feat: add opt-in procedural drive audio

tests/unit/audio-lifecycle.test.ts

@@ -0,0 +1,389 @@
+import { describe, expect, it, vi } from 'vitest';
+import { createAudioController } from '@/audio/create-audio-controller';
+import { createSynthEngine } from '@/audio/synth-engine';
+import type { AudioGraph, AudioGraphFactory } from '@/audio/types';
+
+describe('audio controller lifecycle', () => {
+  it('constructs no graph before activation and only one graph for rapid repeated activation', async () => {
+    const harness = createHarness();
+    const controller = createAudioController({ createGraph: harness.createGraph });
+
+    expect(harness.constructed).toBe(0);
+    const first = controller.startFromGesture();
+    const second = controller.startFromGesture();
+
+    expect(harness.constructed).toBe(1);
+    await Promise.all([first, second]);
+    expect(harness.constructed).toBe(1);
+    expect(controller.snapshot()).toEqual({ kind: 'running', muted: false, volume: 0.4 });
+    expect(harness.graph.connectOutput).toHaveBeenCalledOnce();
+  });
+
+  it('applies clamped volume and mute changes made while starting without changing lifecycle intent', async () => {
+    const resume = deferred<void>();
+    const harness = createHarness({ resume });
+    const controller = createAudioController({ createGraph: harness.createGraph, initialVolume: 3 });
+
+    const starting = controller.startFromGesture();
+    controller.setVolume(-1);
+    controller.setMuted(true);
+    expect(controller.snapshot()).toEqual({ kind: 'starting' });
+
+    resume.resolve();
+    await starting;
+    expect(controller.snapshot()).toEqual({ kind: 'running', muted: true, volume: 0 });
+    expect(harness.graph.setOutputGain).toHaveBeenLastCalledWith(0);
+  });
+
+  it('retains one initialization when hidden then visible before starting completes', async () => {
+    const resume = deferred<void>();
+    const harness = createHarness({ resume });
+    const controller = createAudioController({ createGraph: harness.createGraph });
+
+    const starting = controller.startFromGesture();
+    controller.setVisible(false);
+    controller.setVisible(true);
+    resume.resolve();
+    await starting;
+
+    expect(controller.snapshot().kind).toBe('running');
+    expect(harness.constructed).toBe(1);
+    expect(harness.graph.suspend).not.toHaveBeenCalled();
+    expect(harness.graph.connectOutput).toHaveBeenCalledOnce();
+  });
+
+  it('finishes an interrupted initialization only into safely suspended user-required state', async () => {
+    const resume = deferred<void>();
+    const harness = createHarness({ resume });
+    const controller = createAudioController({ createGraph: harness.createGraph });
+
+    const starting = controller.startFromGesture();
+    controller.noteInterruption();
+    resume.resolve();
+    await starting;
+
+    expect(controller.snapshot()).toEqual({ kind: 'suspended', resumeRequiresGesture: true });
+    expect(harness.graph.connectOutput).not.toHaveBeenCalled();
+    expect(harness.graph.suspend).toHaveBeenCalledOnce();
+  });
+
+  it('automatically suspends and resumes an intact graph across visibility and persisted BFCache', async () => {
+    const harness = createHarness();
+    const controller = createAudioController({ createGraph: harness.createGraph });
+    await controller.startFromGesture();
+
+    await controller.pageHide(true);
+    expect(controller.snapshot()).toEqual({ kind: 'suspended', resumeRequiresGesture: false });
+    expect(harness.graph.disconnectOutput).toHaveBeenCalledOnce();
+
+    await controller.pageShow(true);
+    expect(controller.snapshot()).toEqual({ kind: 'running', muted: false, volume: 0.4 });
+    expect(harness.constructed).toBe(1);
+    expect(harness.graph.resume).toHaveBeenCalledTimes(2);
+    expect(harness.graph.connectOutput).toHaveBeenCalledTimes(2);
+  });
+
