video_decode_plugin/lib/video_decode_plugin.dart

import 'dart:async';
import 'dart:io';
import 'dart:typed_data';

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

import 'video_decode_plugin_platform_interface.dart';

/// 视频帧类型
enum FrameType {
  /// I帧
  iFrame,

  /// P帧
  pFrame,
}

/// 视频编码类型
enum CodecType {
  /// H.264编码
  h264,

  /// H.265编码
  h265,
}

/// 帧可用回调函数类型
typedef FrameAvailableCallback = void Function(int textureId);

/// 解码器实例内部类
class _DecoderInstance {
  final int textureId;
  FrameAvailableCallback? frameCallback;

  _DecoderInstance(this.textureId);
}

/// 视频解码器配置
class VideoDecoderConfig {
  /// 视频宽度，默认640
  final int width;

  /// 视频高度，默认360
  final int height;

  /// 帧率，可为空
  final int? frameRate;

  /// 编码类型，默认h264
  final CodecType codecType;

  /// 缓冲区大小（帧数），默认25帧
  final int bufferSize;

  /// 解码线程数，默认1线程
  final int threadCount;

  /// 是否为调试模式，默认false
  final bool isDebug;

  /// 是否启用硬件解码，默认true
  final bool enableHardwareDecoder;

  /// 构造函数
  VideoDecoderConfig({
    this.width = 640,
    this.height = 360,
    this.frameRate,
    this.codecType = CodecType.h264,
    this.bufferSize = 25,
    this.threadCount = 1,
    this.isDebug = false,
    this.enableHardwareDecoder = true,
  });

  /// 转换为Map
  Map<String, dynamic> toMap() {
    return {
      'width': width,
      'height': height,
      'frameRate': frameRate,
      'codecType': codecType.toString().split('.').last,
      'bufferSize': bufferSize,
      'threadCount': threadCount,
      'isDebug': isDebug,
      'enableHardwareDecoder': enableHardwareDecoder,
    };
  }
}

/// 视频解码插件主类
class VideoDecodePlugin {
  static const MethodChannel _channel = MethodChannel('video_decode_plugin');

  // 解码器映射表，支持多实例
  static final Map<int, _DecoderInstance> _decoders = {};

  // 默认解码器ID
  static int? _defaultTextureId;

  // 监听器初始化标志
  static bool _listenerInitialized = false;

  /// 初始化方法通道监听器
  static void _initializeMethodCallHandler() {
    if (!_listenerInitialized) {
      _channel.setMethodCallHandler((call) async {
        switch (call.method) {
          case 'onFrameAvailable':
            final Map<dynamic, dynamic> args = call.arguments;
            final int textureId = args['textureId'];

            // 调用特定纹理ID的帧回调
            final decoder = _decoders[textureId];
            if (decoder != null && decoder.frameCallback != null) {
              decoder.frameCallback!(textureId);
            }

            return null;
          default:
            throw PlatformException(
              code: 'Unimplemented',
              details: 'The method ${call.method} is not implemented',
            );
        }
      });

      _listenerInitialized = true;
    }
  }

  /// 获取平台版本
  static Future<String?> getPlatformVersion() {
    return VideoDecodePluginPlatform.instance.getPlatformVersion();
  }

  /// 检查当前平台是否支持
  static bool get isPlatformSupported {
    return Platform.isAndroid || Platform.isIOS;
  }

  /// 设置帧回调（默认解码器）
  static void setFrameCallback(FrameAvailableCallback callback) {
    if (_defaultTextureId != null) {
      setFrameCallbackForTexture(_defaultTextureId!, callback);
    }
  }

  /// 为特定纹理ID设置帧回调
  static void setFrameCallbackForTexture(
      int textureId, FrameAvailableCallback callback) {
    _initializeMethodCallHandler();

    final decoder = _decoders[textureId];
    if (decoder != null) {
      decoder.frameCallback = callback;
    }
  }

  /// 初始化解码器
  static Future<int?> initDecoder(VideoDecoderConfig config) async {
    // 先释放之前的默认解码器
    if (_defaultTextureId != null) {
      await releaseDecoder();
    }

    return await createDecoder(config);
  }

  /// 创建新的解码器实例（支持多实例）
  static Future<int?> createDecoder(VideoDecoderConfig config) async {
    if (!isPlatformSupported) {
      debugPrint('当前平台不支持视频解码插件');
      return null;
    }

    // 确保监听器已初始化
    _initializeMethodCallHandler();

    try {
      final textureId =
          await _channel.invokeMethod<int>('initDecoder', config.toMap());

      if (textureId != null) {
        // 创建新解码器实例并保存
        final decoder = _DecoderInstance(textureId);
        _decoders[textureId] = decoder;

