let audioCtx: AudioContext | null = null;

function getCtx(): AudioContext {
  if (!audioCtx) {
    audioCtx = new AudioContext();
  }
  return audioCtx;
}

type OscillatorConfig = {
  freq: number;
  type: OscillatorType;
  duration: number;
  gain?: number;
};

function playTone(config: OscillatorConfig) {
  try {
    const ctx = getCtx();
    const osc = ctx.createOscillator();
    const gain = ctx.createGain();
    osc.type = config.type;
    osc.frequency.setValueAtTime(config.freq, ctx.currentTime);
    gain.gain.setValueAtTime(config.gain ?? 0.3, ctx.currentTime);
    gain.gain.exponentialRampToValueAtTime(0.001, ctx.currentTime + config.duration);
    osc.connect(gain);
    gain.connect(ctx.destination);
    osc.start(ctx.currentTime);
    osc.stop(ctx.currentTime + config.duration);
  } catch {
    // Audio not supported
  }
}

function playNoise(duration: number, gain = 0.15) {
  try {
    const ctx = getCtx();
    const bufferSize = Math.floor(ctx.sampleRate * duration);
    const buffer = ctx.createBuffer(1, bufferSize, ctx.sampleRate);
    const data = buffer.getChannelData(0);
    for (let i = 0; i < bufferSize; i++) {
      data[i] = (Math.random() * 2 - 1) * Math.pow(1 - i / bufferSize, 2);
    }
    const source = ctx.createBufferSource();
    source.buffer = buffer;
    const gainNode = ctx.createGain();
    gainNode.gain.setValueAtTime(gain, ctx.currentTime);
    gainNode.gain.exponentialRampToValueAtTime(0.001, ctx.currentTime + duration);
    source.connect(gainNode);
    gainNode.connect(ctx.destination);
    source.start();
  } catch {
    // Audio not supported
  }
}

export function playHonk() {
  playTone({ freq: 800, type: "square", duration: 0.08, gain: 0.2 });
  setTimeout(() => playTone({ freq: 600, type: "square", duration: 0.12, gain: 0.2 }), 80);
}

export function playReactorAlarm() {
  for (let i = 0; i < 4; i++) {
    setTimeout(() => {
      playTone({ freq: 440 + i * 110, type: "sawtooth", duration: 0.2, gain: 0.15 });
      setTimeout(() => playTone({ freq: 330 + i * 80, type: "sawtooth", duration: 0.2, gain: 0.15 }), 100);
    }, i * 300);
  }
}

export function playHullBreach() {
  playTone({ freq: 100, type: "sine", duration: 0.5, gain: 0.4 });
  setTimeout(() => playTone({ freq: 80, type: "sine", duration: 0.5, gain: 0.3 }), 200);
  playNoise(0.5, 0.1);
}

export function playExplosion() {
  playNoise(0.6, 0.4);
  playTone({ freq: 60, type: "sine", duration: 0.5, gain: 0.5 });
  setTimeout(() => playTone({ freq: 40, type: "sine", duration: 0.3, gain: 0.3 }), 200);
}

export function playMonster() {
  playTone({ freq: 80, type: "sawtooth", duration: 0.4, gain: 0.2 });
  setTimeout(() => playTone({ freq: 60, type: "sawtooth", duration: 0.4, gain: 0.15 }), 200);
  setTimeout(() => playTone({ freq: 50, type: "square", duration: 0.5, gain: 0.2 }), 400);
}

export function playDeath() {
  playTone({ freq: 400, type: "sine", duration: 0.15, gain: 0.2 });
  setTimeout(() => playTone({ freq: 300, type: "sine", duration: 0.15, gain: 0.2 }), 150);
  setTimeout(() => playTone({ freq: 200, type: "sine", duration: 0.3, gain: 0.2 }), 300);
}

export function playBingo() {
  const notes = [523, 659, 784, 1047];
  notes.forEach((freq, i) => {
    setTimeout(() => playTone({ freq, type: "square", duration: 0.2, gain: 0.2 }), i * 120);
  });
  setTimeout(() => playNoise(0.3, 0.1), 480);
}

export function playChaosRiser() {
  const pitches = [200, 250, 300, 400, 500, 600, 800, 1000];
  pitches.forEach((freq, i) => {
    setTimeout(() => playTone({ freq, type: "sawtooth", duration: 0.1, gain: 0.08 }), i * 50);
  });
}

export function playSoundUrl(url: string) {
  try {
    const audio = new Audio(url);
    audio.volume = 0.4;
    audio.play().catch(() => {});
  } catch {}
}

export function playSound(category: string, soundUrl?: string | null) {
  if (soundUrl) {
    playSoundUrl(soundUrl);
    return;
  }
  switch (category) {
    case "horn": playHonk(); break;
    case "alarm": playReactorAlarm(); break;
    case "flood": playHullBreach(); break;
    case "explosion": playExplosion(); break;
    case "monster": playMonster(); break;
    case "death": playDeath(); break;
    case "bingo": playBingo(); break;
    case "chaos": playChaosRiser(); break;
    default: playHonk(); break;
  }
}