import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:forui/forui.dart';
import 'package:go_router/go_router.dart';
import 'package:url_launcher/url_launcher.dart';

import '../../core/contracts/script_widget.dart';
import '../../providers/di_providers.dart';
import '../../shared/theme/app_theme.dart';
import '../../shared/utils/user_error_formatter.dart';
import '../../shared/widgets/app_dialog.dart';
import '../../shared/widgets/app_error_state.dart';
import '../../shared/widgets/app_inline_alert.dart';
import '../../shared/widgets/app_loading_ring.dart';
import '../../shared/widgets/app_snack_bar.dart';
import '../../shared/widgets/empty_state.dart';
import '../../shared/widgets/hover_scrollable_row.dart';
import '../../shared/widgets/script_video_card.dart';
import '../detail/widgets/detail_hero_panel.dart';
import '../detail/widgets/detail_immersive_scaffold.dart';
import '../detail/widgets/detail_nav_bar.dart';
import '../player/player_launcher.dart';

const _moduleDetailChromeColor = Color(0xFF08090C);

class ModuleDetailPage extends ConsumerStatefulWidget {
  final String widgetId;
  final ScriptVideoItem seedItem;

  const ModuleDetailPage({
    super.key,
    required this.widgetId,
    required this.seedItem,
  });

  @override
  ConsumerState<ModuleDetailPage> createState() => _ModuleDetailPageState();
}

class _ModuleDetailPageState extends ConsumerState<ModuleDetailPage> {
  final ScrollController _scrollController = ScrollController();
  final ValueNotifier<double> _scrollProgress = ValueNotifier<double>(0);

  late ScriptVideoItem _item;
  bool _loadingDetail = false;
  bool _loadingResource = false;
  String? _detailError;

  @override
  void initState() {
    super.initState();
    _item = widget.seedItem;
    _scrollController.addListener(_updateScrollProgress);
    unawaited(_loadDetail());
  }

  @override
  void dispose() {
    _scrollController.removeListener(_updateScrollProgress);
    _scrollController.dispose();
    _scrollProgress.dispose();
    super.dispose();
  }

  void _updateScrollProgress() {
    _scrollProgress.value = (_scrollController.offset / 180).clamp(0, 1);
  }

  Future<void> _loadDetail() async {
    final link = widget.seedItem.link.trim();
    if (link.isEmpty) return;
    setState(() {
      _loadingDetail = true;
      _detailError = null;
    });
    try {
      final service = await ref.read(scriptWidgetServiceProvider.future);
      final loadedItem = await service.loadDetail(widget.widgetId, link);
      if (!mounted || loadedItem == null) return;
      setState(() {
        _item = _mergeSeedWithDetail(widget.seedItem, loadedItem);
      });
    } catch (error) {
      if (!mounted) return;
      setState(() {
        _detailError = formatUserError(error);
      });
    } finally {
      if (mounted) {
        setState(() {
          _loadingDetail = false;
        });
      }
    }
  }

  Future<void> _playItem(ScriptVideoItem playableItem) async {
    if (_loadingResource) return;
    setState(() {
      _loadingResource = true;
    });
    try {
      final resources = await _resolveResources(playableItem);
      if (!mounted) return;
      if (resources.isEmpty) {
        showAppToast(context, '模块没有返回可播放地址', tone: AppAlertTone.error);
        return;
      }

      final selectedResource = resources.length == 1
          ? resources.first
          : await showAppRawDialog<ScriptVideoResource>(
              context,
              builder: (_) => _ResourcePickerDialog(resources: resources),
            );
      if (selectedResource == null || !mounted) return;
      await _launchResource(playableItem, selectedResource);
    } catch (error) {
      if (mounted) {
        showAppToast(context, formatUserError(error), tone: AppAlertTone.error);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loadingResource = false;
        });
      }
    }
  }

  Future<List<ScriptVideoResource>> _resolveResources(
    ScriptVideoItem playableItem,
  ) async {
    final service = await ref.read(scriptWidgetServiceProvider.future);
    final itemJson = playableItem.toJson();
    final resources = await service
        .loadResources(widget.widgetId, <String, Object?>{
          ...itemJson,
          'item': itemJson,
          'link': playableItem.link,
          'url': playableItem.videoUrl,
          'videoUrl': playableItem.videoUrl,
        });
    if (resources.isNotEmpty) return resources;
    final videoUrl = playableItem.videoUrl.trim();
    if (videoUrl.isEmpty) return const <ScriptVideoResource>[];
    return <ScriptVideoResource>[
      ScriptVideoResource(
        name: playableItem.title,
        url: videoUrl,
        playerType: playableItem.playerType,
      ),
    ];
  }

