'use client'

import { createContext, type ReactNode, useCallback, useEffect, useState } from 'react'
import { jwtDecode } from 'jwt-decode'
import Cookies from 'js-cookie'

import type {
  SendOtpData,
  CheckOtpData,
  User,
  SaveUserData,
  AuthContextType,
  DecodedToken,
  CompleteProfileData,
  UserAccountStatus,
} from '@/types'
import { addToast } from '@/lib/toast'
import { attemptServerLogout, expireRefreshSessionOnThisOrigin } from '@/lib/logoutSession'
import { parseRefreshExpiry, REFRESH_COOKIE_DAYS } from '@/lib/refreshTokenExpiry'
import { convertPersianToEnglish } from '@/helpers'
import { texts } from '@/texts'
import { REQUEST_OTP, VERIFY_OTP } from '@/services/auth'
import { COMPLETE_PROFILE } from '@/services/users'
import { unsubscribeCurrentDevicePush } from '@/services/push'
import axiosInstance, { refreshAccessTokenProactively } from '@/config/axios'
import useLoading from '@/hooks/useLoading'
import { clearAsyncResourceCache } from '@/hooks/useAsyncResource'
import { clearPersistedQueryCache, getQueryClient } from '@/lib/queryClient'
import { setAccountSuspended } from '@/lib/accountSuspension'

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

interface AuthProviderProps {
  children: ReactNode
}

const RESEND_COOLDOWN_SECONDS = 120

const setStatusCookie = (status?: UserAccountStatus) => {
  if (status) {
    Cookies.set('userStatus', status, { expires: REFRESH_COOKIE_DAYS })
  } else {
    Cookies.remove('userStatus')
  }
}

const setRoleCookie = (role?: User['role']) => {
  // UX hint only (nav chrome). Middleware / RSC must not trust this for gating —
  // see getRoleFromAccessToken in authRouting.ts / proxy.ts.
  if (role) {
    Cookies.set('userRole', role, { expires: REFRESH_COOKIE_DAYS })
  } else {
    Cookies.remove('userRole')
  }
}

/**
 * Write the JS-readable access cookie from an absolute expiry timestamp
 * (ms since epoch). Shared by `saveUser` (fresh JWT) and
 * `syncSessionFromStorage` (hydrated session) so the cookie-lifetime math
 * cannot drift between the two paths.
 *
 * The refresh token is an httpOnly cookie set by Nest — never written here.
 */
const applySessionCookies = (params: { accessToken?: string; accessExpireAtMs?: number }) => {
  const { accessToken, accessExpireAtMs } = params

  if (accessToken && accessExpireAtMs != null) {
    const accessExpireInSeconds = Math.floor((accessExpireAtMs - Date.now()) / 1000)

    if (accessExpireInSeconds > 0) {
      Cookies.set('accessToken', accessToken, { expires: accessExpireInSeconds / 86400, sameSite: 'lax' })
    }
  }
}

const clearLegacyRefreshCookie = () => {
  Cookies.remove('refreshToken')
}

export const AuthProvider = ({ children }: AuthProviderProps) => {
  const { setLoading } = useLoading()
  const [user, setUser] = useState<User | null>(null)
  const [isSessionHydrated, setIsSessionHydrated] = useState(false)

  /** Read session from localStorage only — no profile API call */
  const syncSessionFromStorage = useCallback(() => {
    try {
      setLoading(true)
      const raw = localStorage.getItem('user')

      if (!raw) {
        setUser(null)
        Cookies.remove('accessToken')
        clearLegacyRefreshCookie()
        setStatusCookie(undefined)
        setRoleCookie(undefined)

        return
      }

      const stored = JSON.parse(raw) as User & { refreshToken?: unknown }

      delete stored.refreshToken

      applySessionCookies({
        accessToken: stored.accessToken,
        accessExpireAtMs: stored.AccessTokenExpireTime,
      })
      clearLegacyRefreshCookie()

