// lib/widgets/navigation/nav_bar/nav_bar.dart
import 'package:aves/app_mode.dart';
import 'package:aves/model/settings/settings.dart';
import 'package:aves/model/source/collection_lens.dart';
import 'package:aves/widgets/activity/activity_files_page.dart';
import 'package:aves/widgets/collection/collection_page.dart';
import 'package:aves/widgets/common/basic/draggable_scrollbar/notifications.dart';
import 'package:aves/widgets/common/extensions/build_context.dart';
import 'package:aves/widgets/common/extensions/media_query.dart';
import 'package:aves/widgets/common/identity/aves_app_bar.dart';
import 'package:aves/widgets/navigation/nav_bar/floating.dart';
import 'package:aves/widgets/navigation/nav_item.dart';
import 'package:collection/collection.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

enum AppBottomNavBarMode {
  media,
  activity,
}

class AppBottomNavBar extends StatefulWidget {
  final Stream<DraggableScrollbarEvent> events;

  // collection loaded in the `CollectionPage`, if any
  final CollectionLens? currentCollection;

  final AppBottomNavBarMode mode;

  /// Used only when [mode] is [AppBottomNavBarMode.activity].
  ///
  /// Mapping:
  /// - 0: activity collection
  /// - 1: sport
  /// - 2: favourites
  /// - 3: activity albums
  final int activityIndex;

  /// Used only when [mode] is [AppBottomNavBarMode.activity].
  final ValueChanged<int>? onActivityIndexSelected;

  static double get height => kBottomNavigationBarHeight + AvesFloatingBar.margin.vertical;

  const AppBottomNavBar({
    super.key,
    required this.events,
    this.currentCollection,
    this.mode = AppBottomNavBarMode.media,
    this.activityIndex = 0,
    this.onActivityIndexSelected,
  });

  @override
  State<AppBottomNavBar> createState() => _AppBottomNavBarState();
}

class _AppBottomNavBarState extends State<AppBottomNavBar> {
  String? _lastRoute;

  @override
  void initState() {
    super.initState();
    _registerWidget(widget);
  }

  @override
  void didUpdateWidget(covariant AppBottomNavBar oldWidget) {
    super.didUpdateWidget(oldWidget);
    _unregisterWidget(oldWidget);
    _registerWidget(widget);
  }

  @override
  void dispose() {
    _unregisterWidget(widget);
    super.dispose();
  }

  void _registerWidget(AppBottomNavBar widget) {
    widget.currentCollection?.filterChangeNotifier.addListener(
      _onCollectionFilterChanged,
    );
  }

  void _unregisterWidget(AppBottomNavBar widget) {
    widget.currentCollection?.filterChangeNotifier.removeListener(
      _onCollectionFilterChanged,
    );
  }

  @override
  Widget build(BuildContext context) {
    final mediaItems = context.select<Settings, List<AvesNavItem>>(
      (v) => v.bottomNavigationActions,
    );

    if (mediaItems.length < 2 && widget.mode == AppBottomNavBarMode.media) {
      return const SizedBox();
    }

    Widget child = FloatingNavBar(
      scrollController: PrimaryScrollController.of(context),
      events: widget.events,
      childHeight:
          AppBottomNavBar.height +
          context.select<MediaQueryData, double>(
            (mq) => mq.effectiveBottomPadding,
          ),
      child: SafeArea(
        child: AvesFloatingBar(
          builder: (context, backgroundColor, child) {
            final navItems = widget.mode == AppBottomNavBarMode.activity ? _buildActivityNavItems(context) : _buildMediaNavItems(context, mediaItems);

            return BottomNavigationBar(
              items: navItems,
              onTap: (index) => _goTo(context, mediaItems, index),
              currentIndex: _getCurrentIndex(context, mediaItems),
              type: BottomNavigationBarType.fixed,
              backgroundColor: backgroundColor,
              showSelectedLabels: false,
              showUnselectedLabels: false,
            );
          },
        ),
      ),
    );

    // Important:
    // Do not wrap the Activity bottom bar in the same Hero as the media bottom bar.
    // Otherwise, when Activity replaces Collection, both bars can compete for the
    // same Hero tag and trigger GlobalKey / inactive element issues.
    final animate = widget.mode == AppBottomNavBarMode.media && context.select<Settings, bool>((v) => v.animate);

    if (animate) {
      child = Hero(
        tag: 'nav-bar',
        flightShuttleBuilder:
            (
              flightContext,
              animation,
              flightDirection,
              fromHeroContext,
              toHeroContext,
            ) {
              return MediaQuery.removeViewInsets(
                context: context,
                removeBottom: true,
                child: toHeroContext.widget,
              );
            },
        child: child,
      );
    }

    return child;
  }

  List<BottomNavigationBarItem> _buildMediaNavItems(
    BuildContext context,
    List<AvesNavItem> items,
  ) {
    return [
      _buildToggleItem(context),
      ...items.map((item) {
        final label = item.getText(context);

        return BottomNavigationBarItem(
          icon: item.getIcon(context),
          label: label,
          tooltip: label,
        );
      }),
    ];
  }

