// Author: fruit.com.cn

import 'package:flutter/material.dart';

import '../../../core/data/models/content_category.dart';
import '../../../core/data/models/drama.dart';
import '../../../core/data/models/playlist_detail.dart';
import '../../../core/data/services/category_controller.dart';
import '../../../core/data/services/home_feed_controller.dart';
import '../../../core/data/services/playlist_controller.dart';
import '../../../core/theme/app_colors.dart';
import '../../../core/theme/app_dimens.dart';
import '../../../core/widgets/app_pull_to_refresh.dart';
import '../../../core/widgets/empty_state.dart';
import '../../../l10n/app_localizations.dart';
import '../../home/widgets/home_drama_classification.dart';
import 'recommend_section_card.dart';

const List<String> _costumeNames = ['古装', 'costume', 'kostum'];
const int _sectionPreviewCount = 10;
const double _loadMoreThreshold = 200;

enum RecommendSectionKind { hits, newReleases, costume }

class RecommendSectionsView extends StatelessWidget {
  const RecommendSectionsView({
    super.key,
    required this.feedController,
    required this.categories,
    required this.onOpenDrama,
    required this.onMore,
    this.playlists,
    this.onOpenPlaylist,
  });

  final HomeFeedController feedController;
  final CategoryController categories;
  final ValueChanged<Drama> onOpenDrama;
  final ValueChanged<RecommendSectionKind> onMore;
  final PlaylistController? playlists;
  final ValueChanged<PlaylistDetail>? onOpenPlaylist;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final source = feedController.dramas;
    final remote = playlists;
    return AppPullToRefresh(
      key: const Key('recommend-sections-refresh'),
      onRefresh: () async {
        await Future.wait([
          feedController.refreshCurrent(),
          categories.load(),
          if (remote != null) remote.load(),
        ]);
      },
      child: NotificationListener<ScrollNotification>(
        onNotification: (notification) =>
            remote == null ? false : _onPlaylistScroll(notification, remote),
        child: ListView(
          key: const Key('recommend-sections-scroll'),
          physics: AppPullToRefresh.physics,
          padding: const EdgeInsets.only(bottom: AppDimens.spaceXl),
          children: remote == null
              ? _localSections(context, l10n, source)
              : _remoteSections(context, l10n, remote),
        ),
      ),
    );
  }

  List<Widget> _localSections(
    BuildContext context,
    AppLocalizations l10n,
    List<Drama> source,
  ) {
    final hits = recommendSectionDramas(
      kind: RecommendSectionKind.hits,
      source: source,
    );
    final newest = recommendSectionDramas(
      kind: RecommendSectionKind.newReleases,
      source: source,
    );
    return [
      _section(
        context,
        l10n,
        key: 'hits',
        title: l10n.weeklyHitsTitle,
        subtitle: l10n.weeklyHitsSubtitle,
        dramas: hits.take(_sectionPreviewCount).toList(),
        onMore: () => onMore(RecommendSectionKind.hits),
      ),
      const SizedBox(height: AppDimens.recommendSectionGap),
      _section(
        context,
        l10n,
        key: 'new',
        title: l10n.weeklyNewTitle,
        subtitle: l10n.weeklyNewSubtitle,
        dramas: newest.take(_sectionPreviewCount).toList(),
        onMore: () => onMore(RecommendSectionKind.newReleases),
      ),
      const SizedBox(height: AppDimens.recommendSectionGap),
      _section(
        context,
        l10n,
        key: 'costume',
        title: l10n.costumeAwardsTitle,
        subtitle: l10n.costumeAwardsSubtitle,
        dramas: recommendSectionDramas(
          kind: RecommendSectionKind.costume,
          source: source,
          categories: categories,
        ).take(_sectionPreviewCount).toList(),
        onMore: () => onMore(RecommendSectionKind.costume),
      ),
    ];
  }

  List<Widget> _remoteSections(
    BuildContext context,
    AppLocalizations l10n,
    PlaylistController remote,
  ) {
    if (!remote.loaded && remote.loading) {
      return const [
        SizedBox(
          height: 240,
          child: Center(
            child: CircularProgressIndicator(
              key: Key('recommend-playlists-loading'),
            ),
          ),
        ),
      ];
    }
    if (remote.items.isEmpty) {
      return [
        EmptyState(
          key: const Key('recommend-playlists-empty'),
          icon: Icons.video_library_outlined,
          title: remote.error == null ? l10n.emptyContent : l10n.networkError,
          actionLabel: l10n.retry,
          onAction: remote.load,
        ),
      ];
    }
    final sections = <Widget>[];
    for (final playlist in remote.items) {
      if (sections.isNotEmpty) {
        sections.add(const SizedBox(height: AppDimens.recommendSectionGap));
      }
      sections.add(
        _section(
          context,
          l10n,
          key: playlist.id,
          title: playlist.localizedName(
            Localizations.localeOf(context).languageCode,
          ),
          subtitle: playlist.localizedDescription(
            Localizations.localeOf(context).languageCode,
          ),
          dramas: playlist.dramas.take(_sectionPreviewCount).toList(),
          onMore: () => onOpenPlaylist?.call(playlist),
        ),
      );
    }
    if (remote.loadingMore) {
      sections.add(
        const Padding(
          padding: EdgeInsets.symmetric(vertical: AppDimens.spaceMd),
          child: Center(
            child: CircularProgressIndicator(
              key: Key('recommend-playlists-more'),
            ),
          ),
        ),
      );
    } else if (!remote.hasMore) {
      sections.add(
        Padding(
          key: const Key('paged-list-no-more'),
          padding: const EdgeInsets.symmetric(vertical: 16),
          child: Text(
            l10n.noMoreItems,
            textAlign: TextAlign.center,
            style: const TextStyle(color: AppColors.textHint, fontSize: 12),
          ),
        ),
      );
    }
    return sections;
  }

