/**
 * 管理后台布局
 *
 * 结构：左侧深色栏（品牌=收起/展开按钮 → 菜单 → 底部固定用户胶囊）+
 * 右侧内容区（顶部只有语言与明暗开关，页面信息统一由页面自己的 Header 卡片承载）。
 * 管理员与普通用户共用同一套布局。
 */
import { useCallback, useEffect, useMemo, useState } from 'react';
import { Outlet, useLocation, useNavigate } from 'react-router-dom';
import { Avatar, ConfigProvider, Layout, Menu, Popover, Spin } from 'antd';
import zhCN from 'antd/locale/zh_CN';
import enUS from 'antd/locale/en_US';
import {
  CalendarOutlined,
  ClockCircleOutlined,
  ControlOutlined,
  DashboardOutlined,
  DatabaseOutlined,
  DownOutlined,
  DownloadOutlined,
  GlobalOutlined,
  HomeOutlined,
  IdcardOutlined,
  LogoutOutlined,
  MenuFoldOutlined,
  MenuUnfoldOutlined,
  MoonOutlined,
  RocketOutlined,
  ScheduleOutlined,
  SettingOutlined,
  StarOutlined,
  SunOutlined,
  TeamOutlined,
  UserOutlined,
} from '@ant-design/icons';
import type { MenuProps } from 'antd';

import { authAPI } from '../../utils/request';
import { auth } from '../../utils/auth';
import { useToast } from '../../contexts/ToastContext';
import { adminThemeDark, adminThemeLight } from './adminTheme';
import { AdminPrefsProvider, useAdminPrefs } from './AdminPrefsContext';
import './admin.css';

const { Sider, Content } = Layout;

interface MenuNode {
  id: number;
  parent_id: number | null;
  name: string;
  title: string;
  icon?: string | null;
  path?: string | null;
  children?: MenuNode[];
}

const iconMap: Record<string, React.ReactNode> = {
  dashboard: <DashboardOutlined />,
  database: <DatabaseOutlined />,
  planet: <GlobalOutlined />,
  data: <DatabaseOutlined />,
  download: <DownloadOutlined />,
  settings: <SettingOutlined />,
  users: <TeamOutlined />,
  sliders: <ControlOutlined />,
  profile: <IdcardOutlined />,
  star: <StarOutlined />,
  rocket: <RocketOutlined />,
  schedule: <ScheduleOutlined />,
  // 后端菜单里也直接存了组件名，这里一并兼容
  DashboardOutlined: <DashboardOutlined />,
  DatabaseOutlined: <DatabaseOutlined />,
  DownloadOutlined: <DownloadOutlined />,
  SettingOutlined: <SettingOutlined />,
  TeamOutlined: <TeamOutlined />,
  ControlOutlined: <ControlOutlined />,
  IdcardOutlined: <IdcardOutlined />,
  StarOutlined: <StarOutlined />,
  RocketOutlined: <RocketOutlined />,
  CalendarOutlined: <CalendarOutlined />,
  ClockCircleOutlined: <ClockCircleOutlined />,
  ScheduleOutlined: <ScheduleOutlined />,
  GlobalOutlined: <GlobalOutlined />,
};

function roleLabelOf(user: ReturnType<typeof auth.getUser>): string {
  const roles = (user?.roles as string[] | undefined) ?? [];
  if (roles.includes('admin')) return '管理员';
  if (roles.length > 0) return '普通用户';
  return '已登录用户';
}

function AdminShell() {
  const [collapsed, setCollapsed] = useState(false);
  const [menus, setMenus] = useState<MenuNode[]>([]);
  const [loadingMenus, setLoadingMenus] = useState(true);
  const [userMenuOpen, setUserMenuOpen] = useState(false);
  const [user, setUser] = useState(() => auth.getUser());
  const navigate = useNavigate();
  const location = useLocation();
  const toast = useToast();
  const { lang, themeMode, setLang, setThemeMode, t } = useAdminPrefs();
  const locale = lang === 'en' ? enUS : zhCN;

  const isAdmin = ((user?.roles as string[] | undefined) ?? []).includes('admin');

