// 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/services/auth_controller.dart';
import '../../core/data/services/favorite_controller.dart';
import '../../core/formatting/count_format.dart';
import '../../core/formatting/error_text.dart';
import '../../core/platform/haptics.dart';
import '../../core/theme/app_colors.dart';
import '../../core/theme/app_theme.dart';
import '../../core/widgets/auth_gate.dart';
import '../../core/widgets/empty_state.dart';
import '../../core/widgets/remote_image.dart';
import '../../core/widgets/subpage_header.dart';
import '../../l10n/app_localizations.dart';
import '../drama_detail/drama_detail_view.dart';
import 'favorites_binding.dart';

const double _pageHorizontal = 14;
const double _cardRadius = 14;
const double _cardPadding = 10;
const double _coverWidth = 80;
const double _coverHeight = 106;
const double _coverRadius = 10;
const double _removeSize = 28;
const double _removeIconSize = 20;
const double _statsFontSize = 12;
const double _metaFontSize = 11;
const double _titleFontSize = 15;
const int _maxTags = 2;
const double _emptyListHeight = 360;

final RegExp _tagSplitter = RegExp(r'[,/、·]');

/// 独立我的收藏页。
class FavoritesPage extends StatefulWidget {
  const FavoritesPage({super.key});

  @override
  State<FavoritesPage> createState() => _FavoritesPageState();
}

class _FavoritesPageState extends State<FavoritesPage> {
  bool _requested = false;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    final signedIn = context.watch<AuthController>().isSignedIn;
    if (!signedIn) {
      _requested = false;
      return;
    }
    if (_requested) return;
    _requested = true;
    final favorites = context.read<FavoriteController>();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) unawaited(FavoritesBinding().load(favorites));
    });
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final signedIn = context.watch<AuthController>().isSignedIn;
    return Theme(
      data: AppTheme.light(),
      child: Scaffold(
        key: const Key('favorites-page'),
        backgroundColor: AppColors.ink,
        body: SafeArea(
          child: Column(
            children: [
              AppSubpageHeader(
                title: l10n.myFavorites,
                backKey: const Key('favorites-back'),
              ),
              Expanded(
                child: signedIn
                    ? _FavoritesBody(
                        favorites: context.watch<FavoriteController>(),
                      )
                    : const AuthGatePanel(),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _FavoritesBody extends StatelessWidget {
  const _FavoritesBody({required this.favorites});

  final FavoriteController favorites;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    if (favorites.loading && favorites.cards.isEmpty) {
      return const Center(
        child: CircularProgressIndicator(key: Key('favorites-loading')),
      );
    }
    if (favorites.error != null && favorites.cards.isEmpty) {
      return _refreshable(
        favorites,
        children: [
          SizedBox(
            height: _emptyListHeight,
            child: EmptyState(
              key: const Key('favorites-error'),
              icon: Icons.cloud_off_rounded,
              title: errorText(l10n, favorites.error, l10n.favoritesError),
              actionLabel: l10n.retry,
              actionKey: const Key('favorites-retry'),
              onAction: () => unawaited(favorites.load()),
            ),
          ),
        ],
      );
    }
    if (favorites.cards.isEmpty) {
      return _refreshable(
        favorites,
        children: [
          SizedBox(
            height: _emptyListHeight,
            child: EmptyState(
              key: const Key('favorites-empty'),
              icon: Icons.star_border_rounded,
              title: l10n.noFavorites,
              subtitle: l10n.emptyHint,
            ),
          ),
        ],
      );
    }
    return _refreshable(
      favorites,
      children: [
        _summary(l10n),
        for (final (index, drama) in favorites.cards.indexed) ...[
          if (index > 0) const SizedBox(height: 10),
          _FavoriteCard(
            drama: drama,
            isFavorite: favorites.isSaved(drama.id),
            onOpen: () => _open(context, drama),
            onRemove: () => _remove(context, drama.id),
          ),
        ],
      ],
    );
  }

  Widget _refreshable(
    FavoriteController favorites, {
    required List<Widget> children,
  }) {
    return RefreshIndicator(
      color: AppColors.blue,
      backgroundColor: AppColors.card,
      strokeWidth: 2,
      onRefresh: favorites.load,
      child: ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        padding: const EdgeInsets.fromLTRB(
          _pageHorizontal,
          4,
          _pageHorizontal,
          28,
        ),
        children: children,
      ),
    );
  }

  Widget _summary(AppLocalizations l10n) {
    return Align(
      alignment: Alignment.centerLeft,
      child: Text(
        l10n.favoritesCount(favorites.cards.length),
        key: const Key('favorites-count'),
        style: const TextStyle(
          color: AppColors.muted,
          fontSize: _statsFontSize,
        ),
      ),
    );
  }

  Future<void> _open(BuildContext context, Drama drama) async {
    await Navigator.of(context).push<void>(
      MaterialPageRoute(builder: (_) => DramaDetailPage(drama: drama)),
    );
  }

