import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:logging/logging.dart';
import 'package:path/path.dart' as p;
import 'package:result_monad/result_monad.dart';
import 'package:riverpod_annotation/riverpod_annotation.dart';
import 'package:stack_trace/stack_trace.dart';

import '../models/auth/profile.dart';
import '../models/entry_tree_item.dart';
import '../models/exec_error.dart';
import '../models/flattened_tree_item.dart';
import '../models/image_entry.dart';
import '../models/media_attachment_uploads/media_upload_attachment.dart';
import '../models/media_attachment_uploads/new_entry_media_items.dart';
import '../models/networking/paging_data.dart';
import '../models/timeline_entry.dart';
import '../models/timeline_identifiers.dart';
import '../models/visibility.dart';
import '../riverpod_controllers/networking/friendica_remote_file_client_services.dart';
import '../riverpod_controllers/networking/friendica_timelines_client_services.dart';
import '../utils/entry_tree_item_flattening.dart';
import '../utils/media_upload_attachment_helper.dart';
import 'networking/friendica_statuses_client_services.dart';
import 'timeline_entry_services.dart';
import 'timeline_services.dart';

part 'entry_tree_item_services.g.dart';

@Riverpod(keepAlive: true)
Map<String, String> _parentPostIds(Ref ref, Profile profile) {
  return {};
}

@Riverpod(keepAlive: true)
Map<String, _Node> _postNodes(Ref ref, Profile profile) {
  return {};
}

@Riverpod(keepAlive: true)
Map<String, EntryTreeItem> _entryTreeItems(Ref ref, Profile profile) => {};

final _pteLogger = Logger('PostTreeEntryByIdProvider');

@riverpod
Result<EntryTreeItem, ExecError> postTreeEntryById(
    Ref ref, Profile profile, String id) {
  _pteLogger.finest('Building for $id for $profile');
  final isPostNode = ref.watch(_postNodesProvider(profile)).containsKey(id);
  _pteLogger.finest('$id ${isPostNode ? "is a post" : "is a comment"}');
  final postId =
      isPostNode ? id : ref.watch(_parentPostIdsProvider(profile))[id];
  if (postId == null) {
    _pteLogger.finest('No post entry found for $id for $profile');
    return buildErrorResult(
        type: ErrorType.notFound, message: 'No post entry found for id: $id');
  }

  final entry = ref.watch(entryTreeManagerProvider(profile, postId));
  _pteLogger.finest('Result from ETM: $entry');
  return entry;
}

final _etmLogger = Logger('EntryTreeManagerProvider');

@Riverpod(keepAlive: true)
class EntryTreeManager extends _$EntryTreeManager {
  var entryId = '';

  @override
  Result<EntryTreeItem, ExecError> build(Profile profile, String id) {
    _etmLogger.finest('Building for $id for $profile');
    entryId = id;
    final entries = ref.watch(_entryTreeItemsProvider(profile));
    final entry = entries[id];
    if (entry == null) {
      _etmLogger.finest('EntryTreeItem for $id for $profile not found');
      return buildErrorResult(
        type: ErrorType.notFound,
        message: '$id not found',
      );
    }

    _etmLogger.finest('Return entry for $id for $profile');
    return Result.ok(entry);
  }

  Result<EntryTreeItem, ExecError> upsert(EntryTreeItem entry) {
    _etmLogger.finest('Upserting entry for $id for $profile');
    if (entry.id != entryId) {
      return buildErrorResult(
        type: ErrorType.argumentError,
        message:
            'Trying to add an entry to a provider that does not match the id: $id',
      );
    } else {
      ref.read(_entryTreeItemsProvider(profile))[entryId] = entry;
    }

    if (state.isFailure || entry != state.value) {
      state = Result.ok(entry);
    }

    return state;
  }

  void remove() {
    _etmLogger.finest('Removing for $entryId for $profile');
    ref.read(_entryTreeItemsProvider(profile)).remove(entryId);
    ref.invalidateSelf();
  }

  Result<List<FlattenedTreeItem>, ExecError> flattened({
    int level = FlatteningExtensions.baseLevel,
    bool topLevelOnly = false,
  }) {
    if (state.isFailure) {
      return state.errorCast();
    }
    return Result.ok(
      state.value.flatten(
        level: level,
        topLevelOnly: topLevelOnly,
        profile: profile,
        ref: ref,
      ),
    );
  }
}

final _tluLogger = Logger('TimelineUpdater');

@riverpod
class TimelineUpdater extends _$TimelineUpdater {
  @override
  bool build(Profile profile) {
    return true;
  }

