flutter quick start

import 'dart:math';

import 'package:english_words/english_words.dart';
import 'package:flutter/material.dart';
import 'package:flutter_chat_core/flutter_chat_core.dart';
import 'package:flutter_chat_ui/flutter_chat_ui.dart';
import 'package:provider/provider.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (context) => MyAppState(),
      child: MaterialApp(
        title: 'Namer App',
        theme: ThemeData(
          useMaterial3: true,
          colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepOrange),
        ),
        home: MyHomePage(),
      ),
    );
  }
}

class MyAppState extends ChangeNotifier {
  var current = WordPair.random();
  void getNext() {
    current = WordPair.random();
    notifyListeners();
  }

  var favorites = <WordPair>[];

  void toggleFavorite() {
    if (favorites.contains(current)) {
      favorites.remove(current);
    } else {
      favorites.add(current);
    }
    notifyListeners();
  }
}

class MyHomePage extends StatefulWidget {
  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  var selectedIndex = 0;
  @override
  Widget build(BuildContext context) {
    Widget page;
    switch (selectedIndex) {
      case 0:
        page = GeneratorPage();
        break;
      case 1:
        page = FavoritesPage();
        break;
      case 2:
        page = Basic();
        break;
      default:
        throw UnimplementedError('no widget for $selectedIndex');
    }

    return LayoutBuilder(
      builder: (context, constraints) {
        return Scaffold(
          body: Row(
            children: [
              SafeArea(
                child: NavigationRail(
                  extended: constraints.maxWidth >= 600, // ← Here.
                  destinations: [
                    NavigationRailDestination(
                      icon: Icon(Icons.home),
                      label: Text('Home'),
                    ),
                    NavigationRailDestination(
                      icon: Icon(Icons.favorite),
                      label: Text('Favorites'),
                    ),
                    NavigationRailDestination(
                      icon: Icon(Icons.chat),
                      label: Text('llm'),
                    ),
                  ],
                  selectedIndex: selectedIndex,
                  onDestinationSelected: (value) {
                    setState(() {
                      selectedIndex = value;
                    });
                  },
                ),
              ),
              Expanded(
                child: Container(
                  color: Theme.of(context).colorScheme.primaryContainer,
                  child: page,
                ),
              ),
            ],
          ),
        );
      },
    );
  }
}

// ...

class FavoritesPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    var appState = context.watch<MyAppState>();

    if (appState.favorites.isEmpty) {
      return Center(child: Text('No favorites yet.'));
    }

    return ListView(
      children: [
        Padding(
          padding: const EdgeInsets.all(20),
          child: Text(
            'You have '
            '${appState.favorites.length} favorites:',
          ),
        ),
        for (var pair in appState.favorites)
          ListTile(
            leading: Icon(Icons.favorite),
            title: Text(pair.asLowerCase),
          ),
      ],
    );
  }
}

class GeneratorPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    var appState = context.watch<MyAppState>();
    var pair = appState.current;

    IconData icon;
    if (appState.favorites.contains(pair)) {
      icon = Icons.favorite;
    } else {
      icon = Icons.favorite_border;
    }

    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          BigCard(pair: pair),
          SizedBox(height: 10),
          Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              ElevatedButton.icon(
                onPressed: () {
                  appState.toggleFavorite();
                },
                icon: Icon(icon),
                label: Text('Like'),
              ),
              SizedBox(width: 10),
              ElevatedButton(
                onPressed: () {
                  appState.getNext();
                },
                child: Text('Next'),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

class BigCard extends StatelessWidget {
  const BigCard({super.key, required this.pair});

  final WordPair pair;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final style = theme.textTheme.displayMedium!.copyWith(
      color: theme.colorScheme.onPrimary,
    );
    return Card(
      color: theme.colorScheme.primary,
      child: Padding(
        padding: const EdgeInsets.all(20.0),
        child: Text(
          pair.asLowerCase,
          style: style,
          semanticsLabel: "${pair.first} ${pair.second}",
        ),
      ),
    );
  }
}

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

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

class BasicState extends State<Basic> {
  final _chatController = InMemoryChatController();

  @override
  void dispose() {
    _chatController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Chat(
        chatController: _chatController,
        currentUserId: 'user1',
        onMessageSend: (text) {
          _chatController.insertMessage(
            TextMessage(
              // Better to use UUID or similar for the ID - IDs must be unique
              id: '${Random().nextInt(1000) + 1}',
              authorId: 'user1',
              createdAt: DateTime.now().toUtc(),
              text: text,
            ),
          );
        },
        resolveUser: (UserID id) async {
          return User(id: id, name: 'John Doe');
        },
      ),
    );
  }
}