import 'package:flutter/material.dart';
import 'dart:ui' as ui;

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final _image = ValueNotifier<ui.Image?>(null);
  final size = Size(300, 300);

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Column(
        children: [
          InteractiveViewer(
              maxScale: 100,
              child: CustomPaint(
                size: size,
                painter: _Painter(),
              )),
          ElevatedButton(onPressed: saveImage, child: Text('GOGOGO')),
          ValueListenableBuilder(
            valueListenable: _image,
            builder: (context, value, child) {
              return InteractiveViewer(
                  maxScale: 100,
                  child: CustomPaint(
                    size: size,
                    painter: _PreviewPainter(image: value),
                  ));
            },
          ),
        ],
      ),
    );
  }

  Future<void> saveImage() async {
    ui.PictureRecorder recorder = ui.PictureRecorder();
    Canvas canvas = Canvas(recorder);

    ui.Paint paint = ui.Paint()..color = Colors.pinkAccent;

    canvas.drawPaint(paint..color = Colors.pinkAccent);

    final path = Path()
      ..moveTo(0, 0)
      ..relativeLineTo(size.width, size.height);
    canvas.drawPath(
        path,
        paint
          ..color = Colors.blueAccent
          ..style = PaintingStyle.stroke
          ..isAntiAlias = false
          ..strokeWidth = 30);

    _image.value = await recorder
        .endRecording()
        .toImage(size.width.floor(), size.height.floor());
  }
}

class _PreviewPainter extends CustomPainter {
  final ui.Image? image;
  _PreviewPainter({this.image});

  @override
  void paint(Canvas canvas, Size size) {
    if (image != null) {
      canvas.drawImage(image!, Offset.zero, Paint());
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
}

class _Painter extends CustomPainter {
  final _paint = Paint()..color = Colors.pinkAccent;

  @override
  void paint(Canvas canvas, Size size) {
    canvas.clipRect(Offset.zero & size);
    // canvas.drawRect(Offset.zero & size, _paint..color = Colors.pinkAccent);
    canvas.drawPaint(_paint..color = Colors.pinkAccent);

    final path = Path()
      ..moveTo(0, 0)
      ..relativeLineTo(size.width, size.height);
    canvas.drawPath(
        path,
        _paint
          ..color = Colors.blueAccent
          ..style = PaintingStyle.stroke
          ..isAntiAlias = false
          ..strokeWidth = 30);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
}