// 16-bit mono PCM WAV, normalized to the given peak (default -1 dBFS).
export function encodeWav(x: Float32Array, fs: number, peak = 0.89): Blob {
  let m = 0;
  for (let i = 0; i < x.length; i++) m = Math.max(m, Math.abs(x[i]));
  const g = m > 0 ? peak / m : 0;
  const buf = new ArrayBuffer(44 + 2 * x.length);
  const v = new DataView(buf);
  const str = (o: number, s: string) => {
    for (let i = 0; i < s.length; i++) v.setUint8(o + i, s.charCodeAt(i));
  };
  str(0, 'RIFF');
  v.setUint32(4, 36 + 2 * x.length, true);
  str(8, 'WAVE');
  str(12, 'fmt ');
  v.setUint32(16, 16, true);
  v.setUint16(20, 1, true);
  v.setUint16(22, 1, true);
  v.setUint32(24, fs, true);
  v.setUint32(28, fs * 2, true);
  v.setUint16(32, 2, true);
  v.setUint16(34, 16, true);
  str(36, 'data');
  v.setUint32(40, 2 * x.length, true);
  for (let i = 0; i < x.length; i++) {
    const s = Math.max(-1, Math.min(1, x[i] * g));
    v.setInt16(44 + 2 * i, Math.round(s * 32767), true);
  }
  return new Blob([buf], { type: 'audio/wav' });
}