import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';

import 'ch934x_serial_platform_interface.dart';
import 'src/models/models.dart';

/// MethodChannel 实现的 [Ch934xSerialPlatform]。
///
/// 在 Android 端通过同一 MethodChannel 与原生层通信,
/// 命名规则:方法名使用下划线小写,字段名使用驼峰式以便
/// 直接对应 Java 侧 Map 的 key。
class MethodChannelCh934xSerial extends Ch934xSerialPlatform {
  /// 测试时可被替换的 MethodChannel。
  @visibleForTesting
  final MethodChannel methodChannel =
      const MethodChannel('ch934x_serial');

  /// 通知 Dart 侧的异常事件流,用于支持 `setExceptionCallback`。
  final StreamController<Ch934xException> _exceptionController =
      StreamController<Ch934xException>.broadcast();

  /// 接收来自原生层主动调用的 `onException` 消息。
  Future<void> _onNativeMethodCall(MethodCall call) async {
    if (call.method == 'onException') {
      final args = call.arguments;
      if (args is Map) {
        _exceptionController.add(
          Ch934xException(
            type: (args['type'] as int?) ?? Ch934xExceptionType.unknown,
            message: args['message'] as String?,
            cause: args['cause'] as String?,
          ),
        );
      }
    }
  }

  @override
  Future<List<Ch934xDeviceInfo>> getDeviceList() async {
    final raw = await methodChannel.invokeMethod<List<dynamic>>('getDeviceList');
    if (raw == null) {
      return const <Ch934xDeviceInfo>[];
    }
    return raw
        .whereType<Map>()
        .map((e) => Ch934xDeviceInfo.fromMap(Map<dynamic, dynamic>.from(e)))
        .toList(growable: false);
  }

  @override
  Future<String?> getSerialNumber(int deviceId) {
    return methodChannel.invokeMethod<String>(
      'getSerialNumber',
      <String, Object>{'deviceId': deviceId},
    );
  }

  @override
  Future<int> getDeviceType(int deviceId) async {
    final result = await methodChannel.invokeMethod<int>(
      'getDeviceType',
      <String, Object>{'deviceId': deviceId},
    );
    return result ?? Ch934xDeviceType.unknown;
  }

  @override
  Future<List<Ch934xSerialPortInfo>> getSerialPortList(
    int deviceId, {
    required int interfaceNumber,
  }) async {
    final raw = await methodChannel.invokeMethod<List<dynamic>>(
      'getSerialPortList',
      <String, Object>{
        'deviceId': deviceId,
        'interfaceNumber': interfaceNumber,
      },
    );
    if (raw == null) {
      return const <Ch934xSerialPortInfo>[];
    }
    return raw
        .whereType<Map>()
        .map((e) => Ch934xSerialPortInfo.fromMap(Map<dynamic, dynamic>.from(e)))
        .toList(growable: false);
  }

  @override
  Future<bool> openPort(Ch934xPortTarget target) async {
    final result = await methodChannel.invokeMethod<bool>(
      'openPort',
      target.toMap(),
    );
    return result ?? false;
  }

  @override
  Future<bool> closePort() async {
    final result = await methodChannel.invokeMethod<bool>('closePort');
    return result ?? false;
  }

  @override
  Future<bool> setActivePort(int serialPortIndex) async {
    if (serialPortIndex < 0) {
      return false;
    }
    final result = await methodChannel.invokeMethod<bool>(
      'setActivePort',
      <String, Object>{'serialPortIndex': serialPortIndex},
    );
    return result ?? false;
  }

  @override
  Future<bool> requestUsbPermission(int deviceId) async {
    final result = await methodChannel.invokeMethod<bool>(
      'requestUsbPermission',
      <String, Object>{'deviceId': deviceId},
    );
    return result ?? false;
  }

  @override
  Future<Uint8List> read(int length) async {
    if (length <= 0) {
      return Uint8List(0);
    }
    final raw = await methodChannel.invokeMethod<Uint8List>(
      'read',
      <String, Object>{'length': length},
    );
    return raw ?? Uint8List(0);
  }

  @override
  Future<int> write(Uint8List data) async {
    if (data.isEmpty) {
      return 0;
    }
    final result = await methodChannel.invokeMethod<int>(
      'write',
      <String, Object>{'data': data},
    );
    return result ?? 0;
  }

  @override
  Future<bool> setGpioOutput({
    required int gpioNumber,
    required int level,
  }) async {
    final result = await methodChannel.invokeMethod<bool>(
      'setGpioOutput',
      <String, Object>{
        'gpioNumber': gpioNumber,
        'level': level,
      },
    );
    return result ?? false;
  }

  @override
  Future<int> getGpioInput(int gpioNumber) async {
    final result = await methodChannel.invokeMethod<int>(
      'getGpioInput',
      <String, Object>{'gpioNumber': gpioNumber},
    );
    return result ?? -1;
  }

  @override
  Future<bool> setModemControl({required int dtr, required int rts}) async {
    final result = await methodChannel.invokeMethod<bool>(
      'setModemControl',
      <String, Object>{
        'dtr': dtr,
        'rts': rts,
      },
    );
    return result ?? false;
  }

  @override
  Future<int> getModemStatus() async {
    final result = await methodChannel.invokeMethod<int>('getModemStatus');
    return result ?? 0;
  }

  @override
  Future<void> setExceptionCallback(
    void Function(Ch934xException exception) onException,
  ) async {
    // 注册接收原生层主动推送的 `onException` 事件。
    methodChannel.setMethodCallHandler(_onNativeMethodCall);
    _exceptionController.stream.listen(onException);
    await methodChannel.invokeMethod<void>('setExceptionCallback');
  }

  /// 由原生层主动调用的入口,对应文档 7.3.1 中的 `onException` 回调。
  ///
  /// 必须在原生层将 `MethodChannel` 的 `setMethodCallHandler` 调通后
  /// 才会被触发;此方法在测试中也可直接调用,用于模拟异常事件。
  @visibleForTesting
  void dispatchException({
    required int type,
    String? message,
    String? cause,
  }) {
    _exceptionController.add(
      Ch934xException(type: type, message: message, cause: cause),
    );
  }

  /// 释放内部资源,通常仅在测试或热重载场景下使用。
  @visibleForTesting
  void dispose() {
    _exceptionController.close();
  }
}