `MusicPlayerAutoDisconnect` (which reads the
+bot's gateway voice state rather than JDA's audio manager, see [music.md](music.md)), and
 `TaskCleanup` (see the [task catalog](tasks.md#concrete-task-catalog)).
 
 > **Direction of travel:** the scheduled-task abstraction is intended to eventually replace ad-hoc

docs/utilities-and-bootstrap.md

@@ -86,7 +86,8 @@ An example configuration file is `bot.properties.example`. Key configuration val
 | `MYSQL_*` | Database connection settings (see [persistence.md](persistence.md)). |
 | `NETNEUTRALITY_SENTRY_DSN` | Enables Sentry when present. |
 | `GITLAB_HOST` / `GITLAB_TOKEN` / `GITLAB_PROJECT_ID` | GitLab issue reporting ([`ReportIssueTask`](tasks.md#worked-example--gitlab-bug-report-modal)). |
-| `NETNEUTRALITY_PO_TOKEN` / `NETNEUTRALITY_VISITOR_DATA` / `NETNEUTRALITY_CIPHER_*` | YouTube playback auth/cipher settings for the [music](music.md) source. |
+| `NETNEUTRALITY_LAVALINK_URI` / `_PASSWORD` / `_NAME` | Connection settings for the [Lavalink node](music.md#settings). |
+| `NETNEUTRALITY_PO_TOKEN` / `NETNEUTRALITY_VISITOR_DATA` / `NETNEUTRALITY_CIPHER_*` | YouTube auth/cipher settings, consumed by the node via `lavalink/application.yml`. |
 
 ## Utility helpers
 

lavalink/application.yml

@@ -0,0 +1,65 @@
+server:
+  port: 2333
+  address: 0.0.0.0
+
+lavalink:
+  plugins:
+    # Replacement for the in-process dev.lavalink.youtube:v2 source manager.
+    # Custom SABR-enabled fork (ashton045/youtube-source, feat/sabr-support) built by JitPack.
+    - dependency: "com.github.ashton045.youtube-source:youtube-plugin:33d50abd5f"
+      repository: "https://jitpack.io"
+      snapshot: false
+  server:
+    password: "${SERVER_PASSWORD:youshallnotpass}"
+    sources:
+      # Handled by the youtube-plugin below, must stay disabled here.
+      youtube: false
+      soundcloud: true
+      bandcamp: false
+      twitch: false
+      vimeo: false
+      nico: false
+      http: true
+      local: false
+    filters:
+      volume: true
+    bufferDurationMs: 400
+    frameBufferDurationMs: 5000
+    opusEncodingQuality: 10
+    resamplingQuality: LOW
+    trackStuckThresholdMs: 10000
+    useSeekGhosting: true
+    youtubePlaylistLoadLimit: 6
+    playerUpdateInterval: 5
+    youtubeSearchEnabled: true
+    soundcloudSearchEnabled: true
+
+plugins:
+  youtube:
+    enabled: true
+    allowSearch: true
+    allowDirectVideoIds: true
+    allowDirectPlaylistIds: true
+    clients:
+      - TV
+      - MWEB
+      - WEB
+      - MUSIC
+      - WEBEMBEDDED
+      - ANDROID_VR
+      - TVHTML5_SIMPLY
+    oauth:
+      enabled: true
+      refreshToken: "${NETNEUTRALITY_OAUTH_TOKEN}"
+    remoteCipher:
+      url: "${NETNEUTRALITY_CIPHER_URL:http://ejs-api:8001}"
+      password: "${NETNEUTRALITY_CIPHER_PASSWORD:}"
+    remotePot:
+      url: "${NETNEUTRALITY_POT_URL:http://webpo:8080}"
+
+logging:
+  level:
+    root: INFO
+    lavalink: DEBUG
+    # Set to INFO to see the OAuth flow instructions (device code / verification URL) in the terminal.
+    dev.lavalink.youtube.http.YoutubeOauth2Handler: INFO

pom.xml

@@ -146,35 +146,11 @@
             <artifactId>JDA</artifactId>
             <version>6.4.1</version>
         </dependency>
+        <!-- Lavalink v4 client; audio decoding happens on the remote node. -->
         <dependency>
             <groupId>dev.arbjerg</groupId>
-            <artifactId>lavaplayer</artifactId>
-            <version>2.2.7</version>
-        </dependency>
-        <dependency>
-            <groupId>dev.lavalink.youtube</groupId>
-            <artifactId>v2</artifactId>
-            <version>1.18.2</version>
-        </dependency>
-        <dependency>
-            <groupId>club.minnced</groupId>
-            <artifactId>jdave-api</artifactId>
-            <version>0.1.8</version>
-        </dependency>
-        <dependency>
-            <groupId>club.minnced</groupId>
-            <artifactId>jdave-native-linux-x86-64</artifactId>
-            <version>0.1.8</version>
-        </dependency>
-        <dependency>
-            <groupId>club.minnced</groupId>
-            <artifactId>jdave-native-win-x86-64</artifactId>
-            <version>0.1.8</version>
-        </dependency>
-        <dependency>
-            <groupId>club.minnced</groupId>
-            <artifactId>jdave-native-darwin</artifactId>
-            <version>0.1.8</version>
+            <artifactId>lavalink-client</artifactId>
+            <version>3.4.0</version>
         </dependency>
 
         <dependency>
@@ -183,6 +159,12 @@
             <version>5.3.2</version>
         </dependency>
 
+        <dependency>
+            <groupId>io.javalin</groupId>
+            <artifactId>javalin</artifactId>
+            <version>6.7.0</version>
+        </dependency>
+
         <dependency>
             <groupId>org.hibernate.orm</groupId>
             <artifactId>hibernate-core</artifactId>
@@ -219,6 +201,13 @@
             <groupId>org.gitlab4j</groupId>
             <artifactId>gitlab4j-api</artifactId>
             <version>6.2.0</version>
+            <exclusions>
+                <!-- Clashes with the Servlet 5 API used by Javalin's Jetty 11 in the shaded jar. -->
+                <exclusion>
+                    <groupId>jakarta.servlet</groupId>
+                    <artifactId>jakarta.servlet-api</artifactId>
+                </exclusion>
+            </exclusions>
         </dependency>
 
         <dependency>

src/main/java/me/bobert/netneutrality/App.java

@@ -6,7 +6,7 @@ package me.bobert.netneutrality;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import club.minnced.discord.jdave.interop.JDaveSessionFactory;
+import dev.arbjerg.lavalink.libraries.jda.JDAVoiceUpdateListener;
 import io.sentry.Sentry;
 import me.bobert.netneutrality.bootstrap.ApplicationContext;
 import me.bobert.netneutrality.bootstrap.Lifecycle;
@@ -33,7 +33,6 @@ import me.bobert.netneutrality.utils.Settings;
 import me.bobert.netneutrality.http.WebModule;
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.JDABuilder;
-import net.dv8tion.jda.api.audio.AudioModuleConfig;
 import net.dv8tion.jda.api.entities.Activity;
 import net.dv8tion.jda.api.exceptions.InvalidTokenException;
 import net.dv8tion.jda.api.requests.GatewayIntent;
@@ -47,6 +46,7 @@ public class App {
     private static App instance;
     private final Settings settings;
     private JDA jda;
+    private MusicService music;
     private final ApplicationContext context = new ApplicationContext();
 
     static void main() {
@@ -71,8 +71,7 @@ public class App {
 
         if ("dev".equals(env)) {
             Configurator.setLevel("net.dv8tion.jda", Level.DEBUG);
-            Configurator.setLevel("dev.lavalink.youtube", Level.DEBUG);
-            Configurator.setLevel("com.sedmelluq.discord", Level.DEBUG);
+            Configurator.setLevel("dev.arbjerg.lavalink", Level.DEBUG);
         }
 
         instance = new App(settings);
@@ -137,7 +136,7 @@ public class App {
         JpaUtils.bindGuildServiceLookup(guildServices::get);
 
         // Music sources (priority 40): initialise the shared player manager; disconnect on shutdown.
-        MusicService music = context.register(new MusicServiceImpl(settings, guildServices, tasks));
+        music = context.register(new MusicServiceImpl(settings, guildServices, tasks, executors));
         BotState.bind(guildServices, music);
 
         // JDA gateway; disconnected on shutdown.
@@ -200,8 +199,9 @@ public class App {
                     GatewayIntent.GUILD_MESSAGE_REACTIONS,
                     GatewayIntent.GUILD_VOICE_STATES,
                     GatewayIntent.MESSAGE_CONTENT)
-                .setAudioModuleConfig(
-                    new AudioModuleConfig().withDaveSessionFactory(new JDaveSessionFactory()))
+                // Voice state/server updates are handed to Lavalink instead of JDA's audio stack;
+                // DAVE encryption is handled by the node.
+                .setVoiceDispatchInterceptor(new JDAVoiceUpdateListener(music.getClient()))
                 .setActivity(Activity.watching("me load..."))
                 .build();
             jda.awaitReady();

src/main/java/me/bobert/netneutrality/core/tasks/TaskManagerImpl.java

@@ -23,13 +23,13 @@ import net.dv8tion.jda.api.interactions.InteractionHook;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
@@ -41,7 +41,7 @@ public class TaskManagerImpl implements TaskManager {
     private static final Logger logger = LogManager.getLogger(TaskManagerImpl.class);
     private final TaskService taskService;
     private final Map<String, Task> tasks;
-    private final List<Task> pendingTasks;
+    private final Map<String, Task> pendingTasks;
     private final Map<String, CommandContext> deletableTasksContext;
     private final Map<String, ReentrantLock> tasksLock;
     private final ApplicationContext context;
@@ -55,7 +55,7 @@ public class TaskManagerImpl implements TaskManager {
     public TaskManagerImpl(ApplicationContext context) {
         Objects.requireNonNull(context, "ApplicationContext must not be null");
         this.tasks = new ConcurrentHashMap<>();
-        this.pendingTasks = new CopyOnWriteArrayList<>();
+        this.pendingTasks = new ConcurrentHashMap<>();
         this.deletableTasksContext = new ConcurrentHashMap<>();
         this.tasksLock = new ConcurrentHashMap<>();
         this.taskService = new TaskService(this);
@@ -86,7 +86,14 @@ public class TaskManagerImpl implements TaskManager {
 
     @Override
     public Task getTask(String id) {
-        return tasks.get(id);
+        if (id == null) {
+            return null;
+        }
+        Task task = tasks.get(id);
+        if (task != null) {
+            return task;
+        }
+        return pendingTasks.get(id);
     }
 
     /**
@@ -96,12 +103,17 @@ public class TaskManagerImpl implements TaskManager {
      */
     @Override
     public boolean hasTask(String id) {
-        return tasks.containsKey(id) || pendingTasks.stream().anyMatch(task -> task.getId().equals(id));
+        if (id == null) {
+            return false;
+        }
+        return tasks.containsKey(id) || pendingTasks.containsKey(id);
     }
 
     @Override
     public Collection<Task> getTasks() {
-        return tasks.values();
+        List<Task> allTasks = new ArrayList<>(tasks.values());
+        allTasks.addAll(pendingTasks.values());
+        return allTasks;
     }
 
     @Override
@@ -123,7 +135,7 @@ public class TaskManagerImpl implements TaskManager {
             }
 
             if (task instanceof StepTask) {
-                pendingTasks.add(task);
+                pendingTasks.put(id, task);
             } else {
                 tasks.put(id, task);
             }
@@ -136,7 +148,7 @@ public class TaskManagerImpl implements TaskManager {
         if (task instanceof WithChildren taskWithChildren) {
             List<Task> childrens = taskWithChildren.getChildTasks();
             if (childrens == null || childrens.isEmpty()) {
-                logger.warn("Parent task '{}' doesn't create any childs", task.getName());
+                logger.warn("Parent task '{}' doesn't create any children", task.getName());
                 return;
             }
 
@@ -148,23 +160,37 @@ public class TaskManagerImpl implements TaskManager {
 
     @Override
     public void activateTask(Task task, String oldId) {
-        if (pendingTasks.remove(task)) {
-            tasks.put(task.getId(), task);
-            logger.info("Updating task {} with new id: {} (was: {})",
-                task.getName(), task.getId(), oldId);
+        if (task == null) {
+            return;
         }
+        boolean removed = oldId != null && pendingTasks.remove(oldId) != null;
+        if (!removed) {
+            removed = pendingTasks.remove(task.getId()) != null;
+        }
+        if (!removed) {
+            pendingTasks.values().remove(task);
+        }
+        tasks.put(task.getId(), task);
+        logger.info("Updating task {} with new id: {} (was: {})",
+                task.getName(), task.getId(), oldId);
     }
 
     @Override
     public void removeTask(Task task) {
+        if (task == null) {
+            return;
+        }
         String id = task.getId();
 
-        if (tasks.remove(id) != null) {
+        boolean removed = tasks.remove(id) != null;
+        removed |= pendingTasks.remove(id) != null;
+        removed |= pendingTasks.values().remove(task);
+
+        if (removed) {
             logger.debug("Removing task: {}", id);
 
-            ReentrantLock lock = tasksLock.remove(task.getLockId());
-            if (lock != null) {
-                logger.debug("Cleaning up lock for removed task: {}", task.getId());
+            if (task instanceof PersistableTask persistableTask) {
+                taskService.unpersistTask(persistableTask);
             }
         }
     }
@@ -181,16 +207,16 @@ public class TaskManagerImpl implements TaskManager {
         if (task != null) {
             String lockId = task.getLockId();
             ReentrantLock lock = (task instanceof PersistableTask || task instanceof BuiltInTask)
-                ? null
-                : tasksLock.computeIfAbsent(lockId, _ -> new ReentrantLock());
+                    ? null
+                    : tasksLock.computeIfAbsent(lockId, _ -> new ReentrantLock());
 
             try {
                 if (lock != null) {
-                    logger.debug("Aquiring lock for task: {}", taskId);
+                    logger.debug("Acquiring lock for task: {}", taskId);
                     lock.lock();
 
                     if (!tasks.containsKey(taskId)) {
-                        logger.debug("Task {} is no longer available after aquiring lock", taskId);
+                        logger.debug("Task {} is no longer available after acquiring lock", taskId);
                         return;
                     }
                 }
@@ -224,26 +250,35 @@ public class TaskManagerImpl implements TaskManager {
 
     @Override
     public <E extends Task> Optional<E> findTaskByPartialId(Class<E> clazz, String partialId) {
-        List<E> tasks = findTasksByPartialId(clazz, partialId);
-        return Optional.ofNullable(tasks.isEmpty() ? null : tasks.getFirst());
+        if (clazz == null || partialId == null) {
+            return Optional.empty();
+        }
+        return tasks.values().stream()
+                .filter(clazz::isInstance)
+                .map(clazz::cast)
+                .filter(task -> task.getId() != null && task.getId().contains(partialId))
+                .findFirst();
     }
 
     @Override
     public <E extends Task> List<E> findTasksByPartialId(Class<E> clazz, String partialId) {
+        if (clazz == null || partialId == null) {
+            return List.of();
+        }
         return tasks.values().stream()
-            .filter(clazz::isInstance)
-            .map(clazz::cast)
-            .filter(task -> task.getId().contains(partialId))
-            .collect(Collectors.toList());
+                .filter(clazz::isInstance)
+                .map(clazz::cast)
+                .filter(task -> task.getId() != null && task.getId().contains(partialId))
+                .collect(Collectors.toList());
     }
 
     @Override
     public WithButton findButtonTaskByClass(Class<? extends WithButton> clazz) {
         return tasks.values().stream()
-            .filter(clazz::isInstance)
-            .map(task -> (WithButton) task)
-            .findFirst()
-            .orElse(null);
+                .filter(clazz::isInstance)
+                .map(task -> (WithButton) task)
+                .findFirst()
+                .orElse(null);
     }
 
     @Override
@@ -272,6 +307,9 @@ public class TaskManagerImpl implements TaskManager {
 
 
     private void deleteInteraction(Task task) {
+        if (task == null) {
+            return;
+        }
         if (task instanceof WithParent<?> taskWithParent) {
             Task parent = taskWithParent.getParentTask();
 
@@ -289,18 +327,16 @@ public class TaskManagerImpl implements TaskManager {
     private void deleteInteraction(String taskId, Deletable deletable) {
         logger.debug("Deleting interaction: {}", taskId);
 
