llm_chat/lib/main.dart

import 'package:fluent_ui/fluent_ui.dart';
import 'package:flutter/foundation.dart';
import 'package:provider/provider.dart';
import 'package:system_theme/system_theme.dart';

import 'providers/chat_provider.dart';
import 'screens/chat_screen.dart';
import 'screens/settings_screen.dart';
import 'theme/app_theme.dart';

const String appTitle = 'AI Chat';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  if (!kIsWeb &&
      [
        TargetPlatform.windows,
        TargetPlatform.android,
      ].contains(defaultTargetPlatform)) {
    SystemTheme.accentColor.load();
  }

  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (_) => AppTheme()),
        ChangeNotifierProvider(create: (_) => ChatProvider()),
      ],
      child: Consumer<AppTheme>(
        builder: (context, appTheme, child) {
          return FluentApp(
            title: appTitle,
            themeMode: appTheme.mode,
            debugShowCheckedModeBanner: false,
            color: appTheme.color,
            darkTheme: FluentThemeData(
              brightness: Brightness.dark,
              accentColor: appTheme.color,
              visualDensity: VisualDensity.standard,
              focusTheme: FocusThemeData(
                glowFactor: is10footScreen(context) ? 2.0 : 0.0,
              ),
              fontFamily: 'MiSans',
            ),
            theme: FluentThemeData(
              accentColor: appTheme.color,
              visualDensity: VisualDensity.standard,
              focusTheme: FocusThemeData(
                glowFactor: is10footScreen(context) ? 2.0 : 0.0,
              ),
              fontFamily: 'MiSans',
            ),
            builder: (context, child) {
              return Directionality(
                textDirection: appTheme.textDirection,
                child: child!,
              );
            },
            home: const MyHomePage(),
          );
        },
      ),
    );
  }
}

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

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _selectedIndex = 0;
  final viewKey = GlobalKey(debugLabel: 'Navigation View Key');

  @override
  Widget build(BuildContext context) {
    final appTheme = context.watch<AppTheme>();
    final theme = FluentTheme.of(context);

    return NavigationView(
      key: viewKey,
      appBar: NavigationAppBar(
        automaticallyImplyLeading: false,
        title: const Text(appTitle),
        actions: Row(
          mainAxisAlignment: MainAxisAlignment.end,
          children: [
            Padding(
              padding: const EdgeInsetsDirectional.only(end: 8),
              child: ToggleSwitch(
                checked: theme.brightness == Brightness.dark,
                onChanged: (v) {
                  if (v) {
                    appTheme.mode = ThemeMode.dark;
                  } else {
                    appTheme.mode = ThemeMode.light;
                  }
                },
                content: const Text('Dark Mode'),
              ),
            ),
          ],
        ),
      ),
      pane: NavigationPane(
        selected: _selectedIndex,
        onChanged: (index) => setState(() => _selectedIndex = index),
        header: SizedBox(
          height: kOneLineTileHeight,
          child: ShaderMask(
            shaderCallback: (rect) {
              final color = appTheme.color.defaultBrushFor(theme.brightness);
              return LinearGradient(colors: [color, color]).createShader(rect);
            },
            child: const Row(
              mainAxisSize: MainAxisSize.min,
              children: [
                Icon(FluentIcons.robot, size: 24, color: Colors.white),
                SizedBox(width: 8),
                Text(
                  'AI Chat',
                  style: TextStyle(
                    fontSize: 16,
                    fontWeight: FontWeight.bold,
                    color: Colors.white,
                  ),
                ),
              ],
            ),
          ),
        ),
        displayMode: appTheme.displayMode,
        indicator: () {
          switch (appTheme.indicator) {
            case NavigationIndicators.end:
              return const EndNavigationIndicator();
            case NavigationIndicators.sticky:
              return const StickyNavigationIndicator();
          }
        }(),
        items: [
          PaneItem(
            icon: const Icon(FluentIcons.chat),
            title: const Text('Chat'),
            body: const ChatScreen(),
          ),
        ],
        footerItems: [
          PaneItemSeparator(),
          PaneItem(
            icon: const Icon(FluentIcons.settings),
            title: const Text('Settings'),
            body: const SettingsScreen(),
          ),
        ],
      ),
    );
  }
}