      setStatusCookie(stored.status)
      setRoleCookie(stored.role)
      setUser(stored)
    } catch {
      setUser(null)
      Cookies.remove('accessToken')
      clearLegacyRefreshCookie()
      setStatusCookie(undefined)
      setRoleCookie(undefined)
    } finally {
      setLoading(false)
      setIsSessionHydrated(true)
    }
  }, [setLoading])

  useEffect(() => {
    syncSessionFromStorage()

    const handleUserChanged = () => {
      syncSessionFromStorage()
    }

    const handleStorage = (event: StorageEvent) => {
      if (event.key === 'user') syncSessionFromStorage()
    }

    window.addEventListener('userChanged', handleUserChanged)
    window.addEventListener('storage', handleStorage)

    return () => {
      window.removeEventListener('userChanged', handleUserChanged)
      window.removeEventListener('storage', handleStorage)
    }
  }, [syncSessionFromStorage])

  /**
   * `proxy.ts` checks the `accessToken` cookie and the Nest httpOnly refresh
   * cookie (`__Host-ghabilee_refresh` / `ghabilee_refresh`) on every
   * navigation — including soft/SPA ones — to decide whether a route needs
   * auth. `accessToken` is a ~15m JWT (JWT_ACCESS_EXPIRES_IN); previously it
   * only got refreshed reactively, on the next 401 from an actual API call.
   * If a user navigated (no API call yet) after it lapsed, proxy.ts could
   * see a stale cookie, 307 the soft navigation, and Next.js can only
   * resolve that redirect with a full page reload — which resets the whole
   * app (including the React Query cache), showing a loading skeleton for
   * data that was already fetched. Refreshing shortly before expiry keeps
   * the cookie perpetually valid during an active session so that path is
   * never hit.
   */
  useEffect(() => {
    if (!user?.accessToken || !user.AccessTokenExpireTime) return

    const REFRESH_MARGIN_MS = 60_000
    const delay = Math.max(user.AccessTokenExpireTime - Date.now() - REFRESH_MARGIN_MS, 0)
    const timer = window.setTimeout(() => {
      // Must not use bare getOrRefreshAccessToken(): a 401 refresh used to
      // reject unhandled (Sentry on /chats). This helper soft-expires instead.
      void refreshAccessTokenProactively()
    }, delay)

    return () => {
      window.clearTimeout(timer)
    }
  }, [user?.accessToken, user?.AccessTokenExpireTime])

  const saveUser = (data: SaveUserData) => {
    const { accessToken, sessionId, expiresAt, status } = data

    axiosInstance.defaults.headers.Authorization = `Bearer ${accessToken}`

    const decodedAccessToken: DecodedToken = jwtDecode(accessToken)
    const refreshExpireTime = parseRefreshExpiry(expiresAt)
    const accessExpireAtMs = decodedAccessToken.exp * 1000

    const storageData: User = {
      accessToken,
      userId: decodedAccessToken.sub,
      role: decodedAccessToken.role,
      sessionId: sessionId ?? decodedAccessToken.sessionId,
      AccessTokenExpireTime: accessExpireAtMs,
      refreshTokenExpireTime: refreshExpireTime,
      status,
    }

    localStorage.setItem('user', JSON.stringify(storageData))

    applySessionCookies({
      accessToken,
      accessExpireAtMs,
    })
    clearLegacyRefreshCookie()

    setStatusCookie(status)
    setRoleCookie(storageData.role)
    setUser(storageData)
    if (status === 'active') setAccountSuspended(false)
  }

  const resolveMobile = (mobile: string) => convertPersianToEnglish(mobile).trim()

  const persistAuthTokens = (tokens: { accessToken: string; sessionId: string; expiresAt: string; status: UserAccountStatus }) => {
    saveUser({
      accessToken: tokens.accessToken,
      sessionId: tokens.sessionId,
      expiresAt: tokens.expiresAt,
      status: tokens.status,
    })

