// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// DONAU2SPACE // DEV ENTITY — Audio Synth
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

let ctx = null;

function getCtx() {
  if (!ctx) {
    try { ctx = new (window.AudioContext || window.webkitAudioContext)(); }
    catch { return null; }
  }
  if (ctx.state === 'suspended') ctx.resume().catch(() => {});
  return ctx;
}

export function beep(freq = 880, ms = 70, vol = 0.04, type = 'square') {
  const ac = getCtx();
  if (!ac) return;
  const osc = ac.createOscillator();
  const gain = ac.createGain();
  osc.type = type;
  osc.frequency.value = freq;
  gain.gain.setValueAtTime(vol, ac.currentTime);
  gain.gain.exponentialRampToValueAtTime(0.001, ac.currentTime + ms / 1000);
  osc.connect(gain);
  gain.connect(ac.destination);
  osc.start();
  osc.stop(ac.currentTime + ms / 1000 + 0.05);
}

export function keyClick() {
  beep(800 + Math.random() * 400, 15, 0.008, 'sine');
}

export function errorBeep() {
  beep(220, 90, 0.05, 'square');
  setTimeout(() => beep(180, 120, 0.04, 'square'), 100);
}

export function successChime() {
  beep(523, 60, 0.03, 'sine');
  setTimeout(() => beep(659, 60, 0.03, 'sine'), 70);
  setTimeout(() => beep(784, 80, 0.03, 'sine'), 140);
}

export function warningTone() {
  beep(440, 150, 0.04, 'sawtooth');
  setTimeout(() => beep(440, 150, 0.04, 'sawtooth'), 200);
}

export function sirenBurst(duration = 800) {
  const ac = getCtx();
  if (!ac) return;
  const osc = ac.createOscillator();
  const gain = ac.createGain();
  osc.type = 'sawtooth';
  osc.frequency.setValueAtTime(200, ac.currentTime);
  osc.frequency.linearRampToValueAtTime(600, ac.currentTime + duration / 2000);
  osc.frequency.linearRampToValueAtTime(200, ac.currentTime + duration / 1000);
  gain.gain.setValueAtTime(0.03, ac.currentTime);
  gain.gain.exponentialRampToValueAtTime(0.001, ac.currentTime + duration / 1000);
  osc.connect(gain);
  gain.connect(ac.destination);
  osc.start();
  osc.stop(ac.currentTime + duration / 1000 + 0.05);
}

export function transmitSound() {
  const ac = getCtx();
  if (!ac) return;
  for (let i = 0; i < 8; i++) {
    setTimeout(() => {
      beep(1200 + Math.random() * 800, 30, 0.015, 'sine');
    }, i * 40);
  }
}

export function droneStart() {
  const ac = getCtx();
  if (!ac) return null;
  const osc = ac.createOscillator();
  const gain = ac.createGain();
  osc.type = 'sine';
  osc.frequency.value = 55;
  gain.gain.value = 0;
  gain.gain.linearRampToValueAtTime(0.015, ac.currentTime + 2);
  osc.connect(gain);
  gain.connect(ac.destination);
  osc.start();
  return { osc, gain, stop: () => {
    gain.gain.linearRampToValueAtTime(0.001, ac.currentTime + 1);
    setTimeout(() => { try { osc.stop(); } catch {} }, 1200);
  }};
}

export function bootSound() {
  beep(130, 200, 0.02, 'sine');
  setTimeout(() => beep(165, 200, 0.02, 'sine'), 200);
  setTimeout(() => beep(196, 300, 0.025, 'sine'), 400);
}