import { useState, useEffect, useCallback } from 'react'

export type Profile = {
  id: number
  email: string | null
  display_name: string | null
  is_guest: boolean
}
type AuthState = { profile: Profile | null; token: string | null; loading: boolean }

export function useAuth() {
  const [state, setState] = useState<AuthState>({ profile: null, token: null, loading: true })

  const validate = useCallback(async (token: string) => {
    const r = await fetch('/api/auth/me', {
      headers: { Authorization: `Bearer ${token}` },
    })
    if (!r.ok) throw new Error('invalid session')
    const profile: Profile = await r.json()
    return profile
  }, [])

  useEffect(() => {
    // Check URL for ?session= from magic link redirect
    const params = new URLSearchParams(window.location.search)
    const urlToken = params.get('session')
    if (urlToken) {
      localStorage.setItem('session', urlToken)
      window.history.replaceState({}, '', window.location.pathname)
    }

    const token = urlToken || localStorage.getItem('session')
    if (!token) {
      setState({ profile: null, token: null, loading: false })
      return
    }

    validate(token)
      .then(profile => setState({ profile, token, loading: false }))
      .catch(() => {
        localStorage.removeItem('session')
        setState({ profile: null, token: null, loading: false })
      })
  }, [validate])

  const logout = useCallback(async () => {
    const token = localStorage.getItem('session')
    if (token) {
      await fetch('/api/auth/session', {
        method: 'DELETE',
        headers: { Authorization: `Bearer ${token}` },
      }).catch(() => {})
      localStorage.removeItem('session')
    }
    setState({ profile: null, token: null, loading: false })
  }, [])

  // Used by guest login to inject a session without a round-trip
  const setAuth = useCallback((token: string, profile: Profile) => {
    localStorage.setItem('session', token)
    setState({ profile, token, loading: false })
  }, [])

  return { ...state, logout, setAuth }
}