import { mkdir, writeFile } from 'node:fs/promises';
import { join } from 'node:path';

const sampleRate = 44100;
const outputDir = join('src', 'assets', 'audio', 'sfx');

function envelope(time, start, duration) {
  const local = time - start;
  if (local < 0 || local > duration) {
    return 0;
  }
  const attack = 0.018;
  const release = Math.min(0.24, duration * 0.42);
  if (local < attack) {
    return local / attack;
  }
  if (local > duration - release) {
    return Math.max(0, (duration - local) / release);
  }
  return 1;
}

function tone(time, frequency, start, duration, gain, wave = 'sine') {
  const amp = envelope(time, start, duration) * gain;
  if (amp <= 0) {
    return 0;
  }
  const phase = Math.PI * 2 * frequency * (time - start);
  if (wave === 'triangle') {
    return amp * (2 / Math.PI) * Math.asin(Math.sin(phase));
  }
  if (wave === 'square') {
    return amp * Math.sign(Math.sin(phase));
  }
  return amp * Math.sin(phase);
}

function clamp(sample) {
  return Math.max(-0.92, Math.min(0.92, sample));
}

function levelUpSample(time) {
  const notes = [
    { start: 0, frequency: 523.25, gain: 0.22, duration: 0.52 },
    { start: 0.09, frequency: 659.25, gain: 0.2, duration: 0.56 },
    { start: 0.18, frequency: 783.99, gain: 0.18, duration: 0.62 },
    { start: 0.31, frequency: 1046.5, gain: 0.16, duration: 0.7 }
  ];

  const chord = notes.reduce((sum, note) => sum + tone(time, note.frequency, note.start, note.duration, note.gain), 0);
  const shimmer =
    tone(time, 1318.51, 0.42, 0.36, 0.055, 'triangle') +
    tone(time, 1567.98, 0.52, 0.28, 0.042, 'triangle');
  return clamp(chord + shimmer);
}

function bondResonanceSample(time) {
  const pulse =
    tone(time, 392, 0, 0.34, 0.1, 'triangle') +
    tone(time, 587.33, 0.04, 0.42, 0.13, 'triangle') +
    tone(time, 783.99, 0.1, 0.42, 0.11, 'sine') +
    tone(time, 1174.66, 0.2, 0.38, 0.065, 'sine');
  const sparkle =
    tone(time, 1567.98, 0.34, 0.24, 0.045, 'triangle') +
    tone(time, 1760, 0.42, 0.2, 0.035, 'triangle');
  const tremolo = 1 + Math.sin(time * Math.PI * 18) * 0.08;
  return clamp((pulse + sparkle) * tremolo);
}

function victoryFanfareSample(time) {
  const brass =
    tone(time, 392, 0, 0.26, 0.14, 'triangle') +
    tone(time, 493.88, 0.16, 0.26, 0.14, 'triangle') +
    tone(time, 587.33, 0.32, 0.28, 0.14, 'triangle') +
    tone(time, 783.99, 0.5, 0.58, 0.16, 'triangle');
  const harmony =
    tone(time, 196, 0, 0.92, 0.07, 'sine') +
    tone(time, 293.66, 0.5, 0.64, 0.06, 'sine') +
    tone(time, 987.77, 0.72, 0.34, 0.055, 'sine');
  return clamp(brass + harmony);
}

function defeatStingSample(time) {
  const low =
    tone(time, 174.61, 0, 0.46, 0.16, 'triangle') +
    tone(time, 146.83, 0.24, 0.52, 0.15, 'triangle') +
    tone(time, 110, 0.48, 0.56, 0.15, 'sine');
  const strike =
    tone(time, 87.31, 0, 0.18, 0.13, 'square') +
    tone(time, 261.63, 0.02, 0.16, 0.06, 'triangle');
  return clamp(low + strike);
}

function wavBuffer(samples) {
  const bytesPerSample = 2;
  const dataSize = samples.length * bytesPerSample;
  const buffer = Buffer.alloc(44 + dataSize);
  buffer.write('RIFF', 0);
  buffer.writeUInt32LE(36 + dataSize, 4);
  buffer.write('WAVE', 8);
  buffer.write('fmt ', 12);
  buffer.writeUInt32LE(16, 16);
  buffer.writeUInt16LE(1, 20);
  buffer.writeUInt16LE(1, 22);
  buffer.writeUInt32LE(sampleRate, 24);
  buffer.writeUInt32LE(sampleRate * bytesPerSample, 28);
  buffer.writeUInt16LE(bytesPerSample, 32);
  buffer.writeUInt16LE(16, 34);
  buffer.write('data', 36);
  buffer.writeUInt32LE(dataSize, 40);

  samples.forEach((sample, index) => {
    buffer.writeInt16LE(Math.round(sample * 32767), 44 + index * bytesPerSample);
  });
  return buffer;
}

const clips = [
  { name: 'level-up', duration: 1.12, sampleAt: levelUpSample },
  { name: 'bond-resonance', duration: 0.82, sampleAt: bondResonanceSample },
  { name: 'victory-fanfare', duration: 1.2, sampleAt: victoryFanfareSample },
  { name: 'defeat-sting', duration: 1.08, sampleAt: defeatStingSample }
];

await mkdir(outputDir, { recursive: true });
for (const clip of clips) {
  const samples = Array.from({ length: Math.floor(sampleRate * clip.duration) }, (_, index) => clip.sampleAt(index / sampleRate));
  const outputPath = join(outputDir, `${clip.name}.wav`);
  await writeFile(outputPath, wavBuffer(samples));
  console.log(`Generated ${outputPath}`);
}