import { lazy, Suspense, useEffect, useState } from 'react'
import type { ReactNode } from 'react'
import { Navigate, Route, Routes } from 'react-router'
import { App as AntdApp, ConfigProvider } from 'antd'
import zhCN from 'antd/locale/zh_CN'
import { useAuth } from './lib/auth'
import { useTheme } from './lib/theme'
import useShadcnTheme from './theme/shadcnTheme'
import { BlogLayout, AdminLayout } from './components/Layout'
import Home from './pages/Home'
import TagPage from './pages/TagPage'
import Login from './pages/Login'
import AdminList from './pages/AdminList'
import AdminTrash from './pages/AdminTrash'
import AdminSettings from './pages/AdminSettings'
import NotFound from './pages/NotFound'

// 重依赖路由懒加载：Note 带 markdown 渲染管线，AdminEdit 额外带 CodeMirror，
// 拆出主包以避免单 chunk 过大（vite 500kB 告警）
const Note = lazy(() => import('./pages/Note'))
const AdminEdit = lazy(() => import('./pages/AdminEdit'))

// antd ConfigProvider：跟随应用三态主题切换 light/dark 算法（system 监听系统变化）
function AntdProvider({ children }: { children: ReactNode }) {
  const { mode } = useTheme()
  const [systemDark, setSystemDark] = useState(
    () => window.matchMedia('(prefers-color-scheme: dark)').matches,
  )
  useEffect(() => {
    const mq = window.matchMedia('(prefers-color-scheme: dark)')
    const onChange = (e: MediaQueryListEvent) => setSystemDark(e.matches)
    mq.addEventListener('change', onChange)
    return () => mq.removeEventListener('change', onChange)
  }, [])
  const dark = mode === 'dark' || (mode === 'system' && systemDark)
  const configProps = useShadcnTheme(dark)
  return (
    <ConfigProvider locale={zhCN} {...configProps}>
      <AntdApp>{children}</AntdApp>
    </ConfigProvider>
  )
}

// 登录守卫：401 统一跳转 /admin/login（§8.2）
function RequireAuth({ children }: { children: ReactNode }) {
  const { authenticated, loading } = useAuth()
  if (loading) {
    return <div className="pn-loading">加载中…</div>
  }
  if (!authenticated) {
    return <Navigate to="/admin/login" replace />
  }
  return <>{children}</>
}

export default function App() {
  return (
    <AntdProvider>
      <Suspense fallback={<div className="pn-loading">加载中…</div>}>
        <Routes>
          <Route element={<BlogLayout />}>
            <Route path="/" element={<Home />} />
            <Route path="/notes/:slug" element={<Note />} />
            <Route path="/tags" element={<TagPage />} />
            <Route path="/tags/:tag" element={<TagPage />} />
          </Route>
          <Route path="/admin/login" element={<Login />} />
          <Route element={<RequireAuth><AdminLayout /></RequireAuth>}>
            <Route path="/admin" element={<AdminList />} />
            <Route path="/admin/trash" element={<AdminTrash />} />
            <Route path="/admin/settings" element={<AdminSettings />} />
            <Route path="/admin/notes/new" element={<AdminEdit />} />
            <Route path="/admin/notes/:id/edit" element={<AdminEdit />} />
          </Route>
          <Route path="*" element={<NotFound />} />
        </Routes>
      </Suspense>
    </AntdProvider>
  )
}