-        CommandContext context = deletableTasksContext.get(taskId);
-        if (context != null) {
-            deletableTasksContext.remove(taskId);
-
-            InteractionHook hook = context.getInteractionHook();
+        CommandContext commandContext = deletableTasksContext.remove(taskId);
+        if (commandContext != null) {
+            InteractionHook hook = commandContext.getInteractionHook();
             if (hook != null) {
                 if (hook.isExpired()) {
-                    context.replyEphemeral("This interaction has expired, can't remove it");
-                }
-
-                if (!hook.isExpired()) {
-                    hook.deleteOriginal().queue();
+                    commandContext.replyEphemeral("This interaction has expired, can't remove it");
+                } else {
+                    hook.deleteOriginal().queue(null, error ->
+                            logger.warn("Failed to delete interaction for task {}: {}", taskId, error.getMessage())
+                    );
                 }
             }
         }
@@ -319,12 +355,32 @@ public class TaskManagerImpl implements TaskManager {
                 break;
 
             case REMOVE_SELF_AND_CHILDREN:
-                if (task instanceof WithChildren taskWithChildren) {
-                    for (Task child : taskWithChildren.getChildTasks()) {
-                        removeTask(child);
+                if (task instanceof WithParent<?> taskWithParent) {
+                    Task parent = taskWithParent.getParentTask();
+                    if (parent != null) {
+                        if (parent instanceof WithChildren parentWithChildren) {
+                            List<Task> childTasks = parentWithChildren.getChildTasks();
+                            if (childTasks != null) {
+                                for (Task child : childTasks) {
+                                    removeTask(child);
+                                }
+                            }
+                        }
+                        removeTask(parent);
+                    } else {
+                        removeTask(task);
                     }
+                } else if (task instanceof WithChildren taskWithChildren) {
+                    List<Task> childTasks = taskWithChildren.getChildTasks();
+                    if (childTasks != null) {
+                        for (Task child : childTasks) {
+                            removeTask(child);
+                        }
+                    }
+                    removeTask(task);
+                } else {
+                    removeTask(task);
                 }
-                removeTask(task);
                 break;
 
             case KEEP:

src/main/java/me/bobert/netneutrality/http/ResponseCache.java

@@ -0,0 +1,65 @@
+package me.bobert.netneutrality.http;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Optional;
+
+/**
+ * Small LRU cache holding responses of outbound {@link WebModule} GET requests.
+ */
+final class ResponseCache {
+
+    private static final int MAX_ENTRIES = 50;
+
+    private static final Map<String, CachedResponse> entries = Collections.synchronizedMap(
+        new LinkedHashMap<>(100, 0.75f, true) {
+            @Override
+            protected boolean removeEldestEntry(Map.Entry<String, CachedResponse> eldest) {
+                return size() > MAX_ENTRIES;
+            }
+        }
+    );
+
+    private ResponseCache() {
+    }
+
+    /**
+     * Returns the cached response for the key when it is still valid.
+     *
+     * @param key the cache key
+     * @return the cached response, or empty when absent or expired
+     */
+    static Optional<CachedResponse> get(String key) {
+        CachedResponse cached = entries.get(key);
+        return cached != null && !cached.isExpired() ? Optional.of(cached) : Optional.empty();
+    }
+
+    static void put(String key, CachedResponse response) {
+        entries.put(key, response);
+    }
+
+    static void invalidate(String url) {
+        entries.keySet().removeIf(key -> key.contains(url));
+    }
+
+    /**
+     * A response body kept alongside its status code until {@code expirationTime}.
+     */
+    record CachedResponse(int statusCode, String body, long expirationTime) {
+
+        boolean isExpired() {
+            return System.currentTimeMillis() > expirationTime;
+        }
+
+        Optional<String> getBody() {
+            return Optional.ofNullable(body);
+        }
+    }
+}

src/main/java/me/bobert/netneutrality/http/WebModule.java

@@ -9,7 +9,7 @@ package me.bobert.netneutrality.http;
 import com.google.gson.Gson;
 import io.sentry.Breadcrumb;
 import io.sentry.Sentry;
-import okhttp3.Headers;
+import me.bobert.netneutrality.http.ResponseCache.CachedResponse;
 import okhttp3.MediaType;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
@@ -21,11 +21,8 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
-import java.util.Collections;
 import java.util.HashMap;
-import java.util.LinkedHashMap;
 import java.util.Map;
-import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 
 public class WebModule {
@@ -34,20 +31,13 @@ public class WebModule {
     }
 
     private static final String USER_AGENT = "Net Neutrality/%s (Discord bot, discord.gg/trAqhQ5Wsr)";
+    private static final OkHttpClient CLIENT = new OkHttpClient();
     private static volatile String defaultVersion = "0.0.0";
     private static final Logger log = LoggerFactory.getLogger(WebModule.class);
 
     public static void setDefaultVersion(String version) {
         defaultVersion = version;
     }
-    private static final Map<String, CachedResponse> cache = Collections.synchronizedMap(
-        new LinkedHashMap<>(100, 0.75f, true) {
-            @Override
-            protected boolean removeEldestEntry(Map.Entry<String, CachedResponse> eldest) {
-                return size() > 50; // Limit cache to 50 entries
-            }
-        }
-    );
 
     private final Method method;
     private final String url;
@@ -62,7 +52,7 @@ public class WebModule {
         this.url = builder.url;
         this.client = builder.client;
         this.headers = builder.headers;
-        this.cacheExpirationMillis = builder.timeUnit.toMillis(builder.timeout);
+        this.cacheExpirationMillis = builder.timeUnit.toMillis(builder.cacheTimeout);
         this.request = builder.request;
     }
 
@@ -74,7 +64,7 @@ public class WebModule {
      * @param url the URL of the cached response to invalidate
      */
     public static void invalidateCache(String url) {
-        cache.keySet().removeIf(s -> s.contains(url));
+        ResponseCache.invalidate(url);
     }
 
     /**
@@ -86,60 +76,49 @@ public class WebModule {
      * POST requests do not support caching.
      *
      * @return the {@code WebModule} instance, allowing further interaction with the response
-     * @throws RuntimeException if the request fails
      */
     public WebModule request() {
         String cacheKey = createCacheKey(method, url, headers);
 
-        if (method == Method.GET && cacheKey != null) {
-            CachedResponse cachedResponse = cache.get(cacheKey);
+        if (cacheKey != null) {
+            CachedResponse cached = ResponseCache.get(cacheKey).orElse(null);
 
-            if (cachedResponse != null && !cachedResponse.isExpired()) {
+            if (cached != null) {
                 log.debug("Retrieving cached response: {}", cacheKey);
-                this.cachedResponse = cachedResponse;
+                this.cachedResponse = cached;
                 return this;
             }
         }
 
-        long startTime = System.currentTimeMillis();
         try (Response response = client.newCall(request).execute()) {
-            long elapsedTime = System.currentTimeMillis() - startTime;
             Sentry.addBreadcrumb(Breadcrumb.http(url, method.name(), response.code()));
-            String body = response.body().string();
 
             this.cachedResponse = new CachedResponse(
                 response.code(),
-                response.headers(),
-                elapsedTime,
-                body,
-                System.currentTimeMillis() + cacheExpirationMillis,
-                null
+                response.body().string(),
+                System.currentTimeMillis() + cacheExpirationMillis
             );
         } catch (IOException e) {
-            long elapsedTime = System.currentTimeMillis() - startTime;
             log.error("Request failed: {}", e.getMessage(), e);
             Sentry.captureException(e);
 
             this.cachedResponse = new CachedResponse(
                 0, // Status code 0 indicates a failure
-                new Headers.Builder().build(),
-                elapsedTime,
                 null,
-                System.currentTimeMillis() + cacheExpirationMillis,
-                e.getMessage()
+                System.currentTimeMillis() + cacheExpirationMillis
             );
         }
 
-        if (method == Method.GET && cacheKey != null) {
-            cache.put(cacheKey, this.cachedResponse);
+        if (cacheKey != null) {
+            ResponseCache.put(cacheKey, this.cachedResponse);
         }
 
         return this;
     }
 
     private String createCacheKey(Method method, String url, Map<String, String> headers) {
-        if (method == Method.POST) {
-            return null; // no cache for post requests
+        if (method != Method.GET) {
+            return null; // only GET requests are cached
         }
 
         StringBuilder keyBuilder = new StringBuilder(method.name()).append(":").append(url);
@@ -176,12 +155,9 @@ public class WebModule {
         private final String url;
         private final String version;
         private Method method = Method.GET;
-        private long timeout = 5;
+        private long cacheTimeout = 5;
         private TimeUnit timeUnit = TimeUnit.MINUTES;
-        private OkHttpClient client;
-        private long connectTimeout;
-        private long readTimeout;
-        private long writeTimeout;
+        private OkHttpClient client = CLIENT;
         private final Map<String, String> headers = new HashMap<>();
         private final Map<String, String> params = new HashMap<>();
 
@@ -242,51 +218,24 @@ public class WebModule {
          * @return the current {@code Builder} instance for chaining
          */
         public Builder cache(long timeout, TimeUnit timeUnit) {
-            this.timeout = timeout;
+            this.cacheTimeout = timeout;
             this.timeUnit = timeUnit;
             return this;
         }
 
+        /**
+         * Sets the connect, read and write timeouts of the HTTP client.
+         *
+         * @param timeout  the timeout duration
+         * @param timeUnit the unit of time for the timeout
+         * @return the current {@code Builder} instance for chaining
+         */
         public Builder timeout(long timeout, TimeUnit timeUnit) {
-            this.connectTimeout = timeUnit.toMillis(timeout);
-            this.readTimeout = timeUnit.toMillis(timeout);
-            this.writeTimeout = timeUnit.toMillis(timeout);
-            return this;
-        }
-
-        /**
-         * Sets the connection timeout for the HTTP client.
-         *
-         * @param timeout  the timeout duration
-         * @param timeUnit the unit of time for the timeout
-         * @return the current {@code Builder} instance for chaining
-         */
-        public Builder connectTimeout(long timeout, TimeUnit timeUnit) {
-            this.connectTimeout = timeUnit.toMillis(timeout);
-            return this;
-        }
-
-        /**
-         * Sets the read timeout for the HTTP client.
-         *
-         * @param timeout  the timeout duration
-         * @param timeUnit the unit of time for the timeout
-         * @return the current {@code Builder} instance for chaining
-         */
-        public Builder readTimeout(long timeout, TimeUnit timeUnit) {
-            this.readTimeout = timeUnit.toMillis(timeout);
-            return this;
-        }
-
-        /**
-         * Sets the write timeout for the HTTP client.
-         *
-         * @param timeout  the timeout duration
-         * @param timeUnit the unit of time for the timeout
-         * @return the current {@code Builder} instance for chaining
-         */
-        public Builder writeTimeout(long timeout, TimeUnit timeUnit) {
-            this.writeTimeout = timeUnit.toMillis(timeout);
+            this.client = CLIENT.newBuilder()
+                .connectTimeout(timeout, timeUnit)
+                .readTimeout(timeout, timeUnit)
+                .writeTimeout(timeout, timeUnit)
+                .build();
             return this;
         }
 
@@ -317,30 +266,9 @@ public class WebModule {
          * @return a new {@code WebModule} instance
          */
         public WebModule build() {
-            this.client = new OkHttpClient.Builder()
-                .connectTimeout(connectTimeout, TimeUnit.MILLISECONDS)
-                .writeTimeout(writeTimeout, TimeUnit.MILLISECONDS)
-                .readTimeout(readTimeout, TimeUnit.MILLISECONDS)
-                .build();
             this.request = createRequest();
 
             return new WebModule(this);
         }
     }
-
-    private record CachedResponse(int statusCode, Headers headers, long elapsedTime, String body, long expirationTime,
-                                  String errorMessage) {
-
-        public boolean isExpired() {
-                return System.currentTimeMillis() > expirationTime;
-            }
-
-            public Optional<String> getBody() {
-                return Optional.ofNullable(body);
-            }
-
-            public Optional<String> getErrorMessage() {
-                return Optional.ofNullable(errorMessage);
-            }
-        }
 }

src/main/java/me/bobert/netneutrality/http/server/AbstractHandler.java

@@ -1,33 +0,0 @@
-package me.bobert.netneutrality.http.server;
-
-/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
-
-import com.sun.net.httpserver.HttpExchange;
-import com.sun.net.httpserver.HttpHandler;
-
-import java.io.IOException;
-import java.io.OutputStream;
-
-public abstract class AbstractHandler implements HttpHandler {
-
-    public abstract void handle(HttpExchange exchange) throws IOException;
-
-    public void sendStringResponse(HttpExchange exchange, String str) throws IOException {
-        exchange.sendResponseHeaders(200, str.length());
-        OutputStream os = exchange.getResponseBody();
-        os.write(str.getBytes());
-        os.close();
-    }
-
-    public void sendJsonResponse(HttpExchange exchange, String str) throws IOException {
-        exchange.getResponseHeaders().add("Content-Type", "application/json");
-        exchange.sendResponseHeaders(200, str.length());
-        OutputStream os = exchange.getResponseBody();
-        os.write(str.getBytes());
-        os.close();
-    }
-}

src/main/java/me/bobert/netneutrality/http/server/ActionHandler.java

@@ -1,97 +0,0 @@
-package me.bobert.netneutrality.http.server;
-
-/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
-
-import com.google.gson.Gson;
-import com.sun.net.httpserver.HttpExchange;
-import me.bobert.netneutrality.db.service.GuildServiceProvider;
-import me.bobert.netneutrality.db.service.GuildService;
-import net.dv8tion.jda.api.JDA;
-import net.dv8tion.jda.api.entities.Guild;
-import org.apache.logging.log4j.LogManager;
-import org.json.JSONObject;
-
-import java.io.IOException;
-import java.util.Map;
-import java.util.Objects;
-import java.util.TreeMap;
-import java.util.function.Supplier;
-
-public class ActionHandler extends AbstractHandler {
-    private final Supplier<JDA> jdaSupplier;
-    private final GuildServiceProvider guildServices;
-    private final Runnable shutdownHook;
-
-    public ActionHandler(Supplier<JDA> jdaSupplier, GuildServiceProvider guildServices, Runnable shutdownHook) {
-        this.jdaSupplier = Objects.requireNonNull(jdaSupplier, "jdaSupplier");
-        this.guildServices = Objects.requireNonNull(guildServices, "guildServices");
-        this.shutdownHook = Objects.requireNonNull(shutdownHook, "shutdownHook");
-    }
-
-    @Override
-    public void handle(HttpExchange exchange) throws IOException {
-
-        String path = exchange.getRequestURI().getRawPath();
-
-        if (path.equals("/actions/shutdown")) {
-            LogManager.getLogger(ActionHandler.class).info("Request to shutdown received");
-            shutdownHook.run();
-            sendStringResponse(exchange, "Shutting down..");
-
-            System.exit(0);
-            return;
-        }
-
-        if (path.equals("/actions/status")) {
-            TreeMap<String, String> json = new TreeMap<>();
-            JDA jda = jdaSupplier.get();
-            json.put("health", String.valueOf(jda.getStatus()));
-            json.put("ping", String.valueOf(jda.getGatewayPing()));
-
-            sendJsonResponse(exchange, new Gson().toJson(json));
-            return;
-        }
-
-        if (path.startsWith("/actions/settings/current/")) {
-            JSONObject json = new JSONObject();
-            String[] args = exchange.getRequestURI().toString().split("/");
-            String guildId = args[args.length - 1];
-
-            Guild guild = jdaSupplier.get().getGuildById(guildId);
-            if (guild != null) {
-                GuildService service = guildServices.get(guild);
-                Map<String, String> settings = service.getGuildSettingService().getSettings();
-                JSONObject setting = new JSONObject(settings);
-
-                json.put("status", "ok");
-                json.put("settings", setting);
-            } else {
-                json.put("status", "error");
-            }
-
-            sendJsonResponse(exchange, json.toString());
-            return;
-        }
-
-        if (path.startsWith("/actions/settings/reload/")) {
-            TreeMap<String, String> json = new TreeMap<>();
-            String[] args = exchange.getRequestURI().toString().split("/");
-            String guildId = args[args.length - 1];
-
-            boolean ok = true; //TODO: add bool
-            guildServices.get(guildId).getGuildSettingService().reloadSettingsCache();
-
-            json.put("status", String.valueOf(ok));
-            sendJsonResponse(exchange, new Gson().toJson(json));
-
-            return;
-        }
-
-        sendStringResponse(exchange, path);
-
-    }
-}

src/main/java/me/bobert/netneutrality/http/server/ActionRoutes.java

@@ -0,0 +1,82 @@
+package me.bobert.netneutrality.http.server;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import io.javalin.Javalin;
+import io.javalin.http.Handler;
+import me.bobert.netneutrality.db.service.GuildServiceProvider;
+import net.dv8tion.jda.api.JDA;
+import net.dv8tion.jda.api.entities.Guild;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * Registers the {@code /actions/*} endpoints on a {@link Javalin} instance.
+ */
+public final class ActionRoutes {
+
+    private static final Logger logger = LogManager.getLogger(ActionRoutes.class);
+    private static final long SHUTDOWN_DELAY_MILLIS = 500;
+
+    private ActionRoutes() {
+    }
+
+    public static void register(
+        Javalin app,
+        Supplier<JDA> jdaSupplier,
+        GuildServiceProvider guildServices,
+        Runnable shutdownHook
+    ) {
+        app.get("/actions/status", ctx -> {
+            JDA jda = GuildRoutes.jda(jdaSupplier);
+            ctx.json(Map.of(
+                "health", String.valueOf(jda.getStatus()),
+                "ping", String.valueOf(jda.getGatewayPing())
+            ));
+        });
+
+        Handler shutdown = ctx -> {
+            logger.info("Request to shutdown received");
+            ctx.result("Shutting down..");
+            scheduleShutdown(shutdownHook);
+        };
+        app.post("/actions/shutdown", shutdown);
+        app.get("/actions/shutdown", shutdown);
+
+        app.get("/actions/settings/current/{guildId}", ctx -> {
+            Guild guild = GuildRoutes.guild(jdaSupplier, ctx);
+            Map<String, String> settings = guildServices.get(guild).getGuildSettingService().getSettings();
+
+            ctx.json(Map.of("status", "ok", "settings", settings));
+        });
+
+        app.post("/actions/settings/reload/{guildId}", ctx -> {
+            Guild guild = GuildRoutes.guild(jdaSupplier, ctx);
+            guildServices.get(guild).getGuildSettingService().reloadSettingsCache();
+
+            ctx.json(Map.of("status", "true"));
+        });
+    }
+
+    /**
+     * Runs the shutdown hook off the request thread so the response can be flushed first.
+     */
+    private static void scheduleShutdown(Runnable shutdownHook) {
+        Thread.ofPlatform().name("web-api-shutdown").start(() -> {
+            try {
+                Thread.sleep(SHUTDOWN_DELAY_MILLIS);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+            shutdownHook.run();
+            System.exit(0);
+        });
+    }
+}

src/main/java/me/bobert/netneutrality/http/server/GsonJsonMapper.java

@@ -0,0 +1,33 @@
+package me.bobert.netneutrality.http.server;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import com.google.gson.Gson;
+import io.javalin.json.JsonMapper;
+import org.jetbrains.annotations.NotNull;
+
+import java.lang.reflect.Type;
+
+/**
+ * Javalin {@link JsonMapper} backed by a shared {@link Gson} instance.
+ */
+public class GsonJsonMapper implements JsonMapper {
+
+    private static final Gson GSON = new Gson();
+
+    @NotNull
+    @Override
+    public String toJsonString(@NotNull Object obj, @NotNull Type type) {
+        return GSON.toJson(obj, type);
+    }
+
+    @NotNull
+    @Override
+    public <T> T fromJsonString(@NotNull String json, @NotNull Type targetType) {
+        return GSON.fromJson(json, targetType);
+    }
+}

