import 'dart:math' as math;

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key, this.dark = true, this.useMaterial3 = true});

  final bool dark;
  final bool useMaterial3;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      themeMode: dark ? ThemeMode.dark : ThemeMode.light,
      theme: ThemeData(
        useMaterial3: useMaterial3,
        brightness: Brightness.light,
        colorSchemeSeed: const Color(0xff6750a4),
      ),
      darkTheme: ThemeData(
        useMaterial3: useMaterial3,
        brightness: Brightness.dark,
        colorSchemeSeed: const Color(0xff6750a4),
      ),
      home: const Example(),
    );
  }
}

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

  @override
  State<Example> createState() => _ExampleState();
}

class _ExampleState extends State<Example> {
  int _counter = 0;
  late bool _animateChange;
  late bool _isOnRight;

  @override
  void initState() {
    super.initState();
    _animateChange = true;
    _isOnRight = false;
  }

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('FAB'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                const Text('Has Animation'),
                Checkbox(
                  value: _animateChange,
                  onChanged: (bool? v) {
                    setState(() {
                      _animateChange = v ?? false;
                    });
                  },
                ),
              ],
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                const Text('Button Location: Left'),
                Switch(
                  value: _isOnRight,
                  onChanged: (bool v) {
                    setState(() {
                      _isOnRight = v;
                    });
                  },
                ),
                const Text('Right'),
              ],
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
      floatingActionButtonLocation: _isOnRight
          ? FloatingActionButtonLocation.endFloat
          : FloatingActionButtonLocation.startFloat,
      floatingActionButtonAnimator: _animateChange
          ? FloatingActionButtonAnimator.scaling
          : const NoScalingFabMotionAnimator(),
    );
  }
}

class NoScalingFabMotionAnimator extends FloatingActionButtonAnimator {
  const NoScalingFabMotionAnimator();

  @override
  Offset getOffset(
      {required Offset begin, required Offset end, required double progress}) {
    return progress < 0.5 ? begin : end;
  }

  @override
  Animation<double> getScaleAnimation({required Animation<double> parent}) {
    return Tween<double>(begin: 1.0, end: 1.0).animate(parent);
  }

  @override
  Animation<double> getRotationAnimation({required Animation<double> parent}) {
    return Tween<double>(begin: 1.0, end: 1.0).animate(parent);
  }

  // If the animation was just starting, we'll continue from where we left off.
  // If the animation was finishing, we'll treat it as if we were starting at that point in reverse.
  // This avoids a size jump during the animation.
  @override
  double getAnimationRestart(double previousValue) =>
      math.min(1.0 - previousValue, previousValue);
}