/**
 * Minimal float32 WAV encoder (format tag 3, IEEE float, mono). The
 * header is exactly 44 bytes with no extra chunks, which the offline
 * evaluation harness relies on: numbl has no audioread, so tools/load_wav.m
 * reads the rate at byte 24 and the samples from byte 44. Real MATLAB,
 * Python soundfile, and audio editors read these files normally.
 */
export function wavFloat32(samples: Float32Array, sr: number): Uint8Array {
  const dataLen = samples.length * 4;
  const buf = new ArrayBuffer(44 + dataLen);
  const v = new DataView(buf);
  const ascii = (off: number, s: string) => { for (let i = 0; i < s.length; i++) v.setUint8(off + i, s.charCodeAt(i)); };
  ascii(0, 'RIFF');
  v.setUint32(4, 36 + dataLen, true);
  ascii(8, 'WAVE');
  ascii(12, 'fmt ');
  v.setUint32(16, 16, true);        // fmt chunk size
  v.setUint16(20, 3, true);         // IEEE float
  v.setUint16(22, 1, true);         // mono
  v.setUint32(24, sr, true);
  v.setUint32(28, sr * 4, true);    // byte rate
  v.setUint16(32, 4, true);         // block align
  v.setUint16(34, 32, true);        // bits per sample
  ascii(36, 'data');
  v.setUint32(40, dataLen, true);
  new Float32Array(buf, 44).set(samples);
  return new Uint8Array(buf);
}