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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Welcome to Flutter',
      home: Scaffold(
        appBar: AppBar(
          title: Text('Welcome to Flutter'),
          backgroundColor: Color.fromRGBO(0, 100000, 0, 100),
        ),
        body: Center(
          child: RandomWords(),
        ),
      ),
    );
  }
}

class RandomWords extends StatefulWidget {
  @override
  RandomWordsState createState() => RandomWordsState();
}

class RandomWordsState extends State<RandomWords> {
  final _suggestions = <WordPair>[];
  final _biggerFont = const TextStyle(fontSize: 18.0);
  final _saved = Set<WordPair>();

  Widget _buildSuggestions() {
    return ListView.builder(
        padding: const EdgeInsets.all(16.0),
        itemBuilder: /*1*/ (context, i) {
          if (i.isOdd) return Divider(); /*2*/

          final index = i ~/ 2; /*3*/
          if (index >= _suggestions.length) {
            _suggestions.addAll(generateWordPairs().take(10)); /*4*/
          }
          return _buildRow(_suggestions[index]);
        });
  }

  Widget _buildRow(WordPair pair) {
    final bool saved = _saved.contains(pair);
    return ListTile(
      trailing: IconButton(
          icon: Icon(saved ? Icons.favorite : Icons.favorite_border),
          color: saved
              ? Colors.red
              : null,
          onPressed: () {
            setState(() {
              if (_saved.contains(pair)) {
                _saved.remove(pair);
              } else
                _saved.add(pair);
            });
          }),
      title: Text(
        pair.asPascalCase,
        style: _biggerFont,
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: _buildSuggestions(),
    );
  }
}