// Author: fruit.com.cn

import 'dart:async';

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

import '../../core/data/models/drama.dart';
import '../../core/data/remote/catalog_api.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/widgets/empty_state.dart';
import '../../l10n/app_localizations.dart';
import '../player/open_player.dart';
import '../player/player_view.dart';
import 'recommend_types.dart';
import 'widgets/all_dramas_filter_grid.dart';
import 'widgets/playlist_detail_page.dart';
import 'widgets/recommend_sections_view.dart';
import 'widgets/recommend_top_nav.dart';

class RecommendPage extends StatefulWidget {
  const RecommendPage({
    super.key,
    required this.feedController,
    this.catalogApi,
    required this.active,
    required this.onSearch,
    this.videoOnly = false,
    this.onImmersiveChanged,
  });

  final HomeFeedController feedController;
  final CatalogApi? catalogApi;
  final bool active;
  final VoidCallback onSearch;

  /// 画中画时只留视频，不画顶栏。
  final bool videoOnly;
  final ValueChanged<bool>? onImmersiveChanged;

  @override
  State<RecommendPage> createState() => _RecommendPageState();
}

class _RecommendPageState extends State<RecommendPage>
    with AutomaticKeepAliveClientMixin<RecommendPage> {
  RecommendInnerTab _tab = RecommendInnerTab.feed;
  final PageController _pageController = PageController();
  int _scrubCancelRequest = 0;

  @override
  bool get wantKeepAlive => true;

  @override
  void initState() {
    super.initState();
    if (widget.active) _scheduleRecommendData();
  }

  @override
  void didUpdateWidget(RecommendPage oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.active && !oldWidget.active) _scheduleRecommendData();
  }

  void _scheduleRecommendData() {
    final feed = widget.feedController;
    if (!feed.loaded && !feed.loadingFirstPage) {
      unawaited(feed.refreshCurrent());
    }
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (!mounted || !widget.active) return;
      final playlists = _readPlaylists();
      if (playlists != null && !playlists.loaded && !playlists.loading) {
        unawaited(playlists.load());
      }
    });
  }

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

  @override
  Widget build(BuildContext context) {
    super.build(context);
    final categories = context.read<CategoryController>();
    return ColoredBox(
      key: const Key('recommend-page'),
      color: AppColors.appBackground,
      child: Stack(
        children: [
          Positioned.fill(
            child: ListenableBuilder(
              listenable: Listenable.merge([widget.feedController, categories]),
              builder: (context, _) => PageView(
                key: const Key('recommend-tab-page-view'),
                controller: _pageController,
                scrollDirection: Axis.horizontal,
                onPageChanged: _onPageChanged,
                children: [
                  _KeepAliveTab(
                    key: const PageStorageKey('recommend-tab-feed'),
                    child: _recommendFeed(context),
                  ),
                  _KeepAliveTab(
                    key: const PageStorageKey('recommend-tab-playlists'),
                    child: _recommendPlaylists(categories),
                  ),
                  _KeepAliveTab(
                    key: const PageStorageKey('recommend-tab-all'),
                    child: _withTopNavSpace(
                      AllDramasFilterGrid(
                        feedController: widget.feedController,
                        catalogApi: widget.catalogApi,
                        onOpenDrama: _openDrama,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
          if (!widget.videoOnly)
            Positioned(
              top: 0,
              left: 0,
              right: 0,
              child: IgnorePointer(
                child: SizedBox(
                  height: 72,
                  child: DecoratedBox(
                    key: const Key('recommend-top-gradient'),
                    decoration: const BoxDecoration(
                      gradient: LinearGradient(
                        begin: Alignment.topCenter,
                        end: Alignment.bottomCenter,
                        colors: [AppColors.mediaBlack, AppColors.transparent],
                      ),
                    ),
                  ),
                ),
              ),
            ),
          if (!widget.videoOnly)
            Positioned(
              top: 0,
              left: 0,
              right: 0,
              child: SafeArea(
                bottom: false,
                child: RecommendTopNav(
                  selected: _tab,
                  onVideo: _tab == RecommendInnerTab.feed,
                  onSelected: _selectTab,
                  onSearch: _handleSearch,
                ),
              ),
            ),
        ],
      ),
    );
  }

