// 背景遮罩：夜间主题下给壁纸加暗色遮罩，可开关 + 调明暗度（存 localStorage）
// Wallpaper dim: darkens the wallpaper under dark theme, with toggle + opacity
// control (persisted in localStorage)
(function () {
  const KEY_ON = 'hearth-mask-enabled';
  const KEY_ALPHA = 'hearth-mask-alpha';

  // 判断当前是否深色主题（强制深色，或跟随系统且系统为深色）
  // Whether the current theme is dark (forced dark, or follow-system + system dark)
  function isDark() {
    const t = window.theme.get();
    if (t === 'dark') return true;
    if (t === 'light') return false;
    return window.matchMedia('(prefers-color-scheme: dark)').matches;
  }

  window.mask = {
    enabled() {
      return localStorage.getItem(KEY_ON) === '1';
    },
    alpha() {
      return parseFloat(localStorage.getItem(KEY_ALPHA) || '0.55');
    },
    setEnabled(on) {
      localStorage.setItem(KEY_ON, on ? '1' : '0');
      this.apply();
    },
    setAlpha(a) {
      localStorage.setItem(KEY_ALPHA, String(a));
      this.apply();
    },
    // 应用遮罩：仅深色主题且启用时显示（透明度 = 明暗度）
    // Apply: show only under dark theme when enabled (opacity = alpha)
    apply() {
      const el = document.getElementById('wallpaper-dim');
      if (!el) return;
      el.style.opacity = (isDark() && this.enabled()) ? String(this.alpha()) : '0';
    },
  };
})();