  Future<void> _launchResource(
    ScriptVideoItem playableItem,
    ScriptVideoResource resource,
  ) async {
    final playerType = resource.playerType.trim().toLowerCase();
    final shouldUseInternalPlayer =
        playerType.isEmpty || playerType == 'app' || playerType == 'internal';
    if (!shouldUseInternalPlayer) {
      final launched = await launchUrl(
        Uri.parse(resource.url),
        mode: LaunchMode.externalApplication,
      );
      if (!launched && mounted) {
        showAppToast(context, '无法打开外部播放器', tone: AppAlertTone.error);
      }
      return;
    }

    final itemIdentity = base64Url
        .encode(
          utf8.encode(
            '${widget.widgetId}:${playableItem.id}:${playableItem.link}',
          ),
        )
        .replaceAll('=', '');
    await PlayerLauncher.launch(
      context: context,
      itemId: 'script-$itemIdentity',
      directStream: DirectStreamLaunchData(
        url: resource.url,
        headers: resource.customHeaders,
        title: playableItem.title.isEmpty ? _item.title : playableItem.title,
        durationSeconds: playableItem.duration,
        seriesName: playableItem == _item ? null : _item.title,
        episode: playableItem.episode,
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final backdropUrl = _firstNonEmpty(<String>[
      _item.backdropPath,
      ..._item.backdropPaths,
      _item.detailPoster,
      _item.posterPath,
      _item.coverUrl,
    ]);
    final posterUrl = _firstNonEmpty(<String>[
      _item.detailPoster,
      _item.posterPath,
      _item.coverUrl,
    ]);

    return Scaffold(
      backgroundColor: _moduleDetailChromeColor,
      body: Stack(
        children: [
          DetailImmersiveScaffold(
            scrollController: _scrollController,
            scrollProgress: _scrollProgress,
            backdropUrl: backdropUrl,
            fallbackUrls: _item.backdropPaths,
            compact: MediaQuery.sizeOf(context).width < 700,
            horizontalPadding: MediaQuery.sizeOf(context).width < 700 ? 18 : 32,
            child: _buildDetailContent(posterUrl),
          ),
          DetailNavBar(
            scrollProgress: _scrollProgress,
            title: _item.title,
            onBack: () => context.pop(),
          ),
        ],
      ),
    );
  }

  Widget _buildDetailContent(String? posterUrl) {
    final metaParts = <String>[
      if (_item.releaseDate.isNotEmpty) _item.releaseDate,
      if (_item.mediaType.isNotEmpty) _item.mediaType,
      if (_item.durationText.isNotEmpty) _item.durationText,
    ];
    final genres = _item.genreItems
        .map((genre) => genre.title)
        .where((title) => title.trim().isNotEmpty)
        .toList();
    if (_item.genreTitle.trim().isNotEmpty) genres.add(_item.genreTitle);

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        DetailHeroPanel(
          title: _item.title.isEmpty ? _item.id : _item.title,
          posterUrl: posterUrl,
          rating: _item.rating,
          metaParts: metaParts,
          genres: genres,
          overview: _item.description,
          actions: _buildPlayActions(),
        ),
        if (_loadingDetail)
          const Padding(
            padding: EdgeInsets.only(top: 28),
            child: Center(child: AppLoadingRing(size: 28)),
          ),
        if (_detailError != null) ...[
          const SizedBox(height: 24),
          AppErrorState(
            compact: true,
            message: _detailError!,
            onRetry: _loadDetail,
          ),
        ],
        if (_item.episodeItems.isNotEmpty || _item.childItems.isNotEmpty) ...[
          const SizedBox(height: 36),
          _EpisodeSection(
            items: _item.episodeItems.isNotEmpty
                ? _item.episodeItems
                : _item.childItems,
            onPlay: _playItem,
          ),
        ],
        if (_item.relatedItems.isNotEmpty) ...[
          const SizedBox(height: 36),
          _RelatedSection(widgetId: widget.widgetId, items: _item.relatedItems),
        ],
        if (!_loadingDetail &&
            _item.episodeItems.isEmpty &&
            _item.childItems.isEmpty &&
            _item.relatedItems.isEmpty &&
            _item.description.trim().isEmpty) ...[
          const SizedBox(height: 32),
          const EmptyState(
            compact: true,
            icon: Icons.info_outline_rounded,
            title: '暂无更多详情',
            message: '仍可尝试解析并播放该条目。',
          ),
        ],
      ],
    );
  }

  Widget _buildPlayActions() {
    return FButton(
      onPress: _loadingResource ? null : () => _playItem(_item),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          if (_loadingResource)
            const AppLoadingRing(size: 17)
          else
            const Icon(Icons.play_arrow_rounded, size: 20),
          const SizedBox(width: 7),
          Text(_loadingResource ? '正在解析' : '播放'),
        ],
      ),
    );
  }
}

class _ResourcePickerDialog extends StatelessWidget {
  final List<ScriptVideoResource> resources;

  const _ResourcePickerDialog({required this.resources});