+  it('honors a visible event that arrives before a running suspension completes', async () => {
+    const suspension = deferred<void>();
+    const harness = createHarness({ suspend: suspension });
+    const controller = createAudioController({ createGraph: harness.createGraph });
+    await controller.startFromGesture();
+
+    const hiding = controller.setVisible(false);
+    const showing = controller.setVisible(true);
+    suspension.resolve();
+    await Promise.all([hiding, showing]);
+    await controller.whenSettled();
+
+    expect(controller.snapshot()).toEqual({ kind: 'running', muted: false, volume: 0.4 });
+    expect(harness.graph.suspend).toHaveBeenCalledOnce();
+    expect(harness.graph.resume).toHaveBeenCalledTimes(2);
+    expect(harness.constructed).toBe(1);
+  });
+
+  it('does not convert an interruption into automatic resume on later visibility events', async () => {
+    const harness = createHarness();
+    const controller = createAudioController({ createGraph: harness.createGraph });
+    await controller.startFromGesture();
+
+    await controller.noteInterruption();
+    await controller.setVisible(false);
+    await controller.setVisible(true);
+
+    expect(controller.snapshot()).toEqual({ kind: 'suspended', resumeRequiresGesture: true });
+    expect(harness.graph.resume).toHaveBeenCalledOnce();
+
+    await controller.resumeFromGesture();
+    expect(controller.snapshot().kind).toBe('running');
+    expect(harness.constructed).toBe(1);
+    expect(harness.graph.resume).toHaveBeenCalledTimes(2);
+  });
+
+  it('enters a recoverable visible failure when the first explicit start rejects', async () => {
+    const harness = createHarness({ resumeRejects: true });
+    const controller = createAudioController({ createGraph: harness.createGraph });
+
+    await controller.startFromGesture();
+
+    expect(controller.snapshot()).toEqual({ kind: 'failed', message: 'Audio unavailable' });
+    expect(harness.graph.setOutputGain).toHaveBeenLastCalledWith(0);
+    expect(harness.graph.disconnectOutput).toHaveBeenCalledOnce();
+    expect(harness.graph.close).toHaveBeenCalledOnce();
+  });
+
+  it('keeps an existing graph suspended and user-recoverable when automatic resume rejects', async () => {
+    const harness = createHarness();
+    const controller = createAudioController({ createGraph: harness.createGraph });
+    await controller.startFromGesture();
+    await controller.setVisible(false);
+    harness.rejectNextResume();
+
+    await controller.setVisible(true);
+
+    expect(controller.snapshot()).toEqual({ kind: 'suspended', resumeRequiresGesture: true });
+    expect(harness.graph.close).not.toHaveBeenCalled();
+    expect(harness.constructed).toBe(1);
+  });
+
+  it('forces silence, closes once, and fails when suspension cannot be guaranteed', async () => {
+    const harness = createHarness({ suspendRejects: true });
+    const controller = createAudioController({ createGraph: harness.createGraph });
+    await controller.startFromGesture();
+
+    await controller.setVisible(false);
+    await controller.setVisible(true);
+
+    expect(controller.snapshot()).toEqual({ kind: 'failed', message: 'Audio unavailable' });
+    expect(harness.graph.setOutputGain).toHaveBeenLastCalledWith(0);
+    expect(harness.graph.disconnectOutput).toHaveBeenCalled();
+    expect(harness.graph.close).toHaveBeenCalledOnce();
+  });
+
+  it('invalidates a pending start and closes exactly once on final pagehide or repeated disposal', async () => {
+    const resume = deferred<void>();
+    const harness = createHarness({ resume });
+    const controller = createAudioController({ createGraph: harness.createGraph });
+    const starting = controller.startFromGesture();
+
+    const closing = controller.pageHide(false);
+    controller.dispose();
+    resume.resolve();
+    await Promise.all([starting, closing]);
+    await controller.whenSettled();
+