src/main/java/me/bobert/netneutrality/http/server/GuildHandler.java

@@ -1,100 +0,0 @@
-package me.bobert.netneutrality.http.server;
-
-/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
-
-import com.sun.net.httpserver.HttpExchange;
-import net.dv8tion.jda.api.JDA;
-import org.json.JSONArray;
-import org.json.JSONObject;
-
-import java.io.IOException;
-import java.util.Objects;
-import java.util.function.Supplier;
-
-public class GuildHandler extends AbstractHandler {
-    private final Supplier<JDA> jdaSupplier;
-
-    public GuildHandler(Supplier<JDA> jdaSupplier) {
-        this.jdaSupplier = Objects.requireNonNull(jdaSupplier, "jdaSupplier");
-    }
-
-    @Override
-    public void handle(HttpExchange exchange) throws IOException {
-
-        String path = exchange.getRequestURI().getRawPath();
-
-        if (path.equals("/guilds/owner")) {
-
-            JSONArray array = new JSONArray();
-
-            JDA jda = jdaSupplier.get();
-
-            jda.getGuilds().forEach(guild -> {
-                JSONObject obj = new JSONObject();
-                obj.put("guild_id", guild.getId());
-                obj.put("owner_id", guild.getOwnerId());
-                array.put(obj);
-            });
-
-            sendJsonResponse(exchange, array.toString());
-            return;
-
-        }
-
-        if (path.startsWith("/guilds/channels/")) {
-
-            String[] args = exchange.getRequestURI().toString().split("/");
-            String guild = args[args.length - 1];
-            JSONArray array = new JSONArray();
-
-            JDA jda = jdaSupplier.get();
-
-            if (jda.getGuildById(guild) == null) {
-                sendStringResponse(exchange, path);
-                return;
-            }
-
-            jda.getGuildById(guild).getTextChannels().forEach(channel -> {
-                JSONObject obj = new JSONObject();
-                obj.put("channel_id", channel.getId());
-                obj.put("channel_name", channel.getName());
-                array.put(obj);
-            });
-
-            sendJsonResponse(exchange, array.toString());
-            return;
-
-        }
-
-        if (path.startsWith("/guilds/roles/")) {
-
-            String[] args = exchange.getRequestURI().toString().split("/");
-            String guild = args[args.length - 1];
-            JSONArray array = new JSONArray();
-            JDA jda = jdaSupplier.get();
-
-            if (jda.getGuildById(guild) == null) {
-                sendStringResponse(exchange, path);
-                return;
-            }
-
-            jda.getGuildById(guild).getRoles().forEach(role -> {
-                JSONObject obj = new JSONObject();
-                obj.put("channel_id", role.getId());
-                obj.put("channel_name", role.getName());
-                array.put(obj);
-            });
-
-            sendJsonResponse(exchange, array.toString());
-            return;
-
-        }
-
-        sendStringResponse(exchange, path);
-
-    }
-}

src/main/java/me/bobert/netneutrality/http/server/GuildRoutes.java

@@ -0,0 +1,79 @@
+package me.bobert.netneutrality.http.server;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import io.javalin.Javalin;
+import io.javalin.http.Context;
+import io.javalin.http.NotFoundResponse;
+import io.javalin.http.ServiceUnavailableResponse;
+import net.dv8tion.jda.api.JDA;
+import net.dv8tion.jda.api.entities.Guild;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * Registers the read-only {@code /guilds/*} endpoints on a {@link Javalin} instance.
+ */
+public final class GuildRoutes {
+
+    private GuildRoutes() {
+    }
+
+    public static void register(Javalin app, Supplier<JDA> jdaSupplier) {
+        app.get("/guilds/owner", ctx -> ctx.json(
+            jda(jdaSupplier).getGuilds().stream()
+                .map(guild -> ordered("guild_id", guild.getId(), "owner_id", guild.getOwnerId()))
+                .toList()
+        ));
+
+        app.get("/guilds/channels/{guildId}", ctx -> ctx.json(
+            guild(jdaSupplier, ctx).getTextChannels().stream()
+                .map(channel -> ordered("channel_id", channel.getId(), "channel_name", channel.getName()))
+                .toList()
+        ));
+
+        app.get("/guilds/roles/{guildId}", ctx -> ctx.json(
+            guild(jdaSupplier, ctx).getRoles().stream()
+                .map(role -> ordered("channel_id", role.getId(), "channel_name", role.getName()))
+                .toList()
+        ));
+    }
+
+    /**
+     * Builds a two entry map with a stable key order for JSON serialization.
+     */
+    private static Map<String, String> ordered(String firstKey, String firstValue, String secondKey, String secondValue) {
+        Map<String, String> map = new LinkedHashMap<>();
+        map.put(firstKey, firstValue);
+        map.put(secondKey, secondValue);
+        return map;
+    }
+
+    /**
+     * Resolves the JDA client or fails with 503 while it is not ready yet.
+     */
+    static JDA jda(Supplier<JDA> jdaSupplier) {
+        JDA jda = jdaSupplier.get();
+        if (jda == null) {
+            throw new ServiceUnavailableResponse("Discord client is not ready");
+        }
+        return jda;
+    }
+
+    /**
+     * Resolves the {@code guildId} path parameter or fails with 404.
+     */
+    static Guild guild(Supplier<JDA> jdaSupplier, Context ctx) {
+        Guild guild = jda(jdaSupplier).getGuildById(ctx.pathParam("guildId"));
+        if (guild == null) {
+            throw new NotFoundResponse("Unknown guild");
+        }
+        return guild;
+    }
+}

src/main/java/me/bobert/netneutrality/http/server/RootHandler.java

@@ -1,22 +0,0 @@
-package me.bobert.netneutrality.http.server;
-
-/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
-
-import com.sun.net.httpserver.HttpExchange;
-
-import java.io.IOException;
-
-public class RootHandler extends AbstractHandler {
-
-    @Override
-    public void handle(HttpExchange exchange) throws IOException {
-
-        String response = "<h1>Server start success if you see this message</h1>";
-
-        sendStringResponse(exchange, response);
-    }
-}

src/main/java/me/bobert/netneutrality/http/server/WebApi.java

@@ -6,20 +6,16 @@ package me.bobert.netneutrality.http.server;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sun.net.httpserver.HttpServer;
+import io.javalin.Javalin;
+import io.javalin.http.HttpResponseException;
 import me.bobert.netneutrality.bootstrap.Lifecycle;
-import me.bobert.netneutrality.core.thread.BaseThreadFactory;
 import me.bobert.netneutrality.db.service.GuildServiceProvider;
 import me.bobert.netneutrality.utils.SettingsProvider;
 import net.dv8tion.jda.api.JDA;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-import java.io.IOException;
-import java.net.InetSocketAddress;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.function.IntSupplier;
+import java.util.Map;
 import java.util.function.Supplier;
 
 /**
@@ -28,13 +24,13 @@ import java.util.function.Supplier;
 public class WebApi implements Lifecycle {
 
     private static final Logger logger = LogManager.getLogger(WebApi.class);
+    private static final String LIVENESS_HTML = "<h1>Server start success if you see this message</h1>";
 
     private final SettingsProvider settings;
     private final GuildServiceProvider guildServices;
     private final Supplier<JDA> jdaSupplier;
     private final Runnable shutdownHook;
-    private HttpServer server;
-    private ExecutorService executor;
+    private Javalin app;
 
     public WebApi(
         SettingsProvider settings,
@@ -59,33 +55,36 @@ public class WebApi implements Lifecycle {
         int port = Integer.parseInt(settings.get("NETNEUTRALITY_API_PORT", "9000"));
         logger.info("Starting web server...");
 
-        try {
-            InetSocketAddress sockAddr = new InetSocketAddress(port);
-            server = HttpServer.create(sockAddr, 0);
-        } catch (IOException e) {
-            logger.error("Failed to create HTTP server", e);
-            return;
-        }
+        app = Javalin.create(config -> {
+            config.jsonMapper(new GsonJsonMapper());
+            config.showJavalinBanner = false;
+        });
 
-        server.createContext("/", new RootHandler());
-        server.createContext("/actions", new ActionHandler(jdaSupplier, guildServices, shutdownHook));
-        server.createContext("/guilds", new GuildHandler(jdaSupplier));
-        executor = Executors.newFixedThreadPool(10, new BaseThreadFactory("web-api"));
-        server.setExecutor(executor);
-        server.start();
-        logger.info("Web server started at [{}]", server.getAddress());
+        app.get("/", ctx -> ctx.html(LIVENESS_HTML));
+        GuildRoutes.register(app, jdaSupplier);
+        ActionRoutes.register(app, jdaSupplier, guildServices, shutdownHook);
+
+        app.exception(HttpResponseException.class, (e, ctx) ->
+            ctx.status(e.getStatus()).json(Map.of("status", "error", "message", e.getMessage()))
+        );
+
+        app.exception(Exception.class, (e, ctx) -> {
+            logger.error("Unhandled error while serving [{}]", ctx.path(), e);
+            ctx.status(500).json(Map.of("status", "error"));
+        });
+
+        app.error(404, ctx -> ctx.json(Map.of("status", "error", "message", "Not found")));
+
+        app.start(port);
+        logger.info("Web server started on port [{}]", port);
     }
 
     @Override
     public void stop() {
-        if (server != null) {
+        if (app != null) {
             logger.info("Stopping web server...");
-            server.stop(0);
-            server = null;
-        }
-        if (executor != null) {
-            executor.shutdownNow();
-            executor = null;
+            app.stop();
+            app = null;
         }
     }
 }

src/main/java/me/bobert/netneutrality/music/AudioPlayerSendHandler.java

@@ -1,45 +0,0 @@
-package me.bobert.netneutrality.music;
-/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
-
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
-import com.sedmelluq.discord.lavaplayer.track.playback.AudioFrame;
-import net.dv8tion.jda.api.audio.AudioSendHandler;
-
-import java.nio.ByteBuffer;
-
-/**
- * This is a wrapper around AudioPlayer which makes it behave as an AudioSendHandler for JDA. As JDA calls canProvide
- * before every call to provide20MsAudio(), we pull the frame in canProvide() and use the frame we already pulled in
- * provide20MsAudio().
- */
-public class AudioPlayerSendHandler implements AudioSendHandler {
-    private final AudioPlayer audioPlayer;
-    private AudioFrame lastFrame;
-
-    /**
-     * @param audioPlayer Audio player to wrap.
-     */
-    public AudioPlayerSendHandler(AudioPlayer audioPlayer) {
-        this.audioPlayer = audioPlayer;
-    }
-
-    @Override
-    public boolean canProvide() {
-        lastFrame = audioPlayer.provide();
-        return lastFrame != null;
-    }
-
-    @Override
-    public ByteBuffer provide20MsAudio() {
-        return ByteBuffer.wrap(lastFrame.getData());
-    }
-
-    @Override
-    public boolean isOpus() {
-        return true;
-    }
-}

src/main/java/me/bobert/netneutrality/music/MusicManager.java

@@ -6,51 +6,57 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import me.bobert.netneutrality.utils.MusicUtils;
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayerManager;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.LavalinkClient;
+import dev.arbjerg.lavalink.client.Link;
+import dev.arbjerg.lavalink.client.player.LavalinkPlayer;
+import dev.arbjerg.lavalink.client.player.PlayerUpdateBuilder;
+import dev.arbjerg.lavalink.client.player.Track;
+import me.bobert.netneutrality.core.LogHandler;
 import me.bobert.netneutrality.core.command.CommandExecutionResult;
 import me.bobert.netneutrality.core.context.CommandContext;
+import me.bobert.netneutrality.core.tasks.TaskManager;
 import me.bobert.netneutrality.db.GSettings;
 import me.bobert.netneutrality.db.service.GuildService;
-import me.bobert.netneutrality.core.tasks.TaskManager;
+import me.bobert.netneutrality.utils.MusicUtils;
 import net.dv8tion.jda.api.entities.Guild;
+import net.dv8tion.jda.api.entities.GuildVoiceState;
 import net.dv8tion.jda.api.entities.channel.middleman.AudioChannel;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+import java.util.function.Consumer;
+
 /**
  * Per-guild music player and queue owner.
  *
- * <p>The shared {@link AudioPlayerManager} and the manager cache live on {@link MusicServiceImpl}.
+ * <p>Playback is delegated to the Lavalink node through the {@link Link} of this guild; the
+ * shared {@link LavalinkClient} and the manager cache live on {@link MusicServiceImpl}.
  * Obtain instances via {@link MusicService#get(Guild)}.
+ *
+ * <p>All Lavalink operations return reactive {@code Mono}s. This class subscribes to them
+ * internally so that the command layer keeps its synchronous call style; failures are reported
+ * through {@link LogHandler}.
  */
 public class MusicManager implements MusicManagerCallback {
 
     private static final Logger logger = LogManager.getLogger(MusicManager.class);
     static final int DEFAULT_VOLUME = 50;
     private final Guild guild;
-    private final AudioPlayerManager playerManager;
-    private final AudioPlayer player;
+    private final LavalinkClient client;
     private final TrackScheduler scheduler;
     private final int baseVolume;
     private final GuildService guildService;
     private final TaskManager taskManager;
     private final VoteSkipService voteSkipService;
 
-    MusicManager(Guild guild, AudioPlayerManager playerManager, GuildService guildService, TaskManager taskManager) {
+    MusicManager(Guild guild, LavalinkClient client, GuildService guildService, TaskManager taskManager) {
         this.guild = guild;
-        this.playerManager = playerManager;
-        this.player = playerManager.createPlayer();
+        this.client = client;
         this.scheduler = new TrackScheduler(this);
         this.guildService = guildService;
         this.taskManager = taskManager;
         this.voteSkipService = new VoteSkipService();
         this.baseVolume = parseBaseVolume(guildService);
-
-        guild.getAudioManager().setSendingHandler(new AudioPlayerSendHandler(player));
-        player.addListener(scheduler);
     }
 
     public GuildService getGuildService() {
@@ -69,50 +75,101 @@ public class MusicManager implements MusicManagerCallback {
         return scheduler.getQueueManager();
     }
 
-    public AudioPlayer getPlayer() {
-        return player;
-    }
-
     public Guild getGuild() {
         return guild;
     }
 
+    /**
+     * Returns the {@link Link} binding this guild to a Lavalink node, or {@code null} when no
+     * node is currently available.
+     *
+     * @return the link or {@code null}
+     */
+    public Link getLink() {
+        try {
+            return client.getOrCreateLink(guild.getIdLong());
+        } catch (RuntimeException e) {
+            logger.error("Guild {}: no Lavalink node available", guild.getId(), e);
+            return null;
+        }
+    }
+
+    /**
+     * Returns the voice channel the bot is currently connected to in this guild.
+     *
+     * <p>With Lavalink the voice connection is owned by the node, so JDA's audio manager cannot
+     * be consulted; the gateway voice state of the self member is the source of truth.
+     *
+     * @return the connected channel or {@code null}
+     */
+    public AudioChannel getConnectedChannel() {
+        GuildVoiceState state = guild.getSelfMember().getVoiceState();
+        return state == null ? null : state.getChannel();
+    }
+
     public synchronized boolean isNotConnectedTo(AudioChannel vChannel) {
-        AudioChannel current = guild.getAudioManager().getConnectedChannel();
+        AudioChannel current = getConnectedChannel();
         return vChannel == null || current == null || !vChannel.getId().equals(current.getId());
     }
 
     public synchronized void connect(AudioChannel audioChannel) {
-        if (audioChannel != null) {
-            logger.debug("Guild {}: connecting to voice channel {}", audioChannel.getGuild().getId(), audioChannel.getId());
-            guild.getAudioManager().openAudioConnection(audioChannel);
-            guild.getAudioManager().setSelfDeafened(true);
-            player.setVolume(baseVolume);
-        } else {
+        if (audioChannel == null) {
             throw new IllegalArgumentException("audioChannel must not be null");
         }
+
+        logger.debug("Guild {}: connecting to voice channel {}", audioChannel.getGuild().getId(), audioChannel.getId());
+        // Only the self-deaf flag is read from the audio manager; the connection itself is opened
+        // through the direct audio controller so that Lavalink handles the voice websocket.
+        guild.getAudioManager().setSelfDeafened(true);
+        guild.getJDA().getDirectAudioController().connect(audioChannel);
+
+        setVolume(baseVolume);
     }
 
     public synchronized void disconnect() {
-        if (guild.getAudioManager().getConnectedChannel() != null) {
-            logger.debug("Guild {}: disconnecting from voice channel {}", guild.getId(), guild.getAudioManager().getConnectedChannel().getId());
-            player.stopTrack();
-            guild.getAudioManager().closeAudioConnection();
+        if (getConnectedChannel() != null) {
+            logger.debug("Guild {}: disconnecting from voice channel {}", guild.getId(), getConnectedChannel().getId());
+            stopTrack();
+            guild.getJDA().getDirectAudioController().disconnect(guild);
         }
 
         scheduler.detachContext();
     }
 
-    public synchronized boolean isConnected() {
-        return guild.getAudioManager().getConnectedChannel() != null;
+    /**
+     * Destroys the Lavalink player of this guild, used on shutdown.
+     */
+    synchronized void destroy() {
+        Link link = getLink();
+        if (link != null) {
+            link.destroy().subscribe(
+                ignored -> { },
+                error -> logger.error("Guild {}: failed to destroy player", guild.getId(), error)
+            );
+        }
     }
 
-    public synchronized AudioTrack getCurrentlyPlaying() {
-        return player.getPlayingTrack();
+    public synchronized boolean isConnected() {
+        return getConnectedChannel() != null;
+    }
+
+    public synchronized Track getCurrentlyPlaying() {
+        return scheduler.getCurrentTrack();
+    }
+
+    /**
+     * Returns the playback position of the currently playing track, in milliseconds.
+     *
+     * @return the position, or {@code 0} when nothing is playing
+     */
+    public long getCurrentPosition() {
+        Link link = getLink();
+        LavalinkPlayer player = link == null ? null : link.getCachedPlayer();
+        return player == null ? 0L : player.getPosition();
     }
 
     public synchronized boolean isCurrentlyPlaying() {
-        return player.getPlayingTrack() != null;
+        return scheduler.getCurrentTrack() != null;
     }
 
     public synchronized void play(String query, CommandContext context) {
@@ -122,21 +179,41 @@ public class MusicManager implements MusicManagerCallback {
     public synchronized void play(String query, CommandContext context, boolean silent) {
         logger.debug("Guild {}: request to play '{}' by user {}", guild.getId(), query, context.getGuildUser().getId());
 
-        if (MusicUtils.canConnect(context, this)) {
-            SourceFinder.AudioSourceType type = SourceFinder.getSource(query);
-            String identifier = SourceFinder.getIdentifier(query);
-            if (identifier == null) {
-                context.reply("No source found to play the given url");
-                return;
-            }
-
-            TrackLoadingHandler loadingHandler = new TrackLoadingHandler(context, this, identifier, type, silent);
-            playerManager.loadItemOrdered(this, identifier, loadingHandler);
+        if (!MusicUtils.canConnect(context, this)) {
+            return;
         }
+
+        SourceFinder.AudioSourceType type = SourceFinder.getSource(query);
+        if (type == SourceFinder.AudioSourceType.Udio) {
+            context.reply("Udio playback is temporarily unsupported since the migration to Lavalink");
+            return;
+        }
+
+        String identifier = SourceFinder.getIdentifier(query);
+        if (identifier == null) {
+            context.reply("No source found to play the given url");
+            return;
+        }
+
+        Link link = getLink();
+        if (link == null) {
+            context.reply("The audio node is currently unavailable, please try again later");
+            return;
+        }
+
+        link.loadItem(identifier).subscribe(
+            new TrackLoadingHandler(context, this, identifier, type, silent),
+            error -> {
+                LogHandler.log(new RuntimeException("Failed to load track: " + error.getMessage(), error));
+                if (!silent) {
+                    context.reply("Failed to load the requested track");
+                }
+            }
+        );
     }
 
     public synchronized void stopTrack() {
-        player.stopTrack();
+        updatePlayer("stop track", builder -> builder.stopTrack());
     }
 
     public synchronized CommandExecutionResult resume() {
@@ -144,12 +221,11 @@ public class MusicManager implements MusicManagerCallback {
     }
 
     public synchronized CommandExecutionResult voteSkip(CommandContext context) {
-        AudioChannel audioChannel = guild.getAudioManager().getConnectedChannel();
-        return voteSkipService.voteSkip(context, getQueueManager(), audioChannel, isCurrentlyPlaying());
+        return voteSkipService.voteSkip(context, getQueueManager(), getConnectedChannel(), isCurrentlyPlaying());
     }
 
     public void setVolume(int volume) {
-        player.setVolume(volume);
+        updatePlayer("set volume", builder -> builder.setVolume(volume));
     }
 
     public int getQueueSize() {
@@ -161,6 +237,26 @@ public class MusicManager implements MusicManagerCallback {
         disconnect();
     }
 
