import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../services/reader_direction.dart';
import '../sources/source.dart';
import '../sources/source_flags.dart';
import '../ui/catalog/source_picker_page.dart';
import '../ui/catalog_page.dart';
import '../ui/downloads_page.dart';
import '../ui/history_page.dart';
import '../ui/library_page.dart';
import '../ui/reader_page.dart';
import '../ui/settings_page.dart';
import '../ui/shell.dart';
import '../ui/title_page.dart';

final _rootKey = GlobalKey<NavigatorState>();

SourceId? _parseSourceId(String? raw) {
  if (raw == null) return null;
  return SourceId.tryParse(raw);
}

CatalogMenuKind? _parseMenu(String? raw) {
  if (raw == null) return null;
  for (final k in CatalogMenuKind.values) {
    if (k.pathSegment == raw) return k;
  }
  return null;
}

final routerProvider = Provider<GoRouter>((ref) {
  return GoRouter(
    navigatorKey: _rootKey,
    initialLocation: '/catalog',
    routes: [
      StatefulShellRoute.indexedStack(
        builder: (context, state, navigationShell) {
          return AppShell(navigationShell: navigationShell);
        },
        branches: [
          StatefulShellBranch(
            routes: [
              // Sibling routes (not nested under picker) so back stack is clean.
              GoRoute(
                path: '/catalog',
                redirect: (context, state) {
                  final enabled = enabledSourceIds();
                  if (enabled.length == 1) {
                    return '/catalog/${enabled.first.name}';
                  }
                  return null;
                },
                builder: (context, state) => const SourcePickerPage(),
              ),
              GoRoute(
                path: '/catalog/:sourceId',
                builder: (context, state) {
                  final id = _parseSourceId(state.pathParameters['sourceId']);
                  if (id == null) {
                    return const Scaffold(
                      body: Center(child: Text('Unknown source')),
                    );
                  }
                  final single = enabledSourceIds().length == 1;
                  return SourceHomePage(
                    sourceId: id,
                    embeddedAsRoot: single,
                  );
                },
                routes: [
                  GoRoute(
                    path: ':menu',
                    builder: (context, state) {
                      final id =
                          _parseSourceId(state.pathParameters['sourceId']);
                      final menu = _parseMenu(state.pathParameters['menu']);
                      if (id == null || menu == null) {
                        return const Scaffold(
                          body: Center(child: Text('Unknown catalog feed')),
                        );
                      }
                      return CatalogFeedPage(sourceId: id, menuKind: menu);
                    },
                  ),
                ],
              ),
            ],
          ),
          StatefulShellBranch(
            routes: [
              GoRoute(
                path: '/library',
                builder: (context, state) => const LibraryPage(),
              ),
            ],
          ),
          StatefulShellBranch(
            routes: [
              GoRoute(
                path: '/history',
                builder: (context, state) => const HistoryPage(),
              ),
            ],
          ),
          StatefulShellBranch(
            routes: [
              GoRoute(
                path: '/downloads',
                builder: (context, state) => const DownloadsPage(),
                routes: [
                  GoRoute(
                    path: 'queue',
                    builder: (context, state) => const DownloadsQueuePage(),
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
      GoRoute(
        path: '/settings',
        builder: (context, state) => const SettingsPage(),
      ),
      GoRoute(
        path: '/title/:id',
        builder: (context, state) {
          final id = int.parse(state.pathParameters['id']!);
          return TitlePage(titleId: id);
        },
      ),
      GoRoute(
        path: '/read/:titleId/:chapterId',
        builder: (context, state) {
          final titleId = int.parse(state.pathParameters['titleId']!);
          final chapterId = int.parse(state.pathParameters['chapterId']!);
          final modeParam = state.uri.queryParameters['mode'];
          ReaderMode? initialMode;
          if (modeParam == 'paged') {
            initialMode = ReaderMode.paged;
          } else if (modeParam == 'webtoon') {
            initialMode = ReaderMode.webtoon;
          }
          return ReaderPage(
            titleId: titleId,
            chapterId: chapterId,
            initialMode: initialMode,
          );
        },
      ),
    ],
  );
});