// The room's audio output: the mix (computed on the page by wai-live-web's integer mixer,
// live-compose §6) arrives as blocks of interleaved stereo 16-bit samples, and this
// processor plays them from a bounded queue. It mixes nothing itself: an AudioWorklet's
// scope has no text decoder for the wasm glue, so the mixer runs where the glue does.

class RoomMix extends AudioWorkletProcessor {
  constructor() {
    super();
    this.queue = [];
    this.at = 0;
    this.played = 0;
    this.underruns = 0;
    this.peak = 0;
    this.port.onmessage = (e) => {
      if (e.data && e.data.pcm) {
        this.queue.push(e.data.pcm);
        // At most half a second queued: the oldest goes first.
        while (this.queue.length > 25) this.queue.shift();
      }
    };
    this.tick = 0;
  }

  process(_inputs, outputs) {
    const out = outputs[0];
    const l = out[0], r = out[1] || out[0];
    for (let i = 0; i < l.length; i++) {
      let block = this.queue[0];
      if (!block) {
        l[i] = 0; r[i] = 0;
        if (i === 0) this.underruns++;
        continue;
      }
      const sl = block[this.at] / 32768, sr = block[this.at + 1] / 32768;
      l[i] = sl; r[i] = sr;
      const a = Math.abs(sl) > Math.abs(sr) ? Math.abs(sl) : Math.abs(sr);
      if (a > this.peak) this.peak = a;
      this.at += 2;
      this.played++;
      if (this.at >= block.length) { this.queue.shift(); this.at = 0; }
    }
    if (++this.tick % 100 === 0) this.port.postMessage({ played: this.played, underruns: this.underruns, peak: this.peak });
    return true;
  }
}

registerProcessor("room-mix", RoomMix);