// Author: fruit.com.cn

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

import '../../core/data/models/content_category.dart';
import '../../core/data/models/drama.dart';
import '../../core/data/models/home_feed.dart';
import '../../core/data/repositories/catalog_repository.dart';
import '../../core/data/repositories/search_repository.dart';
import '../../core/data/services/catalog_controller.dart';
import '../../core/data/services/category_controller.dart';
import '../../core/formatting/error_text.dart';
import '../../core/theme/app_colors.dart';
import '../../core/theme/app_dimens.dart';
import '../../core/theme/app_theme.dart';
import '../../core/widgets/app_bottom_nav.dart';
import '../../core/widgets/empty_state.dart';
import '../../l10n/app_localizations.dart';
import '../drama_detail/drama_detail_view.dart';
import 'category_dramas_page.dart';
import 'discover_binding.dart';
import 'discover_logic.dart';
import 'discover_types.dart';
import 'widgets/category_grid.dart';
import 'widgets/discover_header.dart';
import 'widgets/discover_search_field.dart';
import 'widgets/discover_search_results.dart';
import 'widgets/drama_grid.dart';
import 'widgets/feed_banner_carousel.dart';
import 'widgets/ranking_section.dart';

/// 剧场页：搜索 + 分类九宫格 + 榜单 + 全部剧目。
class DiscoverPage extends StatefulWidget {
  const DiscoverPage({
    super.key,
    this.active = true,
    this.searchRequest = 0,
    this.focusSearch = false,
    this.callbacks = const DiscoverPageCallbacks(),
  });

  final bool active;
  final int searchRequest;
  final bool focusSearch;
  final DiscoverPageCallbacks callbacks;

  @override
  State<DiscoverPage> createState() => _DiscoverPageState();
}

class _DiscoverPageState extends State<DiscoverPage> {
  late final DiscoverLogic logic;

  bool get embedded => widget.callbacks.embedded;

  @override
  void initState() {
    super.initState();
    logic = DiscoverBinding().create(search: context.read<SearchRepository>());
    if (widget.focusSearch) _focusOnFirstFrame();
  }

  void _focusOnFirstFrame() {
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted && widget.active) logic.openSearch();
    });
  }

  @override
  void didUpdateWidget(covariant DiscoverPage oldWidget) {
    super.didUpdateWidget(oldWidget);
    logic.syncSearch(
      active: widget.active,
      request: widget.searchRequest,
      previousRequest: oldWidget.searchRequest,
      isActive: () => mounted && widget.active,
    );
  }

  @override
  void dispose() {
    logic.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: logic,
      builder: (context, _) => _page(context),
    );
  }

  Widget _page(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final categories = context.watch<CategoryController>();
    final banners = context.watch<CatalogController>().banners;
    final content = SafeArea(
      bottom: !embedded,
      child: Column(
        children: [
          DiscoverHeader(onSearch: logic.openSearch, onProfile: _openProfile),
          Expanded(child: _feed(l10n, categories, banners)),
          if (!embedded) _bottomNav(l10n),
        ],
      ),
    );
    return AnnotatedRegion<SystemUiOverlayStyle>(
      value: SystemUiOverlayStyle.light,
      child: Theme(
        data: AppTheme.dark(),
        child: embedded
            ? content
            : Scaffold(backgroundColor: AppColors.ink, body: content),
      ),
    );
  }

  Widget _feed(
    AppLocalizations l10n,
    CategoryController categories,
    List<FeedBanner> banners,
  ) {
    return RefreshIndicator(
      key: const Key('discover-refresh'),
      color: AppColors.blue,
      backgroundColor: AppColors.card,
      onRefresh: categories.load,
      child: ListView(
        controller: logic.scroll,
        physics: const AlwaysScrollableScrollPhysics(),
        padding: const EdgeInsets.only(bottom: 24),
        children: [
          Padding(
            padding: const EdgeInsets.only(top: 8),
            child: DiscoverSearchField(
              controller: logic.search,
              focusNode: logic.searchFocus,
              onChanged: (_) => logic.onSearchChanged(),
              loading: logic.searchLoading,
            ),
          ),
          ..._content(l10n, categories, banners),
        ],
      ),
    );
  }

  List<Widget> _content(
    AppLocalizations l10n,
    CategoryController categories,
    List<FeedBanner> banners,
  ) {
    if (logic.hasSearchQuery) return [_searchContent(l10n)];
    return _theaterContent(l10n, categories, banners);
  }

  Widget _searchContent(AppLocalizations l10n) => DiscoverSearchResults(
    loading: logic.searchLoading,
    error: logic.searchError,
    results: logic.searchResults,
    onRetry: logic.retrySearch,
    onOpen: _openDrama,
  );

  List<Widget> _theaterContent(
    AppLocalizations l10n,
    CategoryController categories,
    List<FeedBanner> banners,
  ) {
    if (categories.loading && categories.feed.sections.isEmpty) {
      return [_block(const CircularProgressIndicator(strokeWidth: 2))];
    }
    final error = categories.error;
    if (error != null) {
      return [
        _block(
          EmptyState(
            key: const Key('home-categories-error'),
            icon: Icons.cloud_off_rounded,
            title: errorText(l10n, error, l10n.categoriesError),
            subtitle: l10n.emptyHint,
            actionLabel: l10n.retry,
            onAction: categories.load,
          ),
        ),
      ];
    }
    return _theaterBlocks(l10n, categories, banners);
  }

