import { createContext, useContext, useEffect, useState, type ReactNode } from 'react'
import { authLogin, authLogout, AUTH_EXPIRED_EVENT, clearSession, getUserName, setSession, TOKEN_KEY, USER_KEY } from '../api/client'

interface AuthState {
  token: string
  username: string
  login: (u: string, p: string) => Promise<void>
  logout: () => void
}

const Ctx = createContext<AuthState>({ token: '', username: '', login: async () => {}, logout: () => {} })

export function AuthProvider({ children }: { children: ReactNode }) {
  const [token, setToken] = useState(() => localStorage.getItem(TOKEN_KEY) || '')
  const [username, setUsername] = useState(() => localStorage.getItem(USER_KEY) || '')
  const login = async (u: string, p: string) => {
    const data = await authLogin(u, p)
    setSession(data.token, data.username)
    setToken(data.token)
    setUsername(data.username)
  }
  const logout = () => {
    // 先吊销服务端令牌（fire-and-forget，失败不阻塞退出），再清理本地
    authLogout().catch(() => {})
    clearSession()
    setToken('')
    setUsername('')
  }

  // 任何请求命中 401（登录态无效/过期）时，同步清空内存态，
  // AppLayout 会立即自动跳转到登录页。
  useEffect(() => {
    const onExpired = () => {
      clearSession()
      setToken('')
      setUsername('')
    }
    window.addEventListener(AUTH_EXPIRED_EVENT, onExpired)
    return () => window.removeEventListener(AUTH_EXPIRED_EVENT, onExpired)
  }, [])

  return <Ctx.Provider value={{ token, username, login, logout }}>{children}</Ctx.Provider>
}

export const useAuth = () => useContext(Ctx)