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(24),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('选择播放线路', style: Theme.of(context).textTheme.titleLarge),
          const SizedBox(height: 8),
          Text(
            '模块返回了 ${resources.length} 条可播放线路。',
            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
              color: context.appTokens.mutedForeground,
            ),
          ),
          const SizedBox(height: 16),
          ConstrainedBox(
            constraints: const BoxConstraints(maxHeight: 420),
            child: ListView.separated(
              shrinkWrap: true,
              itemCount: resources.length,
              separatorBuilder: (_, _) => const Divider(height: 1),
              itemBuilder: (context, index) {
                final resource = resources[index];
                return FItemGroup(
                  children: [
                    FItem(
                      prefix: Container(
                        width: 30,
                        height: 30,
                        alignment: Alignment.center,
                        decoration: BoxDecoration(
                          color: Theme.of(
                            context,
                          ).colorScheme.primary.withValues(alpha: 0.12),
                          borderRadius: BorderRadius.circular(8),
                        ),
                        child: Text(
                          '${index + 1}',
                          style: Theme.of(context).textTheme.labelMedium
                              ?.copyWith(
                                color: Theme.of(context).colorScheme.primary,
                                fontWeight: FontWeight.w700,
                              ),
                        ),
                      ),
                      title: Text(
                        resource.name.isEmpty
                            ? '线路 ${index + 1}'
                            : resource.name,
                      ),
                      subtitle: Text(
                        resource.description.trim().isEmpty
                            ? resource.playerType == 'app'
                                  ? '应用内播放'
                                  : '外部播放'
                            : resource.description,
                      ),
                      suffix: const Icon(Icons.chevron_right_rounded),
                      onPress: () => Navigator.of(context).pop(resource),
                    ),
                  ],
                );
              },
            ),
          ),
          const SizedBox(height: 16),
          Align(
            alignment: Alignment.centerRight,
            child: FButton(
              variant: FButtonVariant.outline,
              onPress: () => Navigator.of(context).pop(),
              child: const Text('取消'),
            ),
          ),
        ],
      ),
    );
  }
}

class _EpisodeSection extends StatelessWidget {
  final List<ScriptVideoItem> items;
  final ValueChanged<ScriptVideoItem> onPlay;

  const _EpisodeSection({required this.items, required this.onPlay});

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          '选集',
          style: Theme.of(
            context,
          ).textTheme.titleLarge?.copyWith(fontWeight: FontWeight.w700),
        ),
        const SizedBox(height: 12),
        Wrap(
          spacing: 10,
          runSpacing: 10,
          children: [
            for (var index = 0; index < items.length; index++)
              FButton(
                variant: FButtonVariant.outline,
                onPress: () => onPlay(items[index]),
                child: Text(
                  items[index].title.isNotEmpty
                      ? items[index].title
                      : '第 ${items[index].episode ?? index + 1} 集',
                ),
              ),
          ],
        ),
      ],
    );
  }
}

class _RelatedSection extends StatelessWidget {
  final String widgetId;
  final List<ScriptVideoItem> items;

  const _RelatedSection({required this.widgetId, required this.items});

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          '相关推荐',
          style: Theme.of(
            context,
          ).textTheme.titleLarge?.copyWith(fontWeight: FontWeight.w700),
        ),
        const SizedBox(height: 12),
        SizedBox(
          height: 250,
          child: HoverScrollableRow(
            builder: (context, scrollController) => ListView.separated(
              controller: scrollController,
              scrollDirection: Axis.horizontal,
              itemCount: items.length,
              separatorBuilder: (_, _) => const SizedBox(width: 14),
              itemBuilder: (context, index) {
                final item = items[index];
                return ScriptVideoCard(
                  item: item,
                  width: 138,
                  textColor: Colors.white,
                  onTap: () => context.push(
                    '/modules/${Uri.encodeComponent(widgetId)}/detail',
                    extra: item,
                  ),
                );
              },
            ),
          ),
        ),
      ],
    );
  }
}

ScriptVideoItem _mergeSeedWithDetail(
  ScriptVideoItem seed,
  ScriptVideoItem detail,
) {
  return detail.copyWith(
    id: detail.id.isEmpty ? seed.id : detail.id,
    title: detail.title.isEmpty ? seed.title : detail.title,
    coverUrl: detail.coverUrl.isEmpty ? seed.coverUrl : detail.coverUrl,
    posterPath: detail.posterPath.isEmpty ? seed.posterPath : detail.posterPath,
    detailPoster: detail.detailPoster.isEmpty
        ? seed.detailPoster
        : detail.detailPoster,
    backdropPath: detail.backdropPath.isEmpty
        ? seed.backdropPath
        : detail.backdropPath,
    link: detail.link.isEmpty ? seed.link : detail.link,
    videoUrl: detail.videoUrl.isEmpty ? seed.videoUrl : detail.videoUrl,
  );
}

String? _firstNonEmpty(List<String> values) {
  for (final value in values) {
    if (value.trim().isNotEmpty) return value;
  }
  return null;
}