  FutureResult<List<EntryTreeItem>, ExecError> updateTimeline(
      TimelineIdentifiers type, int maxId, int sinceId) async {
    _tluLogger.fine(() => 'Updating timeline');

    final itemsResult = await ref.read(timelineProvider(profile,
        type: type,
        page: PagingData(
          maxId: maxId > 0 ? maxId : null,
          sinceId: sinceId > 0 ? sinceId : null,
        )).future);
    if (itemsResult.isFailure) {
      _tluLogger.severe(
        'Error getting timeline: ${itemsResult.error}',
        Trace.current(),
      );
      return itemsResult.errorCast();
    }

    itemsResult.value.sort((t1, t2) => t1.id.compareTo(t2.id));
    final updatedPosts = await _processNewItems(
      itemsResult.value,
      profile.userId,
    );
    return Result.ok(updatedPosts);
  }

  FutureResult<EntryTreeItem, ExecError> refreshStatusChain(String id) async {
    _tluLogger.fine('Refreshing post: $id');
    final postResult =
        ref.read(postOrCommentProvider(profile, id, fullContext: false).future);
    final contextResult =
        ref.read(postOrCommentProvider(profile, id, fullContext: true).future);

    final results = await Future.wait([postResult, contextResult]);
    final hadError = results.map((r) => r.isFailure).reduce((e, s) => e && s);
    final entries = results
        .map((r) => r.getValueOrElse(() => []))
        .expand((i) => i)
        .toList();
    if (entries.isNotEmpty) {
      _cleanupEntriesForId(id);
      await _processNewItems(entries, profile.userId);
    }

    if (hadError) {
      return Result.error(results.firstWhere((r) => r.isFailure).error);
    } else {
      final resultFromProvider =
          ref.read(postTreeEntryByIdProvider(profile, id));
      return resultFromProvider;
    }
  }

  FutureResult<bool, ExecError> deleteEntryById(String id) async {
    _tluLogger.finest('Delete entry: $id');
    final result = await ref
        .read(deleteStatusEntryByIdProvider(profile, id).future)
        .withResult((_) {
      ref.read(entryTreeManagerProvider(profile, id).notifier).remove();
      ref.read(timelineEntryManagerProvider(profile, id).notifier).remove();
      _cleanupEntriesForId(id);
    });

    return result.execErrorCast();
  }

  void _cleanupEntriesForId(String id) {
    final parentPostIds = ref.read(_parentPostIdsProvider(profile));
    final postNodes = ref.read(_postNodesProvider(profile));
    if (parentPostIds.containsKey(id)) {
      final parentPostId = parentPostIds.remove(id);
      final parentPostNode = postNodes[parentPostId];
      ref.invalidate(timelineEntryManagerProvider(profile, parentPostId!));
      parentPostNode?.removeChildById(id);
    }

    if (postNodes.containsKey(id)) {
      postNodes.remove(id);
    }
  }

  Future<List<EntryTreeItem>> _processNewItems(
    List<TimelineEntry> items,
    String currentId,
  ) async {
    _tluLogger.fine('Processing new items: ${items.map((e) => e.id).toList()}');
    items.sort((i1, i2) => int.parse(i1.id).compareTo(int.parse(i2.id)));
    final allSeenItems = [...items];
    for (final item in items) {
      _tluLogger.finest('Upserting entry for ${item.id}');
      ref
          .read(timelineEntryManagerProvider(profile, item.id).notifier)
          .upsert(item);
    }

    final orphans = <TimelineEntry>[];
    for (final item in items) {
      if (item.parentId.isEmpty) {
        continue;
      }
      ref.read(timelineEntryManagerProvider(profile, item.parentId)).match(
          onSuccess: (parent) {
        if (parent.parentId.isEmpty) {
          ref.read(_parentPostIdsProvider(profile))[item.id] = parent.id;
        }
      }, onError: (_) {
        orphans.add(item);
      });
    }
    for (final o in orphans) {
      await ref
          .read(postOrCommentProvider(profile, o.id, fullContext: true).future)
          .andThenSuccessAsync((items) async {
        final parentPostId = items.firstWhere((e) => e.parentId.isEmpty).id;
        ref.read(_parentPostIdsProvider(profile))[o.id] = parentPostId;
        allSeenItems.addAll(items);
        for (final item in items) {
          ref
              .read(timelineEntryManagerProvider(profile, item.id).notifier)
              .upsert(item);
          ref.read(_parentPostIdsProvider(profile))[item.id] = parentPostId;
        }
      });
    }

