'use strict';

let audioCtx = null;

function getAudio() {
  if (!audioCtx) audioCtx = new (window.AudioContext || window.webkitAudioContext)();
  return audioCtx;
}

function beep(freq, freq2, dur, type = 'sine', vol = 0.3) {
  try {
    const ac = getAudio();
    const o  = ac.createOscillator();
    const g  = ac.createGain();
    o.type = type;
    o.connect(g); g.connect(ac.destination);
    o.frequency.setValueAtTime(freq, ac.currentTime);
    if (freq2 && freq2 !== freq) o.frequency.exponentialRampToValueAtTime(freq2, ac.currentTime + dur);
    g.gain.setValueAtTime(vol, ac.currentTime);
    g.gain.exponentialRampToValueAtTime(0.001, ac.currentTime + dur);
    o.start(ac.currentTime);
    o.stop(ac.currentTime + dur + 0.01);
  } catch(e) {}
}

const SFX = {
  jump:      () => beep(280, 560, 0.18, 'sine',     0.25),
  attack:    () => beep(140, 70,  0.12, 'sawtooth', 0.30),
  stomp:     () => { beep(200, 80, 0.1, 'square', 0.35); beep(400, 400, 0.08, 'sine', 0.2); },
  hurt:      () => beep(180, 90,  0.28, 'square',   0.40),
  die:       () => beep(380, 50,  0.80, 'square',   0.40),
  collect:   () => beep(550, 880, 0.10, 'sine',     0.20),
  heart:     () => { beep(660, 660, 0.06, 'sine', 0.2); setTimeout(() => beep(880, 880, 0.12, 'sine', 0.2), 70); },
  killEnemy: () => beep(260, 100, 0.25, 'sawtooth', 0.28),
  combo:     (n) => beep(440 + n * 40, 550 + n * 40, 0.08, 'sine', 0.18),
  levelUp:   () => {
    [523, 659, 784, 1047].forEach((f, i) =>
      setTimeout(() => beep(f, f, i === 3 ? 0.25 : 0.08, 'sine', 0.28), i * 100)
    );
  },
};

// ─── Background Music ─────────────────────────────────────────────────────────
let _musicTimer = null;
let _musicStep  = 0;

const MUSIC = {
  menu:  { bpm: 112, notes: [392,0,523,0,659,523,392,330, 392,0,523,659,784,659,523,0] },
  grass: { bpm: 132, notes: [523,0,659,0,784,659,523,0, 440,0,523,0,659,523,440,0] },
  cave:  { bpm:  96, notes: [294,0,330,0,262,0,294,0, 220,0,247,0,262,0,220,0] },
  ice:   { bpm: 108, notes: [440,0,494,523,587,0,523,494, 440,0,392,0,440,494,523,0] },
};

function startMusic(theme) {
  stopMusic();
  try { getAudio(); } catch(e) { return; }
  const pat = MUSIC[theme] || MUSIC.menu;
  const beatMs = (60000 / pat.bpm) / 2; // eighth-note duration
  _musicStep = 0;

  const tick = () => {
    const freq = pat.notes[_musicStep % pat.notes.length];
    if (freq > 0) {
      beep(freq / 2, freq / 2, beatMs / 1000 * 0.75, 'square',   0.04);
      if (_musicStep % 2 === 0) beep(freq, freq, beatMs / 1000 * 0.55, 'triangle', 0.05);
    }
    _musicStep++;
    _musicTimer = setTimeout(tick, beatMs);
  };
  _musicTimer = setTimeout(tick, 0);
}

function stopMusic() {
  if (_musicTimer) { clearTimeout(_musicTimer); _musicTimer = null; }
  _musicStep = 0;
}