import 'dart:async';
import 'dart:math';

import 'package:didvan/config/auth_config.dart';
import 'package:didvan/models/content.dart';
import 'package:didvan/models/enums.dart';
import 'package:didvan/models/news_details_data.dart';
import 'package:didvan/models/overview_data.dart';
import 'package:didvan/models/tag.dart';
import 'package:didvan/models/requests/news.dart';
import 'package:didvan/providers/core.dart';
import 'package:didvan/services/content/content_service.dart';
import 'package:didvan/services/network/request.dart';
import 'package:didvan/services/network/request_helper.dart';
import 'package:didvan/services/s3/s3_media_service.dart';

class NewsDetailsState extends CoreProvier {
  final List<NewsDetailsData?> news = [];
  late final int initialIndex;
  late final NewsRequestArgs args;
  String? initialDescription;
  late Timer _trackingTimer;
  int _trackingTimerCounter = 0;
  bool isFetchingNewItem = false;
  final List<int> relatedQueue = [];
  bool _isRequestInProgress = false;

  int _currentIndex = 0;
  int get currentIndex => _currentIndex;
  bool openComments = false;

  NewsDetailsData get currentNews => news[_currentIndex]!;

  Future<void> getNewsDetails(int id, {bool? isForward}) async {
    if (_isRequestInProgress) {
      return;
    }
    _isRequestInProgress = true;

    if (isForward == null) {
      appState = AppState.busy;
    } else {
      isFetchingNewItem = true;
      notifyListeners();
    }

    try {
      if (RequestService.token == null || RequestService.token!.isEmpty) {
        await Future.delayed(const Duration(milliseconds: 500));
        if (RequestService.token == null || RequestService.token!.isEmpty) {
          throw Exception('Token not available');
        }
      }

      final service = RequestService(RequestHelper.newsDetails(id, args));
      await service.httpGet();
      _handleTracking(sendRequest: isForward != null);

      if (service.isSuccess) {
        final result = service.result;
        final newsItem = NewsDetailsData.fromJson(result['news']);

        if (isForward == null && initialDescription != null) {
          newsItem.description = initialDescription;
        }

        if (isForward == null && newsItem.description == null) {
          await _fetchDescriptionFromList(newsItem.id, newsItem);
        }

        if (args.page == 0) {
          news.add(newsItem);
          initialIndex = 0;
          appState = AppState.idle;
          isFetchingNewItem = false;
          _isRequestInProgress = false;
          return;
        }
        NewsDetailsData? prevNews;
        if (result['prevNews'].isNotEmpty) {
          prevNews = NewsDetailsData.fromJson(result['prevNews']);
        }
        NewsDetailsData? nextNews;
        if (result['nextNews'].isNotEmpty) {
          nextNews = NewsDetailsData.fromJson(result['nextNews']);
        }
        if (isForward == null) {
          news.addAll(
              List.generate(max(newsItem.order - 2, 0), (index) => null));
          if (prevNews != null) {
            news.add(prevNews);
          }
          news.add(newsItem);
          if (nextNews != null) {
            news.add(nextNews);
          }
          _currentIndex = initialIndex = newsItem.order - 1;
        } else if (isForward) {
          if (!exists(nextNews) && nextNews != null) {
            news.add(nextNews);
          }
          _currentIndex++;
        } else if (!isForward) {
          if (!exists(prevNews) && prevNews != null) {
            news[_currentIndex - 2] = prevNews;
          }
          _currentIndex--;
        }
        isFetchingNewItem = false;
        // Always fetch related content — the previous
        // `contents.length == 1` gate was a legacy quirk that hid the
        // "مطالب مرتبط" section for almost every news item.
        getRelatedContents();
        appState = AppState.idle;
      } else {
        isFetchingNewItem = false;
        if (isForward == null) {
          appState = AppState.failed;
        } else {
          notifyListeners();
        }
      }
    } catch (e) {
      // ignore: avoid_print
      print('Error fetching news details: $e');
      isFetchingNewItem = false;
      if (isForward == null) {
        appState = AppState.failed;
      }
      notifyListeners();
    } finally {
      _isRequestInProgress = false;
    }
  }

  /// واکشیِ جزئیات از content-service جدید (با uuid) و نمایش در همان
  /// UI خبر. body فرمتِ Editor.js را به بلوک‌های `Content` ترجمه می‌کند تا
  /// `DidvanPageView` بدون تغییر بتواند رندرش کند.
  Future<void> getContentDetail(String uuid) async {
    appState = AppState.busy;
    notifyListeners();
    try {
      // تایمر tracking را dummy تنظیم می‌کنیم تا در dispose خطای
      // LateInitializationError ندهد (timer قدیمی برای API legacy بود).
      _trackingTimer = Timer(const Duration(seconds: 0), () {});

      final res = await ContentService.instance.getContent(uuid);
      if (!res.isSuccess || res.data == null) {
        appState = AppState.failed;
        notifyListeners();
        return;
      }
      final item = res.data!;
      final contents = await _bodyToContents(item.body);