  bool _onPlaylistScroll(
    ScrollNotification notification,
    PlaylistController remote,
  ) {
    if (notification.depth != 0) return false;
    if (notification.metrics.extentAfter > _loadMoreThreshold) return false;
    if (notification is! ScrollUpdateNotification &&
        notification is! ScrollEndNotification) {
      return false;
    }
    remote.loadMore();
    return false;
  }

  Widget _section(
    BuildContext context,
    AppLocalizations l10n, {
    required String key,
    required String title,
    required String subtitle,
    required List<Drama> dramas,
    required VoidCallback onMore,
  }) {
    return Column(
      key: Key('recommend-section-$key'),
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Padding(
          padding: const EdgeInsets.symmetric(
            horizontal: AppDimens.feedPageHorizontal,
          ),
          child: Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      title,
                      style: const TextStyle(
                        color: AppColors.textPrimary,
                        fontSize: AppDimens.recommendSectionTitle,
                        fontWeight: FontWeight.w400,
                      ),
                    ),
                    const SizedBox(height: 2),
                    Text(
                      subtitle,
                      style: const TextStyle(
                        color: AppColors.textSecondary,
                        fontSize: AppDimens.recommendSectionSubtitle,
                      ),
                    ),
                  ],
                ),
              ),
              TextButton(
                key: Key('recommend-more-$key'),
                onPressed: onMore,
                style: TextButton.styleFrom(
                  foregroundColor: AppColors.textSecondary,
                  padding: const EdgeInsets.symmetric(horizontal: 4),
                  minimumSize: const Size(0, 30),
                ),
                child: Row(
                  children: [
                    Text(
                      l10n.more,
                      style: const TextStyle(
                        color: AppColors.textSecondary,
                        fontSize: AppDimens.recommendSectionMore,
                        fontWeight: FontWeight.w500,
                      ),
                    ),
                    const Icon(Icons.chevron_right_rounded, size: 16),
                  ],
                ),
              ),
            ],
          ),
        ),
        const SizedBox(height: AppDimens.spaceXs),
        SizedBox(
          height: AppDimens.recommendRowHeight,
          child: ListView.separated(
            key: Key('recommend-row-$key'),
            scrollDirection: Axis.horizontal,
            padding: const EdgeInsets.symmetric(
              horizontal: AppDimens.feedPageHorizontal,
            ),
            itemCount: dramas.length,
            separatorBuilder: (_, _) =>
                const SizedBox(width: AppDimens.homeGridGap),
            itemBuilder: (context, index) => RecommendSectionCard(
              sectionKey: key,
              drama: dramas[index],
              onTap: () => onOpenDrama(dramas[index]),
            ),
          ),
        ),
      ],
    );
  }
}

/// 剧单分区的完整片单，横滑预览和更多页共用同一排序。
List<Drama> recommendSectionDramas({
  required RecommendSectionKind kind,
  required List<Drama> source,
  CategoryController? categories,
}) {
  switch (kind) {
    case RecommendSectionKind.hits:
      return [...source]..sort((a, b) => b.viewCount.compareTo(a.viewCount));
    case RecommendSectionKind.newReleases:
      return [...source]..sort(_newestFirst);
    case RecommendSectionKind.costume:
      return _costumeDramas(source, categories);
  }
}

int _newestFirst(Drama leftDrama, Drama rightDrama) {
  final left = publishedAtForDrama(leftDrama);
  final right = publishedAtForDrama(rightDrama);
  if (left == null && right == null) {
    return rightDrama.id.compareTo(leftDrama.id);
  }
  if (left == null) {
    return 1;
  }
  if (right == null) {
    return -1;
  }
  return right.compareTo(left);
}

List<Drama> _costumeDramas(List<Drama> source, CategoryController? categories) {
  final category = _costumeCategory(categories);
  if (category != null) {
    final fromCategory = categories!.dramasOf(category.id);
    if (fromCategory.isNotEmpty) return fromCategory;
  }
  return source.where(_isCostumeDrama).toList(growable: false);
}

ContentCategory? _costumeCategory(CategoryController? categories) {
  if (categories == null) return null;
  for (final category in categories.categories) {
    if (_containsCostume(category.name)) return category;
  }
  return null;
}

bool _isCostumeDrama(Drama drama) {
  return _containsCostume(drama.category) || _containsCostume(drama.genre);
}

bool _containsCostume(String value) {
  final normalized = value.toLowerCase();
  return _costumeNames.any(normalized.contains);
}