public async Task DeleteDislikeAsync(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.Dislike;
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.DecDislikesAsync(itemRowKey));
// User cumulative counts
tasks.Add(_userCountsRepository.DecDislikesAsync(userRowKey));
// User dislikes
tasks.Add(Task.Run(() =>
{
// cancel dislike
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 disliked 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);
}
