import 'dart:convert';
import 'dart:io';

import 'package:crypto/crypto.dart' as crypto;
import 'package:flutter_sdk/starcloud_flutter_sdk.dart';
import 'package:starcloud/blue/blue_features.dart';
import 'package:starcloud/blue/blue_read_write.dart';
import 'package:starcloud/blue/entity/blue_message.dart';
import 'package:starcloud/device/ble/base/base_sender.dart';
import 'package:starcloud/device/ble/ble_reply.dart';
import 'package:starcloud/device/ble/business/ble_type.dart';
import 'package:starcloud/device/ble/tool/ble_tool.dart';
import 'package:starcloud/entity/star_cloud_lock_list.dart';
import 'package:starcloud/tool/sm4_encipher/sm4.dart';

/// 主动监控前将猫眼从省电模式切换到实时监控模式。
///
/// 实时模式由 BLE feature bit 64 写入锁端。
/// 省电模式（catEyeMode=0）下锁固件会忽略主动 TalkRequest。
///
/// 公开 Flutter SDK 文档未定义 cat-eye 云端设置 API；因此这里不能调用
/// 非公开的 `updateCatEyeConfig` 并把其服务端权限错误当作 BLE 操作失败。
class CatEyeMonitorService {
  static const int _catEyeFeatureBit = 64;
  static const int _realtimeMode = 2;

  Future<void> enableRealtimeMode({
    required StarCloudLock lock,
  }) async {
    final context = await StarCloudLockContext.fromLock(lock);
    final featureData = <int>[
      _realtimeMode,
      0, 0, 0, 0, 0, 0, // 非自定义模式的录像参数
      0, 0, // detectionDistance / realTimePicture
      1, 10, 1, 1, // 自动亮屏、亮屏时长、逗留/异常告警
    ];

    final blue = BlueReadWrite.shareManager();
    if (blue == null) {
      throw const StarCloudException('Bluetooth service is unavailable');
    }
    blue.deviceName = lock.bluetooth.bluetoothDeviceName;
    if (!Platform.isAndroid) blue.mac = lock.mac;
    blue.type = BlueFeaturesType.lock;
    blue.clearCallback();

    final reply = await blue.writeAndReturn(
      _SetCatEyeModeCommand(
        keyId: context.keyId,
        userId: context.userId,
        featureData: featureData,
        token: context.token,
        needAuthor: context.needAuthor,
        publicKey: context.publicKey,
        privateKey: context.privateKey,
      ),
      getPrivateKey: () => context.privateKey,
      timeout: const Duration(seconds: 20),
    );
    if (reply.status != 0) {
      throw StarCloudException(
        'Failed to enable cat-eye realtime mode over BLE',
        raw: 'status=0x${reply.status.toRadixString(16)}',
      );
    }
  }
}

class _SetCatEyeModeCommand extends SenderProtocol {
  _SetCatEyeModeCommand({
    required this.keyId,
    required this.userId,
    required this.featureData,
    required List<int> token,
    required this.needAuthor,
    required this.publicKey,
    required this.privateKey,
  })  : token = List<int>.from(token),
        super(CommandType.generalExtendedCommond);

  final String keyId;
  final String userId;
  final List<int> featureData;
  final int needAuthor;
  final List<int> publicKey;
  final List<int> privateKey;

  @override
  List<int>? token;

  @override
  List<int> messageDetail() {
    final data = <int>[0x30, 0x30, 72];
    var subData = <int>[];

    final keyBytes = utf8.encode(keyId);
    subData.addAll(keyBytes);
    subData = BLETool.getFixedLengthList(subData, 40 - keyBytes.length);

    final userBytes = utf8.encode(userId);
    subData.addAll(userBytes);
    subData = BLETool.getFixedLengthList(subData, 20 - userBytes.length);
    subData
      ..add(CatEyeMonitorService._catEyeFeatureBit)
      ..add(featureData.length)
      ..addAll(featureData);

    if (needAuthor == 0) {
      subData.add(0);
    } else {
      final authData = <int>[
        ...userBytes,
        ...keyBytes,
        ...?token,
        ...publicKey,
      ];
      final authCode = crypto.md5.convert(authData).bytes;
      subData
        ..add(authCode.length)
        ..addAll(authCode);
    }

    data
      ..add(subData.length)
      ..addAll(subData);
    while (data.length % 16 != 0) {
      data.add(0);
    }
    return SM4.encrypt(data, key: privateKey, mode: SM4CryptoMode.ECB);
  }

  @override
  BLEReply blueMessageToReply(BlueMessage message) {
    return _SetCatEyeModeReply.parseData(commandType, message.data);
  }
}

class _SetCatEyeModeReply extends BLEReply {
  _SetCatEyeModeReply.parseData(
    CommandType commandType,
    List<int> data,
  ) : super.parseData(commandType, data) {
    // 通用扩展应答：[0x30, 0x30, mainStatus, subCommand, subStatus, ...]
    // 原 App 以 mainStatus 为本次设置结果。
    status = data.length > 2 ? data[2] : 0xff;
    errorWithStatus(status);
    if (status == 0x06 && data.length >= 9) {
      token = data.sublist(5, 9);
    }
  }
}