refactor(split): rename DeepDrftWeb -> DeepDrftPublic and DeepDrftWeb.Client -> DeepDrftPublic.Client (Phase 4)

DeepDrftPublic/Interop/audio/AudioContextManager.ts

@@ -0,0 +1,118 @@
+/**
+ * AudioContextManager - Manages the Web Audio API AudioContext and GainNode.
+ *
+ * Single Responsibility: AudioContext lifecycle and audio routing.
+ *
+ * Audio chain: Source → GainNode → AnalyserNode → destination
+ */
+
+import { SpectrumAnalyzer } from './SpectrumAnalyzer.js';
+
+export class AudioContextManager {
+    private audioContext: AudioContext | null = null;
+    private gainNode: GainNode | null = null;
+    private spectrumAnalyzer: SpectrumAnalyzer;
+
+    constructor() {
+        this.spectrumAnalyzer = new SpectrumAnalyzer();
+    }
+
+    async initialize(sampleRate: number = 44100): Promise<void> {
+        const AudioContextClass = window.AudioContext || (window as any).webkitAudioContext;
+        if (!AudioContextClass) {
+            throw new Error('Web Audio API not supported');
+        }
+
+        this.audioContext = new AudioContextClass({ sampleRate });
+        this.gainNode = this.audioContext.createGain();
+
+        // Initialize spectrum analyzer and insert into chain
+        // Chain: Source → GainNode → AnalyserNode → destination
+        const analyserNode = this.spectrumAnalyzer.initialize(this.audioContext);
+        this.gainNode.connect(analyserNode);
+        analyserNode.connect(this.audioContext.destination);
+
+        console.log(`AudioContext initialized: sampleRate=${this.audioContext.sampleRate}Hz, state=${this.audioContext.state}`);
+    }
+
+    async ensureReady(): Promise<void> {
+        if (!this.audioContext) {
+            throw new Error('AudioContext not initialized');
+        }
+        if (this.audioContext.state === 'suspended') {
+            console.log('🔊 Resuming AudioContext');
+            await this.audioContext.resume();
+            console.log(`✅ AudioContext resumed: state=${this.audioContext.state}`);
+        }
+    }
+
+    async recreateWithSampleRate(sampleRate: number): Promise<void> {
+        if (!this.audioContext) {
+            throw new Error('AudioContext not initialized');
+        }
+
+        if (this.audioContext.sampleRate === sampleRate) {
+            return; // Already correct sample rate
+        }
+
+        console.log(`🔄 Recreating AudioContext: ${this.audioContext.sampleRate}Hz -> ${sampleRate}Hz`);
+        await this.audioContext.close();
+        await this.initialize(sampleRate);
+    }
+
+    getContext(): AudioContext {
+        if (!this.audioContext) {
+            throw new Error('AudioContext not initialized');
+        }
+        return this.audioContext;
+    }
+
+    getGainNode(): GainNode {
+        if (!this.gainNode) {
+            throw new Error('GainNode not initialized');
+        }
+        return this.gainNode;
+    }
+
+    get currentTime(): number {
+        return this.audioContext?.currentTime ?? 0;
+    }
+
+    get sampleRate(): number {
+        return this.audioContext?.sampleRate ?? 0;
+    }
+
+    get state(): AudioContextState | 'uninitialized' {
+        return this.audioContext?.state ?? 'uninitialized';
+    }
+
+    setVolume(volume: number): void {
+        if (!this.gainNode || !this.audioContext) return;
+        const clampedVolume = Math.max(0, Math.min(1, volume));
+        this.gainNode.gain.setValueAtTime(clampedVolume, this.audioContext.currentTime);
+    }
+
+    getVolume(): number {
+        return this.gainNode?.gain.value ?? 0;
+    }
+
+    async decodeAudioData(buffer: ArrayBuffer): Promise<AudioBuffer> {
+        if (!this.audioContext) {
+            throw new Error('AudioContext not initialized');
+        }
+        return this.audioContext.decodeAudioData(buffer);
+    }
+
+    getSpectrumAnalyzer(): SpectrumAnalyzer {
+        return this.spectrumAnalyzer;
+    }
+
+    dispose(): void {
+        this.spectrumAnalyzer.dispose();
+        if (this.audioContext && this.audioContext.state !== 'closed') {
+            this.audioContext.close();
+        }
+        this.audioContext = null;
+        this.gainNode = null;
+    }
+}