    return tokens.status
  }

  const sendLoginOtp = async (data: SendOtpData) => {
    const mobile = resolveMobile(data.mobile)
    const otpResult = await REQUEST_OTP({ mobile }, { errorMode: 'silent' })

    if (!otpResult.ok) throw otpResult.error

    const alreadySent = otpResult.data.alreadySent

    addToast({
      title: alreadySent ? texts.auth.otpAlreadySent : texts.auth.otpSent,
      color: alreadySent ? 'warning' : 'success',
    })

    return {
      purpose: otpResult.data.purpose,
      expiresIn: otpResult.data.expiresIn,
      resendIn: RESEND_COOLDOWN_SECONDS,
      alreadySent,
    }
  }

  const checkLoginOtp = async (data: CheckOtpData) => {
    const mobile = resolveMobile(data.mobile)
    const tokens = await VERIFY_OTP(
      {
        mobile,
        code: convertPersianToEnglish(data.code).trim(),
        termsAccepted: data.termsAccepted,
      },
      { errorMode: 'silent' }
    )

    if (!tokens.ok) throw tokens.error

    return persistAuthTokens(tokens.data)
  }

  const completeProfile = async (data: CompleteProfileData) => {
    const result = await COMPLETE_PROFILE(data, { errorMode: 'silent' })

    if (!result.ok) throw result.error

    updateUserFromOutside({
      status: result.data.status,
      firstName: result.data.firstName,
      lastName: result.data.lastName,
      gender: result.data.gender,
      cityId: result.data.cityId,
      avatarUrl: result.data.avatarUrl,
    })
    setStatusCookie(result.data.status)
  }

  const logout = async () => {
    try {
      if (user?.accessToken) {
        // Only this device's subscription — logging out here shouldn't
        // silence push notifications on the user's other logged-in devices.
        await unsubscribeCurrentDevicePush()
      }

      await attemptServerLogout()
    } catch {
      // Nest logout is best-effort; local + httpOnly cookies still clear below.
    } finally {
      await expireRefreshSessionOnThisOrigin()
      setUser(null)
      Cookies.remove('accessToken')
      clearLegacyRefreshCookie()
      setStatusCookie(undefined)
      setRoleCookie(undefined)
      localStorage.removeItem('user')
      getQueryClient().clear()
      clearPersistedQueryCache()
      clearAsyncResourceCache()
      // Hard navigation is intentional: logout must reset the full client
      // runtime (module-level axios refreshPromise, chat sockets, AuthGate
      // modal state, React Query subscribers, etc.). Soft Next.js router
      // navigation would leave those live. Same pattern as axios
      // `redirectToLogin` (`window.location.replace`). E2e auth logout
      // asserts localStorage/cookies cleared + land on `/`, not soft-nav safety.
      window.location.replace('/')
      addToast({
        title: 'خروج موفقیت آمیز بود',
        color: 'success',
      })
    }
  }

  const updateUserFromOutside = useCallback((data: Record<string, unknown>) => {
    setUser((current) => {
      if (!current) return current

      const sanitizedData = { ...data }

      delete sanitizedData.password
      delete sanitizedData.confirmPassword
      delete sanitizedData.refreshToken

      const updatedData = { ...current, ...sanitizedData } as User & { refreshToken?: unknown }

      delete updatedData.refreshToken

      localStorage.setItem('user', JSON.stringify(updatedData))
      if (typeof sanitizedData.status === 'string') {
        setStatusCookie(sanitizedData.status as UserAccountStatus)
      }

      return updatedData
    })
  }, [])

  return (
    <AuthContext.Provider
      value={{ user, isSessionHydrated, sendLoginOtp, checkLoginOtp, completeProfile, logout, saveUser, updateUserFromOutside }}
    >
      {children}
    </AuthContext.Provider>
  )
}

export { RESEND_COOLDOWN_SECONDS }