bookshelf/books_flutter/lib/main.dart

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:google_fonts/google_fonts.dart';
import 'bloc/book_bloc.dart';
import 'bloc/navigation_bloc.dart';
import 'models/models.dart';
import 'widgets/layout.dart';
import 'screens/library_screen.dart';
import 'screens/categories_screen.dart';
import 'screens/book_details_screen.dart';
import 'screens/add_book_screen.dart';
import 'screens/scanner_screen.dart';
import 'theme/app_theme.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await GoogleFonts.pendingFonts([GoogleFonts.inter()]);
  runApp(const BookshelfApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MultiBlocProvider(
      providers: [
        BlocProvider(create: (_) => BookBloc()),
        BlocProvider(create: (_) => NavigationBloc()),
      ],
      child: MaterialApp(
        title: 'Книжная полка',
        debugShowCheckedModeBanner: false,
        theme: AppTheme.lightTheme(),
        themeMode: ThemeMode.light,
        home: const _AppShell(),
      ),
    );
  }
}

class _AppShell extends StatelessWidget {
  const _AppShell();

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<NavigationBloc, NavigationState>(
      builder: (context, state) {
        final showNav = switch (state.screen) {
          AppScreen.library ||
          AppScreen.categories ||
          AppScreen.wishlist ||
          AppScreen.settings => true,
          _ => false,
        };

        final screen = switch (state.screen) {
          AppScreen.library => _libraryWithFab(context),
          AppScreen.categories => const CategoriesScreen(),
          AppScreen.wishlist => _placeholder(
            'Здесь будут книги, которые вы хотите прочитать.',
          ),
          AppScreen.settings => _placeholder(
            'Персонализируйте ваше приложение.',
          ),
          AppScreen.details => const BookDetailsScreen(),
          AppScreen.addBook => const AddBookScreen(),
          AppScreen.scanner => const ScannerScreen(),
        };

        if (state.screen == AppScreen.scanner) {
          return screen;
        }

        return AppLayout(showBottomNav: showNav, child: screen);
      },
    );
  }

  Widget _libraryWithFab(BuildContext context) {
    return Stack(
      children: [
        const LibraryScreen(),
        Positioned(
          bottom: 16,
          right: 20,
          child: FloatingActionButton(
            onPressed: () {
              context.read<NavigationBloc>().add(
                NavigateTo(
                  AppScreen.addBook,
                  selectedBook: null,
                  prefilledData: null,
                ),
              );
            },
            child: const Icon(Icons.add),
          ),
        ),
      ],
    );
  }

  Widget _placeholder(String message) {
    return Builder(
      builder: (context) {
        final theme = Theme.of(context);
        return Center(
          child: Padding(
            padding: const EdgeInsets.all(48),
            child: Text(
              message,
              textAlign: TextAlign.center,
              style: theme.textTheme.bodyLarge?.copyWith(
                color: theme.colorScheme.onSurface.withValues(alpha: 0.5),
              ),
            ),
          ),
        );
      },
    );
  }
}