    allSeenItems.sort((i1, i2) {
      if (i1.parentId.isEmpty && i2.parentId.isNotEmpty) {
        return -1;
      }

      if (i2.parentId.isEmpty && i1.parentId.isNotEmpty) {
        return 1;
      }

      return int.parse(i1.id).compareTo(int.parse(i2.id));
    });
    final postNodesToReturn = <_Node>{};
    var lastCount = 0;
    final postNodes = ref.read(_postNodesProvider(profile));
    final parentPostIds = ref.read(_parentPostIdsProvider(profile));
    while (allSeenItems.isNotEmpty) {
      final seenItemsCopy = [...allSeenItems];
      for (final item in seenItemsCopy) {
        if (item.parentId.isEmpty) {
          final postNode = postNodes.putIfAbsent(item.id, () => _Node(item.id));
          postNodesToReturn.add(postNode);
          allSeenItems.remove(item);
        } else {
          final parentParentPostId = postNodes.containsKey(item.parentId)
              ? item.parentId
              : parentPostIds[item.parentId];
          if (postNodes[parentParentPostId] == null) {
            _tluLogger.severe(
              'Error finding parent ${item.parentId} for entry ${item.id}',
              Trace.current(),
            );
            continue;
          }

          final parentPostNode = postNodes[parentParentPostId]!;
          postNodesToReturn.add(parentPostNode);
          parentPostIds[item.id] = parentPostNode.id;
          if (parentPostNode.getChildById(item.id) == null) {
            final newNode = _Node(item.id);
            final injectionNode = parentPostNode.id == item.parentId
                ? parentPostNode
                : parentPostNode.getChildById(item.parentId);
            if (injectionNode == null) {
              continue;
            } else {
              injectionNode.addChild(newNode);
            }
          }
          allSeenItems.remove(item);
        }
      }
      if (allSeenItems.isNotEmpty && allSeenItems.length == lastCount) {
        _tluLogger.severe(
          'Had ${allSeenItems.length} items left over after all iterations',
          Trace.current(),
        );
        break;
      }
      lastCount = allSeenItems.length;
    }

    final updatedPosts = postNodesToReturn
        .map((node) => _nodeToTreeItem(node, currentId))
        .toList();

    _tluLogger.finest('Completed processing new items');
    return updatedPosts;
  }

  EntryTreeItem _nodeToTreeItem(_Node node, String currentId) {
    final childenEntries = <String>[];
    for (final c in node.children) {
      childenEntries.add(c.id);
      _nodeToTreeItem(c, currentId);
    }
    final entryId = node.id;
    final isMine = ref
            .read(timelineEntryManagerProvider(profile, entryId))
            .fold(onSuccess: (t) => t.authorId, onError: (_) => '') ==
        currentId;
    final rval = EntryTreeItem(
      entryId,
      isMine: isMine,
      initialChildren: childenEntries,
    );

    ref.read(entryTreeManagerProvider(profile, node.id).notifier).upsert(rval);
    return rval;
  }
}

final _swLogger = Logger('StatusWriter');

@riverpod
class StatusWriter extends _$StatusWriter {
  @override
  bool build(Profile profile) {
    return true;
  }

  FutureResult<TimelineEntry, ExecError> createNewStatus(
    Profile profile,
    String text, {
    String spoilerText = '',
    String inReplyToId = '',
    required NewEntryMediaItems mediaItems,
    required List<ImageEntry> existingMediaItems,
    required Visibility visibility,
  }) async {
    _swLogger.info('Creating new post: $text');
    final mediaIds = existingMediaItems.map((m) => m.scales.first.id).toList();
    for (final item in mediaItems.attachments) {
      if (item.isExistingServerItem) {
        continue;
      }

      final result = await _uploadMediaItems(
              profile, item, mediaItems.albumName, visibility)
          .withResult((newId) => mediaIds.add(newId));

      if (result.isFailure) {
        return Result.error(ExecError(
            type: ErrorType.localError,
            message: 'Error uploading image: ${result.error}'));
      }
    }

