/**
 * Android 系统扫码 API 实现
 * 使用 android.device.ScanDevice + 广播监听
 */

// UTF8 字节数组解码为 Unicode 字符串
function utf8ByteToUnicodeStr(utf8Bytes) {
  var unicodeStr = ''
  for (var pos = 0; pos < utf8Bytes.length;) {
    var flag = utf8Bytes[pos]
    var unicode = 0
    if ((flag >>> 7) === 0) {
      unicodeStr += String.fromCharCode(utf8Bytes[pos])
      pos += 1
    } else if ((flag & 0xFC) === 0xFC) {
      unicode = (utf8Bytes[pos] & 0x3) << 30
      unicode |= (utf8Bytes[pos + 1] & 0x3F) << 24
      unicode |= (utf8Bytes[pos + 2] & 0x3F) << 18
      unicode |= (utf8Bytes[pos + 3] & 0x3F) << 12
      unicode |= (utf8Bytes[pos + 4] & 0x3F) << 6
      unicode |= (utf8Bytes[pos + 5] & 0x3F)
      unicodeStr += String.fromCodePoint(unicode)
      pos += 6
    } else if ((flag & 0xF8) === 0xF8) {
      unicode = (utf8Bytes[pos] & 0x7) << 24
      unicode |= (utf8Bytes[pos + 1] & 0x3F) << 18
      unicode |= (utf8Bytes[pos + 2] & 0x3F) << 12
      unicode |= (utf8Bytes[pos + 3] & 0x3F) << 6
      unicode |= (utf8Bytes[pos + 4] & 0x3F)
      unicodeStr += String.fromCodePoint(unicode)
      pos += 5
    } else if ((flag & 0xF0) === 0xF0) {
      unicode = (utf8Bytes[pos] & 0xF) << 18
      unicode |= (utf8Bytes[pos + 1] & 0x3F) << 12
      unicode |= (utf8Bytes[pos + 2] & 0x3F) << 6
      unicode |= (utf8Bytes[pos + 3] & 0x3F)
      unicodeStr += String.fromCodePoint(unicode)
      pos += 4
    } else if ((flag & 0xE0) === 0xE0) {
      unicode = (utf8Bytes[pos] & 0x1F) << 12
      unicode |= (utf8Bytes[pos + 1] & 0x3F) << 6
      unicode |= (utf8Bytes[pos + 2] & 0x3F)
      unicodeStr += String.fromCharCode(unicode)
      pos += 3
    } else if ((flag & 0xC0) === 0xC0) {
      unicode = (utf8Bytes[pos] & 0x3F) << 6
      unicode |= (utf8Bytes[pos + 1] & 0x3F)
      unicodeStr += String.fromCharCode(unicode)
      pos += 2
    } else {
      unicodeStr += String.fromCharCode(utf8Bytes[pos])
      pos += 1
    }
  }
  return unicodeStr
}

class ScanAndroidImpl {
  constructor() {
    this.scanDevice = null
    this._receiver = null
    this._filter = null
    this._main = null
    this._callback = null
    this._isScanning = false
  }

  /**
   * 初始化：打开扫描设备，设置广播模式
   */
  init() {
    // var ScanDeviceClass = plus.android.importClass('android.device.ScanDevice')
    // this.scanDevice = new ScanDeviceClass()
    
    // 使用 plus.android.newObject 创建实例（更兼容）
    try {
      this.scanDevice = plus.android.newObject('android.device.ScanDevice')
    } catch (e) {
      throw new Error('[Scan-Android] 当前设备不支持 android.device.ScanDevice，请切换到 iData 模式或使用其他扫码方式: ' + e.message)
    }    
    
    this.scanDevice.openScan()
    this.scanDevice.setOutScanMode(0) // 0 = 广播模式

    this._main = plus.android.runtimeMainActivity()
    var IntentFilter = plus.android.importClass('android.content.IntentFilter')
    this._filter = new IntentFilter()
    this._filter.addAction('scan.rcv.message')
  }

  /**
   * 注册扫码结果回调
   * @param {Function} callback - (codeStr: string) => void
   */
  register(callback) {
    this._callback = callback

    var self = this
    this._receiver = plus.android.implements('io.dcloud.feature.internal.reflect.BroadcastReceiver', {
      onReceive: function (context, intent) {
        plus.android.importClass(intent)
        var code = intent.getByteArrayExtra('barocode')
        if (code) {
          var codeStr = utf8ByteToUnicodeStr(code)
          console.log('[Scan-Android] 扫码结果:', codeStr)
          self.scanDevice.stopScan()
          self._isScanning = false
          if (self._callback) {
            self._callback(codeStr)
          }
        }
      }
    })

    this._main.registerReceiver(this._receiver, this._filter)
  }

  /**
   * 注销监听（页面卸载时调用）
   */
  unregister() {
    if (this._receiver && this._main) {
      this._main.unregisterReceiver(this._receiver)
      this._receiver = null
    }
    this._callback = null
  }

  /**
   * 开始扫描
   */
  startScan() {
    if (this.scanDevice) {
      this.scanDevice.stopScan()
      this.scanDevice.startScan()
      this._isScanning = true
    }
  }

  /**
   * 停止扫描
   */
  stopScan() {
    if (this.scanDevice) {
      this.scanDevice.stopScan()
      this._isScanning = false
    }
  }

  /**
   * 是否正在扫描
   */
  isScanning() {
    return this._isScanning
  }

  /**
   * 完全销毁（应用退出时调用）
   */
  destroy() {
    this.unregister()
    if (this.scanDevice) {
      this.scanDevice.closeScan()
      this.scanDevice = null
    }
    this._main = null
    this._filter = null
  }
}

export default ScanAndroidImpl