import { onMounted, onUnmounted, ref } from 'vue'
import {
  ensureBluetoothReady,
  getBluetoothErrorMessage,
  getDiscoveredBluetoothDevices,
  isBluetoothApiSupported,
  startBluetoothDiscovery,
  stopBluetoothDiscovery,
  subscribeBluetoothDevicesFound,
} from '@/utils/bluetooth'
import { buildBindDeviceQuery } from '../add-device.types'
import type { ScannedDeviceItem } from './scan.types'
import { mapBluetoothDevice } from './scan.utils'

const SCAN_SECONDS = 20

export function useScanDevice() {
  const currentStep = 2
  const devices = ref<ScannedDeviceItem[]>([])
  const selectedId = ref('')
  const secondsLeft = ref(SCAN_SECONDS)
  const scanning = ref(true)
  const scanError = ref('')

  let unsubscribeFound: (() => void) | undefined

  function upsertDevice(item: ScannedDeviceItem) {
    const idx = devices.value.findIndex((d) => d.id === item.id)
    if (idx >= 0) {
      devices.value[idx] = item
      return
    }
    devices.value.push(item)
    if (!selectedId.value) selectedId.value = item.id
  }

  function ingestBluetoothDevices(found: UniApp.BluetoothDeviceInfo[]) {
    for (const device of found) {
      upsertDevice(mapBluetoothDevice(device))
    }
  }

  async function beginDiscovery() {
    if (!isBluetoothApiSupported()) {
      scanning.value = false
      scanError.value = '当前环境不支持蓝牙扫描，请使用 App 或微信小程序'
      return
    }

    try {
      await ensureBluetoothReady()

      unsubscribeFound = subscribeBluetoothDevicesFound((found) => {
        ingestBluetoothDevices(found)
      })

      const existing = await getDiscoveredBluetoothDevices()
      ingestBluetoothDevices(existing)

      await startBluetoothDiscovery()
    } catch (err) {
      scanning.value = false
      scanError.value = getBluetoothErrorMessage(err)
      uni.showToast({ title: scanError.value, icon: 'none' })
    }
  }

  onMounted(() => {
    void beginDiscovery()
  })

  const timer = setInterval(() => {
    if (secondsLeft.value <= 0) {
      scanning.value = false
      return
    }
    secondsLeft.value -= 1
    if (secondsLeft.value === 0) {
      scanning.value = false
      void stopBluetoothDiscovery().catch(() => {})
    }
  }, 1000)

  onUnmounted(() => {
    clearInterval(timer)
    unsubscribeFound?.()
    void stopBluetoothDiscovery().catch(() => {})
  })

  function onSelectDevice(id: string) {
    selectedId.value = id
  }

  function onDeviceAction(device: ScannedDeviceItem) {
    selectedId.value = device.id
    if (!device.canAdd) {
      uni.showToast({ title: '暂无法添加该设备', icon: 'none' })
      return
    }
    const q = buildBindDeviceQuery({
      deviceNo: device.deviceNo,
      name: device.name,
      serialMasked: device.serialMasked,
      productId: device.productId,
      model: device.model,
      imei: device.imei,
      mac: device.mac,
    })
    uni.navigateTo({ url: `/pages/add-device/pair/index?${q}` })
  }

  return {
    currentStep,
    devices,
    selectedId,
    secondsLeft,
    scanning,
    scanError,
    onSelectDevice,
    onDeviceAction,
  }
}