VitalApp/lib/helper/sonopost_preview_helper.dart

import 'dart:convert';
import 'dart:math' as math;
import 'dart:typed_data';

import 'package:fis_common/event/event_type.dart';
import 'package:fis_common/logger/logger.dart';
import 'package:flutter/material.dart';

class ShellSonopostPlayController {
  static bool _playing = false;

  final int width;
  final int height;

  static final bufferFragmentReceived = FEventHandler<Uint8List>();

  ShellSonopostPlayController({
    this.width = 1280,
    this.height = 720,
  });

  Future<void> init() {
    return Future(() => null);
  }

  void play() {
    if (_playing) return;
    _playing = true;

    logger.i("ShellSonopost start");
  }

  static void setPreviewImageData(String imageData) {
    try {
      if (_playing) {
        var data = base64Decode(imageData);
        bufferFragmentReceived.emit("shell_sonopost", data);
      } else {
        logger.i(
            "refresh sonopost preview failed since publish already stopped!");
      }
    } catch (e) {}
  }

  void stop() {
    _playing = false;
    logger.i("ShellSonopost stop");
  }
}

class ShellSonopostPlayer extends StatefulWidget {
  final ShellSonopostPlayController controller;

  const ShellSonopostPlayer({super.key, required this.controller});

  @override
  State<StatefulWidget> createState() => _ShellSonopostPlayer();
}

class _ShellSonopostPlayer extends State<ShellSonopostPlayer> {
  static const int _RETRY_LIMIT = 10;
  Uint8List? _frameBuffer;
  // late Uint8List _bufferArea;
  // int _bufferPosition = 0;
  bool _hasError = false;
  int _rgbaSize = 0;
  int _retryCount = 0;

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

    _rgbaSize = 4 * widget.controller.width * widget.controller.height;
    // _bufferArea = Uint8List(_rgbaSize);
    WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
      ShellSonopostPlayController.bufferFragmentReceived
          .addListener(_onBufferOnce);
    });
  }

  @override
  dispose() {
    ShellSonopostPlayController.bufferFragmentReceived
        .removeListener(_onBufferOnce);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    Widget child;
    if (_hasError) {
      child = const Center(
        child: Text("Error", style: TextStyle(color: Colors.white)),
      );
    } else if (_frameBuffer != null) {
      child = Image.memory(
        _frameBuffer!,
        fit: BoxFit.contain,
        gaplessPlayback: true,
      );
      // 水平翻转
      // child = Transform(
      //   alignment: Alignment.center,
      //   transform: Matrix4.rotationY(math.pi),
      //   child: child,
      // );
    } else {
      child = const SizedBox();
    }

    return Container(
      color: Colors.black,
      child: child,
    );
  }

  void _onBufferOnce(Object sender, Uint8List e) {
    setState(() {
      _frameBuffer = e;
    });
  }

  void _onBuffer(Object sender, Uint8List e) {
    try {
      _onBufferOnce(sender, e);
    } catch (e) {
      _handleError();
    }
  }

  void _handleError() {
    widget.controller.stop();

    if (_retryCount > _RETRY_LIMIT) {
      setState(() {
        _hasError = true;
      });
    }

    Future.delayed(const Duration(milliseconds: 800), () {
      widget.controller.play();
    });
    _retryCount++;
  }

  static int readInt64(Uint8List data, [int index = 0]) {
    var intData = data.buffer.asByteData(index, 8);
    return intData.getInt64(0, Endian.little);
  }

  static int readInt64V2(Uint8List data, [int index = 0]) {
    int low = readInt(data, index);
    int high = readInt(data, index + 4);
    int value = high >> 32;
    value |= low;
    return value;
  }

  static int readInt(Uint8List data, [int index = 0]) {
    var intData = data.buffer.asByteData(index, 4);
    return intData.getInt32(0, Endian.little);
  }
}