import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_midi/flutter_midi.dart';
import 'package:tonic/tonic.dart';

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

class MyApp extends StatefulWidget {
 @override
 _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
 @override
 initState() {
   FlutterMidi.unmute();
   rootBundle.load("assets/sounds/Piano.SF2").then((sf2) {
     FlutterMidi.prepare(sf2: sf2, name: "Piano.SF2");
   });
   super.initState();
 }

 double get keyWidth => 80 + (80 * _widthRatio);
 double _widthRatio = 0.0;
 bool _showLabels = true;

 @override
 Widget build(BuildContext context) {
   return MaterialApp(
     title: 'The Pocket Piano',
     theme: ThemeData.dark(),
     home: Scaffold(
         drawer: Drawer(
             child: SafeArea(
                 child: ListView(children: <Widget>[
           Container(height: 20.0),
           ListTile(title: Text("Change Width")),
           Slider(
               activeColor: Colors.redAccent,
               inactiveColor: Colors.white,
               min: 0.0,
               max: 1.0,
               value: _widthRatio,
               onChanged: (double value) =>
                   setState(() => _widthRatio = value)),
           Divider(),
           ListTile(
               title: Text("Show Labels"),
               trailing: Switch(
                   value: _showLabels,
                   onChanged: (bool value) =>
                       setState(() => _showLabels = value))),
           Divider(),
         ]))),
         appBar: AppBar(title: Text("The Pocket Piano")),
         body: ListView.builder(
           itemCount: 7,
           controller: ScrollController(initialScrollOffset: 1500.0),
           scrollDirection: Axis.horizontal,
           itemBuilder: (BuildContext context, int index) {
             final int i = index * 12;
             return SafeArea(
               child: Stack(children: <Widget>[
                 Row(mainAxisSize: MainAxisSize.min, children: <Widget>[
                   _buildKey(24 + i, false),
                   _buildKey(26 + i, false),
                   _buildKey(28 + i, false),
                   _buildKey(29 + i, false),
                   _buildKey(31 + i, false),
                   _buildKey(33 + i, false),
                   _buildKey(35 + i, false),
                 ]),
                 Positioned(
                     left: 0.0,
                     right: 0.0,
                     bottom: 100,
                     top: 0.0,
                     child: Row(
                         mainAxisAlignment: MainAxisAlignment.spaceBetween,
                         mainAxisSize: MainAxisSize.min,
                         children: <Widget>[
                           Container(width: keyWidth * .5),
                           _buildKey(25 + i, true),
                           _buildKey(27 + i, true),
                           Container(width: keyWidth),
                           _buildKey(30 + i, true),
                           _buildKey(32 + i, true),
                           _buildKey(34 + i, true),
                           Container(width: keyWidth * .5),
                         ])),
               ]),
             );
           },
         )),
   );
 }

 Widget _buildKey(int midi, bool accidental) {
   final pitchName = Pitch.fromMidiNumber(midi).toString();
   final pianoKey = Stack(
     children: <Widget>[
       Semantics(
           button: true,
           hint: pitchName,
           child: Material(
               borderRadius: borderRadius,
               color: accidental ? Colors.black : Colors.white,
               child: InkWell(
                 borderRadius: borderRadius,
                 highlightColor: Colors.grey,
                 onTap: () {},
                 onTapDown: (_) => FlutterMidi.playMidiNote(midi: midi),
               ))),
       Positioned(
           left: 0.0,
           right: 0.0,
           bottom: 20.0,
           child: _showLabels
               ? Text(pitchName,
                   textAlign: TextAlign.center,
                   style: TextStyle(
                       color: !accidental ? Colors.black : Colors.white))
               : Container()),
     ],
   );
   if (accidental) {
     return Container(
         width: keyWidth,
         margin: EdgeInsets.symmetric(horizontal: 2.0),
         padding: EdgeInsets.symmetric(horizontal: keyWidth * .1),
         child: Material(
             elevation: 6.0,
             borderRadius: borderRadius,
             shadowColor: Color(0x802196F3),
             child: pianoKey));
   }
   return Container(
       width: keyWidth,
       child: pianoKey,
       margin: EdgeInsets.symmetric(horizontal: 2.0));
 }
}

const BorderRadiusGeometry borderRadius = BorderRadius.only(
   bottomLeft: Radius.circular(10.0), bottomRight: Radius.circular(10.0));