// =============================================================================
// IT智能服务台 — Portal 扫码登录 Composable (Phase 1.3, task #16)
// =============================================================================
// 说明：跟 frontend-agent/src/composables/useQrcodeLogin.ts 同款逻辑
// Portal 端的 onSuccess 由调用方提供,通常实现"按角色跳对应端"
// =============================================================================

import { ref, onUnmounted, type Ref } from 'vue'
import { ElMessage } from 'element-plus'
import { createQrcode, pollQrcode } from '@/api/qrcode'
import type { QrcodePollStatus } from '@/api/qrcode'

const POLL_INTERVAL_MS = 2000
const COUNTDOWN_TICK_MS = 1000

export interface UseQrcodeLoginOptions {
  /** 登录成功回调(token, employeeId, roles)— Portal 一般这里按角色跳对应端 */
  onSuccess: (token: string, employeeId: string, roles: string[]) => void
  onError?: (message: string) => void
}

export interface UseQrcodeLoginReturn {
  qrcodePngBase64: Ref<string | null>
  qrcodeUrl: Ref<string | null>
  countdown: Ref<number>
  status: Ref<QrcodePollStatus>
  scannedBy: Ref<string | null>
  loading: Ref<boolean>
  errorMessage: Ref<string | null>
  startLogin: () => Promise<void>
  refreshQrcode: () => Promise<void>
  stopPolling: () => void
}

export function useQrcodeLogin(options: UseQrcodeLoginOptions): UseQrcodeLoginReturn {
  const qrcodePngBase64 = ref<string | null>(null)
  const qrcodeUrl = ref<string | null>(null)
  const countdown = ref<number>(0)
  const status = ref<QrcodePollStatus>('waiting')
  const scannedBy = ref<string | null>(null)
  const loading = ref<boolean>(false)
  const errorMessage = ref<string | null>(null)

  let ticket: string | null = null
  let pollTimer: ReturnType<typeof setInterval> | null = null
  let countdownTimer: ReturnType<typeof setInterval> | null = null
  let expiresAt: number | null = null

  function clearTimers(): void {
    if (pollTimer) {
      clearInterval(pollTimer)
      pollTimer = null
    }
    if (countdownTimer) {
      clearInterval(countdownTimer)
      countdownTimer = null
    }
  }

  function startCountdown(): void {
    if (countdownTimer) clearInterval(countdownTimer)
    countdownTimer = setInterval(() => {
      if (!expiresAt) {
        countdown.value = 0
        return
      }
      const remaining = Math.max(0, Math.floor((expiresAt - Date.now()) / 1000))
      countdown.value = remaining
      if (remaining === 0 && status.value === 'waiting') {
        status.value = 'expired'
        clearTimers()
      }
    }, COUNTDOWN_TICK_MS)
  }

  function startPolling(): void {
    if (pollTimer) clearInterval(pollTimer)
    pollTimer = setInterval(async () => {
      if (!ticket) return
      try {
        const data = await pollQrcode(ticket)
        status.value = data.status
        scannedBy.value = data.name || null

        if (data.status === 'confirmed' && data.token && data.employee_id) {
          clearTimers()
          const roles = data.roles || ['user']
          options.onSuccess(data.token, data.employee_id, roles)
        } else if (data.status === 'expired') {
          clearTimers()
        }
      } catch (err: any) {
        console.warn('[useQrcodeLogin] poll error:', err)
      }
    }, POLL_INTERVAL_MS)
  }

  function stopPolling(): void {
    clearTimers()
  }

  async function startLogin(): Promise<void> {
    if (loading.value) return
    loading.value = true
    errorMessage.value = null
    clearTimers()

    try {
      const data = await createQrcode()
      ticket = data.ticket
      qrcodeUrl.value = data.qrcode_url
      qrcodePngBase64.value = data.qrcode_png_base64 || null
      countdown.value = data.expires_in
      expiresAt = Date.now() + data.expires_in * 1000
      status.value = 'waiting'
      scannedBy.value = null

      startCountdown()
      startPolling()
    } catch (err: any) {
      const msg = err?.message || '生成二维码失败'
      errorMessage.value = msg
      if (options.onError) {
        options.onError(msg)
      } else {
        ElMessage.error(msg)
      }
    } finally {
      loading.value = false
    }
  }

  async function refreshQrcode(): Promise<void> {
    await startLogin()
  }

  onUnmounted(() => {
    clearTimers()
  })

  return {
    qrcodePngBase64,
    qrcodeUrl,
    countdown,
    status,
    scannedBy,
    loading,
    errorMessage,
    startLogin,
    refreshQrcode,
    stopPolling,
  }
}