class PCM16CaptureProcessor extends AudioWorkletProcessor {
  constructor(options) {
    super();
    this.targetRate = Number(options.processorOptions?.targetSampleRate || 16000);
    this.frameSamples = Number(options.processorOptions?.frameSamples || 320);
    this.ratio = sampleRate / this.targetRate;
    this.source = [];
    this.position = 0;
    this.output = [];
  }

  process(inputs) {
    const channel = inputs[0]?.[0];
    if (!channel?.length) return true;
    for (const sample of channel) this.source.push(sample);
    while (this.position + this.ratio <= this.source.length) {
      const start = Math.floor(this.position);
      const end = Math.max(start + 1, Math.floor(this.position + this.ratio));
      let sum = 0;
      for (let index = start; index < end && index < this.source.length; index += 1) sum += this.source[index];
      this.output.push(sum / Math.max(1, end - start));
      this.position += this.ratio;
      if (this.output.length >= this.frameSamples) this.flush();
    }
    const consumed = Math.floor(this.position);
    if (consumed > 0) {
      this.source.splice(0, consumed);
      this.position -= consumed;
    }
    return true;
  }

  flush() {
    const frame = this.output.splice(0, this.frameSamples);
    const pcm = new Int16Array(frame.length);
    let energy = 0;
    for (let index = 0; index < frame.length; index += 1) {
      const sample = Math.max(-1, Math.min(1, frame[index]));
      energy += sample * sample;
      pcm[index] = sample < 0 ? Math.round(sample * 32768) : Math.round(sample * 32767);
    }
    const volume = Math.min(100, Math.round(Math.sqrt(energy / Math.max(1, frame.length)) * 280));
    this.port.postMessage({ type: "pcm", bytes: pcm.buffer, volume }, [pcm.buffer]);
  }
}

registerProcessor("pcm16-capture", PCM16CaptureProcessor);