class GameAudio {
  private ctx: AudioContext | null = null;
  private ambientOscillators: { osc: OscillatorNode; gain: GainNode }[] = [];
  private isAmbientPlaying = false;

  private initCtx() {
    if (!this.ctx) {
      const AudioCtx = window.AudioContext || (window as any).webkitAudioContext;
      if (AudioCtx) {
        this.ctx = new AudioCtx();
      }
    }
    if (this.ctx && this.ctx.state === 'suspended') {
      this.ctx.resume();
    }
    return this.ctx;
  }

  playPop() {
    const ctx = this.initCtx();
    if (!ctx) return;

    const osc = ctx.createOscillator();
    const gain = ctx.createGain();

    osc.connect(gain);
    gain.connect(ctx.destination);

    const now = ctx.currentTime;
    osc.type = 'sine';
    
    // Quick pitch decay from 800Hz to 150Hz
    osc.frequency.setValueAtTime(800, now);
    osc.frequency.exponentialRampToValueAtTime(150, now + 0.08);

    // Fast volume envelope
    gain.gain.setValueAtTime(0.3, now);
    gain.gain.exponentialRampToValueAtTime(0.001, now + 0.08);

    osc.start(now);
    osc.stop(now + 0.08);
  }

  playExplosion() {
    const ctx = this.initCtx();
    if (!ctx) return;

    const now = ctx.currentTime;
    
    // Create a noise buffer (white noise)
    const bufferSize = ctx.sampleRate * 0.3; // 0.3 seconds
    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;
    }

    const noise = ctx.createBufferSource();
    noise.buffer = buffer;

    // Filter to make it sound like a rumble/thud explosion
    const filter = ctx.createBiquadFilter();
    filter.type = 'lowpass';
    filter.frequency.setValueAtTime(1000, now);
    filter.frequency.exponentialRampToValueAtTime(10, now + 0.3);

    const gain = ctx.createGain();
    gain.gain.setValueAtTime(0.5, now);
    gain.gain.exponentialRampToValueAtTime(0.001, now + 0.3);

    noise.connect(filter);
    filter.connect(gain);
    gain.connect(ctx.destination);

    noise.start(now);
    noise.stop(now + 0.3);

    // Add a low sine sub-bass drop for punch
    const sub = ctx.createOscillator();
    const subGain = ctx.createGain();
    sub.type = 'sine';
    sub.frequency.setValueAtTime(120, now);
    sub.frequency.linearRampToValueAtTime(40, now + 0.2);

    subGain.gain.setValueAtTime(0.6, now);
    subGain.gain.exponentialRampToValueAtTime(0.001, now + 0.25);

    sub.connect(subGain);
    subGain.connect(ctx.destination);

    sub.start(now);
    sub.stop(now + 0.25);
  }

  playLaser() {
    const ctx = this.initCtx();
    if (!ctx) return;

    const osc = ctx.createOscillator();
    const gain = ctx.createGain();

    osc.connect(gain);
    gain.connect(ctx.destination);

    const now = ctx.currentTime;
    osc.type = 'sawtooth';

    // Sweep frequency up rapidly
    osc.frequency.setValueAtTime(200, now);
    osc.frequency.exponentialRampToValueAtTime(1500, now + 0.12);

    // Fast volume envelope
    gain.gain.setValueAtTime(0.15, now);
    gain.gain.exponentialRampToValueAtTime(0.001, now + 0.12);

    osc.start(now);
    osc.stop(now + 0.12);
  }

  playChime() {
    const ctx = this.initCtx();
    if (!ctx) return;

    const now = ctx.currentTime;
    const notes = [523.25, 659.25, 783.99, 1046.50]; // C5, E5, G5, C6 (Arpeggio)

    notes.forEach((freq, index) => {
      const osc = ctx.createOscillator();
      const gain = ctx.createGain();
      const delay = index * 0.06;

      osc.connect(gain);
      gain.connect(ctx.destination);

      osc.type = 'triangle';
      osc.frequency.setValueAtTime(freq, now + delay);

      gain.gain.setValueAtTime(0, now + delay);
      gain.gain.linearRampToValueAtTime(0.25, now + delay + 0.02);
      gain.gain.exponentialRampToValueAtTime(0.001, now + delay + 0.5);

      osc.start(now + delay);
      osc.stop(now + delay + 0.6);
    });
  }

  startAmbient() {
    const ctx = this.initCtx();
    if (!ctx || this.isAmbientPlaying) return;

    this.isAmbientPlaying = true;
    const now = ctx.currentTime;

    // A beautiful major pentatonic warm chord: C3, G3, C4, E4
    const freqs = [130.81, 196.00, 261.63, 329.63];

    this.ambientOscillators = freqs.map((freq) => {
      const osc = ctx.createOscillator();
      const gain = ctx.createGain();

      osc.type = 'sine';
      osc.frequency.value = freq;

      // Soft volume level
      gain.gain.setValueAtTime(0, now);
      gain.gain.linearRampToValueAtTime(0.025, now + 2.0); // Slow fade-in

      osc.connect(gain);
      gain.connect(ctx.destination);

      osc.start(now);

      return { osc, gain };
    });
  }

  stopAmbient() {
    if (!this.isAmbientPlaying) return;
    this.isAmbientPlaying = false;

    if (!this.ctx) return;
    const now = this.ctx.currentTime;

    this.ambientOscillators.forEach(({ osc, gain }) => {
      try {
        gain.gain.setValueAtTime(gain.gain.value, now);
        gain.gain.linearRampToValueAtTime(0, now + 1.5); // Slow fade-out
        setTimeout(() => {
          try {
            osc.stop();
          } catch {}
        }, 1600);
      } catch {}
    });

    this.ambientOscillators = [];
  }

  toggleAmbient() {
    if (this.isAmbientPlaying) {
      this.stopAmbient();
      return false;
    } else {
      this.startAmbient();
      return true;
    }
  }

  isPlayingAmbient() {
    return this.isAmbientPlaying;
  }
}

export const gameAudio = new GameAudio();