  Widget _recommendFeed(BuildContext context) {
    final dramas = widget.feedController.dramas;
    if (dramas.isEmpty) {
      final l10n = AppLocalizations.of(context)!;
      if (widget.feedController.loadingFirstPage) {
        return const _RecommendFeedSkeleton();
      }
      return ColoredBox(
        color: AppColors.mediaBlack,
        child: EmptyState(
          key: const Key('recommend-feed-empty'),
          icon: Icons.movie_outlined,
          title: l10n.noStories,
          actionLabel: l10n.retry,
          onAction: () => unawaited(widget.feedController.refreshCurrent()),
        ),
      );
    }
    return PlayerPage(
      key: const Key('recommend-feed-player'),
      homeMode: true,
      embedded: true,
      active: widget.active && _tab == RecommendInnerTab.feed,
      showHomeFeedHeader: false,
      drama: dramas.first,
      initialIndex: 0,
      feedDramas: dramas,
      feedChannel: widget.feedController.channel,
      onOpenFullPlayer: (drama, episode) =>
          _openDrama(drama, episodeId: episode.id),
      onRefreshFeed: widget.feedController.refreshCurrent,
      onLoadMore: widget.feedController.loadMore,
      onImmersiveChanged: widget.onImmersiveChanged,
      scrubCancelRequest: _scrubCancelRequest,
    );
  }

  PlaylistController? _watchPlaylists(BuildContext context) {
    try {
      return context.watch<PlaylistController>();
    } on ProviderNotFoundException {
      return null;
    }
  }

  PlaylistController? _readPlaylists() {
    try {
      return context.read<PlaylistController>();
    } on ProviderNotFoundException {
      return null;
    }
  }

  Widget _recommendPlaylists(CategoryController categories) {
    return DecoratedBox(
      key: const Key('recommend-playlist-surface'),
      decoration: const BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.topCenter,
          end: Alignment.bottomCenter,
          colors: [
            AppColors.mineGradientTop,
            AppColors.mineGradientMiddle,
            AppColors.mineGradientBottom,
          ],
          stops: [0, 0.4, 0.75],
        ),
      ),
      child: Stack(
        fit: StackFit.expand,
        children: [
          const DecoratedBox(
            key: Key('recommend-playlist-glow'),
            decoration: BoxDecoration(
              gradient: RadialGradient(
                center: Alignment(0, -0.95),
                radius: 0.9,
                colors: [
                  AppColors.recommendPlaylistGlow,
                  AppColors.transparent,
                ],
              ),
            ),
          ),
          _withTopNavSpace(
            RecommendSectionsView(
              feedController: widget.feedController,
              categories: categories,
              onOpenDrama: _openDrama,
              onMore: _handleMore,
              playlists: _watchPlaylists(context),
              onOpenPlaylist: _openPlaylist,
            ),
          ),
        ],
      ),
    );
  }

  void _selectTab(RecommendInnerTab tab) {
    setState(() {
      _tab = tab;
      _scrubCancelRequest++;
    });
    if (_pageController.hasClients) {
      unawaited(
        _pageController.animateToPage(
          tab.index,
          duration: const Duration(milliseconds: 220),
          curve: Curves.easeOut,
        ),
      );
    }
  }

  void _onPageChanged(int index) {
    final next = RecommendInnerTab.values[index];
    if (next == _tab) return;
    setState(() {
      _tab = next;
      _scrubCancelRequest++;
    });
  }

  void _handleSearch() {
    setState(() => _scrubCancelRequest++);
    widget.onSearch();
  }

  Widget _withTopNavSpace(Widget child) {
    return SafeArea(
      bottom: false,
      child: Padding(
        padding: const EdgeInsets.only(top: RecommendTopNav.height),
        child: child,
      ),
    );
  }

