import { computed, ref } from 'vue'
import { defineStore } from 'pinia'
import type { CurrentUser } from '@chongchong/shared'
import { exchangeImpersonationCode, loginMerchant, logoutMerchant } from '@/modules/auth/api/auth'
import { ApiError } from '@/api/http'
import {
  FRONTEND_TO_MERCHANT_PERMISSION_CODES,
  hasMappedMerchantPermission,
  getCurrentMerchantPermissionCodes,
  getMerchantPersonalProfile,
  getTenantProfile,
  updateMerchantPersonalProfile,
} from '@/modules/tenant-management/public'
import { clearSessionTokens, getAccessToken, getRefreshToken, persistTemporaryAccessToken, persistTokenPair } from '@/api/session'
import { decodeMerchantToken, type MerchantJwtPayload } from '@/modules/auth/utils/jwt'

export interface ClientAccountProfile {
  username: string
  realName: string
  phone: string
  email: string
  tenantName: string
}

const emptyProfile: ClientAccountProfile = {
  username: '',
  realName: '',
  phone: '',
  email: '',
  tenantName: '',
}

function mapPermissions(backendPermissionCodes: string[] = []) {
  const backendPermissions = new Set(backendPermissionCodes)
  const result = new Set<string>(['dashboard:view', 'account:profile:view'])
  for (const [frontendCode] of Object.entries(FRONTEND_TO_MERCHANT_PERMISSION_CODES)) {
    if (hasMappedMerchantPermission(frontendCode, backendPermissions)) result.add(frontendCode)
  }
  return [...result]
}

function currentUser(payload: MerchantJwtPayload, tenantName?: string): CurrentUser {
  return {
    id: String(payload.user_id),
    name: payload.username,
    account: payload.username,
    tenantName: tenantName || `企业租户 ${payload.tenant_id}`,
    roles: [],
  }
}

function isExpiredSessionError(error: unknown) {
  return error instanceof ApiError && (error.status === 401 || error.code === 'A0401')
}

export const useAuthStore = defineStore('client-auth', () => {
  const token = ref(getAccessToken())
  const payload = ref<MerchantJwtPayload | null>(null)
  const user = ref<CurrentUser | null>(null)
  const profile = ref<ClientAccountProfile>({ ...emptyProfile })
  const permissionCodes = ref<string[]>([])
  const sessionRestored = ref(false)

  function applyToken(accessToken: string) {
    const decoded = decodeMerchantToken(accessToken)
    payload.value = decoded
    token.value = accessToken
    user.value = currentUser(decoded, user.value?.tenantName)
    profile.value.username = decoded.username
    profile.value.realName = decoded.username
    permissionCodes.value = mapPermissions()
  }

  function clearSession() {
    clearSessionTokens()
    token.value = ''
    payload.value = null
    user.value = null
    permissionCodes.value = []
    profile.value = { ...emptyProfile }
    sessionRestored.value = true
  }

  function applyStoredSession() {
    const storedToken = getAccessToken()
    if (!storedToken) {
      token.value = ''
      payload.value = null
      user.value = null
      permissionCodes.value = []
      profile.value = { ...emptyProfile }
      sessionRestored.value = true
      return
    }
    try {
      applyToken(storedToken)
      sessionRestored.value = false
    } catch {
      clearSession()
    }
  }

  if (token.value) {
    try {
      applyToken(token.value)
    } catch {
      clearSession()
    }
  }

  const isAuthenticated = computed(() => Boolean(token.value && payload.value))

  async function loadSessionContext() {
    if (!payload.value) return
    const currentPermissionCodes = await getCurrentMerchantPermissionCodes()
    const currentAccessToken = getAccessToken()
    if (currentAccessToken && currentAccessToken !== token.value) applyToken(currentAccessToken)
    permissionCodes.value = mapPermissions(currentPermissionCodes)
    const [tenant, personalProfile] = await Promise.all([
      getTenantProfile(),
      getMerchantPersonalProfile(),
    ])
    user.value = currentUser(payload.value, tenant.tenantName)
    profile.value = {
      ...profile.value,
      realName: personalProfile.displayName || payload.value.username,
      phone: personalProfile.phone || '',
      email: personalProfile.email || '',
      tenantName: tenant.tenantName,
    }
  }

  async function restoreSession() {
    if (sessionRestored.value) return
    if (!isAuthenticated.value) {
      sessionRestored.value = true
      return
    }
    try {
      await loadSessionContext()
    } catch (error) {
      if (isExpiredSessionError(error)) {
        clearSession()
        throw error
      }
      sessionRestored.value = true
      return
    }
    sessionRestored.value = true
  }

  async function login(loginId: string, password: string, remember = false) {
    const tokens = await loginMerchant(loginId, password)
    const decoded = decodeMerchantToken(tokens.accessToken)
    persistTokenPair(tokens, remember)
    token.value = tokens.accessToken
    payload.value = decoded
    user.value = currentUser(decoded)
    profile.value = { ...emptyProfile, username: decoded.username, realName: decoded.username }
    permissionCodes.value = mapPermissions()
    sessionRestored.value = false
    try {
      await loadSessionContext()
      sessionRestored.value = true
    } catch (error) {
      if (isExpiredSessionError(error)) {
        clearSession()
        throw error
      }
      sessionRestored.value = true
    }
  }

  async function acceptImpersonationCode(code: string) {
    const exchanged = await exchangeImpersonationCode(code)
    const decoded = decodeMerchantToken(exchanged.accessToken)
    persistTemporaryAccessToken(exchanged.accessToken)
    token.value = exchanged.accessToken
    payload.value = decoded
    user.value = currentUser(decoded)
    profile.value = { ...emptyProfile, username: decoded.username, realName: decoded.username }
    permissionCodes.value = mapPermissions()
    sessionRestored.value = false
    try {
      await loadSessionContext()
    } catch (error) {
      if (isExpiredSessionError(error)) {
        clearSession()
        throw error
      }
    }
    sessionRestored.value = true
  }

  async function logout() {
    const refreshToken = getRefreshToken()
    try {
      if (refreshToken) await logoutMerchant(refreshToken)
    } finally {
      clearSession()
    }
  }

  function hasPermission(permission?: string) {
    return !permission || permissionCodes.value.includes(permission)
  }

  function updateProfile(next: Pick<ClientAccountProfile, 'realName' | 'phone' | 'email'>) {
    profile.value = { ...profile.value, ...structuredClone(next) }
    if (user.value) user.value = { ...user.value, name: next.realName }
  }

  async function savePersonalProfile(next: Pick<ClientAccountProfile, 'realName' | 'email'>) {
    const updated = await updateMerchantPersonalProfile({
      displayName: next.realName.trim(),
      email: next.email.trim(),
    })
    updateProfile({
      realName: updated.displayName,
      phone: updated.phone || '',
      email: updated.email || '',
    })
  }

  window.addEventListener('cc-client-session-expired', clearSession)
  window.addEventListener('storage', (event) => {
    if (event.key === 'cc-client-access-token' || event.key === 'cc-client-refresh-token') applyStoredSession()
  })

  return { token, user, profile, permissionCodes, isAuthenticated, sessionRestored, hasPermission, login, logout, clearSession, restoreSession, acceptImpersonationCode, updateProfile, savePersonalProfile }
})