  List<BottomNavigationBarItem> _buildActivityNavItems(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;

    return [
      _buildToggleItem(context),

      // 0 - Activity collection
      BottomNavigationBarItem(
        icon: Icon(
          Icons.route_outlined,
          color: widget.activityIndex == 0 ? scheme.primary : null,
        ),
        activeIcon: Icon(
          Icons.route,
          color: scheme.primary,
        ),
        label: 'Attività',
        tooltip: 'Tutte le attività',
      ),

      // 1 - Sport
      BottomNavigationBarItem(
        icon: Icon(
          Icons.directions_run_outlined,
          color: widget.activityIndex == 1 ? scheme.primary : null,
        ),
        activeIcon: Icon(
          Icons.directions_run,
          color: scheme.primary,
        ),
        label: 'Sport',
        tooltip: 'Sport',
      ),

      // 2 - Favourite activities
      BottomNavigationBarItem(
        icon: Icon(
          Icons.favorite_border,
          color: widget.activityIndex == 2 ? scheme.primary : null,
        ),
        activeIcon: Icon(
          Icons.favorite,
          color: scheme.primary,
        ),
        label: 'Preferiti',
        tooltip: 'Attività preferite',
      ),

      // 3 - Activity albums
      BottomNavigationBarItem(
        icon: Icon(
          Icons.collections_bookmark_outlined,
          color: widget.activityIndex == 3 ? scheme.primary : null,
        ),
        activeIcon: Icon(
          Icons.collections_bookmark,
          color: scheme.primary,
        ),
        label: 'Album',
        tooltip: 'Album attività',
      ),
    ];
  }

  BottomNavigationBarItem _buildToggleItem(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    final isActivityMode = widget.mode == AppBottomNavBarMode.activity;

    final label = isActivityMode ? 'Foto' : 'Attività';

    return BottomNavigationBarItem(
      icon: Icon(
        isActivityMode ? Icons.photo_library_outlined : Icons.route_outlined,
        color: isActivityMode ? scheme.primary : scheme.tertiary,
      ),
      activeIcon: Icon(
        isActivityMode ? Icons.photo_library : Icons.route,
        color: isActivityMode ? scheme.primary : scheme.tertiary,
      ),
      label: label,
      tooltip: label,
    );
  }

  void _onCollectionFilterChanged() => setState(() {});

  int _getCurrentIndex(BuildContext context, List<AvesNavItem> mediaItems) {
    // Activity mode:
    // index 0 = toggle back to photos
    // index 1..4 = activity sections
    if (widget.mode == AppBottomNavBarMode.activity) {
      return widget.activityIndex + 1;
    }

    // Media mode:
    // index 0 = toggle to activity
    // index 1..N = configured media nav items

    // current route may be null during navigation
    final currentRoute = context.currentRouteName ?? _lastRoute;
    _lastRoute = currentRoute;

    final currentItem = mediaItems.firstWhereOrNull((item) {
      final itemRoute = item.route;
      if (currentRoute != itemRoute) return false;

      switch (itemRoute) {
        case CollectionPage.routeName:
          final currentFilters = widget.currentCollection?.filters ?? {};
          return const SetEquality().equals(
            currentFilters,
            item.filters ?? {},
          );
        default:
          return true;
      }
    });

    // +1 because index 0 is the activity/photo toggle.
    final currentIndex = currentItem != null ? mediaItems.indexOf(currentItem) + 1 : 1;

    return currentIndex;
  }

  void _goTo(BuildContext context, List<AvesNavItem> mediaItems, int index) {
    if (index == 0) {
      _toggleActivityMode(context, mediaItems);
      return;
    }

    if (widget.mode == AppBottomNavBarMode.activity) {
      widget.onActivityIndexSelected?.call(index - 1);
      return;
    }

    // Media mode:
    // -1 because index 0 is the activity/photo toggle.
    final item = mediaItems[index - 1];
    item.goTo(context, topLevel: null);
  }

  void _toggleActivityMode(
    BuildContext context,
    List<AvesNavItem> mediaItems,
  ) {
    if (widget.mode == AppBottomNavBarMode.activity) {
      final collectionItem = mediaItems.firstWhereOrNull(
        (item) => item.route == CollectionPage.routeName,
      );

      if (collectionItem != null) {
        collectionItem.goTo(context, topLevel: null);
        return;
      }

      // Fallback. In normal conditions this should not be used because the
      // default bottom nav actions always contain CollectionPage.routeName.
      Navigator.of(context).pushReplacement(
        MaterialPageRoute(
          settings: const RouteSettings(
            name: CollectionPage.routeName,
          ),
          builder: (_) => const SizedBox(),
        ),
      );

      return;
    }

    // Important:
    // Use pushReplacement, not push, so the media Collection and its
    // GridItemTracker/GlobalKeys are removed while Activity is displayed.
    Navigator.of(context).pushReplacement(
      MaterialPageRoute(
        settings: const RouteSettings(
          name: ActivityFilesPage.routeName,
        ),
        builder: (_) => const ActivityFilesPage(),
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    final canNavigate = context.select<ValueNotifier<AppMode>, bool>(
      (v) => v.value.canNavigate,
    );
    final enableBottomNavigationBar = context.select<Settings, bool>(
      (v) => v.enableBottomNavigationBar,
    );
    final showBottomNavigationBar = canNavigate && enableBottomNavigationBar;

    return SliverToBoxAdapter(
      child: SizedBox(
        height: showBottomNavigationBar ? AppBottomNavBar.height : 0,
      ),
    );
  }
}