#!/bin/bash
# Generate practice audio assets.
# Prerequisites: Node.js, Python 3, edge-tts (pip install edge-tts)
set -e

AUDIO_DIR="$(cd "$(dirname "$0")/../public/audio" && pwd)"
mkdir -p "$AUDIO_DIR"

echo "=== Generating chime sounds (Node.js) ==="
node -e "
const fs = require('fs');

function writeWav(filename, buildSamples, sampleRate, durationSec) {
  const numSamples = Math.floor(sampleRate * durationSec);
  const samples = new Float32Array(numSamples);
  buildSamples(samples, sampleRate, durationSec);

  // Convert to 16-bit PCM
  const buffer = Buffer.alloc(44 + numSamples * 2);
  buffer.write('RIFF', 0);
  buffer.writeUInt32LE(36 + numSamples * 2, 4);
  buffer.write('WAVE', 8);
  buffer.write('fmt ', 12);
  buffer.writeUInt32LE(16, 16);       // chunk size
  buffer.writeUInt16LE(1, 20);        // PCM
  buffer.writeUInt16LE(1, 22);        // mono
  buffer.writeUInt32LE(sampleRate, 24);
  buffer.writeUInt32LE(sampleRate * 2, 28); // byte rate
  buffer.writeUInt16LE(2, 32);        // block align
  buffer.writeUInt16LE(16, 34);       // bits per sample
  buffer.write('data', 36);
  buffer.writeUInt32LE(numSamples * 2, 40);

  for (let i = 0; i < numSamples; i++) {
    const s = Math.max(-1, Math.min(1, samples[i]));
    buffer.writeInt16LE(Math.round(s * 32767), 44 + i * 2);
  }
  fs.writeFileSync(filename, buffer);
  console.log('  Created:', filename);
}

// Bell-like chime: two sine harmonics (fundamental + octave) with quick decay
function bellTone(t, freq1, freq2, tStart, duration) {
  if (t < tStart || t > tStart + duration) return 0;
  const localT = (t - tStart) / duration;
  const env = Math.exp(-localT * 6);  // quick exponential decay
  return 0.35 * env * (
    Math.sin(2 * Math.PI * freq1 * t) * 0.6 +
    Math.sin(2 * Math.PI * freq2 * t) * 0.4
  );
}

// Start chime — welcoming ascending bell, 2s
writeWav('$AUDIO_DIR/start-chime.wav', (samples, sr, dur) => {
  for (let i = 0; i < samples.length; i++) {
    const t = i / sr;
    let v = 0;
    v += bellTone(t, 523.25, 1046.5, 0, 0.9);    // C5
    v += bellTone(t, 659.25, 1318.5, 0.15, 0.8);   // E5
    v += bellTone(t, 783.99, 1568.0, 0.3, 0.7);    // G5
    samples[i] = v;
  }
}, 44100, 1.8);

// Soft tick — very short click, 0.08s
writeWav('$AUDIO_DIR/tick.wav', (samples, sr) => {
  for (let i = 0; i < samples.length; i++) {
    const t = i / sr;
    const env = Math.exp(-t * 80);
    samples[i] = 0.12 * env * Math.sin(2 * Math.PI * 1200 * t);
  }
}, 44100, 0.08);

// End chime — resonant closing chord, 3s
writeWav('$AUDIO_DIR/end-chime.wav', (samples, sr, dur) => {
  for (let i = 0; i < samples.length; i++) {
    const t = i / sr;
    let v = 0;
    v += bellTone(t, 261.63, 523.25, 0, 1.5);      // C4 (deeper)
    v += bellTone(t, 329.63, 659.25, 0.12, 1.3);    // E4
    v += bellTone(t, 392.00, 783.99, 0.24, 1.1);    // G4
    v += bellTone(t, 523.25, 1046.5, 0.36, 0.9);    // C5
    samples[i] = v * 0.9;
  }
}, 44100, 3.0);

console.log('Chimes done.');
"

echo ""
echo "=== Generating voice guidance (Edge TTS neural voices → mp3) ==="

# Chinese — Xiaoxiao (warm, mature female)
python3 -m edge_tts --voice "zh-CN-XiaoxiaoNeural" --rate="-40%" --text "继续专注，你做得很好。" --write-media "$AUDIO_DIR/mid-guidance-zh.mp3"
echo "  Created: mid-guidance-zh.mp3"

python3 -m edge_tts --voice "zh-CN-XiaoxiaoNeural" --rate="-40%" --text "练习完成。请记录你的感受。" --write-media "$AUDIO_DIR/end-guidance-zh.mp3"
echo "  Created: end-guidance-zh.mp3"

# English — Aria (neutral, professional female)
python3 -m edge_tts --voice "en-US-AriaNeural" --rate="-40%" --text "Stay focused. You're doing well." --write-media "$AUDIO_DIR/mid-guidance-en.mp3"
echo "  Created: mid-guidance-en.mp3"

python3 -m edge_tts --voice "en-US-AriaNeural" --rate="-40%" --text "Practice complete. Take a moment to reflect." --write-media "$AUDIO_DIR/end-guidance-en.mp3"
echo "  Created: end-guidance-en.mp3"

echo ""
echo "=== All audio assets generated in $AUDIO_DIR ==="
ls -lh "$AUDIO_DIR"