+    /**
+     * Applies a player update on the node and subscribes to it, logging any failure.
+     *
+     * @param description what the update does, used for logging
+     * @param mutation    the builder mutation to apply
+     */
+    void updatePlayer(String description, Consumer<PlayerUpdateBuilder> mutation) {
+        Link link = getLink();
+        if (link == null) {
+            return;
+        }
+
+        PlayerUpdateBuilder builder = link.createOrUpdatePlayer();
+        mutation.accept(builder);
+        builder.subscribe(
+            ignored -> { },
+            error -> logger.error("Guild {}: failed to {}", guild.getId(), description, error)
+        );
+    }
+
     private static int parseBaseVolume(GuildService guildService) {
         try {
             return Integer.parseInt(guildService.getGuildSettingService().getSetting(GSettings.MUSIC_VOLUME));

src/main/java/me/bobert/netneutrality/music/MusicService.java

@@ -6,15 +6,16 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
+import dev.arbjerg.lavalink.client.LavalinkClient;
 import java.util.Collection;
 import me.bobert.netneutrality.bootstrap.Lifecycle;
 import net.dv8tion.jda.api.entities.Guild;
 
 /**
- * Owns the shared audio player manager and the per-guild {@link MusicManager} cache.
+ * Owns the shared {@link LavalinkClient} and the per-guild {@link MusicManager} cache.
  *
- * <p>As a {@link Lifecycle} component it registers audio sources on {@link #start()} and
- * disconnects every player on {@link #stop()}.
+ * <p>As a {@link Lifecycle} component it registers the Lavalink node on {@link #start()} and
+ * destroys every player on {@link #stop()}.
  */
 public interface MusicService extends Lifecycle {
 
@@ -32,4 +33,11 @@ public interface MusicService extends Lifecycle {
      * @return the managers
      */
     Collection<MusicManager> getManagers();
+
+    /**
+     * Returns the shared Lavalink client used for voice dispatch interception and player control.
+     *
+     * @return the client
+     */
+    LavalinkClient getClient();
 }

src/main/java/me/bobert/netneutrality/music/MusicServiceImpl.java

@@ -6,41 +6,66 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayerManager;
-import com.sedmelluq.discord.lavaplayer.player.DefaultAudioPlayerManager;
-import com.sedmelluq.discord.lavaplayer.source.http.HttpAudioSourceManager;
-import com.sedmelluq.discord.lavaplayer.source.soundcloud.SoundCloudAudioSourceManager;
-import dev.lavalink.youtube.YoutubeAudioSourceManager;
-import dev.lavalink.youtube.YoutubeSourceOptions;
-import me.bobert.netneutrality.db.service.GuildServiceProvider;
+import dev.arbjerg.lavalink.client.Helpers;
+import dev.arbjerg.lavalink.client.LavalinkClient;
+import dev.arbjerg.lavalink.client.LavalinkNode;
+import dev.arbjerg.lavalink.client.NodeOptions;
+import dev.arbjerg.lavalink.client.event.ReadyEvent;
+import dev.arbjerg.lavalink.client.event.TrackEndEvent;
+import dev.arbjerg.lavalink.client.event.TrackExceptionEvent;
+import dev.arbjerg.lavalink.client.event.TrackStartEvent;
+import dev.arbjerg.lavalink.client.event.TrackStuckEvent;
+import dev.arbjerg.lavalink.client.event.WebSocketClosedEvent;
+import dev.arbjerg.lavalink.internal.LavalinkSocket;
 import me.bobert.netneutrality.core.tasks.TaskManager;
-import me.bobert.netneutrality.music.source.UdioAudioSourceManager;
+import me.bobert.netneutrality.core.thread.ExecutorProvider;
+import me.bobert.netneutrality.db.service.GuildServiceProvider;
 import me.bobert.netneutrality.utils.SettingsProvider;
 import net.dv8tion.jda.api.entities.Guild;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import reactor.core.Disposable;
 
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
 
 /**
- * Instance-based {@link MusicService} owning the shared {@link AudioPlayerManager} and the
+ * Instance-based {@link MusicService} owning the shared {@link LavalinkClient} and the
  * per-guild {@link MusicManager} cache.
+ *
+ * <p>Audio decoding and voice sending happen on the remote Lavalink node; this class only
+ * registers the node and dispatches the node's event flux to the owning guild's
+ * {@link TrackScheduler}.
  */
 public class MusicServiceImpl implements MusicService {
     private static final Logger logger = LogManager.getLogger(MusicServiceImpl.class);
 
+    private static final String DEFAULT_URI = "ws://lavalink:2333";
+    private static final String DEFAULT_NAME = "main";
+    private static final long RECONNECT_WATCHDOG_SECONDS = 5;
+
     private final SettingsProvider settings;
     private final GuildServiceProvider guildServices;
     private final TaskManager taskManager;
+    private final ExecutorProvider executors;
     private final Map<String, MusicManager> managers = new ConcurrentHashMap<>();
-    private final AudioPlayerManager playerManager = new DefaultAudioPlayerManager();
+    private final List<Disposable> subscriptions = new ArrayList<>();
+    private final LavalinkClient client;
+    private ScheduledFuture<?> reconnectWatchdog;
 
-    public MusicServiceImpl(SettingsProvider settings, GuildServiceProvider guildServices, TaskManager taskManager) {
+    public MusicServiceImpl(SettingsProvider settings, GuildServiceProvider guildServices, TaskManager taskManager,
+                            ExecutorProvider executors) {
         this.settings = settings;
         this.guildServices = guildServices;
         this.taskManager = taskManager;
+        this.executors = executors;
+        this.client = new LavalinkClient(Helpers.getUserIdFromToken(settings.get("NETNEUTRALITY_BOT_TOKEN")));
     }
 
     @Override
@@ -50,41 +75,38 @@ public class MusicServiceImpl implements MusicService {
 
     @Override
     public void start() {
-        logger.debug("Initializing music player sources..");
-
-        String cipherUrl = settings.get("NETNEUTRALITY_CIPHER_URL");
-        String cipherPassword = settings.get("NETNEUTRALITY_CIPHER_PASSWORD");
-        YoutubeSourceOptions options = new YoutubeSourceOptions()
-            .setAllowSearch(true)
-            .setAllowDirectVideoIds(true)
-            .setAllowDirectPlaylistIds(true)
-            .setRemoteCipher(cipherUrl, cipherPassword, "");
-        playerManager.registerSourceManager(new YoutubeAudioSourceManager(options, YoutubeAudioSourceManager.DEFAULT_CLIENTS));
-        playerManager.registerSourceManager(SoundCloudAudioSourceManager.createDefault());
-        playerManager.registerSourceManager(new UdioAudioSourceManager());
-        playerManager.registerSourceManager(new HttpAudioSourceManager());
-
-        String po = settings.get("NETNEUTRALITY_PO_TOKEN");
-        String visitor = settings.get("NETNEUTRALITY_VISITOR_DATA");
-        dev.lavalink.youtube.clients.Web.setPoTokenAndVisitorData(po, visitor);
+        subscribeToEvents();
+        registerNode();
+        startReconnectWatchdog();
     }
 
     @Override
     public void stop() {
-        for (MusicManager mm : managers.values()) {
-            mm.getQueueManager().clearQueue();
-            mm.getPlayer().destroy();
+        if (reconnectWatchdog != null) {
+            reconnectWatchdog.cancel(false);
+            reconnectWatchdog = null;
         }
+
+        for (Disposable subscription : subscriptions) {
+            subscription.dispose();
+        }
+        subscriptions.clear();
+
+        for (MusicManager manager : managers.values()) {
+            manager.getQueueManager().clearQueue();
+            manager.destroy();
+        }
+        managers.clear();
+
+        client.close();
     }
 
     @Override
     public MusicManager get(Guild guild) {
-        if (managers.containsKey(guild.getId())) {
-            return managers.get(guild.getId());
-        }
-        MusicManager manager = new MusicManager(guild, playerManager, guildServices.get(guild), taskManager);
-        managers.put(guild.getId(), manager);
-        return manager;
+        return managers.computeIfAbsent(
+            guild.getId(),
+            id -> new MusicManager(guild, client, guildServices.get(guild), taskManager)
+        );
     }
 
     @Override
@@ -93,11 +115,106 @@ public class MusicServiceImpl implements MusicService {
     }
 
     /**
-     * Returns the shared Lavaplayer {@link AudioPlayerManager}.
+     * Returns the shared Lavalink client.
      *
-     * @return the player manager
+     * @return the client
      */
-    public AudioPlayerManager getPlayerManager() {
-        return playerManager;
+    @Override
+    public LavalinkClient getClient() {
+        return client;
+    }
+
+    /**
+     * Registers the configured node. A node that is unreachable at startup is retried by the
+     * client itself, so this never prevents the bot from booting.
+     */
+    private void registerNode() {
+        String uri = settings.get("NETNEUTRALITY_LAVALINK_URI", DEFAULT_URI);
+        String password = settings.get("NETNEUTRALITY_LAVALINK_PASSWORD");
+        String name = settings.get("NETNEUTRALITY_LAVALINK_NAME", DEFAULT_NAME);
+
+        if (password == null) {
+            logger.error("No Lavalink password configured (NETNEUTRALITY_LAVALINK_PASSWORD), music will be unavailable");
+            return;
+        }
+
+        try {
+            client.addNode(new NodeOptions.Builder()
+                .setName(name)
+                .setServerUri(uri)
+                .setPassword(password)
+                .build());
+            logger.info("Registered Lavalink node '{}' at {}", name, uri);
+        } catch (RuntimeException e) {
+            logger.error("Failed to register Lavalink node '{}' at {}, music will be unavailable", name, uri, e);
+        }
+    }
+
+    /**
+     * Re-arms the client's own reconnect loop for nodes whose socket was closed.
+     *
+     * <p>The Lavalink client disables reconnection permanently when the node closes the socket
+     * with a normal close code (1000/1001), which is exactly what a graceful node restart does.
+     * Without this watchdog the bot would stay disconnected until it is restarted itself.
+     */
+    private void startReconnectWatchdog() {
+        reconnectWatchdog = executors.getScheduledExecutor().scheduleWithFixedDelay(
+            this::rearmReconnects,
+            RECONNECT_WATCHDOG_SECONDS,
+            RECONNECT_WATCHDOG_SECONDS,
+            TimeUnit.SECONDS
+        );
+    }
+
+    private void rearmReconnects() {
+        try {
+            for (LavalinkNode node : client.getNodes()) {
+                LavalinkSocket socket = node.getWs();
+                if (!socket.getOpen() && !socket.getMayReconnect()) {
+                    logger.warn("Lavalink node '{}' closed the connection normally, re-arming reconnects", node.getName());
+                    socket.setMayReconnect(true);
+                }
+            }
+        } catch (RuntimeException e) {
+            logger.error("Failed to re-arm Lavalink reconnects", e);
+        }
+    }
+
+    /**
+     * Opens the single subscription to the client event flux and routes every guild-scoped event
+     * to the owning guild's {@link TrackScheduler}.
+     */
+    private void subscribeToEvents() {
+        subscriptions.add(client.on(ReadyEvent.class)
+            .subscribe(event -> logger.info("Lavalink node '{}' is ready (session {})", event.getNode().getName(), event.getSessionId())));
+
+        subscriptions.add(client.on(TrackStartEvent.class)
+            .subscribe(event -> dispatch(event.getGuildId(), scheduler -> scheduler.onTrackStart(event.getTrack()))));
+
+        subscriptions.add(client.on(TrackEndEvent.class)
+            .subscribe(event -> dispatch(event.getGuildId(), scheduler -> scheduler.onTrackEnd(event.getTrack(), event.getEndReason()))));
+
+        subscriptions.add(client.on(TrackExceptionEvent.class)
+            .subscribe(event -> dispatch(event.getGuildId(), scheduler -> scheduler.onTrackException(event.getTrack(), event.getException()))));
+
+        subscriptions.add(client.on(TrackStuckEvent.class)
+            .subscribe(event -> dispatch(event.getGuildId(), scheduler -> scheduler.onTrackStuck(event.getTrack(), event.getThresholdMs()))));
+
+        subscriptions.add(client.on(WebSocketClosedEvent.class)
+            .subscribe(event -> dispatch(event.getGuildId(), scheduler -> scheduler.onWebSocketClosed(event.getCode(), event.getReason(), event.getByRemote()))));
+    }
+
+    private void dispatch(long guildId, Consumer<TrackScheduler> action) {
+        MusicManager manager = managers.get(String.valueOf(guildId));
+        if (manager == null) {
+            logger.debug("Received a Lavalink event for unknown guild {}", guildId);
+            return;
+        }
+
+        try {
+            action.accept(manager.getScheduler());
+        } catch (RuntimeException e) {
+            logger.error("Guild {}: failed to handle Lavalink event", guildId, e);
+        }
     }
 }

src/main/java/me/bobert/netneutrality/music/QueueManager.java

@@ -5,8 +5,7 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.player.Track;
 import me.bobert.netneutrality.core.command.CommandExecutionResult;
 import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
@@ -23,13 +22,11 @@ import java.util.function.Predicate;
 public class QueueManager {
     private final Logger logger = LogManager.getLogger(QueueManager.class);
     private final TrackScheduler scheduler;
-    private final AudioPlayer player;
     private final Guild guild;
     private final Deque<TrackInfo> queue;
 
     public QueueManager(TrackScheduler scheduler) {
         this.scheduler = scheduler;
-        this.player = scheduler.getPlayer();
         this.guild = scheduler.getGuild();
 
         this.queue = new LinkedBlockingDeque<>();
@@ -110,20 +107,20 @@ public class QueueManager {
         }
     }
 
-    public List<AudioTrack> getAllQueuedTracks() {
+    public List<Track> getAllQueuedTracks() {
         synchronized (queue) {
-            ArrayList<AudioTrack> tracks = new ArrayList<>();
+            ArrayList<Track> tracks = new ArrayList<>();
 
             queue.forEach(trackInfo -> tracks.add(trackInfo.getTrack()));
             return tracks;
         }
     }
 
-    public void queue(List<AudioTrack> tracks, Member member) {
+    public void queue(List<Track> tracks, Member member) {
         tracks.forEach(track -> queue(track, member));
     }
 
-    public void queue(AudioTrack track, Member member) {
+    public void queue(Track track, Member member) {
         TrackInfo info = new TrackInfo(track, member);
 
         synchronized (queue) {
@@ -131,42 +128,67 @@ public class QueueManager {
                 return;
             }
 
-            if (player.getPlayingTrack() == null && !queue.isEmpty()) {
+            boolean idle = scheduler.getCurrentTrack() == null;
+
+            if (idle && !queue.isEmpty()) {
                 queue.addFirst(info);
             } else {
                 queue.add(info);
             }
 
-            if (player.getPlayingTrack() == null) {
-                AudioTrack toPlay = queue.peek() == null ? null : queue.peek().getTrack();
-                player.startTrack(toPlay, true);
+            if (idle) {
+                TrackInfo head = queue.peek();
+                if (head != null) {
+                    startTrack(head.getTrack(), true);
+                }
             }
         }
     }
 
+    /**
+     * Sends a play request to the node. The cached current track is updated eagerly so that a
+     * burst of enqueues does not start several tracks at once while waiting for the node's
+     * {@code TrackStartEvent}.
+     *
+     * @param track     the track to play
+     * @param noReplace whether an already playing track must not be interrupted
+     */
+    private void startTrack(Track track, boolean noReplace) {
+        scheduler.setCurrentTrack(track);
+        scheduler.getMusicManager().updatePlayer(
+            "start track " + track.getInfo().getIdentifier(),
+            builder -> builder.setTrack(track).setNoReplace(noReplace)
+        );
+    }
+
+    private void stopTrack() {
+        scheduler.setCurrentTrack(null);
+        scheduler.getMusicManager().stopTrack();
+    }
+
     public CommandExecutionResult resume() {
         synchronized (queue) {
             TrackInfo next = queue.peek();
 
             if (next != null) {
-                player.startTrack(next.getTrack().makeClone(), false);
-                return CommandExecutionResult.success("Starting playback of track " + next.getTrack().getInfo().title);
+                startTrack(next.getTrack().makeClone(), false);
+                return CommandExecutionResult.success("Starting playback of track " + next.getTrack().getInfo().getTitle());
             }
 
-            player.stopTrack();
+            stopTrack();
             return CommandExecutionResult.info("Queue is empty, leaving voice channel");
         }
     }
 
     public void startNextTrack() {
         synchronized (queue) {
-            TrackInfo last = queue.poll();
+            queue.poll();
             TrackInfo next = queue.peek();
 
             if (next != null) {
-                player.startTrack(next.getTrack().makeClone(), false);
+                startTrack(next.getTrack().makeClone(), false);
             } else {
-                player.stopTrack();
+                stopTrack();
             }
         }
     }

src/main/java/me/bobert/netneutrality/music/SourceFinder.java

@@ -68,8 +68,10 @@ public class SourceFinder {
         String identifier;
 
         identifier = switch (getSource(url)) {
-            case Youtube, YTMusic, Soundcloud, Udio, DirectLinkMp3 -> url;
+            case Youtube, YTMusic, Soundcloud, DirectLinkMp3 -> url;
             case YTSearch -> "ytsearch:" + url;
+            // Udio is not resolvable by the Lavalink node until the source is ported to a
+            // server-side plugin, see docs/reference/udio-lavalink-plugin.
             default -> null;
         };
 

src/main/java/me/bobert/netneutrality/music/StuckTrackRecoveryHandler.java

@@ -5,8 +5,7 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.player.Track;
 import me.bobert.netneutrality.core.LogHandler;
 import me.bobert.netneutrality.core.context.Context;
 import org.apache.logging.log4j.LogManager;
@@ -14,19 +13,19 @@ import org.apache.logging.log4j.Logger;
 
