// Procedural sound engine (Web Audio) — no audio files.
// Synthesizes UI/game SFX and a gentle ambient background loop.

export type Sfx =
  | "click"
  | "cardPlay"
  | "deal"
  | "trump"
  | "trickWin"
  | "win"
  | "lose"
  | "message"
  | "notify"
  | "award"
  | "levelUp"
  | "purchase"
  | "kot";

const LS_SFX = "hokm.sfx";
const LS_MUSIC = "hokm.music";

function loadBool(key: string, def = true): boolean {
  if (typeof window === "undefined") return def;
  const v = localStorage.getItem(key);
  return v == null ? def : v === "1";
}

class SoundManager {
  private ctx: AudioContext | null = null;
  private master: GainNode | null = null;
  private musicGain: GainNode | null = null;
  private musicTimer: ReturnType<typeof setInterval> | null = null;
  private step = 0;

  sfxEnabled = loadBool(LS_SFX);
  musicEnabled = loadBool(LS_MUSIC);

  /** Must be called from a user gesture to unlock audio. */
  init() {
    if (typeof window === "undefined") return;
    if (!this.ctx) {
      const AC = window.AudioContext || (window as unknown as { webkitAudioContext: typeof AudioContext }).webkitAudioContext;
      if (!AC) return;
      this.ctx = new AC();
      this.master = this.ctx.createGain();
      this.master.gain.value = 0.5;
      this.master.connect(this.ctx.destination);
      this.musicGain = this.ctx.createGain();
      this.musicGain.gain.value = 0.12;
      this.musicGain.connect(this.master);
    }
    if (this.ctx.state === "suspended") void this.ctx.resume();
    if (this.musicEnabled) this.startMusic();
  }

  setSfxEnabled(b: boolean) {
    this.sfxEnabled = b;
    if (typeof window !== "undefined") localStorage.setItem(LS_SFX, b ? "1" : "0");
    if (b) this.init();
  }

  setMusicEnabled(b: boolean) {
    this.musicEnabled = b;
    if (typeof window !== "undefined") localStorage.setItem(LS_MUSIC, b ? "1" : "0");
    if (b) {
      this.init();
      this.startMusic();
    } else {
      this.stopMusic();
    }
  }

  private tone(
    freq: number,
    start: number,
    dur: number,
    opts: { type?: OscillatorType; gain?: number; to?: number } = {}
  ) {
    if (!this.ctx || !this.master) return;
    const osc = this.ctx.createOscillator();
    const g = this.ctx.createGain();
    osc.type = opts.type ?? "sine";
    osc.frequency.setValueAtTime(freq, start);
    if (opts.to) osc.frequency.exponentialRampToValueAtTime(opts.to, start + dur);
    const peak = opts.gain ?? 0.3;
    g.gain.setValueAtTime(0.0001, start);
    g.gain.exponentialRampToValueAtTime(peak, start + 0.012);
    g.gain.exponentialRampToValueAtTime(0.0001, start + dur);
    osc.connect(g);
    g.connect(this.master);
    osc.start(start);
    osc.stop(start + dur + 0.02);
  }

  private seq(notes: [number, number][], gap = 0.11, opts?: { type?: OscillatorType; gain?: number }) {
    if (!this.ctx) return;
    const t0 = this.ctx.currentTime;
    notes.forEach(([freq, dur], i) => this.tone(freq, t0 + i * gap, dur, opts));
  }

  play(name: Sfx) {
    if (!this.sfxEnabled) return;
    this.init();
    if (!this.ctx) return;
    const t = this.ctx.currentTime;
    switch (name) {
      case "click":
        this.tone(520, t, 0.06, { type: "square", gain: 0.12 });
        break;
      case "cardPlay":
        this.tone(360, t, 0.09, { type: "triangle", gain: 0.18, to: 220 });
        break;
      case "deal":
        for (let i = 0; i < 4; i++)
          this.tone(320 + i * 20, t + i * 0.08, 0.07, { type: "triangle", gain: 0.14, to: 200 });
        break;
      case "trump":
        this.seq([[440, 0.12], [660, 0.18]], 0.1, { type: "sine", gain: 0.25 });
        break;
      case "trickWin":
        this.seq([[880, 0.12], [1320, 0.16]], 0.08, { type: "sine", gain: 0.22 });
        break;
      case "win":
        this.seq([[523, 0.16], [659, 0.16], [784, 0.16], [1047, 0.4]], 0.13, { type: "sine", gain: 0.3 });
        break;
      case "lose":
        this.seq([[440, 0.2], [392, 0.2], [311, 0.45]], 0.16, { type: "triangle", gain: 0.25 });
        break;
      case "message":
        this.tone(720, t, 0.1, { type: "sine", gain: 0.2, to: 900 });
        break;
      case "notify":
        this.seq([[660, 0.12], [880, 0.14]], 0.1, { type: "sine", gain: 0.2 });
        break;
      case "award":
        this.seq([[784, 0.1], [988, 0.1], [1319, 0.25]], 0.09, { type: "sine", gain: 0.25 });
        break;
      case "levelUp":
        this.seq([[523, 0.1], [659, 0.1], [784, 0.1], [988, 0.1], [1319, 0.35]], 0.09, { type: "sine", gain: 0.28 });
        break;
      case "purchase":
        this.seq([[1047, 0.08], [1319, 0.12]], 0.07, { type: "square", gain: 0.16 });
        break;
      case "kot":
        this.seq([[330, 0.14], [262, 0.14], [196, 0.4]], 0.12, { type: "sawtooth", gain: 0.2 });
        break;
    }
  }

  // Gentle ambient loop on a Persian-flavored scale (Dastgah-ish).
  private MUSIC = [293.66, 311.13, 392, 440, 466.16, 392, 311.13, 293.66];

  startMusic() {
    if (!this.musicEnabled || this.musicTimer || !this.ctx || !this.musicGain) return;
    const playNote = () => {
      if (!this.ctx || !this.musicGain) return;
      const freq = this.MUSIC[this.step % this.MUSIC.length];
      this.step++;
      const osc = this.ctx.createOscillator();
      const g = this.ctx.createGain();
      const t = this.ctx.currentTime;
      osc.type = "sine";
      osc.frequency.value = freq;
      g.gain.setValueAtTime(0.0001, t);
      g.gain.exponentialRampToValueAtTime(0.5, t + 0.3);
      g.gain.exponentialRampToValueAtTime(0.0001, t + 1.6);
      osc.connect(g);
      g.connect(this.musicGain);
      osc.start(t);
      osc.stop(t + 1.7);
      // soft fifth harmony every other note
      if (this.step % 2 === 0) {
        const o2 = this.ctx.createOscillator();
        const g2 = this.ctx.createGain();
        o2.type = "sine";
        o2.frequency.value = freq * 1.5;
        g2.gain.setValueAtTime(0.0001, t);
        g2.gain.exponentialRampToValueAtTime(0.22, t + 0.3);
        g2.gain.exponentialRampToValueAtTime(0.0001, t + 1.4);
        o2.connect(g2);
        g2.connect(this.musicGain);
        o2.start(t);
        o2.stop(t + 1.5);
      }
    };
    playNote();
    this.musicTimer = setInterval(playNote, 900);
  }

  stopMusic() {
    if (this.musicTimer) {
      clearInterval(this.musicTimer);
      this.musicTimer = null;
    }
  }
}

export const sound = new SoundManager();