import { ooAudioBus } from "./oo-audio-bus";
import { readOoSoundEnabled } from "./oo-sound-pref";

const SESSION_KEY = "evoo_voice_mark_played";

function prefersReducedMotion(): boolean {
  if (typeof window === "undefined" || !window.matchMedia) return false;
  return window.matchMedia("(prefers-reduced-motion: reduce)").matches;
}

function hasPlayedThisSession(): boolean {
  if (typeof window === "undefined" || !window.sessionStorage) return true;
  return window.sessionStorage.getItem(SESSION_KEY) === "1";
}

function markPlayed(): void {
  if (typeof window === "undefined" || !window.sessionStorage) return;
  window.sessionStorage.setItem(SESSION_KEY, "1");
}

function playVoiceMarkOnContext(ctx: AudioContext) {
  const master = ooAudioBus.sfxDestination(ctx);
  const t0 = ctx.currentTime + 0.01;

  const eOsc = ctx.createOscillator();
  const eGain = ctx.createGain();
  const eFilter = ctx.createBiquadFilter();
  eFilter.type = "bandpass";
  eFilter.frequency.value = 480;
  eFilter.Q.value = 5;
  eOsc.type = "triangle";
  eOsc.frequency.setValueAtTime(320, t0);
  eGain.gain.setValueAtTime(0.0001, t0);
  eGain.gain.exponentialRampToValueAtTime(0.05, t0 + 0.02);
  eGain.gain.exponentialRampToValueAtTime(0.0001, t0 + 0.12);
  eOsc.connect(eFilter);
  eFilter.connect(eGain);
  eGain.connect(master);
  eOsc.start(t0);
  eOsc.stop(t0 + 0.14);

  const ooOsc = ctx.createOscillator();
  const ooGain = ctx.createGain();
  const ooFilter = ctx.createBiquadFilter();
  ooFilter.type = "bandpass";
  ooFilter.frequency.value = 360;
  ooFilter.Q.value = 4;
  ooOsc.type = "sine";
  ooOsc.frequency.setValueAtTime(280, t0 + 0.1);
  ooOsc.frequency.exponentialRampToValueAtTime(220, t0 + 0.38);
  ooGain.gain.setValueAtTime(0.0001, t0 + 0.1);
  ooGain.gain.exponentialRampToValueAtTime(0.055, t0 + 0.14);
  ooGain.gain.exponentialRampToValueAtTime(0.0001, t0 + 0.42);
  ooOsc.connect(ooFilter);
  ooFilter.connect(ooGain);
  ooGain.connect(master);
  ooOsc.start(t0 + 0.1);
  ooOsc.stop(t0 + 0.45);
}

class OoVoiceMarkEngine {
  maybePlayColdOpen() {
    if (!readOoSoundEnabled()) return;
    if (prefersReducedMotion()) return;
    if (hasPlayedThisSession()) return;

    const ctx = ooAudioBus.ensureContext();
    if (!ctx) return;

    const run = () => {
      try {
        playVoiceMarkOnContext(ctx);
        markPlayed();
      } catch {
        // Ignore playback failures.
      }
    };

    if (ctx.state === "suspended") {
      void ctx
        .resume()
        .then(run)
        .catch(() => undefined);
      return;
    }
    run();
  }
}

export const ooVoiceMark = new OoVoiceMarkEngine();

export function resetOoVoiceMarkForTests(): void {
  if (typeof window !== "undefined" && window.sessionStorage) {
    window.sessionStorage.removeItem(SESSION_KEY);
  }
}