      // اولین audio Content را به‌عنوان podcast صفحه می‌گیریم تا
      // پلیر در بالای صفحه نمایش داده شود.
      String? podcastUrl;
      for (final ct in contents) {
        if (ct.audio != null && ct.audio!.isNotEmpty) {
          podcastUrl = ct.audio;
          break;
        }
      }
      // duration از S3MediaService با audioId/videoId.
      int? podcastDuration;
      if (item.audioId != null) {
        podcastDuration = S3MediaService.instance.durationFor(item.audioId);
      }
      podcastDuration ??= item.mediaDuration;

      news.clear();
      news.add(NewsDetailsData(
        id: item.id.hashCode,
        title: item.title,
        reference: item.author ?? '',
        image: item.coverImage ?? '',
        createdAt: (item.publishedAt ?? item.createdAt)?.toIso8601String() ??
            DateTime.now().toIso8601String(),
        marked: item.isBookmarked,
        liked: item.isLiked,
        likes: item.likeCount,
        comments: 0,
        order: 1,
        tags: item.tagNames
            .where((n) => n.isNotEmpty)
            .map((n) => Tag(id: n.hashCode, label: n))
            .toList(),
        contents: contents,
        description: item.summary,
        // false تا UI placeholder loading نشان دهد. پس از fetch، اگر
        // واقعا چیزی نیامد به true تغییر می‌کند.
        relatedContentsIsEmpty: false,
        podcast: podcastUrl,
        duration: podcastDuration,
        keycloakId: item.id,
      ));
      initialIndex = 0;
      _currentIndex = 0;
      // args قبلاً در news_details.dart initState ست شده است؛ نباید
      // دوباره assign شود (late final).
      appState = AppState.idle;
      notifyListeners();
      // مطالب مرتبط بر اساس تگ‌ها (در پس‌زمینه).
      getRelatedContents();
    } catch (e) {
      // ignore: avoid_print
      print('getContentDetail error: $e');
      appState = AppState.failed;
      notifyListeners();
    }
  }

  /// ترجمه‌ی body فرمتِ Editor.js به `List<Content>`:
  ///   - header / paragraph → text (HTML)
  ///   - image → image با URL signed-شده‌ی S3
  ///   - بقیه‌ی بلوک‌ها (table, chart, ...) به‌شکل ساده به متن یا حذف
  Future<List<Content>> _bodyToContents(dynamic body) async {
    final result = <Content>[];
    if (body is! Map) return result;
    final blocks = body['blocks'];
    if (blocks is! List) return result;
    var order = 0;
    for (final block in blocks) {
      if (block is! Map) continue;
      final type = block['type'];
      final data = block['data'];
      if (data is! Map) continue;
      order++;
      switch (type) {
        case 'header':
          final lvl = (data['level'] as num?)?.toInt() ?? 2;
          final t = (data['text'] ?? '').toString();
          result.add(Content(
              order: order,
              text: '<h$lvl>$t</h$lvl>',
              audio: null,
              video: null,
              image: null,
              largeImage: null,
              caption: null));
          break;
        case 'paragraph':
          final t = (data['text'] ?? '').toString();
          if (t.trim().isEmpty) break;
          result.add(Content(
              order: order,
              text: t.contains('<') ? t : '<p>$t</p>',
              audio: null,
              video: null,
              image: null,
              largeImage: null,
              caption: null));
          break;
        case 'image':
          final id = data['id'];
          if (id is String && id.isNotEmpty) {
            final url = await S3MediaService.instance.resolveUrl(id);
            if (url != null) {
              result.add(Content(
                  order: order,
                  text: null,
                  audio: null,
                  video: null,
                  image: url,
                  largeImage: url,
                  caption: data['caption']?.toString()));
            }
          }
          break;
        case 'mediaLibrary':
        case 'medialibrary':
        case 'media':
          final id = data['id'];
          if (id is String && id.isNotEmpty) {
            final url = await S3MediaService.instance.resolveUrl(id);
            if (url != null) {
              final mime = S3MediaService.instance.mimeFor(id) ?? '';
              final isAudio = mime.startsWith('audio/');
              final isVideo = mime.startsWith('video/');
              final isImage = mime.startsWith('image/');
              result.add(Content(
                  order: order,
                  text: null,
                  audio: isAudio ? url : null,
                  video: isVideo ? url : null,
                  image: isImage ? url : null,
                  largeImage: isImage ? url : null,
                  caption: data['caption']?.toString()));
            }
          }
          break;
        case 'table':
          final rows = data['content'];
          if (rows is List) {
            final sb = StringBuffer('<table border="1" cellpadding="6">');
            for (var i = 0; i < rows.length; i++) {
              final row = rows[i];
              if (row is! List) continue;
              sb.write('<tr>');
              for (final cell in row) {
                final tag = i == 0 ? 'th' : 'td';
                sb.write('<$tag>${cell ?? ''}</$tag>');
              }
              sb.write('</tr>');
            }
            sb.write('</table>');
            result.add(Content(
                order: order,
                text: sb.toString(),
                audio: null,
                video: null,
                image: null,
                largeImage: null,
                caption: null));
          }
          break;
        default:
          // chart / towColumnTool / carouselTool و ... فعلا رد می‌شوند.
          break;
      }
    }
    return result;
  }

  bool exists(NewsDetailsData? newsItem) =>
      news.any((n) => newsItem != null && n != null && n.id == newsItem.id);

  void onCommentsChanged(int count) {
    news.firstWhere((item) => item?.id == currentNews.id)!.comments = count;
    notifyListeners();
  }