+    expect(controller.snapshot()).toEqual({ kind: 'disposed' });
+    expect(harness.graph.connectOutput).not.toHaveBeenCalled();
+    expect(harness.graph.close).toHaveBeenCalledOnce();
+  });
+
+  it('ignores lifecycle events before activation and after failure without creating another graph', async () => {
+    const harness = createHarness({ resumeRejects: true });
+    const controller = createAudioController({ createGraph: harness.createGraph });
+
+    await controller.setVisible(false);
+    await controller.pageShow(true);
+    expect(harness.constructed).toBe(0);
+    await controller.startFromGesture();
+    await controller.setVisible(true);
+    await controller.pageShow(true);
+
+    expect(harness.constructed).toBe(1);
+    expect(controller.snapshot().kind).toBe('failed');
+  });
+
+  it('clamps and slowly smooths drive intensity before forwarding it to the graph', async () => {
+    const harness = createHarness();
+    const controller = createAudioController({ createGraph: harness.createGraph });
+    await controller.startFromGesture();
+
+    controller.setIntensity(2);
+    controller.setIntensity(Number.NaN);
+
+    expect(harness.graph.setIntensity).toHaveBeenNthCalledWith(3, 0.12);
+    expect(harness.graph.setIntensity).toHaveBeenNthCalledWith(4, 0.1056);
+  });
+});
+
+describe('procedural audio graph', () => {
+  it('builds an original oscillator, filtered-noise, gain, and dynamics bed while output stays disconnected', async () => {
+    const context = new FakeAudioContext();
+
+    const graph = createSynthEngine(() => context as unknown as AudioContext);
+
+    expect(context.oscillators).toHaveLength(3);
+    expect(context.bufferSources).toHaveLength(1);
+    expect(context.filters).toHaveLength(2);
+    expect(context.gains.length).toBeGreaterThanOrEqual(4);
+    expect(context.compressors).toHaveLength(1);
+    expect(context.startedNodes).toBe(4);
+    expect(context.destinationConnections).toBe(0);
+
+    graph.connectOutput();
+    graph.setOutputGain(0.6);
+    graph.setIntensity(1);
+    expect(context.destinationConnections).toBe(1);
+    expect(context.parameters.some((parameter) => parameter.targetValues.includes(930))).toBe(true);
+
+    graph.disconnectOutput();
+    await graph.close();
+    await graph.close();
+    expect(context.destinationConnections).toBe(0);
+    expect(context.closeCalls).toBe(1);
+    expect(context.stoppedNodes).toBe(4);
+  });
+});
+
+interface HarnessOptions {
+  resume?: Deferred<void>;
+  suspend?: Deferred<void>;
+  resumeRejects?: boolean;
+  suspendRejects?: boolean;
+}
+
+function createHarness(options: HarnessOptions = {}) {
+  let rejectNextResume = options.resumeRejects === true;
+  const stateListeners = new Set<(state: string) => void>();
+  const graph: AudioGraph = {
+    resume: vi.fn(async () => {
+      if (options.resume) return options.resume.promise;
+      if (rejectNextResume) {
+        rejectNextResume = false;
+        throw new DOMException('blocked', 'NotAllowedError');
+      }
+    }),
+    suspend: vi.fn(async () => {
+      if (options.suspend) return options.suspend.promise;
+      if (options.suspendRejects) throw new Error('suspend failed');
+    }),
+    close: vi.fn(async () => undefined),
+    connectOutput: vi.fn(),
+    disconnectOutput: vi.fn(),
+    setOutputGain: vi.fn(),
+    setIntensity: vi.fn(),
+    onContextStateChange: vi.fn((listener) => {
+      stateListeners.add(listener);
+      return () => stateListeners.delete(listener);
+    }),
+  };
+  let constructed = 0;
+  const createGraph: AudioGraphFactory = () => {
+    constructed += 1;
+    return graph;
+  };
+  return {
+    graph,
+    createGraph,
+    get constructed() { return constructed; },
+    rejectNextResume() { rejectNextResume = true; },
+    emitState(state: string) { for (const listener of stateListeners) listener(state); },
+  };
+}
+
+interface Deferred<T> {