  List<Widget> _theaterBlocks(
    AppLocalizations l10n,
    CategoryController categories,
    List<FeedBanner> banners,
  ) {
    final dramas = categories.feed.dramas;
    return [
      Padding(
        padding: const EdgeInsets.only(top: 12),
        child: CategoryGrid(
          categories: categories.categories,
          onTap: (category) => _openCategory(category, categories),
        ),
      ),
      if (banners.isNotEmpty)
        Padding(
          padding: const EdgeInsets.only(top: 12),
          child: FeedBannerCarousel(
            banners: banners,
            active: widget.active,
            onOpen: _openBanner,
          ),
        ),
      if (categories.feed.sections.isNotEmpty || dramas.isNotEmpty)
        RankingSection(
          sections: categories.feed.sections,
          fallback: dramas,
          onOpen: _openDrama,
        ),
      _sectionTitle(l10n.allDramas),
      if (dramas.isEmpty) _emptyCatalog(l10n) else _dramaGrid(l10n, dramas),
    ];
  }

  Widget _block(Widget child) =>
      SizedBox(height: 280, child: Center(child: child));

  Widget _emptyCatalog(AppLocalizations l10n) => Padding(
    padding: const EdgeInsets.symmetric(vertical: 40),
    child: EmptyState(
      key: const Key('discover-empty'),
      icon: Icons.movie_filter_outlined,
      title: l10n.noStories,
      subtitle: l10n.emptyHint,
    ),
  );

  Widget _dramaGrid(AppLocalizations l10n, List<Drama> dramas) {
    return DramaGrid(l10n: l10n, dramas: dramas, onOpen: _openDrama);
  }

  Widget _sectionTitle(String title) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(14, 18, 14, 10),
      child: Row(
        children: [
          Container(
            width: 3,
            height: 18,
            decoration: BoxDecoration(
              color: AppColors.blue,
              borderRadius: BorderRadius.circular(2),
            ),
          ),
          const SizedBox(width: 6),
          Expanded(
            child: Text(
              title,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: const TextStyle(
                color: AppColors.onSurface,
                fontSize: AppDimens.previewSectionTitle,
                fontWeight: FontWeight.w800,
              ),
            ),
          ),
        ],
      ),
    );
  }

  void _openProfile() {
    final callback = widget.callbacks.onProfile;
    if (callback != null) {
      callback();
      return;
    }
    _act(DiscoverPageAction.my);
  }

  void _act(DiscoverPageAction action) {
    logic.act(
      context,
      action,
      embedded: embedded,
      onAction: widget.callbacks.onAction,
    );
  }

  void _openCategory(ContentCategory category, CategoryController categories) {
    Navigator.of(context).push<void>(
      MaterialPageRoute(
        builder: (_) => CategoryDramasPage(
          title: category.name,
          dramas: categories.dramasOf(category.id),
          onOpen: widget.callbacks.onDramaSelected == null ? null : _openDrama,
        ),
      ),
    );
  }

  void _openDrama(Drama drama) {
    final callback = widget.callbacks.onDramaSelected;
    if (callback != null) {
      callback(drama);
      return;
    }
    _pushDetail(drama);
  }

  void _pushDetail(Drama drama) {
    Navigator.of(context).push<void>(
      MaterialPageRoute(builder: (_) => DramaDetailPage(drama: drama)),
    );
  }

  Future<void> _openBanner(FeedBanner banner) async {
    final dramaId = banner.dramaId;
    if (dramaId == null) return;
    for (final drama in context.read<CatalogController>().dramas) {
      if (drama.id == dramaId) {
        _pushDetail(drama);
        return;
      }
    }
    try {
      final drama = await context.read<CatalogRepository>().fetchDrama(dramaId);
      if (mounted) _pushDetail(drama);
    } catch (_) {
      if (!mounted) return;
      final message = AppLocalizations.of(context)!.detailLoadFailed;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(message)));
    }
  }

  Widget _bottomNav(AppLocalizations l10n) => AppBottomNav(
    items: [
      AppBottomNavItem(
        tabKey: const Key('discover-nav-home'),
        icon: Icons.play_circle_outline_rounded,
        selectedIcon: Icons.play_circle_fill_rounded,
        label: l10n.homeTab,
        onTap: () => _act(DiscoverPageAction.home),
      ),
      AppBottomNavItem(
        tabKey: const Key('discover-nav-current'),
        icon: Icons.explore_outlined,
        selectedIcon: Icons.explore_rounded,
        label: l10n.discoverTab,
        selected: true,
        onTap: () {},
      ),
      AppBottomNavItem(
        tabKey: const Key('discover-nav-my'),
        icon: Icons.video_library_outlined,
        selectedIcon: Icons.video_library_rounded,
        label: l10n.myTab,
        onTap: () => _act(DiscoverPageAction.my),
      ),
    ],
  );
}