/**
 * AudioWorklet processor for VoicePaste.
 *
 * Captures raw Float32 PCM from the microphone, accumulates samples into
 * ~200ms frames, and posts them to the main thread for resampling + WS send.
 *
 * Communication:
 *   Main → Processor: { command: "start" | "stop" }
 *   Processor → Main: { type: "audio", samples: Float32Array, sampleRate: number }
 */
class AudioProcessor extends AudioWorkletProcessor {
  constructor() {
    super();
    this.recording = false;
    this.buffer = [];
    this.bufferLen = 0;
    // ~200ms worth of samples at current sample rate
    // sampleRate is a global in AudioWorkletGlobalScope
    this.frameSize = Math.floor(sampleRate * 0.2);

    this.port.onmessage = (e) => {
      if (e.data.command === "start") {
        this.recording = true;
        this.buffer = [];
        this.bufferLen = 0;
      } else if (e.data.command === "stop") {
        // Flush remaining samples
        if (this.bufferLen > 0) {
          this._flush();
        }
        this.recording = false;
      }
    };
  }

  process(inputs) {
    if (!this.recording) return true;

    const input = inputs[0];
    if (!input || !input[0]) return true;

    // Mono channel 0
    const channelData = input[0];
    this.buffer.push(new Float32Array(channelData));
    this.bufferLen += channelData.length;

    if (this.bufferLen >= this.frameSize) {
      this._flush();
    }

    return true;
  }

  _flush() {
    // Merge buffer chunks into a single Float32Array
    const merged = new Float32Array(this.bufferLen);
    let offset = 0;
    for (const chunk of this.buffer) {
      merged.set(chunk, offset);
      offset += chunk.length;
    }

    this.port.postMessage(
      { type: "audio", samples: merged, sampleRate: sampleRate },
      [merged.buffer] // Transfer ownership for zero-copy
    );

    this.buffer = [];
    this.bufferLen = 0;
  }
}

registerProcessor("audio-processor", AudioProcessor);