// 主题常量与持久化 — 主流主题 + 开发者主题 + 跟随系统 // Logan.Li

import { getItem, setItem, STORAGE_KEYS } from './storage';
import i18n from '@/i18n';

/** 用户选择的主题偏好（含跟随系统） */
export type ThemePreference =
  | 'system'
  | 'ocean-deep'
  | 'light-professional'
  | 'one-dark'
  | 'catppuccin'
  | 'dracula'
  | 'tokyo-night'
  | 'nord';

/** 实际应用到 data-theme 的具体主题 */
export type ResolvedTheme = Exclude<ThemePreference, 'system'>;

export interface ThemeOption {
  id: ThemePreference;
  name: string;
  description: string;
  isDark: boolean;
  primaryColor: string;
}

export interface ThemeGroup {
  label: string;
  options: ThemeOption[];
}

/** 主流主题 — 默认推荐 */
const MAINSTREAM_THEMES: ThemeOption[] = [
  { id: 'system', name: i18n.t('common.lightDark'), description: i18n.t('跟随系统'), isDark: false, primaryColor: 'linear-gradient(135deg, #2563eb 50%, #0d1117 50%)' },
  { id: 'ocean-deep', name: i18n.t('深海蓝'), description: i18n.t('深海蓝'), isDark: true, primaryColor: '#0d1117' },
  { id: 'light-professional', name: i18n.t('明亮白'), description: i18n.t('企业控制台清爽浅色'), isDark: false, primaryColor: '#2563eb' },
];

/** 开发者主题 — 高辨识度扩展 */
const DEVELOPER_THEMES: ThemeOption[] = [
  { id: 'one-dark', name: 'One Dark', description: i18n.t('Atom 暖灰 IDE，紫绿语法渐变'), isDark: true, primaryColor: '#c678dd' },
  { id: 'dracula', name: 'Dracula', description: i18n.t('经典紫粉暗色，极高辨识度'), isDark: true, primaryColor: '#bd93f9' },
  { id: 'tokyo-night', name: 'Tokyo Night', description: i18n.t('东京霓虹深蓝紫，VS Code 热门'), isDark: true, primaryColor: '#7aa2f7' },
  { id: 'catppuccin', name: 'Catppuccin', description: i18n.t('马卡龙柔和暗色，护眼'), isDark: true, primaryColor: '#89b4fa' },
];

export const THEME_GROUPS: ThemeGroup[] = [
  { label: i18n.t('主流'), options: MAINSTREAM_THEMES },
  { label: i18n.t('开发者'), options: DEVELOPER_THEMES },
];

export const THEME_OPTIONS: ThemeOption[] = [
  ...MAINSTREAM_THEMES,
  ...DEVELOPER_THEMES,
];

export const THEME_ORDER: ThemePreference[] = THEME_OPTIONS.map((o) => o.id);
export const DEFAULT_THEME: ThemePreference = 'system';

const LEGACY_THEME_MAP: Record<string, ThemePreference> = {
  dark: 'ocean-deep',
  light: 'light-professional',
  'midnight-purple': 'one-dark',
  'pine-green': 'catppuccin',
  'orange-vitality': 'tokyo-night',
  nord: 'tokyo-night',
};

export function migrateLegacyTheme(value: string | null): ThemePreference | null {
  if (!value) return null;
  return LEGACY_THEME_MAP[value] ?? null;
}

/** 读取系统 color-scheme 偏好 // Logan.Li */
export function getSystemColorScheme(): 'light' | 'dark' {
  if (typeof window === 'undefined') return 'dark';
  return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
}

/** 将用户偏好解析为具体主题 // Logan.Li */
export function resolveThemePreference(pref: ThemePreference): ResolvedTheme {
  if (pref === 'system') {
    return getSystemColorScheme() === 'dark' ? 'ocean-deep' : 'light-professional';
  }
  return pref;
}

export function isThemeDark(pref: ThemePreference): boolean {
  if (pref === 'system') return getSystemColorScheme() === 'dark';
  const opt = THEME_OPTIONS.find((o) => o.id === pref);
  return opt?.isDark ?? true;
}

export function getInitialTheme(): ThemePreference {
  if (typeof window === 'undefined') return DEFAULT_THEME;
  const stored = getItem(STORAGE_KEYS.theme);
  const migrated = migrateLegacyTheme(stored);
  if (migrated) {
    setItem(STORAGE_KEYS.theme, migrated);
    return migrated;
  }
  if (stored && THEME_ORDER.includes(stored as ThemePreference)) {
    return stored as ThemePreference;
  }
  /* nord 已下架，自动迁移到 Tokyo Night // Logan.Li */
  if (stored === 'nord') {
    setItem(STORAGE_KEYS.theme, 'tokyo-night');
    return 'tokyo-night';
  }
  return DEFAULT_THEME;
}

export function persistTheme(theme: ThemePreference): void {
  setItem(STORAGE_KEYS.theme, theme);
}

export function applyThemeToDocument(pref: ThemePreference): void {
  if (typeof document === 'undefined') return;
  const resolved = resolveThemePreference(pref);
  document.documentElement.setAttribute('data-theme', resolved);
  document.documentElement.setAttribute('data-theme-preference', pref);
  document.documentElement.style.colorScheme = isThemeDark(pref) ? 'dark' : 'light';
}

export function getNextTheme(current: ThemePreference): ThemePreference {
  const idx = THEME_ORDER.indexOf(current);
  return THEME_ORDER[(idx + 1) % THEME_ORDER.length];
}