import 'dart:async';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart' show ByteData, Uint8List, rootBundle;
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:star_lock/app_settings/app_colors.dart';
import 'package:star_lock/talk/startChart/handle/other/talk_data_repository.dart';
import 'package:star_lock/talk/startChart/proto/talk_data.pbserver.dart';
import 'package:star_lock/tools/titleAppBar.dart';
import 'package:webview_flutter/webview_flutter.dart';

class H264WebView extends StatefulWidget {
  @override
  _H264WebViewState createState() => _H264WebViewState();
}

class _H264WebViewState extends State<H264WebView> {
  late final WebViewController _controller;
  Timer? timer;
  Timer? _sendTimer;

  // 私有缓冲区，外部无法直接访问
  final List<int> _buffer = [];

  // 发送数据至html文件间隔时间
  final int sendDataToHtmlIntervalTime = 820;

  // 通话数据流的单例流数据处理类
  final TalkDataRepository talkDataRepository = TalkDataRepository.instance;

  @override
  void initState() {
    super.initState();

    _controller = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..enableZoom(false)
      ..addJavaScriptChannel(
        'Flutter',
        onMessageReceived: (message) {
          print("来自 HTML 的消息: ${message.message}");
        },
      );

    // 加载本地 HTML
    _loadLocalHtml();
    simulateStreamFromAsset();
    _sendFramesToHtml();
  }

  void simulateStreamFromAsset() async {
    // 读取 assets 文件
    final ByteData data = await rootBundle.load('assets/talk.h264');
    final List<int> byteData = data.buffer.asUint8List();
    int current = 0;
    int start = 0;
    int end = 0;
    final List<int> chunks = extractChunks(byteData);
    // 定时器控制发送数据块的节奏
    timer ??= Timer.periodic(Duration(milliseconds: 10), (timer) {
      if (current >= chunks.length) {
        print('数据已经发完,重新进行发送');
        start = 0;
        end = 0;
        current = 0;
        timer.cancel();
        return;
      }
      // 提取 NALU 边界并生成 chunks
      end = chunks[current];
      current++;
      List<int> frameData = byteData.sublist(start, end);
      if (frameData.length == 0) timer.cancel();

      talkDataRepository.addTalkData(TalkData(contentType: TalkData_ContentTypeE.H264,content: frameData));
      start = end;
    });
  }

  void _sendFramesToHtml() async {
    // 接收到流数据，保存到缓冲区
    talkDataRepository.talkDataStream.listen((TalkData event) async {
      _buffer.addAll(event.content);
    });
    // 缓冲800ms的数据，定时发送
    _sendTimer ??= Timer.periodic(
        Duration(milliseconds: sendDataToHtmlIntervalTime), (timer) async {
      // 发送累积的数据
      if (_buffer.isNotEmpty) {
        await _sendBufferedData(_buffer);
        _buffer.clear(); // 清空缓冲区
      }
    });
  }

  // 提取 NALU 边界并生成 chunks
  List<int> extractChunks(List<int> byteData) {
    int i = 0;
    int length = byteData.length;
    int naluCount = 0;
    int value;
    int state = 0;
    int lastIndex = 0;
    List<int> result = [];
    const minNaluPerChunk = 22; // 每个数据块包含的最小NALU数量

    while (i < length) {
      value = byteData[i++];
      // finding 3 or 4-byte start codes (00 00 01 OR 00 00 00 01)
      switch (state) {
        case 0:
          if (value == 0) {
            state = 1;
          }
          break;
        case 1:
          if (value == 0) {
            state = 2;
          } else {
            state = 0;
          }
          break;
        case 2:
        case 3:
          if (value == 0) {
            state = 3;
          } else if (value == 1 && i < length) {
            if (lastIndex > 0) {
              naluCount++;
            }
            if (naluCount >= minNaluPerChunk) {
              result.add(lastIndex - state - 1);
              naluCount = 0;
            }
            state = 0;
            lastIndex = i;
          } else {
            state = 0;
          }
          break;
        default:
          break;
      }
    }

    if (naluCount > 0) {
      result.add(lastIndex);
    }



    return result;
  }

  /// 加载html文件
  Future<void> _loadLocalHtml() async {
    final String fileHtmlContent =
        await rootBundle.loadString('assets/html/h264.html');
    _controller.loadHtmlString(fileHtmlContent);
  }

  // 发送数据给js处理
  _sendBufferedData(List<int> buffer) async {
    String jsCode = "feedDataFromFlutter(${buffer});";
    await _controller.runJavaScript(jsCode);
  }

  @override
  Widget build(BuildContext context) {
    return WebViewWidget(controller: _controller);
  }

  @override
  void dispose() {
    timer?.cancel();
    timer = null;
    _sendTimer?.cancel();
    timer = null;
    // talkDataRepository.dispose();
    super.dispose();
  }
}