import { useEffect, useState } from 'react'
import { NavLink, Navigate, Route, Routes, useLocation } from 'react-router-dom'
import {
  KeyRound,
  LogOut,
  Menu,
  Moon,
  Router,
  ScrollText,
  Sun,
  UserCog,
  Users as UsersIcon,
  Wifi,
  X,
} from 'lucide-react'
import { useAuth } from '@/auth/auth'
import { useTheme } from '@/lib/theme'
import { Login } from '@/pages/Login'
import { Clients } from '@/pages/Clients'
import { Devices } from '@/pages/Devices'
import { Vlans } from '@/pages/Vlans'
import { Users } from '@/pages/Users'
import { ApiKeys } from '@/pages/ApiKeys'
import { Logs } from '@/pages/Logs'
import { ChangePassword } from '@/pages/ChangePassword'
import { Button } from '@/components/ui/button'
import { cn } from '@/lib/utils'

function ThemeToggle() {
  const { theme, toggle } = useTheme()
  return (
    <Button
      variant="ghost"
      size="icon"
      onClick={toggle}
      className="text-muted-foreground"
      title={theme === 'dark' ? 'Switch to light mode' : 'Switch to dark mode'}
      aria-label="Toggle theme"
    >
      {theme === 'dark' ? <Sun className="h-4 w-4" /> : <Moon className="h-4 w-4" />}
    </Button>
  )
}

type NavItem = { to: string; label: string; icon: typeof Wifi }

const linkClass = ({ isActive }: { isActive: boolean }) =>
  cn(
    'flex items-center gap-3 rounded-md px-3 py-2 text-sm font-medium transition-colors',
    isActive ? 'bg-primary text-primary-foreground' : 'text-muted-foreground hover:bg-accent',
  )

function SidebarContent({
  username,
  isAdmin,
  onNavigate,
}: {
  username: string
  isAdmin: boolean
  onNavigate?: () => void
}) {
  const { logout } = useAuth()

  const items: NavItem[] = [
    { to: '/clients', label: 'Clients', icon: UsersIcon },
    { to: '/devices', label: 'Devices', icon: Router },
    { to: '/vlans', label: 'VLANs', icon: Wifi },
  ]
  const adminItems: NavItem[] = [
    { to: '/users', label: 'Users', icon: UserCog },
    { to: '/apikeys', label: 'API Keys', icon: KeyRound },
    { to: '/logs', label: 'Activity Log', icon: ScrollText },
  ]

  const renderItem = ({ to, label, icon: Icon }: NavItem) => (
    <NavLink key={to} to={to} className={linkClass} onClick={onNavigate}>
      <Icon className="h-4 w-4 shrink-0" /> {label}
    </NavLink>
  )

  return (
    <div className="flex h-full flex-col">
      <div className="flex h-14 items-center gap-2 px-4 font-semibold">
        <Wifi className="h-5 w-5 text-primary" />
        RADIUS Admin
      </div>
      <nav className="flex flex-1 flex-col gap-1 overflow-y-auto px-3 py-2">
        {items.map(renderItem)}
        {isAdmin && (
          <>
            <div className="mt-4 px-3 pb-1 text-xs font-semibold uppercase tracking-wider text-muted-foreground">
              Admin
            </div>
            {adminItems.map(renderItem)}
          </>
        )}
      </nav>
      <div className="border-t p-3">
        <NavLink to="/account" className={linkClass} onClick={onNavigate} title="Change password">
          <UserCog className="h-4 w-4 shrink-0" />
          <span className="truncate">{username}</span>
        </NavLink>
        <Button
          variant="ghost"
          className="mt-1 w-full justify-start gap-3 px-3 text-muted-foreground"
          onClick={logout}
        >
          <LogOut className="h-4 w-4 shrink-0" /> Sign out
        </Button>
      </div>
    </div>
  )
}

function Shell({
  username,
  isAdmin,
  children,
}: {
  username: string
  isAdmin: boolean
  children: React.ReactNode
}) {
  const [open, setOpen] = useState(false)
  const location = useLocation()

  // Close the mobile drawer whenever the route changes.
  useEffect(() => {
    setOpen(false)
  }, [location.pathname])

  return (
    <div className="min-h-screen bg-muted/20">
      {/* Desktop sidebar */}
      <aside className="fixed inset-y-0 left-0 z-30 hidden w-60 border-r bg-background md:block">
        <SidebarContent username={username} isAdmin={isAdmin} />
      </aside>

      {/* Mobile drawer */}
      {open && (
        <div className="fixed inset-0 z-40 md:hidden">
          <div
            className="absolute inset-0 bg-black/50"
            onClick={() => setOpen(false)}
            aria-hidden="true"
          />
          <aside className="absolute inset-y-0 left-0 w-64 border-r bg-background shadow-lg">
            <SidebarContent
              username={username}
              isAdmin={isAdmin}
              onNavigate={() => setOpen(false)}
            />
          </aside>
        </div>
      )}

      {/* Mobile top bar */}
      <header className="sticky top-0 z-20 flex h-14 items-center gap-2 border-b bg-background px-4 md:hidden">
        <Button
          variant="ghost"
          size="icon"
          onClick={() => setOpen((v) => !v)}
          aria-label={open ? 'Close menu' : 'Open menu'}
        >
          {open ? <X className="h-5 w-5" /> : <Menu className="h-5 w-5" />}
        </Button>
        <div className="flex items-center gap-2 font-semibold">
          <Wifi className="h-5 w-5 text-primary" />
          RADIUS Admin
        </div>
        <div className="ml-auto">
          <ThemeToggle />
        </div>
      </header>

      <div className="md:pl-60">
        {/* Desktop top-right theme toggle */}
        <div className="hidden items-center justify-end px-6 pt-4 md:flex">
          <ThemeToggle />
        </div>
        <main className="mx-auto max-w-6xl px-4 py-6">{children}</main>
      </div>
    </div>
  )
}

export default function App() {
  const { user } = useAuth()

  if (!user) return <Login />

  if (user.must_change_password) return <ChangePassword forced />

  const admin = user.is_admin

  return (
    <Shell username={user.username} isAdmin={admin}>
      <Routes>
        <Route path="/clients" element={<Clients />} />
        <Route path="/devices" element={<Devices />} />
        <Route path="/vlans" element={<Vlans />} />
        <Route path="/account" element={<ChangePassword />} />
        <Route path="/users" element={admin ? <Users /> : <Navigate to="/clients" replace />} />
        <Route
          path="/apikeys"
          element={admin ? <ApiKeys /> : <Navigate to="/clients" replace />}
        />
        <Route path="/logs" element={admin ? <Logs /> : <Navigate to="/clients" replace />} />
        <Route path="*" element={<Navigate to="/clients" replace />} />
      </Routes>
    </Shell>
  )
}