// Audio utility for toast notifications using Web Audio API

class AudioManager {
  private audioContext: AudioContext | null = null;

  private getAudioContext(): AudioContext {
    if (!this.audioContext) {
      this.audioContext = new (window.AudioContext || (window as any).webkitAudioContext)();
    }
    return this.audioContext;
  }

  // Generate a simple tone using oscillator
  private playTone(frequency: number, duration: number, type: OscillatorType = 'sine', volume: number = 0.3) {
    try {
      const ctx = this.getAudioContext();
      const oscillator = ctx.createOscillator();
      const gainNode = ctx.createGain();

      oscillator.connect(gainNode);
      gainNode.connect(ctx.destination);

      oscillator.frequency.value = frequency;
      oscillator.type = type;

      gainNode.gain.setValueAtTime(volume, ctx.currentTime);
      gainNode.gain.exponentialRampToValueAtTime(0.01, ctx.currentTime + duration);

      oscillator.start(ctx.currentTime);
      oscillator.stop(ctx.currentTime + duration);
    } catch (error) {
      console.error('Error playing audio:', error);
    }
  }

  // Success sound - pleasant ascending tones
  playSuccess() {
    const ctx = this.getAudioContext();
    const now = ctx.currentTime;

    // First tone
    this.playToneAt(523.25, 0.08, 'sine', 0.2, now); // C5
    // Second tone
    this.playToneAt(659.25, 0.08, 'sine', 0.2, now + 0.08); // E5
    // Third tone
    this.playToneAt(783.99, 0.15, 'sine', 0.25, now + 0.16); // G5
  }

  // Error sound - descending tones
  playError() {
    const ctx = this.getAudioContext();
    const now = ctx.currentTime;

    // First tone
    this.playToneAt(392.00, 0.1, 'square', 0.15, now); // G4
    // Second tone
    this.playToneAt(329.63, 0.2, 'square', 0.2, now + 0.1); // E4
  }

  // Warning sound - alternating tones
  playWarning() {
    const ctx = this.getAudioContext();
    const now = ctx.currentTime;

    // First tone
    this.playToneAt(440.00, 0.1, 'triangle', 0.2, now); // A4
    // Second tone
    this.playToneAt(493.88, 0.1, 'triangle', 0.2, now + 0.12); // B4
  }

  // Info sound - single soft tone
  playInfo() {
    this.playTone(523.25, 0.15, 'sine', 0.15); // C5
  }

  // Helper method to play tone at specific time
  private playToneAt(frequency: number, duration: number, type: OscillatorType, volume: number, startTime: number) {
    try {
      const ctx = this.getAudioContext();
      const oscillator = ctx.createOscillator();
      const gainNode = ctx.createGain();

      oscillator.connect(gainNode);
      gainNode.connect(ctx.destination);

      oscillator.frequency.value = frequency;
      oscillator.type = type;

      gainNode.gain.setValueAtTime(volume, startTime);
      gainNode.gain.exponentialRampToValueAtTime(0.01, startTime + duration);

      oscillator.start(startTime);
      oscillator.stop(startTime + duration);
    } catch (error) {
      console.error('Error playing audio:', error);
    }
  }
}

// Export singleton instance
export const audioManager = new AudioManager();

// Helper functions for easy use
export const playSuccessSound = () => audioManager.playSuccess();
export const playErrorSound = () => audioManager.playError();
export const playWarningSound = () => audioManager.playWarning();
export const playInfoSound = () => audioManager.playInfo();