+  promise: Promise<T>;
+  resolve(value: T | PromiseLike<T>): void;
+  reject(reason?: unknown): void;
+}
+
+function deferred<T>(): Deferred<T> {
+  let resolve!: (value: T | PromiseLike<T>) => void;
+  let reject!: (reason?: unknown) => void;
+  const promise = new Promise<T>((onResolve, onReject) => {
+    resolve = onResolve;
+    reject = onReject;
+  });
+  return { promise, resolve, reject };
+}
+
+class FakeAudioParam {
+  value = 0;
+  readonly targetValues: number[] = [];
+
+  setValueAtTime(value: number): void { this.value = value; }
+  setTargetAtTime(value: number): void { this.targetValues.push(value); this.value = value; }
+  linearRampToValueAtTime(value: number): void { this.value = value; }
+  exponentialRampToValueAtTime(value: number): void { this.value = value; }
+  cancelScheduledValues(): void {}
+}
+
+class FakeNode extends EventTarget {
+  readonly connections = new Set<unknown>();
+  constructor(protected readonly owner: FakeAudioContext) { super(); }
+  connect(target: unknown): unknown {
+    this.connections.add(target);
+    if (target === this.owner.destination) this.owner.destinationConnections += 1;
+    return target;
+  }
+  disconnect(target?: unknown): void {
+    if (target === undefined) {
+      if (this.connections.delete(this.owner.destination)) this.owner.destinationConnections -= 1;
+      this.connections.clear();
+      return;
+    }
+    if (this.connections.delete(target) && target === this.owner.destination) this.owner.destinationConnections -= 1;
+  }
+}
+
+class FakeScheduledNode extends FakeNode {
+  start(): void { this.owner.startedNodes += 1; }
+  stop(): void { this.owner.stoppedNodes += 1; }
+}
+
+class FakeAudioContext extends EventTarget {
+  readonly destination = {};
+  readonly sampleRate = 8_000;
+  readonly currentTime = 0;
+  readonly parameters: FakeAudioParam[] = [];
+  readonly oscillators: Array<FakeScheduledNode & { type: string; frequency: FakeAudioParam }> = [];
+  readonly bufferSources: Array<FakeScheduledNode & { buffer: unknown; loop: boolean }> = [];
+  readonly filters: Array<FakeNode & { type: string; frequency: FakeAudioParam; Q: FakeAudioParam }> = [];
+  readonly gains: Array<FakeNode & { gain: FakeAudioParam }> = [];
+  readonly compressors: FakeNode[] = [];
+  destinationConnections = 0;
+  startedNodes = 0;
+  stoppedNodes = 0;
+  closeCalls = 0;
+  state: AudioContextState = 'suspended';
+
+  private parameter(value = 0): FakeAudioParam {
+    const parameter = new FakeAudioParam();
+    parameter.value = value;
+    this.parameters.push(parameter);
+    return parameter;
+  }
+
+  createOscillator() {
+    const node = Object.assign(new FakeScheduledNode(this), { type: 'sine', frequency: this.parameter(440) });
+    this.oscillators.push(node);
+    return node;
+  }
+  createBufferSource() {
+    const node = Object.assign(new FakeScheduledNode(this), { buffer: null as unknown, loop: false });
+    this.bufferSources.push(node);
+    return node;
+  }
+  createBiquadFilter() {
+    const node = Object.assign(new FakeNode(this), {
+      type: 'lowpass', frequency: this.parameter(350), Q: this.parameter(1),
+    });
+    this.filters.push(node);
+    return node;
+  }
+  createGain() {
+    const node = Object.assign(new FakeNode(this), { gain: this.parameter(1) });
+    this.gains.push(node);
+    return node;
+  }
+  createDynamicsCompressor() {
+    const node = new FakeNode(this);
+    this.compressors.push(node);
+    return node;
+  }
+  createBuffer(channels: number, length: number) {
+    const data = Array.from({ length: channels }, () => new Float32Array(length));
+    return { getChannelData: (channel: number) => data[channel] };
+  }
+  async resume(): Promise<void> { this.state = 'running'; }
+  async suspend(): Promise<void> { this.state = 'suspended'; }
+  async close(): Promise<void> { this.closeCalls += 1; this.state = 'closed'; }
+}