    final result = await ref
        .read(createNewStatusProvider(profile,
                text: text,
                spoilerText: spoilerText,
                inReplyToId: inReplyToId,
                mediaIds: mediaIds,
                visibility: visibility)
            .future)
        .withResultAsync((item) async {
          ref
              .read(timelineEntryManagerProvider(profile, item.id).notifier)
              .upsert(item);
        })
        .withResultAsync((item) async {
          if (inReplyToId.isNotEmpty) {
            late final String rootPostId;
            if (ref
                .read(_postNodesProvider(profile))
                .containsKey(inReplyToId)) {
              rootPostId = inReplyToId;
            } else {
              rootPostId =
                  ref.read(_parentPostIdsProvider(profile))[inReplyToId]!;
            }
            await ref
                .read(timelineUpdaterProvider(profile).notifier)
                .refreshStatusChain(rootPostId);
          }
        })
        .withResultAsync((item) async {
          await ref
              .read(timelineMaintainerProvider(profile).notifier)
              .loadNewerForPersonalTimelines();
        })
        .withResult((status) => _swLogger.finest('${status.id} status created'))
        .withError((error) => _swLogger.finest('Error creating post: $error'));

    return result.execErrorCast();
  }

  FutureResult<TimelineEntry, ExecError> editStatus(
    Profile profile,
    String statusId,
    String text, {
    String spoilerText = '',
    required NewEntryMediaItems mediaItems,
    required List<ImageEntry> existingMediaItems,
    required Visibility newMediaItemVisibility,
  }) async {
    _swLogger.info('Editing post: $text');
    final mediaIds = existingMediaItems
        .map((m) => m.scales.isEmpty ? m.id : m.scales.first.id)
        .toList();
    for (final item in mediaItems.attachments) {
      if (item.isExistingServerItem) {
        continue;
      }

      final result = await _uploadMediaItems(
              profile, item, mediaItems.albumName, newMediaItemVisibility)
          .withResult((newId) => mediaIds.add(newId));

      if (result.isFailure) {
        return Result.error(ExecError(
            type: ErrorType.localError,
            message: 'Error uploading image: ${result.error}'));
      }
    }

    final result = await ref
        .read(editStatusProvider(profile,
                id: statusId,
                text: text,
                spoilerText: spoilerText,
                mediaIds: mediaIds)
            .future)
        .withResult((item) async {
          ref
              .read(timelineEntryManagerProvider(profile, item.id).notifier)
              .upsert(item);
        })
        .withResult((item) async {
          final inReplyToId = item.parentId;
          if (inReplyToId.isNotEmpty) {
            late final String rootPostId;
            if (ref
                .read(_postNodesProvider(profile))
                .containsKey(inReplyToId)) {
              rootPostId = inReplyToId;
            } else {
              rootPostId =
                  ref.read(_parentPostIdsProvider(profile))[inReplyToId]!;
            }
            await ref
                .read(timelineUpdaterProvider(profile).notifier)
                .refreshStatusChain(rootPostId);
          }
        })
        .withResult((status) => _swLogger.finest('${status.id} status created'))
        .withError((error) => _swLogger.finest('Error creating post: $error'));

    return result.execErrorCast();
  }

  FutureResult<String, ExecError> _uploadMediaItems(
    Profile profile,
    MediaUploadAttachment item,
    String albumName,
    Visibility visibility,
  ) async {
    final String extension = p.extension(item.localFilePath);
    late final String filename;
    if (item.remoteFilename.isEmpty) {
      filename = p.basename(item.localFilePath);
    } else {
      if (item.remoteFilename.toLowerCase().endsWith(extension.toLowerCase())) {
        filename = item.remoteFilename;
      } else {
        filename = "${item.remoteFilename}$extension";
      }
    }

    final uploadResult =
        await MediaUploadAttachmentHelper.getUploadableImageBytes(
      item.localFilePath,
    )
            .andThenAsync((imageBytes) async =>
                await ref.read(uploadFileAsAttachmentProvider(
                  profile,
                  bytes: imageBytes,
                  album: albumName,
                  description: item.description,
                  fileName: filename,
                  visibility: visibility,
                ).future))
            .transform((v) => v.scales.first.id);

    return uploadResult.execErrorCast();
  }
}

class _Node {
  final String id;
  final _children = <String, _Node>{};

  List<_Node> get children => _children.values.toList();

  _Node(this.id, {Map<String, _Node>? initialChildren}) {
    if (initialChildren != null) {
      _children.addAll(initialChildren);
    }
  }

  void addChild(_Node node) {
    _children[node.id] = node;
  }

  void removeChildById(String id) {
    if (_children.containsKey(id)) {
      _children.remove(id);
    }

    for (final c in _children.values) {
      c.removeChildById(id);
    }
  }

  _Node? getChildById(String id) {
    if (_children.containsKey(id)) {
      return _children[id]!;
    }

    for (final c in _children.values) {
      final result = c.getChildById(id);
      if (result != null) {
        return result;
      }
    }

    return null;
  }

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is _Node && runtimeType == other.runtimeType && id == other.id;

  @override
  int get hashCode => id.hashCode;
}