public async Task DeleteLikeAsync(string space, string itemId, string userId) { if (string.IsNullOrEmpty(itemId)) { throw new ArgumentNullException("itemId"); } if (string.IsNullOrEmpty(userId)) { throw new ArgumentNullException("userId"); } // Writing to all required key families const SignalType signal = SignalType.Like; DateTime dateTime = DateTime.UtcNow; var tasks = new List <Task>(); // 1. Item and user relations // Building composite row key to isolated different spaces of statistics string itemRowKey = BuildGlobalId(space, itemId); string userRowKey = BuildGlobalId(space, userId); // Item cumulative counts tasks.Add(_itemCountsRepository.DecLikesAsync(itemRowKey)); // User cumulative counts tasks.Add(_userCountsRepository.DecLikesAsync(userRowKey)); // User likes tasks.Add(Task.Run(() => { // cancel like var deleteTasks = new List <Task>(); var deleteOptions = new UserSignalsInsertDeleteOptions { ItemId = itemId, Signal = signal, UserId = userRowKey, DateTime = dateTime }; deleteTasks.Add(_userSignalsUnorderedRepository.DeleteAsync(deleteOptions)); deleteTasks.Add(_userSignalsRepository.DeleteAsync(deleteOptions)); return(Task.WhenAll(deleteTasks)); })); // Users who liked an item tasks.Add(_itemSignalsRepository.DeleteAsync(new ItemSignalsInsertDeleteOptions { ItemId = itemRowKey, UserId = userId, Signal = signal, DateTime = dateTime })); // 2. Affinity groups IEnumerable <string> affinityGroups = BuildAffinityGroups(dateTime); foreach (string affinityGroup in affinityGroups) { // Building composite row keys to isolated different spaces of statistics string groupId = BuildGlobalId(space, affinityGroup); // Affinity group most liked tasks.Add(Task.Run(async() => { // getting current version of most signaled items AffinityGroupMostSignaledVersionEntity currentVersion = await _affinityGroupMostSignaledVersionRepository.GetAsync(groupId, signal); // getting item counts IEnumerable <AffinityGroupItemCountsEntity> itemCounts = await _affinityGroupItemCountsRepository.GetSequenceAsync(groupId, signal, 1000); // building new version of most liked Dictionary <string, AffinityGroupItemCountsEntity> itemCountsDict = itemCounts.ToDictionary(i => i.ItemId); var insertOptions = new List <AffinityGroupMostSignaledInsertOptions>(); foreach (var i in itemCountsDict) { var insertItem = new AffinityGroupMostSignaledInsertOptions { ItemId = i.Key, Count = i.Value.Count }; if (insertItem.ItemId == itemId) { insertItem.Count = insertItem.Count - 1; } insertOptions.Add(insertItem); } await _affinityGroupMostSignaledRepository.AddAsync(groupId, signal, currentVersion.Version + 1, insertOptions); // decrementing counter of itemId await _affinityGroupItemCountsRepository.DecAsync(groupId, signal, itemId); // incrementing version await _affinityGroupMostSignaledVersionRepository.UpdateAsync(groupId, signal, currentVersion.Version + 1); })); // decrementing affinity group cumulative counts tasks.Add(_affinityGroupCountsRepository.DecAsync(groupId, signal)); } await Task.WhenAll(tasks); }