 /**
  * Encapsulates the retry-or-skip logic for stuck tracks, extracted from
- * {@link TrackScheduler#onTrackStuck(AudioPlayer, AudioTrack, long)}.
+ * {@link TrackScheduler#onTrackStuck(Track, long)}.
  */
 class StuckTrackRecoveryHandler {
 
     private static final Logger logger = LogManager.getLogger(StuckTrackRecoveryHandler.class);
 
-    private final AudioPlayer player;
+    private final MusicManager manager;
     private final QueueManager queueManager;
 
-    private AudioTrack lastStuckTrack;
+    private Track lastStuckTrack;
 
-    StuckTrackRecoveryHandler(AudioPlayer player, QueueManager queueManager) {
-        this.player = player;
+    StuckTrackRecoveryHandler(MusicManager manager, QueueManager queueManager) {
+        this.manager = manager;
         this.queueManager = queueManager;
     }
 
@@ -40,11 +39,11 @@ class StuckTrackRecoveryHandler {
 
     /**
      * Handles a stuck-track event.  On the first occurrence for a given track
-     * identifier the handler attempts to clone and re-queue the track; on the
+     * identifier the handler attempts to re-queue the track; on the
      * second consecutive occurrence it skips to the next track.
      */
-    void handle(AudioTrack track, Context context) {
-        if (lastStuckTrack == null || !lastStuckTrack.getIdentifier().equals(track.getIdentifier())) {
+    void handle(Track track, Context context) {
+        if (lastStuckTrack == null || !identifierOf(lastStuckTrack).equals(identifierOf(track))) {
             lastStuckTrack = track;
             attemptRecovery(track, context);
         } else {
@@ -53,28 +52,26 @@ class StuckTrackRecoveryHandler {
         }
     }
 
-    private void attemptRecovery(AudioTrack track, Context context) {
-        logger.debug("Trying to load stuck track again: {}", track.getIdentifier());
+    private void attemptRecovery(Track track, Context context) {
+        logger.debug("Trying to load stuck track again: {}", identifierOf(track));
 
         context.async("Current track is stuck, trying to load it again", asyncContext -> {
             try {
                 TrackInfo info = queueManager.peekHeadOfQueue();
-                if (info != null && info.getTrack().getIdentifier().equals(track.getIdentifier())) {
-                    AudioTrack clone = track.makeClone();
-                    long lastPosition = track.getPosition();
+                if (info != null && identifierOf(info.getTrack()).equals(identifierOf(track))) {
+                    long lastPosition = manager.getCurrentPosition();
 
-                    player.stopTrack();
+                    manager.stopTrack();
 
-                    if (queueManager.peekHeadOfQueue() != null
-                        && queueManager.peekHeadOfQueue().getTrack().getIdentifier().equals(track.getIdentifier())) {
+                    TrackInfo head = queueManager.peekHeadOfQueue();
+                    if (head != null && identifierOf(head.getTrack()).equals(identifierOf(track))) {
                         queueManager.removeHeadOfQueue();
                     }
 
-                    queueManager.queue(clone, info.getRequester());
+                    queueManager.queue(track.makeClone(), info.getRequester());
 
-                    AudioTrack playing = player.getPlayingTrack();
-                    if (playing != null && playing.getIdentifier().equals(track.getIdentifier())) {
-                        playing.setPosition(lastPosition);
+                    if (lastPosition > 0) {
+                        manager.updatePlayer("seek to " + lastPosition, builder -> builder.setPosition(lastPosition));
                         lastStuckTrack = null;
                     } else {
                         asyncContext.edit("Failed to seek track to last timestamp, the track will play from the beginning");
@@ -90,4 +87,8 @@ class StuckTrackRecoveryHandler {
             }
         });
     }
+
+    private static String identifierOf(Track track) {
+        return track.getInfo().getIdentifier();
+    }
 }

src/main/java/me/bobert/netneutrality/music/TrackInfo.java

@@ -5,7 +5,7 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.player.Track;
 import net.dv8tion.jda.api.entities.Member;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -16,18 +16,18 @@ import java.util.Objects;
 import java.util.Set;
 
 public class TrackInfo {
-    private final AudioTrack track;
+    private final Track track;
     private final Member member;
     private final Set<String> skips;
     private static final Logger logger = LogManager.getLogger(TrackInfo.class);
 
-    public TrackInfo(AudioTrack track, Member member) {
+    public TrackInfo(Track track, Member member) {
         this.track = track;
         this.member = member;
         this.skips = new HashSet<>();
     }
 
-    public AudioTrack getTrack() {
+    public Track getTrack() {
         return track;
     }
 
@@ -54,6 +54,11 @@ public class TrackInfo {
         return member;
     }
 
+    /**
+     * Two entries are equal when they wrap the same encoded track, which is what makes the queue
+     * reject duplicates. The Lavalink {@link Track} type has no value equality, so the encoded
+     * payload is compared instead.
+     */
     @Override
     public boolean equals(Object o) {
         if (this == o) {
@@ -63,18 +68,18 @@ public class TrackInfo {
             return false;
         }
         TrackInfo trackInfo = (TrackInfo) o;
-        return track.equals(trackInfo.track);
+        return track.getEncoded().equals(trackInfo.track.getEncoded());
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(track);
+        return Objects.hash(track.getEncoded());
     }
 
     @Override
     public String toString() {
         return "TrackInfo{" +
-            "track=" + track.getInfo().title +
+            "track=" + track.getInfo().getTitle() +
             ", member=" + member.getEffectiveName() +
             ", skips=" + skips +
             '}';

src/main/java/me/bobert/netneutrality/music/TrackLoadingHandler.java

@@ -6,20 +6,27 @@ package me.bobert.netneutrality.music;
  */
 
 
-import me.bobert.netneutrality.utils.MusicUtils;
-import com.sedmelluq.discord.lavaplayer.player.AudioLoadResultHandler;
-import com.sedmelluq.discord.lavaplayer.tools.FriendlyException;
-import com.sedmelluq.discord.lavaplayer.track.AudioPlaylist;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.AbstractAudioLoadResultHandler;
+import dev.arbjerg.lavalink.client.player.LoadFailed;
+import dev.arbjerg.lavalink.client.player.PlaylistLoaded;
+import dev.arbjerg.lavalink.client.player.SearchResult;
+import dev.arbjerg.lavalink.client.player.Track;
+import dev.arbjerg.lavalink.client.player.TrackLoaded;
 import me.bobert.netneutrality.core.LogHandler;
 import me.bobert.netneutrality.core.context.CommandContext;
-import me.bobert.netneutrality.tasks.music.LoadPlaylistTask;
 import me.bobert.netneutrality.shared.util.MessageFunction;
+import me.bobert.netneutrality.tasks.music.LoadPlaylistTask;
+import me.bobert.netneutrality.utils.MusicUtils;
 import net.dv8tion.jda.api.entities.Guild;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-public class TrackLoadingHandler implements AudioLoadResultHandler {
+import java.util.List;
+
+/**
+ * Translates a Lavalink load result into queue operations and user feedback.
+ */
+public class TrackLoadingHandler extends AbstractAudioLoadResultHandler {
     private static final Logger logger = LogManager.getLogger(TrackLoadingHandler.class);
 
     private final String identifier;
@@ -42,24 +49,42 @@ public class TrackLoadingHandler implements AudioLoadResultHandler {
     }
 
     @Override
-    public void trackLoaded(AudioTrack audioTrack) {
-        logger.debug("Guild {}: track loaded: {}", guild.getId(), audioTrack.getIdentifier());
+    public void ontrackLoaded(TrackLoaded result) {
+        Track track = result.getTrack();
+        logger.debug("Guild {}: track loaded: {}", guild.getId(), track.getInfo().getIdentifier());
 
         context.deleteMessage();
         if (MusicUtils.connect(context, manager)) {
-            queueManager.queue(audioTrack, context.getGuildUser());
+            queueManager.queue(track, context.getGuildUser());
 
             if (!silent) {
-                context.reply(MessageFunction.buildAddingTrackMessage(audioTrack, context.getGuildUser(), type));
+                context.reply(MessageFunction.buildAddingTrackMessage(track, context.getGuildUser(), type));
             }
         }
     }
 
     @Override
-    public void playlistLoaded(AudioPlaylist playlist) {
+    public void onPlaylistLoaded(PlaylistLoaded result) {
         logger.debug("Guild {}: playlist loaded: {}", guild.getId(), identifier);
 
-        new LoadPlaylistTask(playlist, type, manager).insert(context);
+        new LoadPlaylistTask(result.getInfo().getName(), result.getTracks(), false, type, manager).insert(context);
+    }
+
+    /**
+     * Search results keep the pre-migration behaviour: the user is offered the first few hits
+     * through the same playlist task that lavaplayer's search playlists used to produce.
+     */
+    @Override
+    public void onSearchResultLoaded(SearchResult result) {
+        List<Track> tracks = result.getTracks();
+        logger.debug("Guild {}: search returned {} results for {}", guild.getId(), tracks.size(), identifier);
+
+        if (tracks.isEmpty()) {
+            noMatches();
+            return;
+        }
+
+        new LoadPlaylistTask("Search results", tracks, true, type, manager).insert(context);
     }
 
     @Override
@@ -72,11 +97,11 @@ public class TrackLoadingHandler implements AudioLoadResultHandler {
     }
 
     @Override
-    public void loadFailed(FriendlyException e) {
+    public void loadFailed(LoadFailed result) {
         logger.debug("Guild {}: load failed for identifier {}", guild.getId(), identifier);
 
         //TODO: better error messages
-        RuntimeException exception = new RuntimeException("Failed to load track: " + e.getMessage(), e);
+        RuntimeException exception = new RuntimeException("Failed to load track: " + result.getException().getMessage());
         LogHandler.log(exception);
 
         if (!silent) {

src/main/java/me/bobert/netneutrality/music/TrackScheduler.java

@@ -5,11 +5,9 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
-import com.sedmelluq.discord.lavaplayer.player.event.AudioEventAdapter;
-import com.sedmelluq.discord.lavaplayer.tools.FriendlyException;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrackEndReason;
+import dev.arbjerg.lavalink.client.player.Track;
+import dev.arbjerg.lavalink.client.player.TrackException;
+import dev.arbjerg.lavalink.protocol.v4.Message.EmittedEvent.TrackEndEvent;
 import me.bobert.netneutrality.context.MusicChannelContext;
 import me.bobert.netneutrality.core.LogHandler;
 import me.bobert.netneutrality.core.context.Context;
@@ -19,23 +17,28 @@ import net.dv8tion.jda.api.entities.Member;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-public class TrackScheduler extends AudioEventAdapter {
+/**
+ * Sink for the track lifecycle events emitted by the Lavalink node.
+ *
+ * <p>Events are delivered by the central dispatcher in {@link MusicServiceImpl}, which routes
+ * them to the scheduler of the guild they belong to.
+ */
+public class TrackScheduler {
     private static final Logger logger = LogManager.getLogger(TrackScheduler.class);
     private final QueueManager queueManager;
     private final MusicManager manager;
     private final MusicManagerCallback callback;
-    private final AudioPlayer player;
     private final Guild guild;
     private volatile Context context;
+    private volatile Track currentTrack;
     private final StuckTrackRecoveryHandler stuckTrackRecoveryHandler;
 
     public TrackScheduler(MusicManager manager) {
         this.manager = manager;
         this.callback = manager;
-        this.player = manager.getPlayer();
         this.guild = manager.getGuild();
         this.queueManager = new QueueManager(this);
-        this.stuckTrackRecoveryHandler = new StuckTrackRecoveryHandler(player, queueManager);
+        this.stuckTrackRecoveryHandler = new StuckTrackRecoveryHandler(manager, queueManager);
     }
 
     public QueueManager getQueueManager() {
@@ -50,14 +53,26 @@ public class TrackScheduler extends AudioEventAdapter {
         return callback;
     }
 
-    public AudioPlayer getPlayer() {
-        return player;
-    }
-
     public Guild getGuild() {
         return guild;
     }
 
+    /**
+     * Returns the track the node is currently playing.
+     *
+     * <p>The Lavalink player state is only readable through a REST call, so the last known track
+     * is cached here and kept up to date by the node's events.
+     *
+     * @return the current track or {@code null}
+     */
+    public Track getCurrentTrack() {
+        return currentTrack;
+    }
+
+    void setCurrentTrack(Track track) {
+        this.currentTrack = track;
+    }
+
     public Member getDj() {
         Context ctx = context;
         if (ctx != null) {
@@ -83,36 +98,30 @@ public class TrackScheduler extends AudioEventAdapter {
         return stuckTrackRecoveryHandler;
     }
 
-    @Override
-    public void onPlayerPause(AudioPlayer player) {
-        // Player was paused
-    }
-
-    @Override
-    public void onPlayerResume(AudioPlayer player) {
-        // Player was resumed
-    }
-
-    @Override
-    public void onTrackStart(AudioPlayer player, AudioTrack track) {
-        logger.debug("Guild {}: starting track: {}", guild.getId(), track.getIdentifier());
+    public void onTrackStart(Track track) {
+        logger.debug("Guild {}: starting track: {}", guild.getId(), track.getInfo().getIdentifier());
+        currentTrack = track;
         stuckTrackRecoveryHandler.reset();
     }
 
-    @Override
-    public void onTrackEnd(AudioPlayer player, AudioTrack track, AudioTrackEndReason endReason) {
-        logger.debug("Guild {}: currently playing track ended: {}", guild.getId(), track.getIdentifier());
+    public void onTrackEnd(Track track, TrackEndEvent.AudioTrackEndReason endReason) {
+        logger.debug("Guild {}: currently playing track ended: {}", guild.getId(), track.getInfo().getIdentifier());
 
-        if (endReason == AudioTrackEndReason.LOAD_FAILED) {
-            logger.debug("Guild {}: failed loading track: {}", guild.getId(), track.getIdentifier());
+        if (endReason != TrackEndEvent.AudioTrackEndReason.REPLACED) {
+            currentTrack = null;
+        }
+
+        if (endReason == TrackEndEvent.AudioTrackEndReason.LOAD_FAILED) {
+            logger.debug("Guild {}: failed loading track: {}", guild.getId(), track.getInfo().getIdentifier());
         }
 
         // check if mayStartNext
-        if (endReason == AudioTrackEndReason.FINISHED || endReason == AudioTrackEndReason.LOAD_FAILED) {
+        if (endReason == TrackEndEvent.AudioTrackEndReason.FINISHED
+            || endReason == TrackEndEvent.AudioTrackEndReason.LOAD_FAILED) {
             queueManager.startNextTrack();
         }
 
-        if (endReason == AudioTrackEndReason.STOPPED) {
+        if (endReason == TrackEndEvent.AudioTrackEndReason.STOPPED) {
             // maybe skip removing head to make resuming easier?
             queueManager.removeHeadOfQueue();
         }
@@ -125,16 +134,23 @@ public class TrackScheduler extends AudioEventAdapter {
         //                       clone of this back to your queue
     }
 
-    @Override
-    public void onTrackException(AudioPlayer player, AudioTrack track, FriendlyException exception) {
-        logger.error("Guild {}: exception while playing track: {}", guild.getId(), track.getIdentifier());
+    public void onTrackException(Track track, TrackException exception) {
+        logger.error("Guild {}: exception while playing track: {}", guild.getId(), track.getInfo().getIdentifier());
 
-        LogHandler.log(new ContextException(String.format("Error while playing track: %s", track.getInfo().title), getContext(), exception));
+        LogHandler.log(new ContextException(
+            String.format("Error while playing track: %s", track.getInfo().getTitle()),
+            getContext(),
+            new RuntimeException(exception.getMessage())
+        ));
     }
 
-    @Override
-    public void onTrackStuck(AudioPlayer player, AudioTrack track, long thresholdMs) {
-        logger.error("Guild {}: currently playing track is stuck: {}", guild.getId(), track.getIdentifier());
+    public void onTrackStuck(Track track, long thresholdMs) {
+        logger.error("Guild {}: currently playing track is stuck: {} (threshold {}ms)", guild.getId(), track.getInfo().getIdentifier(), thresholdMs);
         stuckTrackRecoveryHandler.handle(track, context);
     }
+
+    public void onWebSocketClosed(int code, String reason, boolean byRemote) {
+        logger.warn("Guild {}: voice websocket closed with code {} ({}), by remote: {}", guild.getId(), code, reason, byRemote);
+        currentTrack = null;
+    }
 }

src/main/java/me/bobert/netneutrality/scheduled/music/MusicPlayerAutoDisconnect.java

@@ -50,7 +50,7 @@ public class MusicPlayerAutoDisconnect implements ScheduledTask {
     }
 
     private void processManager(MusicManager manager) throws InterruptedException {
-        AudioChannel channel = manager.getGuild().getAudioManager().getConnectedChannel();
+        AudioChannel channel = manager.getConnectedChannel();
 
         if (channel != null) {
             logger.debug("Processing MusicPlayerAutoDisconnectThread for guild {}", manager.getGuild().getId());
@@ -68,7 +68,7 @@ public class MusicPlayerAutoDisconnect implements ScheduledTask {
     }
 
     private boolean conditionsMetToDisconnect(MusicManager manager) {
-        AudioChannel channel = manager.getGuild().getAudioManager().getConnectedChannel();
+        AudioChannel channel = manager.getConnectedChannel();
         if (channel != null) {
             List<Member> members = channel.getMembers().stream().filter(member -> !member.getId().equals(channel.getJDA().getSelfUser().getId())).toList();
 

src/main/java/me/bobert/netneutrality/shared/util/MessageFunction.java

@@ -6,9 +6,8 @@ package me.bobert.netneutrality.shared.util;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.track.AudioPlaylist;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrackInfo;
+import dev.arbjerg.lavalink.client.player.Track;
+import dev.arbjerg.lavalink.protocol.v4.TrackInfo;
 import io.sentry.Sentry;
 import me.bobert.netneutrality.core.command.Command;
 import me.bobert.netneutrality.core.command.CommandCategory;
@@ -20,7 +19,6 @@ import me.bobert.netneutrality.core.context.TaskContext;
 import me.bobert.netneutrality.exceptions.ContextException;
 import me.bobert.netneutrality.music.MusicManager;
 import me.bobert.netneutrality.music.SourceFinder;
-import me.bobert.netneutrality.music.TrackInfo;
 import net.dv8tion.jda.api.EmbedBuilder;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.Message;
@@ -40,32 +38,30 @@ public class MessageFunction {
     private static final Logger logger = LogManager.getLogger(MessageFunction.class);
 
     public static MessageEmbed buildCurrentlyPlayingMessage(MusicManager manager) {
-        AudioTrack current = manager.getCurrentlyPlaying();
+        Track current = manager.getCurrentlyPlaying();
+        TrackInfo currentInfo = current.getInfo();
 
