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, refreshAuthenticatedSession } from '@/api/http'
import {
  FRONTEND_TO_MERCHANT_PERMISSION_CODES,
  hasMappedMerchantPermission,
  getCurrentMerchantPermissionCodes,
  getMerchantPersonalProfile,
  getTenantProfile,
  updateMerchantPersonalProfile,
} from '@/modules/tenant-management/public'
import { clearSessionTokens, getAccessToken, getRefreshToken, persistRememberedLoginId, persistTemporaryAccessToken, persistTokenPair } from '@/api/session'
import { decodeMerchantToken, MerchantTokenExpiredError, 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)

  let logoutRequest: { accessToken: string; refreshToken: string; promise: Promise<void> } | undefined
  let generation = 0
  let contextRequest: { generation: number; promise: Promise<void> } | undefined
  let restoreTimer: ReturnType<typeof setTimeout> | undefined

  function identity(value: MerchantJwtPayload | null) {
    return value ? JSON.stringify([value.user_id, value.tenant_id, value.membership_id, value.operator_tenant_id, value.app_code, value.client_type]) : ''
  }

  function applyToken(accessToken: string) {
    const decoded = decodeMerchantToken(accessToken)
    const changedIdentity = identity(decoded) !== identity(payload.value)
    if (accessToken === token.value && payload.value && !changedIdentity) return
    generation++
    if (changedIdentity) {
      user.value = null
      profile.value = { ...emptyProfile }
      permissionCodes.value = mapPermissions()
    }
    payload.value = decoded
    token.value = accessToken
    user.value = currentUser(decoded, user.value?.tenantName)
    profile.value.username = decoded.username
    sessionRestored.value = false
  }

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

  function clearSession() {
    clearSessionTokens()
    resetLocalSession()
  }

  function applyStoredSession() {
    const storedToken = getAccessToken()
    if (!storedToken) {
      resetLocalSession()
      return
    }
    try {
      applyToken(storedToken)
    } catch (error) {
      resetLocalSession()
      if (error instanceof MerchantTokenExpiredError && getRefreshToken()) sessionRestored.value = false
    }
  }

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

  async function restoreSession() {
    if (sessionRestored.value) return
    if (contextRequest?.generation === generation) return contextRequest.promise
    let requestGeneration = generation
    let requestAccessToken = getAccessToken()
    const isCurrent = () => requestGeneration === generation && getAccessToken() === requestAccessToken
    const promise = (async () => {
      try {
        if (!isAuthenticated.value) {
          if (!getRefreshToken()) return
          const refreshedToken = await refreshAuthenticatedSession()
          if (requestGeneration !== generation) return restoreSession()
          applyToken(refreshedToken)
          requestAccessToken = refreshedToken
          requestGeneration = generation
          if (contextRequest) contextRequest.generation = generation
        }
        const requestPayload = payload.value
        if (!requestPayload) return
        const [codes, tenant, personalProfile] = await Promise.all([
          getCurrentMerchantPermissionCodes(), getTenantProfile(), getMerchantPersonalProfile(),
        ])
        if (!isCurrent()) {
          applyStoredSession()
          return restoreSession()
        }
        permissionCodes.value = mapPermissions(codes)
        user.value = currentUser(requestPayload, tenant.tenantName)
        profile.value = {
          username: requestPayload.username,
          realName: personalProfile.displayName || requestPayload.username,
          phone: personalProfile.phone || '', email: personalProfile.email || '', tenantName: tenant.tenantName,
        }
        sessionRestored.value = true
      } catch (error) {
        if (!isCurrent()) return
        sessionRestored.value = false
        if (isExpiredSessionError(error)) {
          clearSession()
          throw error
        }
      }
    })()
    contextRequest = { generation: requestGeneration, promise }
    try { await promise } finally {
      if (contextRequest?.promise === promise) contextRequest = undefined
    }
  }

  function synchronizeSession() {
    // Identity changes and logout revoke local rights immediately. Coalesce pair writes
    // before loading the new context; same-identity rotation retains confirmed rights.
    applyStoredSession()
    if (restoreTimer) clearTimeout(restoreTimer)
    restoreTimer = setTimeout(() => {
      restoreTimer = undefined
      void restoreSession().catch(() => {})
    }, 0)
  }

  async function login(loginId: string, password: string, remember = false) {
    const attempt = ++generation
    const tokens = await loginMerchant(loginId, password)
    if (attempt !== generation) return
    decodeMerchantToken(tokens.accessToken)
    persistTokenPair(tokens)
    persistRememberedLoginId(loginId, remember)
    applyToken(tokens.accessToken)
    await restoreSession()
  }

  async function acceptImpersonationCode(code: string) {
    const attempt = ++generation
    const exchanged = await exchangeImpersonationCode(code)
    if (attempt !== generation) return
    decodeMerchantToken(exchanged.accessToken)
    persistTemporaryAccessToken(exchanged.accessToken)
    applyToken(exchanged.accessToken)
    await restoreSession()
  }

  function logout() {
    const accessToken = getAccessToken()
    const refreshToken = getRefreshToken()
    if (logoutRequest && ((!accessToken && !refreshToken)
      || (logoutRequest.accessToken === accessToken && logoutRequest.refreshToken === refreshToken))) return logoutRequest.promise
    const pending = accessToken || refreshToken
      ? logoutMerchant(accessToken, refreshToken)
      : Promise.resolve()
    clearSession()
    const request = { accessToken, refreshToken, promise: pending.finally(() => {
      if (logoutRequest === request) logoutRequest = undefined
    }) }
    logoutRequest = request
    return request.promise
  }

  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 requestGeneration = generation
    const requestToken = getAccessToken()
    const updated = await updateMerchantPersonalProfile({
      displayName: next.realName.trim(),
      email: next.email.trim(),
    })
    if (requestGeneration !== generation || requestToken !== getAccessToken()) return
    updateProfile({
      realName: updated.displayName,
      phone: updated.phone || '',
      email: updated.email || '',
    })
  }

  window.addEventListener('cc-client-session-expired', clearSession)
  window.addEventListener('cc-client-session-updated', synchronizeSession)
  window.addEventListener('storage', (event) => {
    if (event.storageArea === localStorage && (event.key === null || event.key === 'cc-client-access-token' || event.key === 'cc-client-refresh-token')) synchronizeSession()
  })

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