import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart' show Ticker;

enum ImageFilterMode {
  outerShaderInnerBlurWorks,
  innerShaderOuterBlurNotWorks,
  outerShaderInnerShaderNotWorks,
  outerShaderInnerMatrixWorksWithProblem,
  innerShaderOuterMatrixNotWorks,
}

void main() {
  runApp(App());
}

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(debugShowCheckedModeBanner: false, home: Home());
  }
}

class Home extends StatefulWidget {
  const Home({super.key});

  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> with TickerProviderStateMixin {
  late FragmentProgram program;
  FragmentShader? shader;

  Ticker? ticker;

  ImageFilterMode mode = ImageFilterMode.outerShaderInnerBlurWorks;

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

    FragmentProgram.fromAsset('shaders/one.frag').then((program) {
      this.program = program;
      setState(() {
        shader = program.fragmentShader();
      });
      ticker = createTicker((Duration elapsed) {
        shader!.setFloat(2, elapsed.inMilliseconds.toDouble());
        setState(() {});
      })..start();
    });
  }

  ImageFilter _getImageFilter() {
    return switch (mode) {
      ImageFilterMode.outerShaderInnerBlurWorks => ImageFilter.compose(
        outer: ImageFilter.shader(shader!),
        inner: ImageFilter.blur(sigmaX: 1, sigmaY: 1),
      ),
      ImageFilterMode.innerShaderOuterBlurNotWorks => ImageFilter.compose(
        inner: ImageFilter.shader(shader!),
        outer: ImageFilter.blur(sigmaX: 1, sigmaY: 1),
      ),
      ImageFilterMode.outerShaderInnerShaderNotWorks => ImageFilter.compose(
        inner: ImageFilter.shader(shader!),
        outer: ImageFilter.shader(shader!),
      ),
      ImageFilterMode.outerShaderInnerMatrixWorksWithProblem =>
        ImageFilter.compose(
          outer: ImageFilter.shader(shader!),
          inner: ImageFilter.matrix(
            (Matrix4.identity()
                  ..translate(100.0, 50.0)
                  ..scale(0.5)
                  ..translate(-100.0, -50.0))
                .storage,
          ),
        ),
      ImageFilterMode.innerShaderOuterMatrixNotWorks => ImageFilter.compose(
        inner: ImageFilter.shader(shader!),
        outer: ImageFilter.matrix(
          (Matrix4.identity()
                ..translate(100.0, 50.0)
                ..scale(0.5)
                ..translate(-100.0, -50.0))
              .storage,
        ),
      ),
    };
  }

  @override
  void dispose() {
    ticker?.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    if (shader == null) {
      return const SizedBox();
    }
    return SafeArea(
      child: Scaffold(
        body: Center(
          child: Column(
            spacing: 100,
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              DropdownButton<ImageFilterMode>(
                items: ImageFilterMode.values
                    .map(
                      (item) =>
                          DropdownMenuItem(value: item, child: Text(item.name)),
                    )
                    .toList(),
                value: mode,
                onChanged: (value) {
                  if (value != null && value != mode) {
                    setState(() {
                      mode = value;
                    });
                  }
                },
              ),
              SizedBox(
                width: 200,
                height: 100,
                child: ColoredBox(
                  color: Colors.blue.withAlpha(50),
                  child: ImageFiltered(
                    imageFilter: _getImageFilter(),
                    child: Column(
                      spacing: 20,
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Icon(Icons.flutter_dash),
                        Text('Hello, world'),
                      ],
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}