  Future<void> _handleTracking({bool sendRequest = true}) async {
    if (!sendRequest) {
      _trackingTimerCounter = 0;
      _trackingTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
        _trackingTimerCounter++;
      });
      return;
    }
    final service = RequestService(
      RequestHelper.tracking(currentNews.id, 'news'),
      body: {
        'sec': _trackingTimerCounter,
      },
    );
    service.put();
    _trackingTimerCounter = 0;
    _trackingTimer.cancel();
  }

  Future<void> _fetchDescriptionFromList(
      int newsId, NewsDetailsData newsItem) async {
    try {
      final service = RequestService(
        RequestHelper.newsOverviews(
          args: const NewsRequestArgs(page: 1),
        ),
      );
      await service.httpGet();

      if (service.isSuccess) {
        final newsList = service.result['news'] as List?;
        if (newsList != null) {
          for (var item in newsList) {
            if (item['id'] == newsId) {
              final newsData = OverviewData.fromJson(item);
              if (newsData.description.isNotEmpty) {
                newsItem.description = newsData.description;
              }
              break;
            }
          }
        }
      }
    } catch (e) {
      // ignore: avoid_print
      print('Error fetching description from list: $e');
    }
  }

  Future<void> getRelatedContents() async {
    if (currentNews.relatedContents.isNotEmpty &&
        currentNews.relatedContentsIsEmpty) {
      return;
    }
    relatedQueue.add(currentNews.id);

    // مسیر جدید: بر اساس نامِ تگ‌ها از content-service.
    if (!AuthConfig.useLegacyApi) {
      final tagNames = currentNews.tags
          .map((t) => t.label)
          .where((l) => l.isNotEmpty)
          .toList();
      if (tagNames.isEmpty) {
        _markRelatedEmpty();
        return;
      }
      final res = await ContentService.instance.getContentsByTagNames(
        tagNames: tagNames,
        page: 1,
        limit: 30,
      );
      if (!res.isSuccess || res.data == null) {
        _markRelatedEmpty();
        return;
      }
      // Backend already filtered by tag name — don't re-filter here.
      // Persian text normalization (Arabic vs Persian YEH, ZWNJ) makes
      // exact string equality unreliable and would drop legitimate matches.
      // Rank by shared-tag count when we can, but keep everything else.
      final tagSet = tagNames.toSet();
      final scored = <MapEntry<int, dynamic>>[];
      for (final c in res.data!.data) {
        if (c.id.hashCode == currentNews.id) continue;
        final shared = c.tagNames.where(tagSet.contains).length;
        scored.add(MapEntry(shared, c));
      }
      scored.sort((a, b) => b.key.compareTo(a.key));
      final target = news.firstWhere((e) => e?.id == currentNews.id);
      if (target == null) return;
      for (final e in scored.take(3)) {
        target.relatedContents.add(OverviewData.fromContentItem(e.value));
      }
      if (target.relatedContents.isEmpty) {
        target.relatedContentsIsEmpty = true;
      }
      notifyListeners();
      return;
    }

    final service = RequestService(RequestHelper.tag(
      ids: currentNews.tags.map((tag) => tag.id).toList(),
      itemId: currentNews.id,
      type: 'news',
    ));
    await service.httpGet();
    if (service.isSuccess) {
      final relateds = service.result['contents'];
      for (var i = 0; i < relateds.length; i++) {
        news
            .where((element) => element != null)
            .firstWhere((element) => element!.id == currentNews.id)!
            .relatedContents
            .add(OverviewData.fromJson(relateds[i]));
      }
      if (relateds.isEmpty) {
        news
            .where((element) => element != null)
            .firstWhere((element) => element!.id == currentNews.id)
            ?.relatedContentsIsEmpty = true;
      }
    } else {
      news
          .where((element) => element != null)
          .firstWhere((element) => element!.id == currentNews.id)
          ?.relatedContentsIsEmpty = true;
    }
    notifyListeners();
  }

  void _markRelatedEmpty() {
    final target = news.firstWhere(
      (e) => e?.id == currentNews.id,
      orElse: () => null,
    );
    if (target != null) target.relatedContentsIsEmpty = true;
    notifyListeners();
  }

  @override
  void dispose() {
    _handleTracking(sendRequest: true);
    _trackingTimer.cancel();
    super.dispose();
  }
}