/**
 * Continuous mic capture for streaming dictation.
 *
 * The AudioContext is created at 16 kHz so no resampling is needed here. Frames
 * arrive 128 samples at a time (8 ms), which would be ~125 postMessage calls per
 * second; they are batched to 480 samples (30 ms) instead -- the same frame size
 * the energy gate measures RMS over, so the gate never has to re-frame a partial
 * block.
 */
const BATCH = 480; // 30 ms at 16 kHz

class CaptureProcessor extends AudioWorkletProcessor {
    constructor() {
        super();
        this.buf = new Float32Array(BATCH);
        this.at = 0;
    }

    process(inputs) {
        const channel = inputs[0]?.[0];
        if (!channel) return true;
        for (let i = 0; i < channel.length; i++) {
            this.buf[this.at++] = channel[i];
            if (this.at === BATCH) {
                // Transfer a copy: `buf` is reused, and the render quantum's own
                // input buffer is recycled by the engine after process() returns.
                const out = this.buf.slice();
                this.port.postMessage(out, [out.buffer]);
                this.at = 0;
            }
        }
        return true;
    }
}

registerProcessor('ctc-capture', CaptureProcessor);