        // 设置为默认解码器
        _defaultTextureId = textureId;
      }

      return _defaultTextureId;
    } catch (e) {
      debugPrint('初始化解码器失败: $e');
      return null;
    }
  }

  /// 获取默认纹理ID
  static int? get textureId => _defaultTextureId;

  /// 获取所有活跃的纹理ID
  static List<int> get allTextureIds => _decoders.keys.toList();

  /// 解码视频帧（默认解码器）
  static Future<bool> decodeFrame(
      Uint8List frameData, FrameType frameType) async {
    if (_defaultTextureId == null) {
      debugPrint('解码器未初始化');
      return false;
    }

    return decodeFrameForTexture(_defaultTextureId!, frameData, frameType);
  }

  /// 为特定纹理ID解码视频帧
  static Future<bool> decodeFrameForTexture(
      int textureId, Uint8List frameData, FrameType frameType) async {
    if (!_decoders.containsKey(textureId)) {
      debugPrint('找不到纹理ID: $textureId');
      return false;
    }

    try {
      return await _channel.invokeMethod<bool>('decodeFrame', {
            'textureId': textureId,
            'frameData': frameData,
            'frameType': frameType.index,
          }) ??
          false;
    } catch (e) {
      debugPrint('解码帧失败: $e');
      return false;
    }
  }

  /// 释放默认解码器资源
  static Future<bool> releaseDecoder() async {
    if (_defaultTextureId == null) {
      return true;
    }

    final result = await releaseDecoderForTexture(_defaultTextureId!);
    if (result) {
      _defaultTextureId = null;
    }

    return result;
  }

  /// 释放特定纹理ID的解码器资源
  static Future<bool> releaseDecoderForTexture(int textureId) async {
    if (!_decoders.containsKey(textureId)) {
      return true;
    }

    try {
      final result = await _channel.invokeMethod<bool>('releaseDecoder', {
            'textureId': textureId,
          }) ??
          false;

      if (result) {
        // 从映射表中移除
        _decoders.remove(textureId);

        // 如果释放的是默认解码器，重置默认ID
        if (_defaultTextureId == textureId) {
          _defaultTextureId = null;
        }
      }

      return result;
    } catch (e) {
      debugPrint('释放解码器失败: $e');
      return false;
    }
  }

  /// 释放所有解码器
  static Future<bool> releaseAllDecoders() async {
    bool allSuccess = true;

    // 复制键列表，因为我们会在迭代过程中修改映射
    final textureIds = List<int>.from(_decoders.keys);

    // 释放每个解码器
    for (final textureId in textureIds) {
      final success = await releaseDecoderForTexture(textureId);
      if (!success) {
        allSuccess = false;
      }
    }

    // 清空状态
    _decoders.clear();
    _defaultTextureId = null;

    return allSuccess;
  }

  /// 清除特定纹理ID的回调
  static void clearCallbackForTexture(int textureId) {
    final decoder = _decoders[textureId];
    if (decoder != null) {
      decoder.frameCallback = null;
    }
  }

  /// 清除所有回调
  static void clearAllCallbacks() {
    for (final decoder in _decoders.values) {
      decoder.frameCallback = null;
    }
  }

  /// 注册插件（不需要手动调用）
  static void registerWith() {
    // 仅用于插件注册
  }

  /// 获取解码器统计信息
  ///
  /// [textureId] 纹理ID
  /// 返回包含统计信息的Map，包括:
  /// - totalFramesReceived: 接收的总帧数
  /// - framesRendered: 成功渲染的帧数
  /// - framesDropped: 丢弃的帧数
  /// - lastFrameTimestamp: 最后一帧时间戳
  /// - averageProcessingTimeMs: 平均处理时间(毫秒)
  /// - decoderCount: 当前活跃的解码器数量
  static Future<Map<String, dynamic>> getDecoderStats(int textureId) async {
    try {
      final params = {
        'textureId': textureId,
      };

      final result = await _channel.invokeMethod<Map<Object?, Object?>>(
          'getDecoderStats', params);
      if (result == null) {
        return {};
      }

      // 将Object?类型转换为明确的类型
      final Map<String, dynamic> typedResult = {};
      result.forEach((key, value) {
        if (key is String) {
          typedResult[key] = value;
        }
      });

      return typedResult;
    } catch (e) {
      if (kDebugMode) {
        print('获取解码器统计信息失败: $e');
      }
      return {};
    }
  }
}