daniel-c-harvey
119 lines
3.8 KiB
TypeScript
119 lines
3.8 KiB
TypeScript
/**
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* AudioContextManager - Manages the Web Audio API AudioContext and GainNode.
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*
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* Single Responsibility: AudioContext lifecycle and audio routing.
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*
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* Audio chain: Source → GainNode → AnalyserNode → destination
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*/
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import { SpectrumAnalyzer } from './SpectrumAnalyzer.js';
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export class AudioContextManager {
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private audioContext: AudioContext | null = null;
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private gainNode: GainNode | null = null;
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private spectrumAnalyzer: SpectrumAnalyzer;
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constructor() {
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this.spectrumAnalyzer = new SpectrumAnalyzer();
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}
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async initialize(sampleRate: number = 44100): Promise<void> {
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const AudioContextClass = window.AudioContext || (window as any).webkitAudioContext;
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if (!AudioContextClass) {
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throw new Error('Web Audio API not supported');
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}
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this.audioContext = new AudioContextClass({ sampleRate });
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this.gainNode = this.audioContext.createGain();
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// Initialize spectrum analyzer and insert into chain
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// Chain: Source → GainNode → AnalyserNode → destination
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const analyserNode = this.spectrumAnalyzer.initialize(this.audioContext);
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this.gainNode.connect(analyserNode);
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analyserNode.connect(this.audioContext.destination);
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console.log(`AudioContext initialized: sampleRate=${this.audioContext.sampleRate}Hz, state=${this.audioContext.state}`);
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}
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async ensureReady(): Promise<void> {
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if (!this.audioContext) {
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throw new Error('AudioContext not initialized');
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}
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if (this.audioContext.state === 'suspended') {
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console.log('🔊 Resuming AudioContext');
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await this.audioContext.resume();
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console.log(`✅ AudioContext resumed: state=${this.audioContext.state}`);
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}
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}
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async recreateWithSampleRate(sampleRate: number): Promise<void> {
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if (!this.audioContext) {
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throw new Error('AudioContext not initialized');
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}
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if (this.audioContext.sampleRate === sampleRate) {
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return; // Already correct sample rate
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}
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console.log(`🔄 Recreating AudioContext: ${this.audioContext.sampleRate}Hz -> ${sampleRate}Hz`);
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await this.audioContext.close();
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await this.initialize(sampleRate);
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}
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getContext(): AudioContext {
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if (!this.audioContext) {
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throw new Error('AudioContext not initialized');
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}
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return this.audioContext;
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}
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getGainNode(): GainNode {
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if (!this.gainNode) {
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throw new Error('GainNode not initialized');
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}
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return this.gainNode;
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}
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get currentTime(): number {
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return this.audioContext?.currentTime ?? 0;
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}
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get sampleRate(): number {
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return this.audioContext?.sampleRate ?? 0;
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}
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get state(): AudioContextState | 'uninitialized' {
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return this.audioContext?.state ?? 'uninitialized';
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}
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setVolume(volume: number): void {
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if (!this.gainNode || !this.audioContext) return;
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const clampedVolume = Math.max(0, Math.min(1, volume));
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this.gainNode.gain.setValueAtTime(clampedVolume, this.audioContext.currentTime);
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}
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getVolume(): number {
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return this.gainNode?.gain.value ?? 0;
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}
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async decodeAudioData(buffer: ArrayBuffer): Promise<AudioBuffer> {
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if (!this.audioContext) {
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throw new Error('AudioContext not initialized');
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}
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return this.audioContext.decodeAudioData(buffer);
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}
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getSpectrumAnalyzer(): SpectrumAnalyzer {
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return this.spectrumAnalyzer;
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}
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dispose(): void {
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this.spectrumAnalyzer.dispose();
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if (this.audioContext && this.audioContext.state !== 'closed') {
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this.audioContext.close();
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}
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this.audioContext = null;
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this.gainNode = null;
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}
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}
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