  Future<void> _remove(BuildContext context, String dramaId) async {
    unawaited(context.read<Haptics>().lightImpact());
    final ok = await favorites.remove(dramaId);
    if (ok || !context.mounted) return;
    final l10n = AppLocalizations.of(context)!;
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(l10n.favoriteToggleFailed)));
  }
}

class _FavoriteCard extends StatelessWidget {
  const _FavoriteCard({
    required this.drama,
    required this.isFavorite,
    required this.onOpen,
    required this.onRemove,
  });

  final Drama drama;
  final bool isFavorite;
  final VoidCallback onOpen;
  final VoidCallback onRemove;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final tags = _tags();
    return Container(
      key: ValueKey('favorite-card-${drama.id}'),
      decoration: BoxDecoration(
        color: AppColors.card,
        borderRadius: BorderRadius.circular(_cardRadius),
        boxShadow: const [AppTheme.cardShadow],
      ),
      child: Material(
        color: Colors.transparent,
        borderRadius: BorderRadius.circular(_cardRadius),
        clipBehavior: Clip.antiAlias,
        child: InkWell(
          onTap: onOpen,
          child: Padding(
            padding: const EdgeInsets.all(_cardPadding),
            child: Stack(
              children: [
                Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    ClipRRect(
                      borderRadius: BorderRadius.circular(_coverRadius),
                      child: RemoteImage(
                        drama.posterUrl,
                        key: ValueKey('favorite-cover-${drama.id}'),
                        width: _coverWidth,
                        height: _coverHeight,
                      ),
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      child: Padding(
                        padding: const EdgeInsets.only(
                          right: _removeSize,
                          top: 2,
                        ),
                        child: SizedBox(
                          height: _coverHeight,
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Text(
                                drama.title,
                                key: ValueKey('favorite-title-${drama.id}'),
                                maxLines: 2,
                                overflow: TextOverflow.ellipsis,
                                style: const TextStyle(
                                  color: AppColors.onSurface,
                                  fontSize: _titleFontSize,
                                  fontWeight: FontWeight.w700,
                                ),
                              ),
                              const SizedBox(height: 6),
                              if (tags.isNotEmpty)
                                SizedBox(
                                  height: 20,
                                  child: SingleChildScrollView(
                                    scrollDirection: Axis.horizontal,
                                    physics:
                                        const NeverScrollableScrollPhysics(),
                                    child: Row(
                                      children: [
                                        for (final tag in tags)
                                          Padding(
                                            padding: const EdgeInsets.only(
                                              right: 5,
                                            ),
                                            child: Container(
                                              padding:
                                                  const EdgeInsets.symmetric(
                                                    horizontal: 6,
                                                    vertical: 2,
                                                  ),
                                              decoration: BoxDecoration(
                                                color: AppColors.raised,
                                                borderRadius:
                                                    BorderRadius.circular(6),
                                              ),
                                              child: Text(
                                                tag,
                                                maxLines: 1,
                                                overflow: TextOverflow.ellipsis,
                                                style: const TextStyle(
                                                  color: AppColors.muted,
                                                  fontSize: _metaFontSize,
                                                ),
                                              ),
                                            ),
                                          ),
                                      ],
                                    ),
                                  ),
                                ),
                              const Spacer(),
                              Row(
                                children: [
                                  const Icon(
                                    Icons.local_fire_department_rounded,
                                    color: AppColors.blue,
                                    size: 13,
                                  ),
                                  const SizedBox(width: 3),
                                  Text(
                                    formatInteractionCount(drama.viewCount),
                                    style: const TextStyle(
                                      color: AppColors.muted,
                                      fontSize: _metaFontSize,
                                    ),
                                  ),
                                  const Spacer(),
                                  Text(
                                    l10n.episodeCountLabel(drama.episodeCount),
                                    style: const TextStyle(
                                      color: AppColors.muted,
                                      fontSize: _metaFontSize,
                                    ),
                                  ),
                                ],
                              ),
                            ],
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
                Positioned(
                  top: 0,
                  right: 0,
                  child: SizedBox.square(
                    dimension: _removeSize,
                    child: Material(
                      color: AppColors.raised,
                      shape: const CircleBorder(),
                      clipBehavior: Clip.antiAlias,
                      child: IconButton(
                        key: ValueKey('favorite-remove-${drama.id}'),
                        tooltip: l10n.remove,
                        padding: EdgeInsets.zero,
                        onPressed: onRemove,
                        icon: Icon(
                          isFavorite
                              ? Icons.star_rounded
                              : Icons.star_border_rounded,
                          color: isFavorite ? AppColors.blue : AppColors.muted,
                          size: _removeIconSize,
                        ),
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  List<String> _tags() {
    final values = <String>[];
    for (final source in [drama.genre, drama.category]) {
      for (final part in source.split(_tagSplitter)) {
        final value = part.trim();
        if (value.isNotEmpty && !values.contains(value)) values.add(value);
        if (values.length == _maxTags) return values;
      }
    }
    return values;
  }
}