// Author: fruit.com.cn

import 'dart:async';

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

import '../../../core/data/models/content_category.dart';
import '../../../core/data/models/drama.dart';
import '../../../core/data/services/auth_controller.dart';
import '../../../core/data/services/category_controller.dart';
import '../../../core/data/services/home_feed_controller.dart';
import '../../../core/data/services/wallet_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 '../../../core/widgets/paged_list_footer.dart';
import '../../../l10n/app_localizations.dart';
import 'home_drama_classification.dart';
import 'home_feed_card.dart';
import 'home_grid_header.dart';

const double _loadMoreThreshold = 240;
const List<String> _costumeAliases = ['古装', 'costume', 'period'];
const List<String> _communityAliases = ['社群', 'community', 'komunitas'];

class HomeFeedGrid extends StatefulWidget {
  const HomeFeedGrid({
    super.key,
    required this.feedController,
    required this.callbacks,
    required this.onOpenDrama,
  });

  final HomeFeedController feedController;
  final HomeGridCallbacks callbacks;
  final ValueChanged<Drama> onOpenDrama;

  @override
  State<HomeFeedGrid> createState() => _HomeFeedGridState();
}

class _HomeFeedGridState extends State<HomeFeedGrid> {
  String? _selectedCategory;
  String? _selectedTag;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final categories = context.watch<CategoryController>().categories;
    final auth = context.watch<AuthController>();
    final wallet = context.watch<WalletController>();
    final shortcuts = _categoryShortcuts(categories, l10n);
    final tags = _availableTags(l10n);
    final activeCategory =
        shortcuts.any((shortcut) => shortcut.categoryName == _selectedCategory)
        ? _selectedCategory
        : null;
    final activeTag = tags.any((tag) => tag.id == _selectedTag)
        ? _selectedTag
        : null;
    final dramas = _filteredDramas(activeCategory, activeTag);
    final walletBadge = auth.isSignedIn && wallet.snapshot != null
        ? wallet.balance
        : null;
    return ColoredBox(
      key: const Key('home-grid'),
      color: AppColors.appBackground,
      child: SafeArea(
        bottom: false,
        child: LayoutBuilder(
          builder: (context, constraints) {
            final itemWidth =
                (constraints.maxWidth -
                    AppDimens.feedPageHorizontal * 2 -
                    AppDimens.homeGridGap * 2) /
                3;
            final itemExtent = itemWidth * 6 / 5 + AppDimens.homeCardBodyExtent;
            return NotificationListener<ScrollNotification>(
              onNotification: _onScroll,
              child: AppPullToRefresh(
                key: const Key('home-grid-refresh'),
                onRefresh: _refresh,
                child: CustomScrollView(
                  key: const Key('home-grid-scroll'),
                  physics: AppPullToRefresh.physics,
                  slivers: [
                    SliverToBoxAdapter(
                      child: HomeGridHeader(
                        callbacks: widget.callbacks,
                        categories: shortcuts,
                        tags: tags,
                        selectedCategory: activeCategory,
                        selectedTag: activeTag,
                        onCategorySelected: _selectCategory,
                        onTagSelected: (tag) =>
                            setState(() => _selectedTag = tag),
                        walletBadge: walletBadge,
                      ),
                    ),
                    if (widget.feedController.loadingFirstPage)
                      const SliverFillRemaining(
                        hasScrollBody: false,
                        child: Center(
                          child: SizedBox.square(
                            dimension: 24,
                            child: CircularProgressIndicator(strokeWidth: 2),
                          ),
                        ),
                      )
                    else if (dramas.isEmpty)
                      SliverFillRemaining(
                        hasScrollBody: false,
                        child: _emptyState(l10n, activeCategory, activeTag),
                      )
                    else
                      SliverPadding(
                        padding: const EdgeInsets.symmetric(
                          horizontal: AppDimens.feedPageHorizontal,
                        ),
                        sliver: SliverGrid(
                          key: const Key('home-grid-cards'),
                          gridDelegate:
                              SliverGridDelegateWithFixedCrossAxisCount(
                                crossAxisCount: 3,
                                crossAxisSpacing: AppDimens.homeGridGap,
                                mainAxisSpacing: AppDimens.homeGridRowGap,
                                mainAxisExtent: itemExtent,
                              ),
                          delegate: SliverChildBuilderDelegate(
                            (context, index) => HomeFeedCard(
                              drama: dramas[index],
                              onTap: () => widget.onOpenDrama(dramas[index]),
                            ),
                            childCount: dramas.length,
                          ),
                        ),
                      ),
                    if (dramas.isNotEmpty)
                      SliverToBoxAdapter(
                        child: Padding(
                          padding: const EdgeInsets.only(
                            bottom: AppDimens.spaceXl,
                          ),
                          child: PagedListFooter(
                            loading: widget.feedController.loadingMore,
                            hasMore: widget.feedController.hasMore,
                            hasItems: dramas.isNotEmpty,
                            errorMessage:
                                widget.feedController.lastError == null
                                ? null
                                : l10n.catalogError,
                            onRetry: widget.feedController.loadMore,
                          ),
                        ),
                      ),
                  ],
                ),
              ),
            );
          },
        ),
      ),
    );
  }

