/**
 * Android / iOS 权限与能力检测
 * Android 6+ 扫描 BLE 需要位置权限 + 位置服务开启
 * Android 12+ 需要 BLUETOOTH_SCAN / BLUETOOTH_CONNECT
 * iOS 需要 NSBluetoothAlwaysUsageDescription (在 manifest.json 中配置)
 *
 * 仅在 APP-PLUS 环境下调用 plus API, H5 / 小程序环境跳过
 */

export function getPlatform() {
  try { return uni.getSystemInfoSync().platform } catch (_) { return '' }
}

/** 是否 App 环境 (plus 存在) */
export function isAppPlus() {
  // #ifdef APP-PLUS
  return typeof plus !== 'undefined'
  // #endif
  // #ifndef APP-PLUS
  return false
  // #endif
}

/** 检查位置服务是否已开启 (Android) */
export function isLocationEnabled() {
  return new Promise(resolve => {
    if (!isAppPlus() || getPlatform() !== 'android') return resolve(true)
    // #ifdef APP-PLUS
    try {
      const main = plus.android.runtimeMainActivity()
      const LocationManager = plus.android.importClass('android.location.LocationManager')
      const context = plus.android.importClass('android.content.Context')
      const lm = main.getSystemService(context.LOCATION_SERVICE)
      const gps = lm.isProviderEnabled(LocationManager.GPS_PROVIDER)
      const net = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
      resolve(gps || net)
    } catch (e) { resolve(true) }
    // #endif
  })
}

/** 跳转到系统位置服务设置 */
export function openLocationSettings() {
  // #ifdef APP-PLUS
  if (!isAppPlus() || getPlatform() !== 'android') return
  try {
    const main = plus.android.runtimeMainActivity()
    const Intent = plus.android.importClass('android.content.Intent')
    const Settings = plus.android.importClass('android.provider.Settings')
    const intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS)
    main.startActivity(intent)
  } catch (e) { console.error(e) }
  // #endif
}

/** 请求 Android 运行时权限(定位/蓝牙扫描/连接). 返回 true/false */
export function requestAndroidPermissions() {
  return new Promise(resolve => {
    if (!isAppPlus() || getPlatform() !== 'android') return resolve(true)
    // #ifdef APP-PLUS
    try {
      const main = plus.android.runtimeMainActivity()
      const Build = plus.android.importClass('android.os.Build')
      const sdkInt = Build.VERSION.SDK_INT

      const perms = ['android.permission.ACCESS_FINE_LOCATION']
      if (sdkInt >= 31) {
        perms.push('android.permission.BLUETOOTH_SCAN')
        perms.push('android.permission.BLUETOOTH_CONNECT')
      }

      const PackageManager = plus.android.importClass('android.content.pm.PackageManager')
      const need = perms.filter(p => main.checkSelfPermission(p) !== PackageManager.PERMISSION_GRANTED)
      if (!need.length) return resolve(true)

      const ActivityCompat = plus.android.importClass('androidx.core.app.ActivityCompat')
      // 注册结果回调
      const onReq = (activity, requestCode, permsArr, grantResults) => {
        plus.android.clearRequestPermissions && plus.android.clearRequestPermissions()
        const granted = grantResults && Array.from(grantResults).every(r => r === 0)
        resolve(!!granted)
      }
      if (plus.android.requestPermissions) {
        plus.android.requestPermissions(need, res => {
          resolve(res && res.granted && res.granted.length === need.length)
        }, () => resolve(false))
      } else {
        ActivityCompat.requestPermissions(main, need, 1001)
        // 无结果回调能力时, 乐观等待 2s 后查询
        setTimeout(() => {
          const still = need.filter(p => main.checkSelfPermission(p) !== PackageManager.PERMISSION_GRANTED)
          resolve(!still.length)
        }, 2000)
      }
    } catch (e) {
      console.error(e); resolve(false)
    }
    // #endif
  })
}

/** 检查系统蓝牙是否已开启 (Android 使用原生 API，iOS 依赖 uni API) */
export function isBluetoothEnabled() {
  return new Promise(resolve => {
    const platform = getPlatform()
    if (!isAppPlus()) return resolve(true)
    // #ifdef APP-PLUS
    if (platform === 'android') {
      try {
        const BluetoothAdapter = plus.android.importClass('android.bluetooth.BluetoothAdapter')
        const adapter = BluetoothAdapter.getDefaultAdapter()
        resolve(adapter != null && adapter.isEnabled())
      } catch (e) {
        // 无法检测时放行，让后续流程处理
        resolve(true)
      }
    } else if (platform === 'ios') {
      // iOS 无法直接通过原生 API 检测，依赖 uni.openBluetoothAdapter 的结果
      resolve(true)
    } else {
      resolve(true)
    }
    // #endif
    // #ifndef APP-PLUS
    resolve(true)
    // #endif
  })
}

/** 跳转到系统蓝牙设置页面 */
export function openBluetoothSettings() {
  // #ifdef APP-PLUS
  const platform = getPlatform()
  if (platform === 'android') {
    try {
      const main = plus.android.runtimeMainActivity()
      const Intent = plus.android.importClass('android.content.Intent')
      const Settings = plus.android.importClass('android.provider.Settings')
      const intent = new Intent(Settings.ACTION_BLUETOOTH_SETTINGS)
      main.startActivity(intent)
    } catch (e) { console.error('跳转蓝牙设置失败', e) }
  } else if (platform === 'ios') {
    plus.runtime.openURL('App-Prefs:root=Bluetooth')
  }
  // #endif
}

/** 一键: 申请权限 + 校验定位服务 + 检测蓝牙开启. 失败抛异常 */
export async function ensureBlePrerequisite() {
  const platform = getPlatform()
  if (platform === 'android') {
    const ok = await requestAndroidPermissions()
    if (!ok) throw new Error('BLE_PERMISSION_DENIED')
    const loc = await isLocationEnabled()
    if (!loc) throw new Error('BLE_LOCATION_OFF')
  }
  // 检测蓝牙是否开启（Android 原生检测，iOS 跳过此步）
  const bleOn = await isBluetoothEnabled()
  if (!bleOn) throw new Error('BLE_ADAPTER_OFF')
  return true
}