/**
 * @file Sound effect utilities using the Web Audio API.
 * @copyright nhcarrigan
 * @license Naomi's Public License
 * @author Naomi Carrigan
 */

type SoundEvent =
  | "achievement"
  | "apotheosis"
  | "bossVictory"
  | "prestige"
  | "questCompleted"
  | "questFailed"
  | "transcendence";

interface SoundPattern {
  frequencies:  Array<number>;
  gain:         number;
  noteDuration: number;
  type:         OscillatorType;
}

// eslint-disable-next-line @typescript-eslint/naming-convention -- intentional constant name
const SOUND_PATTERNS: Record<SoundEvent, SoundPattern> = {
  achievement: {
    frequencies:  [ 523, 659, 784, 1047 ],
    gain:         0.3,
    noteDuration: 0.12,
    type:         "triangle",
  },
  apotheosis: {
    frequencies:  [ 1047, 880, 784, 659, 523 ],
    gain:         0.35,
    noteDuration: 0.25,
    type:         "sine",
  },
  bossVictory: {
    frequencies:  [ 523, 784, 1047 ],
    gain:         0.4,
    noteDuration: 0.18,
    type:         "square",
  },
  prestige: {
    frequencies:  [ 392, 523, 659, 784 ],
    gain:         0.35,
    noteDuration: 0.15,
    type:         "sawtooth",
  },
  questCompleted: {
    frequencies:  [ 523, 659 ],
    gain:         0.25,
    noteDuration: 0.15,
    type:         "sine",
  },
  questFailed: {
    frequencies:  [ 392, 330, 261 ],
    gain:         0.25,
    noteDuration: 0.18,
    type:         "triangle",
  },
  transcendence: {
    frequencies:  [ 261, 329, 392, 523 ],
    gain:         0.3,
    noteDuration: 0.3,
    type:         "sine",
  },
};

// eslint-disable-next-line @typescript-eslint/init-declarations -- lazily initialised on first use
let audioContext: AudioContext | undefined;

const getAudioContext = (): AudioContext => {
  if (audioContext === undefined) {
    audioContext = new AudioContext();
  }
  return audioContext;
};

/**
 * Plays a sound effect for a given game event using the Web Audio API.
 * @param event - The game event to play a sound for.
 */
const playSound = (event: SoundEvent): void => {
  try {
    const context = getAudioContext();
    const pattern = SOUND_PATTERNS[event];
    for (const [ index, frequency ] of pattern.frequencies.entries()) {
      const oscillator = context.createOscillator();
      const gainNode = context.createGain();
      oscillator.connect(gainNode);
      gainNode.connect(context.destination);
      oscillator.type = pattern.type;
      oscillator.frequency.value = frequency;
      const noteOffset = index * pattern.noteDuration;
      const startTime = context.currentTime + noteOffset;
      const endTime = startTime + pattern.noteDuration;
      gainNode.gain.setValueAtTime(0, startTime);
      gainNode.gain.linearRampToValueAtTime(pattern.gain, startTime + 0.01);
      gainNode.gain.linearRampToValueAtTime(0, endTime);
      oscillator.start(startTime);
      oscillator.stop(endTime);
    }
  } catch {
    // Silently ignore — audio may not be available in all environments
  }
};

export type { SoundEvent };
export { playSound };