import {
  createContext,
  useContext,
  useState,
  useEffect,
  useCallback,
  useMemo,
  type ReactNode,
} from 'react'
import {
  authService,
  type LoginResponse,
  type CreateAccountResponse,
  type OrganizationMembership,
} from '../services/authService'

interface AuthContextType {
  user: LoginResponse | null
  isAuthenticated: boolean
  isLoading: boolean
  activeOrg: OrganizationMembership | null
  login: (email: string, password: string) => Promise<LoginResponse>
  register: (name: string, email: string, password: string) => Promise<CreateAccountResponse>
  logout: () => void
  refreshUser: () => Promise<void>
  updateUser: (updated: Partial<LoginResponse>) => void
  setActiveOrg: (id: number) => void
}

const STORAGE_KEYS = {
  USER: 'user',
  ACTIVE_ORG_ID: 'activeOrgId',
} as const

const AuthContext = createContext<AuthContextType | undefined>(undefined)

export const AuthProvider = ({ children }: { children: ReactNode }) => {
  const [user, setUser] = useState<LoginResponse | null>(null)
  const [activeOrgId, setActiveOrgId] = useState<number | null>(null)
  const [isLoading, setIsLoading] = useState(true)

  const setupActiveOrg = useCallback((organizations: OrganizationMembership[]) => {
    const storedOrgId = localStorage.getItem(STORAGE_KEYS.ACTIVE_ORG_ID)
    const parsedStoredId = storedOrgId ? Number(storedOrgId) : null

    const isValidOrg = organizations.some((org) => org.id === parsedStoredId)

    if (isValidOrg && parsedStoredId !== null) {
      setActiveOrgId(parsedStoredId)
    } else if (organizations.length > 0) {
      const firstOrgId = organizations[0].id
      setActiveOrgId(firstOrgId)
      localStorage.setItem(STORAGE_KEYS.ACTIVE_ORG_ID, firstOrgId.toString())
    }
  }, [])

  const logout = useCallback(() => {
    localStorage.removeItem(STORAGE_KEYS.USER)
    localStorage.removeItem(STORAGE_KEYS.ACTIVE_ORG_ID)
    setUser(null)
    setActiveOrgId(null)
  }, [])

  const renewToken = useCallback(async (refreshToken: string) => {
    try {
      const response = await authService.refresh(refreshToken)
      response.issuedAt = new Date().toISOString()
      localStorage.setItem(STORAGE_KEYS.USER, JSON.stringify(response))
      setUser(response)
      return response
    } catch {
      logout()
      return null
    }
  }, [logout])

  useEffect(() => {
    const initAuth = async () => {
      const storedUser = localStorage.getItem(STORAGE_KEYS.USER)
      if (storedUser) {
        try {
          const userData: LoginResponse = JSON.parse(storedUser)
          const issuedAt = new Date(userData.issuedAt).getTime()
          const expiresAt = issuedAt + userData.expiresIn * 1000
          const now = Date.now()

          if (now >= expiresAt) {
            if (userData.refreshToken) {
              const renewed = await renewToken(userData.refreshToken)
              if (renewed) {
                setupActiveOrg(renewed.organizations)
              }
            } else {
              logout()
            }
          } else {
            setUser(userData)
            setupActiveOrg(userData.organizations)

            // Se expirar em menos de 24 horas, renova proativamente
            if (expiresAt - now < 86400000 && userData.refreshToken) {
              renewToken(userData.refreshToken)
            }
          }
        } catch {
          localStorage.removeItem(STORAGE_KEYS.USER)
        }
      }
      setIsLoading(false)
    }

    initAuth()
  }, [logout, renewToken, setupActiveOrg])

  // Verificação periódica a cada 60 segundos
  useEffect(() => {
    if (!user) return

    const interval = setInterval(() => {
      const issuedAt = new Date(user.issuedAt).getTime()
      const expiresAt = issuedAt + user.expiresIn * 1000
      const now = Date.now()

      if (now >= expiresAt) {
        if (user.refreshToken) {
          renewToken(user.refreshToken)
        } else {
          logout()
        }
      } else if (expiresAt - now < 86400000 && user.refreshToken) {
        // Se expirar em menos de 24 horas, renova proativamente
        renewToken(user.refreshToken)
      }
    }, 60000)

    return () => clearInterval(interval)
  }, [user, logout, renewToken])

  const login = async (email: string, password: string) => {
    const response = await authService.login(email, password)
    response.issuedAt = new Date().toISOString()
    localStorage.setItem(STORAGE_KEYS.USER, JSON.stringify(response))
    setUser(response)
    setupActiveOrg(response.organizations)
    return response
  }

  const register = async (name: string, email: string, password: string) => {
    return authService.register(name, email, password)
  }

  const refreshUser = async () => {
    try {
      const response = await authService.me()
      const storedUser = localStorage.getItem(STORAGE_KEYS.USER)
      if (storedUser) {
        const userData = JSON.parse(storedUser)
        const updatedUser = { ...userData, ...response }
        localStorage.setItem(STORAGE_KEYS.USER, JSON.stringify(updatedUser))
        setUser(updatedUser)
        setupActiveOrg(updatedUser.organizations)
      }
    } catch {
      // Ignora erro
    }
  }

  const updateUser = useCallback((updated: Partial<LoginResponse>) => {
    setUser((prev) => {
      if (!prev) return null
      const next = { ...prev, ...updated }
      localStorage.setItem(STORAGE_KEYS.USER, JSON.stringify(next))
      return next
    })
  }, [])

  const setActiveOrg = (id: number) => {
    setActiveOrgId(id)
    localStorage.setItem(STORAGE_KEYS.ACTIVE_ORG_ID, id.toString())
  }

  const activeOrg = useMemo(
    () => user?.organizations.find((org) => org.id === activeOrgId) || null,
    [user, activeOrgId]
  )

  return (
    <AuthContext.Provider
      value={{
        user,
        isAuthenticated: !!user,
        isLoading,
        activeOrg,
        login,
        register,
        logout,
        refreshUser,
        updateUser,
        setActiveOrg,
      }}
    >
      {children}
    </AuthContext.Provider>
  )
}

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