import 'dart:async';

import 'package:body_detection/body_detection.dart';
import 'package:body_detection/models/image_result.dart';
import 'package:body_detection/models/pose.dart';
import 'package:flutter/material.dart';

import 'pose_painter.dart';

class PoseDetector extends StatefulWidget {
  const PoseDetector({Key? key}) : super(key: key);

  @override
  State<PoseDetector> createState() => _PoseDetectorState();
}

class _PoseDetectorState extends State<PoseDetector> {
  Image? _cameraImage;
  Pose? _detectedPose;
  Size _imageSize = Size.zero;
  late Future<void> _startCamera;

  @override
  initState() {
    super.initState();
    _startCamera = _startCameraStream();
  }

  Future<void> _startCameraStream() async {
    await BodyDetection.startCameraStream(onFrameAvailable: _handleCameraImage, onPoseAvailable: _handlePose);
    await BodyDetection.enablePoseDetection();
  }

  Future<void> _stopCameraStream() async {
    await BodyDetection.disablePoseDetection();
    await BodyDetection.stopCameraStream();
  }

  void _handleCameraImage(ImageResult result) {
    // To avoid a memory leak issue.
    // https://github.com/flutter/flutter/issues/60160
    PaintingBinding.instance?.imageCache?.clear();
    PaintingBinding.instance?.imageCache?.clearLiveImages();

    final image = Image.memory(
      result.bytes,
      gaplessPlayback: true,
      fit: BoxFit.contain,
    );

    setState(() {
      _cameraImage = image;
      _imageSize = result.size;
    });
  }

  void _handlePose(Pose? pose) {
    setState(() {
      _detectedPose = pose;
    });
  }

  @override
  void dispose() {
    _stopCameraStream();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<void>(
      future: _startCamera,
      builder: (context, snapshot) {
        if (snapshot.connectionState == ConnectionState.waiting) {
          return const Center(child: CircularProgressIndicator());
        }
        return Center(
          child: CustomPaint(
            size: _imageSize,
            child: _cameraImage,
            foregroundPainter: PosePainter(
              pose: _detectedPose,
              imageSize: _imageSize,
            ),
          ),
        );
      },
    );
  }
}