         EmbedBuilder message = new EmbedBuilder();
-        message.setAuthor("Link to track (click me)", String.format("https://youtu.be/%s", current.getIdentifier()));
-        message.setThumbnail(String.format("https://img.youtube.com/vi/%s/default.jpg", current.getIdentifier()));
+        message.setAuthor("Link to track (click me)", String.format("https://youtu.be/%s", currentInfo.getIdentifier()));
+        message.setThumbnail(String.format("https://img.youtube.com/vi/%s/default.jpg", currentInfo.getIdentifier()));
         //message.setTitle("Currently playing:");
         message.setColor(Color.BLUE);
-        message.addField("Currently playing: ", current.getInfo().title, true);
-        message.addField("Duration: ", DurationFormatUtils.formatDuration(current.getPosition(), "HH:mm:ss", true) + " / " + DurationFormatUtils.formatDuration(current.getDuration(), "HH:mm:ss", true), true);
+        message.addField("Currently playing: ", currentInfo.getTitle(), true);
+        message.addField("Duration: ", DurationFormatUtils.formatDuration(manager.getCurrentPosition(), "HH:mm:ss", true) + " / " + DurationFormatUtils.formatDuration(currentInfo.getLength(), "HH:mm:ss", true), true);
         message.setTimestamp(OffsetDateTime.now());
 
         return message.build();
     }
 
-    public static MessageEmbed buildAddingTrackMessage(AudioTrack track, Member member, SourceFinder.AudioSourceType type) {
+    public static MessageEmbed buildAddingTrackMessage(Track track, Member member, SourceFinder.AudioSourceType type) {
         EmbedBuilder message = new EmbedBuilder();
-        String url = track.getIdentifier();
-        String thumbnail = null;
+        TrackInfo info = track.getInfo();
+        String url = info.getIdentifier();
+        String thumbnail = info.getArtworkUrl();
 
         if (type == SourceFinder.AudioSourceType.Youtube || type == SourceFinder.AudioSourceType.YTSearch || type == SourceFinder.AudioSourceType.YTMusic) {
-            url = String.format("https://youtu.be/%s", track.getIdentifier());
-            thumbnail = String.format("https://i3.ytimg.com/vi/%s/hqdefault.jpg", track.getIdentifier());
-        }
-
-        if (type == SourceFinder.AudioSourceType.Udio) {
-            thumbnail = track.getInfo().artworkUrl;
+            url = String.format("https://youtu.be/%s", info.getIdentifier());
+            thumbnail = String.format("https://i3.ytimg.com/vi/%s/hqdefault.jpg", info.getIdentifier());
         }
 
         if (thumbnail != null) {
@@ -73,26 +69,26 @@ public class MessageFunction {
         }
         message.setTitle("Adding track to queue..");
         message.setColor(Color.BLUE);
-        message.addField("Track title: ", String.format("[**`%s`**](%s)", track.getInfo().title, url), false);
-        message.addField("Duration: ", DurationFormatUtils.formatDuration(track.getDuration(), "**HH:mm:ss**", true), false);
+        message.addField("Track title: ", String.format("[**`%s`**](%s)", info.getTitle(), url), false);
+        message.addField("Duration: ", DurationFormatUtils.formatDuration(info.getLength(), "**HH:mm:ss**", true), false);
         message.setFooter(member.getEffectiveName(), member.getEffectiveAvatarUrl());
         message.setTimestamp(OffsetDateTime.now());
 
         return message.build();
     }
 
-    public static MessageEmbed buildAddingPlaylistMessage(List<AudioTrack> tracks, String playlistName, Member member, SourceFinder.AudioSourceType type) {
+    public static MessageEmbed buildAddingPlaylistMessage(List<Track> tracks, String playlistName, Member member, SourceFinder.AudioSourceType type) {
         EmbedBuilder message = new EmbedBuilder();
         String url = "";
         String thumbnail = null;
 
         if (type == SourceFinder.AudioSourceType.Youtube || type == SourceFinder.AudioSourceType.YTSearch) {
-            url = String.format("https://youtu.be/%s", tracks.get(0).getIdentifier());
-            thumbnail = String.format("https://i3.ytimg.com/vi/%s/hqdefault.jpg", tracks.get(0).getIdentifier());
+            url = String.format("https://youtu.be/%s", tracks.get(0).getInfo().getIdentifier());
+            thumbnail = String.format("https://i3.ytimg.com/vi/%s/hqdefault.jpg", tracks.get(0).getInfo().getIdentifier());
         }
 
         if (type == SourceFinder.AudioSourceType.YTMusic) {
-            thumbnail = String.format("https://i3.ytimg.com/vi/%s/hqdefault.jpg", tracks.get(0).getIdentifier());
+            thumbnail = String.format("https://i3.ytimg.com/vi/%s/hqdefault.jpg", tracks.get(0).getInfo().getIdentifier());
         }
 
         if (thumbnail != null) {
@@ -109,13 +105,13 @@ public class MessageFunction {
     }
 
     public static String buildViewQueueMessage(MusicManager manager) {
-        List<AudioTrack> tracks = manager.getQueueManager().getAllQueuedTracks();
+        List<Track> tracks = manager.getQueueManager().getAllQueuedTracks();
         if (tracks.isEmpty()) {
             return "Queue is empty!";
         }
 
         int limit = 10;
-        AudioTrack current = manager.getCurrentlyPlaying();
+        Track current = manager.getCurrentlyPlaying();
         int numberofTracksShown = Math.min(tracks.size(), limit);
 
         StringBuilder message = new StringBuilder();
@@ -127,15 +123,15 @@ public class MessageFunction {
             .append(" items):\n");
 
         int index = 0;
-        for (AudioTrack track : tracks) {
+        for (Track track : tracks) {
             index++;
-            AudioTrackInfo info = track.getInfo();
+            TrackInfo info = track.getInfo();
 
             message.append("\n");
-            if (current != null && current.getInfo().title.equals(info.title)) {
-                message.append("- ").append("**").append(info.title).append("**");
+            if (current != null && current.getInfo().getTitle().equals(info.getTitle())) {
+                message.append("- ").append("**").append(info.getTitle()).append("**");
             } else {
-                message.append("- ").append(info.title);
+                message.append("- ").append(info.getTitle());
             }
 
             if (index == limit) {
@@ -147,8 +143,8 @@ public class MessageFunction {
     }
 
     public static MessageEmbed buildUserTracksMessage(MusicManager manager, Member member) {
-        List<TrackInfo> tracks = manager.getQueueManager().getQueueWithFilter(trackInfo -> member.equals(trackInfo.getRequester()));
-        AudioTrack current = manager.getCurrentlyPlaying();
+        List<me.bobert.netneutrality.music.TrackInfo> tracks = manager.getQueueManager().getQueueWithFilter(trackInfo -> member.equals(trackInfo.getRequester()));
+        Track current = manager.getCurrentlyPlaying();
         int numberofTracksShown = Math.min(tracks.size(), 10);
 
         EmbedBuilder message = new EmbedBuilder();
@@ -156,13 +152,13 @@ public class MessageFunction {
         message.setColor(Color.BLUE);
 
         int index = 0;
-        for (TrackInfo track : tracks) {
-            AudioTrackInfo info = track.getTrack().getInfo();
+        for (me.bobert.netneutrality.music.TrackInfo track : tracks) {
+            TrackInfo info = track.getTrack().getInfo();
 
-            if (current != null && current.getInfo().title.equals(info.title)) {
-                message.addField("Track #" + ++index + " (Currently playing)", info.title, false);
+            if (current != null && current.getInfo().getTitle().equals(info.getTitle())) {
+                message.addField("Track #" + ++index + " (Currently playing)", info.getTitle(), false);
             } else {
-                message.addField("Track #" + ++index, info.title, false);
+                message.addField("Track #" + ++index, info.getTitle(), false);
             }
 
             if (index == 10) {
@@ -174,7 +170,7 @@ public class MessageFunction {
         return message.build();
     }
 
-    public static MessageEmbed buildSearchResultsMessage(List<AudioTrack> tracks, Member member) {
+    public static MessageEmbed buildSearchResultsMessage(List<Track> tracks, Member member) {
         EmbedBuilder embed = new EmbedBuilder();
 
         embed.setTitle("Search results");
@@ -182,8 +178,8 @@ public class MessageFunction {
         embed.setColor(Color.MAGENTA);
 
         int i = 0;
-        for (AudioTrack track : tracks) {
-            embed.addField(++i + ": ", track.getInfo().title, false);
+        for (Track track : tracks) {
+            embed.addField(++i + ": ", track.getInfo().getTitle(), false);
         }
 
         embed.setFooter(member.getEffectiveName(), member.getEffectiveAvatarUrl());
@@ -192,11 +188,11 @@ public class MessageFunction {
         return embed.build();
     }
 
-    public static MessageEmbed buildPlaylistLoadMessage(AudioPlaylist playlist, Member member) {
+    public static MessageEmbed buildPlaylistLoadMessage(String playlistName, int trackCount, Member member) {
         EmbedBuilder embed = new EmbedBuilder();
 
-        embed.setTitle(String.format("Loading playlist: %s", playlist.getName()));
-        embed.setDescription(String.format("You are about to load %d tracks from this playlist, are you sure?", playlist.getTracks().size()));
+        embed.setTitle(String.format("Loading playlist: %s", playlistName));
+        embed.setDescription(String.format("You are about to load %d tracks from this playlist, are you sure?", trackCount));
         embed.setColor(Color.CYAN);
 
         embed.setFooter(member.getEffectiveName(), member.getEffectiveAvatarUrl());

src/main/java/me/bobert/netneutrality/tasks/music/LoadPlaylistTask.java

@@ -5,8 +5,7 @@ package me.bobert.netneutrality.tasks.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.track.AudioPlaylist;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.player.Track;
 import me.bobert.netneutrality.core.context.CommandContext;
 import me.bobert.netneutrality.core.tasks.Task;
 import me.bobert.netneutrality.core.tasks.impl.ButtonTask;
@@ -28,13 +27,18 @@ import java.util.List;
 
 public class LoadPlaylistTask extends ButtonTask implements WithChildren, Deletable {
     private final List<Task> childrens = new ArrayList<>();
-    private final AudioPlaylist playlist;
+    private final String playlistName;
+    private final List<Track> playlistTracks;
+    private final boolean searchResult;
     private final SourceFinder.AudioSourceType sourceType;
     private final MusicManager musicManager;
 
-    public LoadPlaylistTask(AudioPlaylist playlist, SourceFinder.AudioSourceType sourceType, MusicManager musicManager) {
+    public LoadPlaylistTask(String playlistName, List<Track> playlistTracks, boolean searchResult,
+                            SourceFinder.AudioSourceType sourceType, MusicManager musicManager) {
         super(musicManager.getTaskManager(), null, null);
-        this.playlist = playlist;
+        this.playlistName = playlistName;
+        this.playlistTracks = playlistTracks;
+        this.searchResult = searchResult;
         this.sourceType = sourceType;
         this.musicManager = musicManager;
     }
@@ -51,7 +55,7 @@ public class LoadPlaylistTask extends ButtonTask implements WithChildren, Deleta
 
     @Override
     public void replyToInteraction(CommandContext context) {
-        if (playlist.getTracks().isEmpty()) {
+        if (playlistTracks.isEmpty()) {
             context.reply("No tracks found");
             return;
         }
@@ -62,12 +66,12 @@ public class LoadPlaylistTask extends ButtonTask implements WithChildren, Deleta
             .getSetting(GSettings.MUSIC_MAXPLAYLISTSIZE));
 
         // Search results
-        if (playlist.isSearchResult()) {
-            List<AudioTrack> searchResults = playlist.getTracks().stream().limit(searchResultsLimit).toList();
+        if (searchResult) {
+            List<Track> searchResults = playlistTracks.stream().limit(searchResultsLimit).toList();
             List<Task> loadTasks = new ArrayList<>();
 
             for (int i = 0; i < searchResults.size(); i++) {
-                AudioTrack track = searchResults.get(i);
+                Track track = searchResults.get(i);
                 loadTasks.add(new LoadTrackFromPlaylistTask(this, String.valueOf(i + 1), track, musicManager));
             }
 
@@ -79,11 +83,11 @@ public class LoadPlaylistTask extends ButtonTask implements WithChildren, Deleta
             return;
         }
 
-        List<AudioTrack> tracks = playlist.getTracks();
+        List<Track> tracks = playlistTracks;
         if (tracks.size() > maxPlaylistSizeBeforeAsking) {
-            ActionRow firstRow = commonButtons(playlist.getTracks(), "I'm ready", "Please don't");
+            ActionRow firstRow = commonButtons(tracks, "I'm ready", "Please don't");
 
-            context.edit(MessageFunction.buildPlaylistLoadMessage(playlist, context.getGuildUser()), List.of(firstRow));
+            context.edit(MessageFunction.buildPlaylistLoadMessage(playlistName, tracks.size(), context.getGuildUser()), List.of(firstRow));
             return;
         }
 
@@ -91,17 +95,17 @@ public class LoadPlaylistTask extends ButtonTask implements WithChildren, Deleta
         if (MusicUtils.connect(context, musicManager)) {
             musicManager.getQueueManager().queue(tracks, context.getGuildUser());
 
-            context.edit(MessageFunction.buildAddingPlaylistMessage(tracks, playlist.getName(), context.getGuildUser(), sourceType));
+            context.edit(MessageFunction.buildAddingPlaylistMessage(tracks, playlistName, context.getGuildUser(), sourceType));
         }
     }
 
-    private ActionRow commonButtons(List<AudioTrack> tracks, String addAllText, String cancelText) {
+    private ActionRow commonButtons(List<Track> tracks, String addAllText, String cancelText) {
         Task accept = AcceptButton.createSuccessButton(taskManager(), this, addAllText, context -> {
             Member member = context.getGuildUser();
 
             if (MusicUtils.connect(context, musicManager)) {
                 musicManager.getQueueManager().queue(tracks, member);
-                context.reply(MessageFunction.buildAddingPlaylistMessage(tracks, playlist.getName(), member, SourceFinder.AudioSourceType.Youtube));
+                context.reply(MessageFunction.buildAddingPlaylistMessage(tracks, playlistName, member, SourceFinder.AudioSourceType.Youtube));
 
                 return Lifecycle.REMOVE_SELF_AND_CHILDREN;
             }

src/main/java/me/bobert/netneutrality/tasks/music/LoadTrackFromPlaylistTask.java

@@ -5,7 +5,7 @@ package me.bobert.netneutrality.tasks.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.player.Track;
 import me.bobert.netneutrality.music.MusicManager;
 import me.bobert.netneutrality.music.SourceFinder;
 import me.bobert.netneutrality.core.tasks.generic.AcceptButton;
@@ -15,9 +15,9 @@ import net.dv8tion.jda.api.components.buttons.ButtonStyle;
 import net.dv8tion.jda.api.entities.Member;
 
 public class LoadTrackFromPlaylistTask extends AcceptButton<LoadPlaylistTask> {
-    private final AudioTrack track;
+    private final Track track;
 
-    public LoadTrackFromPlaylistTask(LoadPlaylistTask parentTask, String buttonLabel, AudioTrack track, MusicManager musicManager) {
+    public LoadTrackFromPlaylistTask(LoadPlaylistTask parentTask, String buttonLabel, Track track, MusicManager musicManager) {
         super(musicManager.getTaskManager(), parentTask, ButtonStyle.PRIMARY, buttonLabel, context -> {
             Member member = context.getGuildUser();
 
@@ -36,6 +36,6 @@ public class LoadTrackFromPlaylistTask extends AcceptButton<LoadPlaylistTask> {
 
