import {
  createContext,
  useContext,
  useState,
  useEffect,
  useCallback,
  useMemo,
  useRef,
} from 'react'
import api, { ACTIVE_CLUB_STORAGE_KEY } from '../utils/api'
import { activeClubMemberships } from '../utils/activeClub'
import { clearCoachSessionStorage } from '../utils/trainingPlanUtils'

const AuthContext = createContext(null)

function syncStoredActiveClub(profile) {
  const clubs = activeClubMemberships(profile?.clubs)
  const ids = new Set(clubs.map((c) => String(c.id)))
  const eff = profile?.effective_club_id
  if (eff != null && eff !== '' && ids.has(String(eff))) {
    localStorage.setItem(ACTIVE_CLUB_STORAGE_KEY, String(eff))
    return
  }
  const stored = localStorage.getItem(ACTIVE_CLUB_STORAGE_KEY)
  if (stored && ids.has(stored)) return

  const ac =
    profile?.active_club_id != null && profile.active_club_id !== ''
      ? String(profile.active_club_id)
      : ''
  if (ac && ids.has(ac)) {
    localStorage.setItem(ACTIVE_CLUB_STORAGE_KEY, ac)
    return
  }
  if (clubs.length >= 1) {
    localStorage.setItem(ACTIVE_CLUB_STORAGE_KEY, String(clubs[0].id))
    return
  }
  try {
    localStorage.removeItem(ACTIVE_CLUB_STORAGE_KEY)
  } catch {
    /* ignore */
  }
}

export function AuthProvider({ children }) {
  const [user, setUser] = useState(null)
  const [loading, setLoading] = useState(true)
  const userRef = useRef(null)

  useEffect(() => {
    userRef.current = user
  }, [user])

  const checkAuth = useCallback(async () => {
    const token = localStorage.getItem('authToken')
    if (!token) {
      setLoading(false)
      return
    }

    try {
      const profile = await api.getCurrentProfile()
      syncStoredActiveClub(profile)
      setUser(profile)
    } catch (err) {
      console.error('Auth check failed:', err)
      localStorage.removeItem('authToken')
    } finally {
      setLoading(false)
    }
  }, [])

  useEffect(() => {
    checkAuth()
  }, [checkAuth])

  const setActiveClub = useCallback(async (clubId) => {
    const cid = Number(clubId)
    const uid = userRef.current?.id
    if (!Number.isFinite(cid) || cid < 1 || !uid) return
    localStorage.setItem(ACTIVE_CLUB_STORAGE_KEY, String(cid))
    setUser((prev) =>
      prev?.id
        ? { ...prev, active_club_id: cid, effective_club_id: cid }
        : prev
    )
    try {
      await api.updateProfile(uid, { active_club_id: cid })
      const profile = await api.getCurrentProfile()
      syncStoredActiveClub(profile)
      setUser(profile)
    } catch (e) {
      console.error(e)
      try {
        const profile = await api.getCurrentProfile()
        syncStoredActiveClub(profile)
        setUser(profile)
      } catch {
        /* ignore */
      }
    }
  }, [])

  /** Fallback, falls ohne checkAuth gesetzt wird (Legacy / Token-Injektion) */
  const login = useCallback((payload) => {
    if (payload?.profile != null) {
      syncStoredActiveClub(payload.profile)
      setUser(payload.profile)
      return
    }
    const p = payload
    if (p?.profile_id != null || p?.id != null) {
      setUser({
        id: p.profile_id ?? p.id,
        name: p.name ?? null,
        email: p.email ?? null,
        role: p.role ?? 'user',
        tier: p.tier ?? 'free',
      })
      return
    }
    setUser(payload)
  }, [])

  const logout = useCallback(async () => {
    try {
      await api.logout()
    } catch {
      /* Session lokal trotzdem beenden */
    }
    setUser(null)
    localStorage.removeItem('authToken')
    localStorage.removeItem(ACTIVE_CLUB_STORAGE_KEY)
    clearCoachSessionStorage()
  }, [])

  const value = useMemo(
    () => ({
      user,
      isAuthenticated: !!user,
      loading,
      login,
      logout,
      checkAuth,
      setActiveClub,
    }),
    [user, loading, login, logout, checkAuth, setActiveClub],
  )

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

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

export default AuthContext