  Future<void> _refresh() async {
    await widget.feedController.refreshCurrent();
  }

  bool _onScroll(ScrollNotification notification) {
    if (notification.depth != 0) return false;
    final reachedBottom =
        notification.metrics.extentAfter <= _loadMoreThreshold;
    if (reachedBottom &&
        (notification is ScrollUpdateNotification ||
            notification is ScrollEndNotification ||
            notification is OverscrollNotification)) {
      unawaited(widget.feedController.loadMore());
    }
    return false;
  }

  void _selectCategory(String? category) {
    setState(() {
      _selectedCategory = category;
      _selectedTag = null;
    });
  }

  List<HomeGridCategoryShortcut> _categoryShortcuts(
    List<ContentCategory> categories,
    AppLocalizations l10n,
  ) {
    final shortcuts = <HomeGridCategoryShortcut>[];
    final costume = _findCategory(categories, _costumeAliases);
    final community = _findCategory(categories, _communityAliases);
    if (costume != null) {
      shortcuts.add(
        HomeGridCategoryShortcut(
          label: l10n.homeSectionCostume,
          categoryName: costume.name,
        ),
      );
    }
    if (community != null) {
      shortcuts.add(
        HomeGridCategoryShortcut(
          label: l10n.homeSectionCommunity,
          categoryName: community.name,
        ),
      );
    }
    return shortcuts;
  }

  ContentCategory? _findCategory(
    List<ContentCategory> categories,
    List<String> aliases,
  ) {
    for (final category in categories) {
      final name = category.name.toLowerCase();
      if (aliases.any(name.contains)) return category;
    }
    return null;
  }

  List<HomeGridTagOption> _availableTags(AppLocalizations l10n) {
    final definitions = [
      HomeGridTagOption(id: 'hot', label: l10n.homeTagHot),
      HomeGridTagOption(id: 'uplifting', label: l10n.homeTagUplifting),
      HomeGridTagOption(id: 'sweet', label: l10n.homeTagSweet),
      HomeGridTagOption(id: 'faceSlap', label: l10n.homeTagFaceSlap),
      HomeGridTagOption(id: 'angst', label: l10n.homeTagAngst),
    ];
    final categoryText = context
        .read<CategoryController>()
        .categories
        .map((category) => category.name)
        .toList(growable: false);
    return definitions
        .where((option) {
          if (option.id == 'hot') {
            return widget.feedController.dramas.any(isHotDrama);
          }
          return categoryText.any((text) => tagMatchesText(option.id, text)) ||
              widget.feedController.dramas.any(
                (drama) => matchesHomeTag(drama, option.id),
              );
        })
        .toList(growable: false);
  }

  List<Drama> _filteredDramas(String? category, String? tag) {
    final normalizedCategory = category?.toLowerCase();
    return widget.feedController.dramas
        .where((drama) {
          final categoryMatches =
              normalizedCategory == null ||
              drama.category.toLowerCase().contains(normalizedCategory) ||
              drama.genre.toLowerCase().contains(normalizedCategory);
          final tagMatches = tag == null || matchesHomeTag(drama, tag);
          return categoryMatches && tagMatches;
        })
        .toList(growable: false);
  }

  Widget _emptyState(AppLocalizations l10n, String? category, String? tag) {
    if (widget.feedController.lastError != null) {
      return EmptyState(
        key: const Key('home-grid-error'),
        icon: Icons.cloud_off_rounded,
        title: l10n.catalogError,
        actionLabel: l10n.retry,
        onAction: () => unawaited(widget.feedController.refreshCurrent()),
      );
    }
    final filtered = category != null || tag != null;
    return EmptyState(
      key: const Key('home-grid-empty'),
      icon: Icons.movie_filter_outlined,
      title: filtered ? l10n.homeGridFilterEmpty : l10n.noStories,
      subtitle: filtered ? null : l10n.emptyHint,
      actionLabel: filtered ? l10n.homeGridClearFilter : null,
      onAction: filtered
          ? () => setState(() {
              _selectedCategory = null;
              _selectedTag = null;
            })
          : null,
    );
  }
}