import { useState, useEffect } from 'react'
import { authApi } from '../api'

export interface User {
  id: number
  username: string
  email: string
  is_active: boolean
}

// Simple module-level state (no external lib needed)
let currentUser: User | null = null
let isLoading = true
let fetchPromise: Promise<void> | null = null
const listeners = new Set<() => void>()

export function useAuth() {
  const [user, setUser] = useState<User | null>(currentUser)
  const [loading, setLoading] = useState(isLoading)

  useEffect(() => {
    const update = () => { setUser(currentUser); setLoading(isLoading) }
    listeners.add(update)
    if (!fetchPromise) {
      fetchPromise = authApi.me()
        .then((res) => { currentUser = res.data })
        .catch(() => { currentUser = null })
        .finally(() => { isLoading = false; listeners.forEach((l) => l()) })
    }
    return () => { listeners.delete(update) }
  }, [])

  const logout = async () => {
    await authApi.logout()
    currentUser = null
    listeners.forEach((l) => l())
    window.location.href = '/login'
  }

  return { user, loading, logout }
}