     @Override
     public String getName() {
-        return String.format("load-track-%s", track.getIdentifier());
+        return String.format("load-track-%s", track.getInfo().getIdentifier());
     }
 }

src/test/java/me/bobert/netneutrality/core/tasks/TaskManagerImplTest.java

@@ -0,0 +1,498 @@
+package me.bobert.netneutrality.core.tasks;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.bootstrap.ApplicationContext;
+import me.bobert.netneutrality.context.tasks.ButtonTaskContext;
+import me.bobert.netneutrality.core.context.CommandContext;
+import me.bobert.netneutrality.core.context.InteractionContext;
+import me.bobert.netneutrality.core.context.TaskContext;
+import me.bobert.netneutrality.core.tasks.impl.AbstractTask;
+import me.bobert.netneutrality.core.tasks.trait.Deletable;
+import me.bobert.netneutrality.core.tasks.trait.WithButton;
+import me.bobert.netneutrality.core.tasks.trait.WithChildren;
+import me.bobert.netneutrality.core.tasks.trait.WithParent;
+import me.bobert.netneutrality.db.service.TaskService;
+import me.bobert.netneutrality.scheduled.cleanup.TaskCleanup;
+import net.dv8tion.jda.api.components.buttons.Button;
+import net.dv8tion.jda.api.interactions.InteractionHook;
+import net.dv8tion.jda.api.requests.RestAction;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.lang.reflect.Field;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class TaskManagerImplTest {
+
+    @Mock
+    private ApplicationContext applicationContext;
+
+    @Mock
+    private CommandContext commandContext;
+
+    @Mock
+    private ButtonTaskContext buttonTaskContext;
+
+    @Mock
+    private TaskService taskService;
+
+    private TaskManagerImpl taskManager;
+
+    @BeforeEach
+    void setUp() throws Exception {
+        taskManager = new TaskManagerImpl(applicationContext);
+
+        Field taskServiceField = TaskManagerImpl.class.getDeclaredField("taskService");
+        taskServiceField.setAccessible(true);
+        taskServiceField.set(taskManager, taskService);
+    }
+
+    private static class TestTask extends AbstractTask {
+        private final String id;
+        private final String lockId;
+        private boolean expired;
+        private Lifecycle lifecycleToReturn = Lifecycle.REMOVE_SELF;
+        private Consumer<TaskContext> onExecute;
+
+        TestTask(TaskManager taskManager, String id) {
+            this(taskManager, id, id);
+        }
+
+        TestTask(TaskManager taskManager, String id, String lockId) {
+            super(taskManager);
+            this.id = id;
+            this.lockId = lockId;
+        }
+
+        @Override
+        public String getId() {
+            return id;
+        }
+
+        @Override
+        public String getName() {
+            return "TestTask-" + id;
+        }
+
+        @Override
+        public String getLockId() {
+            return lockId;
+        }
+
+        @Override
+        public boolean isInsertable() {
+            return true;
+        }
+
+        @Override
+        public boolean isExpired() {
+            return expired;
+        }
+
+        public void setExpired(boolean expired) {
+            this.expired = expired;
+        }
+
+        public void setLifecycleToReturn(Lifecycle lifecycleToReturn) {
+            this.lifecycleToReturn = lifecycleToReturn;
+        }
+
+        public void setOnExecute(Consumer<TaskContext> onExecute) {
+            this.onExecute = onExecute;
+        }
+
+        @Override
+        public Lifecycle execute(TaskContext context) {
+            if (onExecute != null) {
+                onExecute.accept(context);
+            }
+            return lifecycleToReturn;
+        }
+
+        @Override
+        public void replyToInteraction(CommandContext context) {
+        }
+    }
+
+    private static class TestParentTask extends TestTask implements WithChildren {
+        private final List<Task> childTasks;
+
+        TestParentTask(TaskManager taskManager, String id, List<Task> childTasks) {
+            super(taskManager, id);
+            this.childTasks = childTasks;
+        }
+
+        @Override
+        public List<Task> getChildTasks() {
+            return childTasks;
+        }
+    }
+
+    private static class TestChildTask extends TestTask implements WithParent<TestParentTask> {
+        private final TestParentTask parent;
+
+        TestChildTask(TaskManager taskManager, String id, TestParentTask parent) {
+            super(taskManager, id, parent != null ? parent.getLockId() : id);
+            this.parent = parent;
+        }
+
+        @Override
+        public TestParentTask getParentTask() {
+            return parent;
+        }
+    }
+
+    private static class TestButtonTask extends TestTask implements WithButton {
+        TestButtonTask(TaskManager taskManager, String id) {
+            super(taskManager, id);
+        }
+
+        @Override
+        public Button createButton() {
+            return Button.primary(getId(), getName());
+        }
+    }
+
+    private static class TestStepTask extends TestTask implements StepTask {
+        TestStepTask(TaskManager taskManager, String id) {
+            super(taskManager, id);
+        }
+
+        @Override
+        public StepType getStepType() {
+            return StepType.STRING;
+        }
+
+        @Override
+        public String getStepQuestion() {
+            return "Question?";
+        }
+
+        @Override
+        public String getStepDescription() {
+            return "Description";
+        }
+
+        @Override
+        public StepResult executeStep(Object answer) {
+            return StepResult.success("Done");
+        }
+    }
+
+    private static class TestPersistableTask extends TestTask implements PersistableTask {
+        TestPersistableTask(TaskManager taskManager, String id) {
+            super(taskManager, id);
+        }
+
+        @Override
+        public void save() {
+        }
+
+        @Override
+        public void delete() {
+        }
+
+        @Override
+        public String toPayload() {
+            return "{}";
+        }
+    }
+
+    private static class TestDeletableTask extends TestTask implements Deletable {
+        private final AtomicBoolean deleted = new AtomicBoolean(false);
+
+        TestDeletableTask(TaskManager taskManager, String id) {
+            super(taskManager, id);
+        }
+
+        @Override
+        public void onInteractionDelete() {
+            deleted.set(true);
+        }
+
+        public boolean isDeleted() {
+            return deleted.get();
+        }
+    }
+
+    @Test
+    void testInsertAndLookup() {
+        TestTask task = new TestTask(taskManager, "task-1");
+
+        taskManager.insert(commandContext, task);
+
+        assertTrue(taskManager.hasTask("task-1"));
+        assertEquals(task, taskManager.getTask("task-1"));
+        assertTrue(taskManager.getTasks().contains(task));
+    }
+
+    @Test
+    void testInsertDuplicateRejected() {
+        TestTask task1 = new TestTask(taskManager, "duplicate-id");
+        TestTask task2 = new TestTask(taskManager, "duplicate-id");
+
+        taskManager.insert(commandContext, task1);
+        taskManager.insert(commandContext, task2);
+
+        verify(commandContext).reply("A task with the same ID already exists!");
+        assertEquals(1, taskManager.getTasks().size());
+    }
+
+    @Test
+    void testRemoveTask() {
+        TestTask task = new TestTask(taskManager, "task-to-remove");
+
+        taskManager.insert(commandContext, task);
+        assertTrue(taskManager.hasTask("task-to-remove"));
+
+        taskManager.removeTask(task);
+        assertFalse(taskManager.hasTask("task-to-remove"));
+        assertNull(taskManager.getTask("task-to-remove"));
+    }
+
+    @Test
+    void testParentAndChildInsertion() {
+        TestChildTask child1 = new TestChildTask(taskManager, "child-1", null);
+        TestChildTask child2 = new TestChildTask(taskManager, "child-2", null);
+        TestParentTask parent = new TestParentTask(taskManager, "parent-1", List.of(child1, child2));
+
+        taskManager.insert(commandContext, parent);
+
+        assertTrue(taskManager.hasTask("parent-1"));
+        assertTrue(taskManager.hasTask("child-1"));
+        assertTrue(taskManager.hasTask("child-2"));
+    }
+
+    @Test
+    void testChildRemoveSelfAndChildrenCascades() {
+        java.util.List<Task> children = new java.util.ArrayList<>();
+        TestParentTask parent = new TestParentTask(taskManager, "parent-task", children);
+        TestChildTask child1 = new TestChildTask(taskManager, "child-task-1", parent);
+        TestChildTask child2 = new TestChildTask(taskManager, "child-task-2", parent);
+        children.add(child1);
+        children.add(child2);
+
+        taskManager.insert(commandContext, parent);
+        assertTrue(taskManager.hasTask("parent-task"));
+        assertTrue(taskManager.hasTask("child-task-1"));
+        assertTrue(taskManager.hasTask("child-task-2"));
+
+        child1.setLifecycleToReturn(Task.Lifecycle.REMOVE_SELF_AND_CHILDREN);
+        when(buttonTaskContext.getId()).thenReturn("child-task-1");
+        when(buttonTaskContext.isAcknowledged()).thenReturn(true);
+
+        taskManager.handle(buttonTaskContext);
+
+        assertFalse(taskManager.hasTask("parent-task"));
+        assertFalse(taskManager.hasTask("child-task-1"));
+        assertFalse(taskManager.hasTask("child-task-2"));
+    }
+
+    @Test
+    void testParentRemoveSelfAndChildrenCascades() {
+        java.util.List<Task> children = new java.util.ArrayList<>();
+        TestParentTask parent = new TestParentTask(taskManager, "parent-task", children);
+        TestChildTask child1 = new TestChildTask(taskManager, "child-task-1", parent);
+        TestChildTask child2 = new TestChildTask(taskManager, "child-task-2", parent);
+        children.add(child1);
+        children.add(child2);
+
+        taskManager.insert(commandContext, parent);
+        parent.setLifecycleToReturn(Task.Lifecycle.REMOVE_SELF_AND_CHILDREN);
+        when(buttonTaskContext.getId()).thenReturn("parent-task");
+        when(buttonTaskContext.isAcknowledged()).thenReturn(true);
+
+        taskManager.handle(buttonTaskContext);
+
+        assertFalse(taskManager.hasTask("parent-task"));
+        assertFalse(taskManager.hasTask("child-task-1"));
+        assertFalse(taskManager.hasTask("child-task-2"));
+    }
+
+    @Test
+    void testChildRemoveSelfRemovesOnlySelf() {
+        java.util.List<Task> children = new java.util.ArrayList<>();
+        TestParentTask parent = new TestParentTask(taskManager, "parent-task", children);
+        TestChildTask child1 = new TestChildTask(taskManager, "child-task-1", parent);
+        TestChildTask child2 = new TestChildTask(taskManager, "child-task-2", parent);
+        children.add(child1);
+        children.add(child2);
+
+        taskManager.insert(commandContext, parent);
+        child1.setLifecycleToReturn(Task.Lifecycle.REMOVE_SELF);
+        when(buttonTaskContext.getId()).thenReturn("child-task-1");
+        when(buttonTaskContext.isAcknowledged()).thenReturn(true);
+
+        taskManager.handle(buttonTaskContext);
+
+        assertFalse(taskManager.hasTask("child-task-1"));
+        assertTrue(taskManager.hasTask("parent-task"));
+        assertTrue(taskManager.hasTask("child-task-2"));
+    }
+
+    @Test
+    void testStepTaskPendingAndActivation() {
+        TestStepTask stepTask = new TestStepTask(taskManager, "initial-uuid");
+
+        taskManager.insert(commandContext, stepTask);
+
+        assertTrue(taskManager.hasTask("initial-uuid"));
+        assertEquals(stepTask, taskManager.getTask("initial-uuid"));
+        assertTrue(taskManager.getTasks().contains(stepTask));
+
+        TestStepTask activatedTask = new TestStepTask(taskManager, "message-id-123");
+        taskManager.activateTask(activatedTask, "initial-uuid");
+
+        assertTrue(taskManager.hasTask("message-id-123"));
+        assertEquals(activatedTask, taskManager.getTask("message-id-123"));
+        assertFalse(taskManager.hasTask("initial-uuid"));
+    }
+
+    @Test
+    void testTaskCleanupPrunesExpiredStepTasks() {
+        TestStepTask expiredStepTask = new TestStepTask(taskManager, "expired-step");
+        expiredStepTask.setExpired(true);
+
+        TestStepTask activeStepTask = new TestStepTask(taskManager, "active-step");
+        activeStepTask.setExpired(false);
+
+        taskManager.insert(commandContext, expiredStepTask);
+        taskManager.insert(commandContext, activeStepTask);
+
+        TaskCleanup cleanup = new TaskCleanup(taskManager);
+        cleanup.run();
+
+        assertFalse(taskManager.hasTask("expired-step"));
+        assertTrue(taskManager.hasTask("active-step"));
+    }
+
+    @Test
+    void testPersistableTaskUnpersistedOnRemoval() {
+        TestPersistableTask persistableTask = new TestPersistableTask(taskManager, "persist-1");
+
+        taskManager.insert(commandContext, persistableTask);
+        verify(taskService).persistTask(persistableTask);
+
+        taskManager.removeTask(persistableTask);
+        verify(taskService).unpersistTask(persistableTask);
+    }
+
+    @Test
+    void testFindTaskByPartialId() {
+        TestButtonTask button1 = new TestButtonTask(taskManager, "btn_action_play");
+        TestButtonTask button2 = new TestButtonTask(taskManager, "btn_action_pause");
+        TestTask regularTask = new TestTask(taskManager, "regular_play");
+
+        taskManager.insert(commandContext, button1);
+        taskManager.insert(commandContext, button2);
+        taskManager.insert(commandContext, regularTask);
+
+        Optional<TestButtonTask> found = taskManager.findTaskByPartialId(TestButtonTask.class, "action_play");
+        assertTrue(found.isPresent());
+        assertEquals(button1, found.get());
+
+        List<TestButtonTask> allButtons = taskManager.findTasksByPartialId(TestButtonTask.class, "btn_action");
+        assertEquals(2, allButtons.size());
+        assertTrue(allButtons.contains(button1));
+        assertTrue(allButtons.contains(button2));
+
+        WithButton foundButton = taskManager.findButtonTaskByClass(TestButtonTask.class);
+        assertNotNull(foundButton);
+    }
+
+    @Test
+    void testConcurrentExecutionSharingLock() throws Exception {
+        int threadCount = 4;
+        ExecutorService executor = Executors.newFixedThreadPool(threadCount);
+        CountDownLatch startLatch = new CountDownLatch(1);
+        CountDownLatch finishLatch = new CountDownLatch(threadCount);
+
+        AtomicInteger concurrentExecutions = new AtomicInteger(0);
+        AtomicInteger maxConcurrentSeen = new AtomicInteger(0);
+
+        String sharedLockId = "shared-lock-123";
+
+        for (int i = 0; i < threadCount; i++) {
+            String taskId = "task-lock-" + i;
+            TestTask task = new TestTask(taskManager, taskId, sharedLockId);
+            task.setLifecycleToReturn(Task.Lifecycle.KEEP);
+            task.setOnExecute(ctx -> {
+                int active = concurrentExecutions.incrementAndGet();
+                maxConcurrentSeen.updateAndGet(curr -> Math.max(curr, active));
+                try {
+                    Thread.sleep(50);
+                } catch (InterruptedException ignored) {
+                }
+                concurrentExecutions.decrementAndGet();
+            });
+
+            taskManager.insert(commandContext, task);
+
+            executor.submit(() -> {
+                try {
+                    startLatch.await();
+                    TaskContext mockContext = mock(TaskContext.class);
+                    when(mockContext.getId()).thenReturn(taskId);
+                    when(mockContext.isAcknowledged()).thenReturn(true);
+                    taskManager.handle(mockContext);
+                } catch (Exception e) {
+                    e.printStackTrace();
+                } finally {
+                    finishLatch.countDown();
+                }
+            });
+        }
+
+        startLatch.countDown();
+        boolean completed = finishLatch.await(5, TimeUnit.SECONDS);
+        executor.shutdown();
+
+        assertTrue(completed);
+        assertEquals(1, maxConcurrentSeen.get(), "Tasks sharing a lockId must be executed mutually exclusively");
+    }
+
+    @Test
+    void testDeletableInteractionExecution() {
+        TestDeletableTask deletableTask = new TestDeletableTask(taskManager, "deletable-1");
+        deletableTask.setLifecycleToReturn(Task.Lifecycle.REMOVE_SELF);
+
+        InteractionHook mockHook = mock(InteractionHook.class);
+        when(mockHook.isExpired()).thenReturn(false);
+        @SuppressWarnings("unchecked")
+        RestAction<Void> restAction = mock(RestAction.class);
+        when(mockHook.deleteOriginal()).thenReturn(restAction);
+
+        when(commandContext.getInteractionHook()).thenReturn(mockHook);
+        taskManager.insert(commandContext, deletableTask);
+
+        when(buttonTaskContext.getId()).thenReturn("deletable-1");
+        when(buttonTaskContext.isAcknowledged()).thenReturn(true);
+
+        taskManager.handle(buttonTaskContext);
+
+        assertTrue(deletableTask.isDeleted());
+        verify(mockHook).deleteOriginal();
+        verify(restAction).queue(any(), any());
+    }
+}

src/test/java/me/bobert/netneutrality/http/WebModuleTest.java

@@ -0,0 +1,88 @@
+package me.bobert.netneutrality.http;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import io.javalin.Javalin;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class WebModuleTest {
+
+    private Javalin server;
+    private int port;
+    private final AtomicInteger hits = new AtomicInteger();
+
+    @BeforeEach
+    void setUp() {
+        server = Javalin.create(config -> config.showJavalinBanner = false);
+        server.get("/counter", ctx -> ctx.result("{\"hits\":" + hits.incrementAndGet() + "}"));
+        server.post("/counter", ctx -> ctx.result("{\"hits\":" + hits.incrementAndGet() + "}"));
+        server.start(0);
+        port = server.port();
+    }
+
+    @AfterEach
+    void tearDown() {
+        server.stop();
+    }
+
+    @Test
+    void getRequestsAreServedFromTheCache() {
+        String url = url("cache-hit");
+
+        assertEquals(1, new WebModule.Builder(url).get().cache(1, TimeUnit.MINUTES).build().request()
+            .getAsObject().getInt("hits"));
+        assertEquals(1, new WebModule.Builder(url).get().cache(1, TimeUnit.MINUTES).build().request()
+            .getAsObject().getInt("hits"));
+
+        assertEquals(1, hits.get());
+    }
+
+    @Test
+    void expiredEntriesAreRefetched() throws Exception {
+        String url = url("cache-expiry");
+
+        new WebModule.Builder(url).get().cache(1, TimeUnit.MILLISECONDS).build().request();
+        Thread.sleep(20);
+        new WebModule.Builder(url).get().cache(1, TimeUnit.MILLISECONDS).build().request();
+
+        assertEquals(2, hits.get());
+    }
+
+    @Test
+    void invalidateCacheForcesANewRequest() {
+        String url = url("cache-invalidate");
+
+        new WebModule.Builder(url).get().cache(1, TimeUnit.MINUTES).build().request();
+        WebModule.invalidateCache(url);
+        new WebModule.Builder(url).get().cache(1, TimeUnit.MINUTES).build().request();
+
+        assertEquals(2, hits.get());
+    }
+
+    @Test
+    void postRequestsBypassTheCache() {
+        String url = url("cache-post");
+
+        assertTrue(new WebModule.Builder(url).post(Map.of("a", "b")).build().request().isSuccess());
+        new WebModule.Builder(url).post(Map.of("a", "b")).build().request();
+
+        assertEquals(2, hits.get());
+    }
+
+    private String url(String marker) {
+        return "http://localhost:" + port + "/counter?marker=" + marker + "-" + System.nanoTime();
+    }
+}