  // 用户信息可能在其它标签页或个人信息页被更新，这里保持同步。
  useEffect(() => {
    const handleStorageChange = (event: StorageEvent) => {
      if (event.key === 'cosmo_user') {
        setUser(event.newValue ? JSON.parse(event.newValue) : null);
      }
    };
    window.addEventListener('storage', handleStorageChange);
    return () => window.removeEventListener('storage', handleStorageChange);
  }, []);

  const loadMenus = useCallback(async () => {
    setLoadingMenus(true);
    try {
      const { data } = await authAPI.getMenus();
      setMenus(Array.isArray(data) ? data : []);
    } catch {
      setMenus([]);
      toast.error('加载菜单失败');
    } finally {
      setLoadingMenus(false);
    }
  }, [toast]);

  useEffect(() => {
    void loadMenus();
  }, [loadMenus]);

  // 切换页面时收起用户二级菜单，避免菜单悬停在旧页面上。
  useEffect(() => {
    setUserMenuOpen(false);
  }, [location.pathname]);

  // 访问 /admin 或 /user 根路径时跳到第一个可用菜单。
  useEffect(() => {
    if (menus.length === 0) return;
    if (location.pathname === '/admin' || location.pathname === '/user') {
      const firstPath = menus.find((menu) => menu.path)?.path;
      if (firstPath) navigate(firstPath, { replace: true });
    }
  }, [menus, location.pathname, navigate]);

  const menuItems = useMemo<MenuProps['items']>(
    () =>
      menus.map((menu) => ({
        key: menu.path || `menu-${menu.id}`,
        icon: iconMap[menu.icon || ''] ?? undefined,
        label: menu.title,
        children: menu.children?.length
          ? menu.children.map((child) => ({
              key: child.path || `menu-${child.id}`,
              label: child.title,
            }))
          : undefined,
      })),
    [menus],
  );

  /** 顶栏左侧显示当前所属分组（页面标题由页面自己的 Header 卡片展示）。 */
  const headerSection = useMemo(() => {
    for (const menu of menus) {
      if (menu.children?.some((child) => child.path === location.pathname)) return menu.title;
    }
    if (location.pathname.endsWith('/profile')) return '账号';
    if (location.pathname.startsWith('/user')) return '用户中心';
    return 'COSMO 管理后台';
  }, [menus, location.pathname]);

  const handleLogout = useCallback(async () => {
    setUserMenuOpen(false);
    try {
      await authAPI.logout();
    } catch {
      // 后端不可用时也要清理本地登录态。
    }
    auth.logout();
    toast.success('已退出登录');
    navigate('/login', { replace: true });
  }, [navigate, toast]);

  const go = (path: string) => {
    setUserMenuOpen(false);
    navigate(path);
  };

  const avatarUrl = user?.avatar_url ? `/upload/${user.avatar_url}` : undefined;
  const displayName = (user?.full_name as string) || (user?.username as string) || '未登录';

  const userMenuContent = (
    <div style={{ width: 232 }}>
      <div className="adm-user-menu-head">
        <Avatar size={38} src={avatarUrl} icon={<UserOutlined />} />
        <div className="adm-user-menu-head-meta">
          <strong>{displayName}</strong>
          <span>{user?.email || t(roleLabelOf(user))}</span>
        </div>
      </div>

      <div className="adm-user-menu-group">{t('个人资料')}</div>
      <button
        type="button"
        className={`adm-user-menu-item ${location.pathname.endsWith('/profile') ? 'is-active' : ''}`}
        onClick={() => go('/user/profile')}
      >
        <IdcardOutlined />
        {t('个人资料')}
      </button>

