class VoiceCaptureProcessor extends AudioWorkletProcessor {
  constructor() {
    super();
    this.pending = [];
    this.pendingLength = 0;
    this.flushSamples = Math.max(1024, Math.floor(sampleRate * 0.25));
    this.totalSamples = 0;
    this.voiceSamples = 0;
    this.silentSamples = 0;
    this.trailingSilentSamples = 0;
    this.sumSquares = 0;
    this.peak = 0;
    this.voiceThreshold = 0.018;
    this.port.onmessage = (event) => {
      if (event.data && event.data.type === "flush") {
        this.flush();
      }
    };
  }

  process(inputs) {
    const input = inputs[0];
    const channel = input && input[0];
    if (!channel || channel.length === 0) return true;

    const pcm = new Int16Array(channel.length);
    for (let i = 0; i < channel.length; i += 1) {
      const sample = Math.max(-1, Math.min(1, channel[i]));
      const abs = Math.abs(sample);
      this.totalSamples += 1;
      this.sumSquares += sample * sample;
      if (abs > this.peak) this.peak = abs;
      if (abs >= this.voiceThreshold) {
        this.voiceSamples += 1;
        this.trailingSilentSamples = 0;
      } else {
        this.silentSamples += 1;
        this.trailingSilentSamples += 1;
      }
      pcm[i] = sample < 0 ? sample * 0x8000 : sample * 0x7fff;
    }

    this.pending.push(pcm);
    this.pendingLength += pcm.length;
    if (this.pendingLength >= this.flushSamples) {
      this.flush();
    }
    return true;
  }

  flush() {
    if (this.pendingLength <= 0) return;
    const merged = new Int16Array(this.pendingLength);
    let offset = 0;
    for (const chunk of this.pending) {
      merged.set(chunk, offset);
      offset += chunk.length;
    }
    this.pending = [];
    this.pendingLength = 0;
    this.port.postMessage(
      {
        type: "chunk",
        sampleRate,
        channels: 1,
        sampleWidth: 2,
        metrics: this.metrics(),
        pcm: merged.buffer,
      },
      [merged.buffer],
    );
  }

  metrics() {
    const durationMs = (this.totalSamples / sampleRate) * 1000;
    const voiceMs = (this.voiceSamples / sampleRate) * 1000;
    const silenceMs = (this.silentSamples / sampleRate) * 1000;
    const trailingSilenceMs = (this.trailingSilentSamples / sampleRate) * 1000;
    const rms = this.totalSamples > 0 ? Math.sqrt(this.sumSquares / this.totalSamples) : 0;
    return {
      durationMs,
      voiceMs,
      silenceMs,
      trailingSilenceMs,
      rms,
      peak: this.peak,
    };
  }
}

registerProcessor("voice-capture-processor", VoiceCaptureProcessor);