  Future<void> _openPlaylist(PlaylistDetail playlist) async {
    final controller = _readPlaylists();
    const pageSize = CatalogApi.playlistDramaPageSize;
    final fresh = controller == null
        ? playlist
        : await controller.detail(playlist.id, pageSize: pageSize);
    if (!mounted) return;
    final shown = fresh.dramas.isEmpty && playlist.dramas.isNotEmpty
        ? playlist
        : fresh;
    await Navigator.of(context).push<void>(
      MaterialPageRoute<void>(
        builder: (_) => PlaylistDetailPage(
          title: shown.name,
          subtitle: shown.description,
          source: shown,
          dramas: shown.dramas,
          dramaCount: shown.dramaCount,
          loadPage: controller == null
              ? null
              : (pageIndex) => controller.detail(
                  playlist.id,
                  pageIndex: pageIndex,
                  pageSize: pageSize,
                ),
        ),
      ),
    );
  }

  void _handleMore(RecommendSectionKind section) {
    final l10n = AppLocalizations.of(context)!;
    final copy = _sectionCopy(l10n, section);
    Navigator.of(context).push<void>(
      MaterialPageRoute<void>(
        builder: (_) => PlaylistDetailPage(
          title: copy.$1,
          subtitle: copy.$2,
          dramas: recommendSectionDramas(
            kind: section,
            source: widget.feedController.dramas,
            categories: context.read<CategoryController>(),
          ),
        ),
      ),
    );
  }

  (String, String) _sectionCopy(
    AppLocalizations l10n,
    RecommendSectionKind section,
  ) {
    return switch (section) {
      RecommendSectionKind.hits => (
        l10n.weeklyHitsTitle,
        l10n.weeklyHitsSubtitle,
      ),
      RecommendSectionKind.newReleases => (
        l10n.weeklyNewTitle,
        l10n.weeklyNewSubtitle,
      ),
      RecommendSectionKind.costume => (
        l10n.costumeAwardsTitle,
        l10n.costumeAwardsSubtitle,
      ),
    };
  }

  Future<void> _openDrama(Drama drama, {String? episodeId}) async {
    await playDramaFromCatalog(context, drama, episodeId: episodeId);
  }
}

class _RecommendFeedSkeleton extends StatelessWidget {
  const _RecommendFeedSkeleton();

  @override
  Widget build(BuildContext context) {
    return const ColoredBox(
      key: Key('recommend-feed-skeleton'),
      color: AppColors.mediaBlack,
      child: Stack(
        children: [
          Center(
            child: SizedBox(
              width: 132,
              height: 176,
              child: DecoratedBox(
                decoration: BoxDecoration(
                  color: AppColors.skeletonSurface,
                  borderRadius: BorderRadius.all(Radius.circular(12)),
                ),
              ),
            ),
          ),
          Positioned(
            left: 14,
            right: 72,
            bottom: 42,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                _SkeletonLine(width: 190, height: 18),
                SizedBox(height: 10),
                _SkeletonLine(width: 140, height: 12),
                SizedBox(height: 8),
                _SkeletonLine(width: 220, height: 10),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class _SkeletonLine extends StatelessWidget {
  const _SkeletonLine({required this.width, required this.height});

  final double width;
  final double height;

  @override
  Widget build(BuildContext context) {
    return Container(
      width: width,
      height: height,
      decoration: BoxDecoration(
        color: AppColors.skeletonSurface,
        borderRadius: BorderRadius.circular(6),
      ),
    );
  }
}

class _KeepAliveTab extends StatefulWidget {
  const _KeepAliveTab({super.key, required this.child});

  final Widget child;

  @override
  State<_KeepAliveTab> createState() => _KeepAliveTabState();
}

class _KeepAliveTabState extends State<_KeepAliveTab>
    with AutomaticKeepAliveClientMixin<_KeepAliveTab> {
  @override
  bool get wantKeepAlive => true;

  @override
  Widget build(BuildContext context) {
    super.build(context);
    return widget.child;
  }
}