import 'package:flutter/material.dart';
import 'package:worldhopper/l10n/app_localizations.dart';
import 'package:go_router/go_router.dart';
import 'package:worldhopper/config/constants.dart';
import 'package:worldhopper/screens/servers/server_list_screen.dart';
import 'package:worldhopper/screens/servers/add_server_screen.dart';
import 'package:worldhopper/screens/servers/edit_server_screen.dart';
import 'package:worldhopper/screens/browse/library_browser_screen.dart';
import 'package:worldhopper/screens/browse/feed_screen.dart';
import 'package:worldhopper/screens/publication/publication_detail_screen.dart';
import 'package:worldhopper/screens/reader/reader_screen.dart';
import 'package:worldhopper/screens/reader/epub_reader_screen.dart';
import 'package:worldhopper/screens/library/library_screen.dart';
import 'package:worldhopper/screens/settings/settings_screen.dart';
import 'package:worldhopper/screens/shell/main_shell_screen.dart';
import 'package:worldhopper/models/opds_entry.dart';

/// Application router configuration using GoRouter
class AppRouter {
  AppRouter._();

  static final GlobalKey<NavigatorState> _libraryNavigatorKey =
      GlobalKey<NavigatorState>(debugLabel: 'library');
  static final GlobalKey<NavigatorState> _serversNavigatorKey =
      GlobalKey<NavigatorState>(debugLabel: 'servers');
  static final GlobalKey<NavigatorState> _settingsNavigatorKey =
      GlobalKey<NavigatorState>(debugLabel: 'settings');

  /// Navigator keys for each bottom navigation branch, indexed by tab position.
  static final List<GlobalKey<NavigatorState>> branchNavigatorKeys = [
    _libraryNavigatorKey,
    _serversNavigatorKey,
    _settingsNavigatorKey,
  ];

  static final GoRouter router = GoRouter(
    initialLocation: AppConstants.routeLibrary,
    routes: [
      // StatefulShellRoute for bottom navigation
      StatefulShellRoute.indexedStack(
        builder: (context, state, navigationShell) {
          return MainShellScreen(navigationShell: navigationShell);
        },
        branches: [
          // Branch 1: Library
          StatefulShellBranch(
            navigatorKey: _libraryNavigatorKey,
            routes: [
              GoRoute(
                path: AppConstants.routeLibrary,
                name: 'library',
                builder: (context, state) => const LibraryScreen(),
              ),
            ],
          ),
          // Branch 2: Servers (home)
          StatefulShellBranch(
            navigatorKey: _serversNavigatorKey,
            routes: [
              GoRoute(
                path: AppConstants.routeServerList,
                name: 'server-list',
                builder: (context, state) => const ServerListScreen(),
                routes: [
                  // Nested browse routes
                  GoRoute(
                    path: 'browse/:serverId',
                    name: 'browse-library',
                    builder: (context, state) {
                      final serverId = state.pathParameters['serverId']!;
                      return LibraryBrowserScreen(serverId: serverId);
                    },
                    routes: [
                      GoRoute(
                        path: 'feed',
                        name: 'browse-feed',
                        builder: (context, state) {
                          final serverId = state.pathParameters['serverId']!;
                          final extra = state.extra as Map<String, dynamic>;
                          return FeedScreen(
                            serverId: serverId,
                            feedUrl: extra['feedUrl'] as String,
                            feedTitle: extra['feedTitle'] as String,
                          );
                        },
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
          // Branch 3: Settings
          StatefulShellBranch(
            navigatorKey: _settingsNavigatorKey,
            routes: [
              GoRoute(
                path: AppConstants.routeSettings,
                name: 'settings',
                builder: (context, state) => const SettingsScreen(),
              ),
            ],
          ),
        ],
      ),

      // Standalone routes (full-screen, no bottom navigation)
      GoRoute(
        path: AppConstants.routeAddServer,
        name: 'add-server',
        builder: (context, state) => const AddServerScreen(),
      ),
      GoRoute(
        path: '${AppConstants.routeEditServer}/:id',
        name: 'edit-server',
        builder: (context, state) {
          final serverId = state.pathParameters['id']!;
          return EditServerScreen(serverId: serverId);
        },
      ),
      GoRoute(
        path: AppConstants.routePublicationDetail,
        name: 'publication-detail',
        builder: (context, state) {
          final entry = state.extra as Map<String, dynamic>;
          return PublicationDetailScreen(
            entry: entry['entry'] as OPDSEntry,
            serverId: entry['serverId'] as String,
            feedUrl: entry['feedUrl'] as String?,
          );
        },
      ),
      GoRoute(
        path: AppConstants.routeReader,
        name: 'reader',
        builder: (context, state) {
          final data = state.extra as Map<String, dynamic>;
          return ReaderScreen(
            entry: data['entry'] as OPDSEntry,
            serverId: data['serverId'] as String,
            initialPage: data['initialPage'] as int? ?? 0,
            feedUrl: data['feedUrl'] as String?,
          );
        },
      ),
      GoRoute(
        path: AppConstants.routeEpubReader,
        name: 'epub-reader',
        builder: (context, state) {
          final data = state.extra as Map<String, dynamic>;
          return EpubReaderScreen(
            entry: data['entry'] as OPDSEntry,
            serverId: data['serverId'] as String,
            feedUrl: data['feedUrl'] as String?,
          );
        },
      ),
    ],
    errorBuilder: (context, state) => Scaffold(
      body: Center(
        child: Text(
            AppLocalizations.of(context).routeNotFound(state.uri.toString())),
      ),
    ),
  );
}