src/test/java/me/bobert/netneutrality/http/server/WebApiTest.java

@@ -0,0 +1,172 @@
+package me.bobert.netneutrality.http.server;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.service.GuildService;
+import me.bobert.netneutrality.db.service.GuildServiceProvider;
+import me.bobert.netneutrality.db.service.GuildSettingService;
+import me.bobert.netneutrality.utils.SettingsProvider;
+import net.dv8tion.jda.api.JDA;
+import net.dv8tion.jda.api.entities.Guild;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+class WebApiTest {
+
+    private static final String GUILD_ID = "1234567890";
+
+    private WebApi webApi;
+    private int port;
+    private GuildSettingService settingService;
+    private final HttpClient http = HttpClient.newHttpClient();
+
+    @BeforeEach
+    void setUp() throws IOException {
+        port = freePort();
+
+        Guild guild = mock(Guild.class);
+        when(guild.getId()).thenReturn(GUILD_ID);
+        when(guild.getOwnerId()).thenReturn("42");
+
+        JDA jda = mock(JDA.class);
+        when(jda.getGuilds()).thenReturn(List.of(guild));
+        when(jda.getGuildById(GUILD_ID)).thenReturn(guild);
+        when(jda.getGuildById(any(String.class))).thenAnswer(inv ->
+            GUILD_ID.equals(inv.getArgument(0)) ? guild : null);
+        when(jda.getStatus()).thenReturn(JDA.Status.CONNECTED);
+        when(jda.getGatewayPing()).thenReturn(12L);
+
+        settingService = mock(GuildSettingService.class);
+        when(settingService.getSettings()).thenReturn(Map.of("prefix", "ü!"));
+
+        GuildService guildService = mock(GuildService.class);
+        when(guildService.getGuildSettingService()).thenReturn(settingService);
+
+        GuildServiceProvider provider = mock(GuildServiceProvider.class);
+        when(provider.get(guild)).thenReturn(guildService);
+
+        SettingsProvider settings = mock(SettingsProvider.class);
+        when(settings.get("NETNEUTRALITY_API_PORT", "9000")).thenReturn(String.valueOf(port));
+
+        webApi = new WebApi(settings, provider, () -> jda, () -> { });
+        webApi.start();
+    }
+
+    @AfterEach
+    void tearDown() {
+        webApi.stop();
+    }
+
+    @Test
+    void rootReturnsLivenessHtml() throws Exception {
+        HttpResponse<String> response = get("/");
+
+        assertEquals(200, response.statusCode());
+        assertTrue(response.body().contains("Server start success"));
+    }
+
+    @Test
+    void statusReturnsHealthAndPing() throws Exception {
+        HttpResponse<String> response = get("/actions/status");
+
+        assertEquals(200, response.statusCode());
+        assertTrue(response.body().contains("\"health\":\"CONNECTED\""));
+        assertTrue(response.body().contains("\"ping\":\"12\""));
+    }
+
+    @Test
+    void ownerReturnsGuildOwners() throws Exception {
+        HttpResponse<String> response = get("/guilds/owner");
+
+        assertEquals(200, response.statusCode());
+        assertEquals("[{\"guild_id\":\"" + GUILD_ID + "\",\"owner_id\":\"42\"}]", response.body());
+    }
+
+    @Test
+    void currentSettingsAreReturnedForKnownGuild() throws Exception {
+        HttpResponse<String> response = get("/actions/settings/current/" + GUILD_ID);
+
+        assertEquals(200, response.statusCode());
+        assertTrue(response.body().contains("\"status\":\"ok\""));
+        assertTrue(response.body().contains("ü!"));
+    }
+
+    @Test
+    void unknownGuildReturnsNotFound() throws Exception {
+        HttpResponse<String> response = get("/guilds/channels/999");
+
+        assertEquals(404, response.statusCode());
+        assertTrue(response.body().contains("\"status\":\"error\""));
+    }
+
+    @Test
+    void unknownPathReturnsNotFound() throws Exception {
+        assertEquals(404, get("/nope").statusCode());
+    }
+
+    @Test
+    void wrongMethodIsNotRouted() throws Exception {
+        HttpRequest request = HttpRequest.newBuilder(uri("/guilds/owner"))
+            .POST(HttpRequest.BodyPublishers.noBody())
+            .build();
+
+        assertEquals(404, http.send(request, HttpResponse.BodyHandlers.ofString()).statusCode());
+    }
+
+    @Test
+    void reloadRefreshesTheSettingCache() throws Exception {
+        HttpRequest request = HttpRequest.newBuilder(uri("/actions/settings/reload/" + GUILD_ID))
+            .POST(HttpRequest.BodyPublishers.noBody())
+            .build();
+        HttpResponse<String> response = http.send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertEquals(200, response.statusCode());
+        assertTrue(response.body().contains("\"status\":\"true\""));
+        verify(settingService).reloadSettingsCache();
+    }
+
+    @Test
+    void stopReleasesThePort() throws Exception {
+        webApi.stop();
+
+        try (ServerSocket socket = new ServerSocket(port)) {
+            assertEquals(port, socket.getLocalPort());
+        }
+    }
+
+    private HttpResponse<String> get(String path) throws Exception {
+        HttpRequest request = HttpRequest.newBuilder(uri(path)).GET().build();
+        return http.send(request, HttpResponse.BodyHandlers.ofString());
+    }
+
+    private URI uri(String path) {
+        return URI.create("http://localhost:" + port + path);
+    }
+
+    private static int freePort() throws IOException {
+        try (ServerSocket socket = new ServerSocket(0)) {
+            return socket.getLocalPort();
+        }
+    }
+}

src/test/java/me/bobert/netneutrality/music/QueueManagerTest.java

@@ -5,9 +5,7 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrackInfo;
+import dev.arbjerg.lavalink.client.player.Track;
 import me.bobert.netneutrality.core.command.CommandExecutionResult;
 import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
@@ -21,22 +19,20 @@ import static org.mockito.Mockito.*;
 
 public class QueueManagerTest {
 
-    private AudioPlayer player;
+    private TrackScheduler scheduler;
     private MusicManager musicManager;
     private MusicManagerCallback callback;
     private QueueManager queueManager;
 
     @BeforeEach
     void setUp() {
-        player = mock(AudioPlayer.class);
         Guild guild = mock(Guild.class);
         when(guild.getId()).thenReturn("guild1");
 
-        TrackScheduler scheduler = mock(TrackScheduler.class);
+        scheduler = mock(TrackScheduler.class);
         musicManager = mock(MusicManager.class);
         callback = mock(MusicManagerCallback.class);
 
-        when(scheduler.getPlayer()).thenReturn(player);
         when(scheduler.getGuild()).thenReturn(guild);
         when(scheduler.getMusicManager()).thenReturn(musicManager);
         when(scheduler.getCallback()).thenReturn(callback);
@@ -44,11 +40,14 @@ public class QueueManagerTest {
         queueManager = new QueueManager(scheduler);
     }
 
-    private AudioTrack mockTrack(String id) {
-        AudioTrack track = mock(AudioTrack.class);
-        when(track.getIdentifier()).thenReturn(id);
-        AudioTrackInfo info = new AudioTrackInfo("Title " + id, "Author", 1000L, id, false, "http://example.com/" + id);
+    static Track mockTrack(String id) {
+        Track track = mock(Track.class);
+        dev.arbjerg.lavalink.protocol.v4.TrackInfo info = mock(dev.arbjerg.lavalink.protocol.v4.TrackInfo.class);
+        when(info.getIdentifier()).thenReturn(id);
+        when(info.getTitle()).thenReturn("Title " + id);
+        when(info.getLength()).thenReturn(1000L);
         when(track.getInfo()).thenReturn(info);
+        when(track.getEncoded()).thenReturn("encoded-" + id);
         when(track.makeClone()).thenReturn(track);
         return track;
     }
@@ -64,23 +63,24 @@ public class QueueManagerTest {
 
     @Test
     public void queueAddsToTailAndStartsPlaybackWhenEmpty() {
-        AudioTrack track = mockTrack("t1");
+        Track track = mockTrack("t1");
         Member member = mockMember("u1");
-        when(player.getPlayingTrack()).thenReturn(null);
+        when(scheduler.getCurrentTrack()).thenReturn(null);
 
         queueManager.queue(track, member);
 
         assertEquals(1, queueManager.getQueueSize());
-        verify(player).startTrack(track, true);
+        verify(scheduler).setCurrentTrack(track);
+        verify(musicManager).updatePlayer(contains("t1"), any());
     }
 
     @Test
     public void queueAddsToTailWhenAlreadyPlaying() {
-        AudioTrack t1 = mockTrack("t1");
-        AudioTrack t2 = mockTrack("t2");
+        Track t1 = mockTrack("t1");
+        Track t2 = mockTrack("t2");
         Member member = mockMember("u1");
 
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(t1);
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(t1);
 
         queueManager.queue(t1, member);
         queueManager.queue(t2, member);
@@ -93,31 +93,28 @@ public class QueueManagerTest {
 
     @Test
     public void queueAddsToFrontWhenNothingPlayingAndQueueNotEmpty() {
-        AudioTrack t1 = mockTrack("t1");
-        AudioTrack t2 = mockTrack("t2");
+        Track t1 = mockTrack("t1");
+        Track t2 = mockTrack("t2");
         Member member = mockMember("u1");
 
-        // First queue: nothing playing, queue empty -> add to tail, start track
-        when(player.getPlayingTrack()).thenReturn(null);
-        queueManager.queue(t1, member);
+        // Nothing playing on both calls: the second track jumps to the head so that it is the
+        // one actually started.
+        when(scheduler.getCurrentTrack()).thenReturn(null);
 
-        // Second queue: nothing playing (startTrack with noInterrupt=true didn't actually start),
-        // queue not empty -> should addFirst so t2 is at head and gets played
-        when(player.getPlayingTrack()).thenReturn(null);
+        queueManager.queue(t1, member);
         queueManager.queue(t2, member);
 
         assertEquals(2, queueManager.getQueueSize());
         List<TrackInfo> q = queueManager.getQueue();
-        // t2 should be at the front since nothing was playing and queue was not empty
         assertSame(t2, q.get(0).getTrack());
         assertSame(t1, q.get(1).getTrack());
     }
 
     @Test
     public void queueRejectsDuplicate() {
-        AudioTrack track = mockTrack("t1");
+        Track track = mockTrack("t1");
         Member member = mockMember("u1");
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(track);
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(track);
 
         queueManager.queue(track, member);
         queueManager.queue(track, member);
@@ -136,7 +133,7 @@ public class QueueManagerTest {
 
     @Test
     public void clearQueueRemovesAllAndCallsCallback() {
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(mockTrack("t1"));
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(mockTrack("t1"));
         queueManager.queue(mockTrack("t1"), mockMember("u1"));
         queueManager.queue(mockTrack("t2"), mockMember("u1"));
 
@@ -158,10 +155,10 @@ public class QueueManagerTest {
 
     @Test
     public void skipSingleTrack() {
-        AudioTrack t1 = mockTrack("t1");
-        AudioTrack t2 = mockTrack("t2");
+        Track t1 = mockTrack("t1");
+        Track t2 = mockTrack("t2");
         Member member = mockMember("u1");
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(t1).thenReturn(t1);
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(t1);
 
         queueManager.queue(t1, member);
         queueManager.queue(t2, member);
@@ -174,18 +171,16 @@ public class QueueManagerTest {
 
     @Test
     public void skipMoreThanQueueSizeSkipsAll() {
-        AudioTrack t1 = mockTrack("t1");
-        AudioTrack t2 = mockTrack("t2");
+        Track t1 = mockTrack("t1");
+        Track t2 = mockTrack("t2");
         Member member = mockMember("u1");
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(t1).thenReturn(t1);
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(t1);
 
         queueManager.queue(t1, member);
         queueManager.queue(t2, member);
 
         // skip(10) should clamp to queue.size() = 2, removing all
-        CommandExecutionResult result = queueManager.skip(10);
-        // After removing (nbTrack-1)=1 via poll, queue has 1 left, then startNextTrack polls that
-        // Actually with nbTrack clamped to 2: poll 1 track, then startNextTrack polls the last
+        queueManager.skip(10);
         assertTrue(queueManager.isEmpty());
     }
 
@@ -193,8 +188,8 @@ public class QueueManagerTest {
 
     @Test
     public void shuffleTooSmallQueueReturnsWarn() {
-        AudioTrack t1 = mockTrack("t1");
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(t1);
+        Track t1 = mockTrack("t1");
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(t1);
         queueManager.queue(t1, mockMember("u1"));
 
         CommandExecutionResult result = queueManager.shuffle();
@@ -204,10 +199,10 @@ public class QueueManagerTest {
     @Test
     public void shufflePreservesCurrentTrackAtHead() {
         Member member = mockMember("u1");
-        AudioTrack playing = mockTrack("t1");
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(playing).thenReturn(playing).thenReturn(playing).thenReturn(playing);
+        Track playing = mockTrack("t1");
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(playing);
 
-        queueManager.queue(mockTrack("t1"), member);
+        queueManager.queue(playing, member);
         queueManager.queue(mockTrack("t2"), member);
         queueManager.queue(mockTrack("t3"), member);
         queueManager.queue(mockTrack("t4"), member);
@@ -218,7 +213,7 @@ public class QueueManagerTest {
         // First track should still be t1
         List<TrackInfo> q = queueManager.getQueue();
         assertEquals(4, q.size());
-        assertEquals("t1", q.get(0).getTrack().getIdentifier());
+        assertEquals("t1", q.get(0).getTrack().getInfo().getIdentifier());
     }
 
     // --- RemoveFromQueue ---
@@ -231,7 +226,7 @@ public class QueueManagerTest {
 
     @Test
     public void removeFromQueueOutOfBoundsReturnsError() {
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(mockTrack("t1"));
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(mockTrack("t1"));
         queueManager.queue(mockTrack("t1"), mockMember("u1"));
 
         CommandExecutionResult result = queueManager.removeFromQueue(5);
@@ -240,7 +235,7 @@ public class QueueManagerTest {
 
     @Test
     public void removeFromQueueIndexZeroReturnsNone() {
-        when(player.getPlayingTrack()).thenReturn(null).thenReturn(mockTrack("t1"));
+        when(scheduler.getCurrentTrack()).thenReturn(null).thenReturn(mockTrack("t1"));
         queueManager.queue(mockTrack("t1"), mockMember("u1"));
 
         CommandExecutionResult result = queueManager.removeFromQueue(0);

src/test/java/me/bobert/netneutrality/music/TrackInfoTest.java

@@ -5,7 +5,7 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import dev.arbjerg.lavalink.client.player.Track;
 import net.dv8tion.jda.api.entities.Member;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -18,13 +18,13 @@ import static org.mockito.Mockito.when;
 
 public class TrackInfoTest {
 
-    private AudioTrack track;
+    private Track track;
     private Member member;
     private TrackInfo trackInfo;
 
     @BeforeEach
     void setUp() {
-        track = mock(AudioTrack.class);
+        track = QueueManagerTest.mockTrack("t1");
         member = mock(Member.class);
         when(member.getId()).thenReturn("user1");
         when(member.getEffectiveName()).thenReturn("User1");
@@ -101,7 +101,7 @@ public class TrackInfoTest {
 
     @Test
     public void notEqualWithDifferentTrack() {
-        AudioTrack otherTrack = mock(AudioTrack.class);
+        Track otherTrack = QueueManagerTest.mockTrack("t2");
         TrackInfo other = new TrackInfo(otherTrack, member);
         assertNotEquals(trackInfo, other);
     }

src/test/java/me/bobert/netneutrality/music/TrackSchedulerTest.java

@@ -5,28 +5,27 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
-import com.sedmelluq.discord.lavaplayer.track.AudioTrackEndReason;
+import dev.arbjerg.lavalink.client.player.Track;
+import dev.arbjerg.lavalink.protocol.v4.Message.EmittedEvent.TrackEndEvent;
 import net.dv8tion.jda.api.entities.Guild;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.mockito.Mockito.*;
 
 public class TrackSchedulerTest {
 
-    private AudioPlayer player;
+    private MusicManager musicManager;
     private TrackScheduler scheduler;
 
     @BeforeEach
     void setUp() {
-        player = mock(AudioPlayer.class);
         Guild guild = mock(Guild.class);
         when(guild.getId()).thenReturn("guild1");
 
-        MusicManager musicManager = mock(MusicManager.class);
-        when(musicManager.getPlayer()).thenReturn(player);
+        musicManager = mock(MusicManager.class);
         when(musicManager.getGuild()).thenReturn(guild);
 
         scheduler = new TrackScheduler(musicManager);
@@ -34,45 +33,51 @@ public class TrackSchedulerTest {
 
     @Test
     public void onTrackEndFinishedStartsNextTrack() {
-        AudioTrack track = mock(AudioTrack.class);
-        when(track.getIdentifier()).thenReturn("t1");
+        Track track = QueueManagerTest.mockTrack("t1");
 
-        // With empty queue, startNextTrack will just stopTrack
-        scheduler.onTrackEnd(player, track, AudioTrackEndReason.FINISHED);
-        verify(player).stopTrack();
+        // With empty queue, startNextTrack will just stop playback on the node
+        scheduler.onTrackEnd(track, TrackEndEvent.AudioTrackEndReason.FINISHED);
+        verify(musicManager).stopTrack();
     }
 
     @Test
     public void onTrackEndLoadFailedStartsNextTrack() {
-        AudioTrack track = mock(AudioTrack.class);
-        when(track.getIdentifier()).thenReturn("t1");
+        Track track = QueueManagerTest.mockTrack("t1");
 
-        scheduler.onTrackEnd(player, track, AudioTrackEndReason.LOAD_FAILED);
-        verify(player).stopTrack();
+        scheduler.onTrackEnd(track, TrackEndEvent.AudioTrackEndReason.LOAD_FAILED);
+        verify(musicManager).stopTrack();
     }
 
     @Test
     public void onTrackEndReplacedDoesNotStartNext() {
-        AudioTrack track = mock(AudioTrack.class);
-        when(track.getIdentifier()).thenReturn("t1");
+        Track track = QueueManagerTest.mockTrack("t1");
 
-        scheduler.onTrackEnd(player, track, AudioTrackEndReason.REPLACED);
-        verify(player, never()).stopTrack();
-        verify(player, never()).startTrack(any(), anyBoolean());
+        scheduler.onTrackEnd(track, TrackEndEvent.AudioTrackEndReason.REPLACED);
+        verify(musicManager, never()).stopTrack();
+        verify(musicManager, never()).updatePlayer(anyString(), any());
     }
 
     @Test
-    public void onTrackStartResetsStuckHandler() {
-        AudioTrack track = mock(AudioTrack.class);
-        when(track.getIdentifier()).thenReturn("t1");
+    public void onTrackStartCachesCurrentTrack() {
+        Track track = QueueManagerTest.mockTrack("t1");
 
-        // After onTrackStart, the stuck handler should be reset
-        scheduler.onTrackStart(player, track);
-        // No exception means reset was called successfully
+        scheduler.onTrackStart(track);
+
+        assertSame(track, scheduler.getCurrentTrack());
+    }
+
+    @Test
+    public void onTrackEndClearsCurrentTrack() {
+        Track track = QueueManagerTest.mockTrack("t1");
+        scheduler.onTrackStart(track);
+
+        scheduler.onTrackEnd(track, TrackEndEvent.AudioTrackEndReason.STOPPED);
+
+        assertNull(scheduler.getCurrentTrack());
     }
 
     @Test
     public void getDjReturnsNullWhenNoContext() {
-        assert scheduler.getDj() == null;
+        assertNull(scheduler.getDj());
     }
 }

src/test/java/me/bobert/netneutrality/music/VoteSkipServiceTest.java

@@ -5,7 +5,6 @@ package me.bobert.netneutrality.music;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
 import me.bobert.netneutrality.core.command.CommandExecutionResult;
 import me.bobert.netneutrality.core.context.CommandContext;
 import net.dv8tion.jda.api.entities.Guild;
@@ -39,7 +38,7 @@ public class VoteSkipServiceTest {
         when(guild.getId()).thenReturn("guild1");
         when(context.getGuild()).thenReturn(guild);
 
-        AudioTrack track = mock(AudioTrack.class);
+        dev.arbjerg.lavalink.client.player.Track track = QueueManagerTest.mockTrack("t1");
         Member requester = mock(Member.class);
         when(requester.getId()).thenReturn("requester");
         trackInfo = new TrackInfo(track, requester);