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

class MyIconButton extends StatefulWidget {
  const MyIconButton({
    Key key,
    @required this.icon,
    this.pressedIcon,
    this.disabledIcon,
    this.iconColor,
    this.pressedIconColor,
    this.disabledIconColor,
    this.splashColor,
    this.highlightColor,
    this.tooltip,
    @required this.onPressed,
  }) : assert(icon != null),
       assert(onPressed != null),
       super(key: key);

  final Widget icon;
  final Widget pressedIcon;
  final Widget disabledIcon;
  final Color iconColor;
  final Color pressedIconColor;
  final Color disabledIconColor;
  final Color splashColor;
  final Color highlightColor;
  final String tooltip;
  final VoidCallback onPressed;

  @override
  _MyIconButtonState createState() => _MyIconButtonState();
}

class _MyIconButtonState extends State<MyIconButton> {
  bool _isPressed = false;

  @override
  Widget build(BuildContext context) {
    assert(debugCheckHasMaterial(context));

    final ThemeData theme = Theme.of(context);
    final bool enabled = widget.onPressed != null;

    Widget icon;
    Color iconColor;
    if (enabled) {
      icon = _isPressed ? widget.pressedIcon ?? widget.icon : widget.icon;
      iconColor = (_isPressed ? widget.pressedIconColor : widget.iconColor) ?? theme.primaryColor;
    } else {
      icon = widget.disabledIcon ?? widget.icon;
      iconColor = widget.disabledIconColor ?? theme.disabledColor;
    }

    Widget result = Semantics(
      button: true,
      enabled: enabled,
      child: Container(
        width: 48.0, // minium tap target size for a button
        height: 48.0,
        alignment: Alignment.center,
        child: IconTheme.merge(
          data: IconThemeData(
            size: 32.0,
            color: iconColor
          ),
          child: AnimatedSwitcher(
            child: KeyedSubtree(
              key: ValueKey<int>(!enabled ? 0 : (_isPressed ? 1 : 2)),
              child: icon,
            ),
            duration: kThemeChangeDuration, // used by all buttons
          ),
        ),
      ),
    );

    if (widget.tooltip != null) {
      result = Tooltip(
        message: widget.tooltip,
        child: result,
      );
    }
    return InkResponse(
      onTap: widget.onPressed,
      highlightColor: widget.highlightColor ?? theme.highlightColor,
      splashColor: widget.splashColor ?? theme.splashColor,
      radius: 35.0,
      onHighlightChanged: (bool value) {
        setState(() { _isPressed = value; });
      },
      child: result,
    );
  }
}


class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: MyIconButton(
          icon: Icon(Icons.add_circle_outline),
          pressedIcon: Icon(Icons.add_circle),
          onPressed: () {
            print('Hello World');
          },
        ),
      ),
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) => HomePage();
}

void main() {
  runApp(MaterialApp(home: MyApp()));
}