// Author: fruit.com.cn
// 职责：追剧收藏网格、分页和编辑选择，不承载顶部续播或重复区块标题。

import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

import '../../core/data/services/favorite_controller.dart';
import '../../core/formatting/error_text.dart';
import '../../core/widgets/empty_state.dart';
import '../../l10n/app_localizations.dart';
import '../player/open_player.dart';
import 'following_grid_card.dart';
import 'following_paged_grid.dart';

/// 追剧编辑中的选中状态。
class FollowingFavoriteSelection {
  const FollowingFavoriteSelection({
    required this.editing,
    required this.selected,
    required this.onToggle,
  });

  final ValueListenable<bool> editing;
  final ValueListenable<Set<String>> selected;
  final ValueChanged<String> onToggle;
}

/// 追剧列表。编辑时点卡片只切换选中，不进入播放。
class FollowingFavoritesGrid extends StatelessWidget {
  const FollowingFavoritesGrid({
    super.key,
    required this.controller,
    required this.selection,
    required this.scrollController,
    required this.onGoHome,
  });

  final FavoriteController controller;
  final FollowingFavoriteSelection selection;
  final ScrollController scrollController;
  final VoidCallback onGoHome;

  @override
  Widget build(BuildContext context) {
    return ValueListenableBuilder<bool>(
      valueListenable: selection.editing,
      builder: (context, isEditing, _) {
        return ValueListenableBuilder<Set<String>>(
          valueListenable: selection.selected,
          builder: (context, picked, _) {
            return ListenableBuilder(
              listenable: controller,
              builder: (context, _) => _grid(context, isEditing, picked),
            );
          },
        );
      },
    );
  }

  Widget _grid(BuildContext context, bool isEditing, Set<String> picked) {
    final l10n = AppLocalizations.of(context)!;
    final hasFavorites = controller.cards.isNotEmpty;
    final extra = !isEditing && hasFavorites ? 1 : 0;
    return FollowingPagedGrid(
      key: const Key('following-favorites-grid'),
      scrollController: scrollController,
      loading: controller.loading,
      loadingMore: controller.loadingMore,
      hasMore: controller.hasMore,
      hasItems: hasFavorites,
      showInitialLoading: false,
      errorMessage: controller.error == null
          ? null
          : errorText(l10n, controller.error, l10n.favoritesError),
      loadMoreError: controller.loadMoreError == null
          ? null
          : errorText(l10n, controller.loadMoreError, l10n.favoritesError),
      onRefresh: controller.load,
      onLoadMore: controller.loadMore,
      itemCount: controller.cards.length + extra,
      empty: EmptyState(
        key: const Key('following-favorites-empty'),
        icon: Icons.bookmark_border_rounded,
        title: l10n.noFavoritesYet,
      ),
      itemBuilder: (context, index) => _item(context, index, isEditing, picked),
    );
  }

  Widget _item(
    BuildContext context,
    int index,
    bool isEditing,
    Set<String> picked,
  ) {
    if (index == controller.cards.length) {
      return FollowingAddCard(onTap: onGoHome);
    }
    final drama = controller.cards[index];
    return FollowingGridCard(
      dramaId: drama.id,
      title: drama.localizedTitle(Localizations.localeOf(context).languageCode),
      posterUrl: drama.posterUrl,
      viewCount: drama.viewCount,
      editing: isEditing,
      selected: isEditing ? picked.contains(drama.id) : null,
      // TODO(backend): Drama 增加 hasUpdate 字段后，在此传 updateBadge。
      onTap: () => _openOrToggle(context, drama.id, isEditing),
    );
  }

  void _openOrToggle(BuildContext context, String dramaId, bool isEditing) {
    if (isEditing) {
      selection.onToggle(dramaId);
      return;
    }
    final drama = controller.cards.firstWhere((item) => item.id == dramaId);
    unawaited(playDramaFromCatalog(context, drama));
  }
}