import * as React from 'react'

import * as authApi from './api'
import type { CurrentUser } from './types'

type AuthContextValue = {
  user: CurrentUser | null
  loading: boolean
  authenticated: boolean
  login: (username: string, password: string) => Promise<void>
  logout: () => Promise<void>
  refresh: () => Promise<void>
}

const AuthContext = React.createContext<AuthContextValue | null>(null)

type AuthProviderProps = {
  children: React.ReactNode
}

export function AuthProvider({ children }: AuthProviderProps) {
  const [user, setUser] = React.useState<CurrentUser | null>(null)
  const [loading, setLoading] = React.useState(true)

  const refresh = React.useCallback(async () => {
    try {
      const currentUser = await authApi.getCurrentUser()
      setUser(currentUser)
    } catch {
      setUser(null)
    }
  }, [])

  React.useEffect(() => {
    let mounted = true

    authApi
      .getCurrentUser()
      .then((currentUser) => {
        if (mounted) {
          setUser(currentUser)
        }
      })
      .catch(() => {
        if (mounted) {
          setUser(null)
        }
      })
      .finally(() => {
        if (mounted) {
          setLoading(false)
        }
      })

    return () => {
      mounted = false
    }
  }, [])

  const handleLogin = React.useCallback(async (username: string, password: string) => {
    const currentUser = await authApi.login(username, password)
    setUser(currentUser)
  }, [])

  const handleLogout = React.useCallback(async () => {
    await authApi.logout()
    setUser(null)
    window.location.hash = '/'
  }, [])

  const value = React.useMemo<AuthContextValue>(
    () => ({
      user,
      loading,
      authenticated: Boolean(user),
      login: handleLogin,
      logout: handleLogout,
      refresh
    }),
    [handleLogin, handleLogout, loading, refresh, user]
  )

  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>
}

export function useAuth() {
  const context = React.useContext(AuthContext)
  if (!context) {
    throw new Error('useAuth must be used within AuthProvider')
  }
  return context
}