      <div className="adm-user-menu-divider" />
      <button type="button" className="adm-user-menu-item" onClick={() => go('/')}>
        <HomeOutlined />
        {t('返回可视化首页')}
      </button>
      <button type="button" className="adm-user-menu-item is-danger" onClick={() => void handleLogout()}>
        <LogoutOutlined />
        {t('退出登录')}
      </button>
    </div>
  );

  return (
    <ConfigProvider theme={themeMode === 'dark' ? adminThemeDark : adminThemeLight} locale={locale}>
      <Layout className="adm-shell" data-adm-theme={themeMode}>
        <Sider
          width={236}
          theme={themeMode === 'dark' ? 'dark' : 'light'}
          trigger={null}
          collapsible
          collapsed={collapsed}
          className={`adm-sider ${collapsed ? 'adm-sider--collapsed' : ''}`}
        >
          {/* 品牌区 = 收起 / 展开按钮：收起后悬停显示展开图标 */}
          <button
            type="button"
            className="adm-brand"
            onClick={() => setCollapsed((value) => !value)}
            aria-label={collapsed ? t('展开菜单') : t('收起菜单')}
            title={collapsed ? t('展开菜单') : t('收起菜单')}
          >
            <span className="adm-brand-mark">🌌</span>
            <MenuUnfoldOutlined className="adm-brand-hover-icon" />
            {!collapsed && (
              <>
                <span className="adm-brand-text">
                  <strong>COSMO</strong>
                  <span>{isAdmin ? t('管理后台') : t('用户中心')}</span>
                </span>
                <MenuFoldOutlined className="adm-brand-toggle" />
              </>
            )}
          </button>

          <div className="adm-menu">
            {loadingMenus ? (
              <div style={{ display: 'flex', justifyContent: 'center', padding: '24px 0' }}>
                <Spin size="small" />
              </div>
            ) : (
              <Menu
                theme={themeMode === 'dark' ? 'dark' : 'light'}
                mode="inline"
                selectedKeys={[location.pathname]}
                defaultOpenKeys={menus.filter((menu) => menu.children?.length).map((menu) => `menu-${menu.id}`)}
                items={menuItems}
                onClick={({ key }) => navigate(key)}
                style={{ background: 'transparent', borderInlineEnd: 'none' }}
              />
            )}
          </div>

          {/* 用户胶囊：位于菜单下方，点击展开二级菜单 */}
          <div className={`adm-user-dock ${collapsed ? 'adm-user-dock--collapsed' : ''}`}>
            <Popover
              open={userMenuOpen}
              onOpenChange={setUserMenuOpen}
              trigger="click"
              placement="topLeft"
              arrow={false}
              overlayClassName="adm-user-menu"
              content={userMenuContent}
            >
              <button type="button" className="adm-user-pill" aria-expanded={userMenuOpen}>
                <Avatar size={30} src={avatarUrl} icon={<UserOutlined />} />
                {!collapsed && (
                  <>
                    <span className="adm-user-pill-meta">
                      <strong>{displayName}</strong>
                      <span>{t(roleLabelOf(user))}</span>
                    </span>
                    <DownOutlined className="adm-user-pill-arrow" />
                  </>
                )}
              </button>
            </Popover>
          </div>
        </Sider>

        <Layout>
          {/* 统一框架 Header：左侧当前分组，右侧全局开关 */}
          <header className="adm-header">
            <div className="adm-header-left">
              <span className="adm-header-section">{t(headerSection)}</span>
            </div>
            <div className="adm-header-right">
              <div className="adm-switch-group" role="group" aria-label={t('语言切换')}>
                <button
                  type="button"
                  className={lang === 'zh' ? 'is-active' : ''}
                  onClick={() => setLang('zh')}
                  title="中文"
                >
                  中文
                </button>
                <button
                  type="button"
                  className={lang === 'en' ? 'is-active' : ''}
                  onClick={() => setLang('en')}
                  title="English"
                >
                  EN
                </button>
              </div>
              <button
                type="button"
                className="adm-icon-switch"
                onClick={() => setThemeMode(themeMode === 'dark' ? 'light' : 'dark')}
                aria-label={t('主题切换')}
                title={themeMode === 'dark' ? t('浅色') : t('深色')}
              >
                {themeMode === 'dark' ? <SunOutlined /> : <MoonOutlined />}
              </button>
            </div>
          </header>

          <Content className="adm-content">
            <Outlet />
          </Content>
        </Layout>
      </Layout>
    </ConfigProvider>
  );
}

export function AdminLayout() {
  return (
    <AdminPrefsProvider>
      <AdminShell />
    </AdminPrefsProvider>
  );
}