private async Task <IList <int> > GetCategoryIdsInPostAsync(Post post)
{
var filter = new PostCategoryFilterSpecification(post);
var postCategories = await postsCategoriesRepository.ListAsync(filter);
return(postCategories.Select(pc => pc.CategoryId).ToList());
}
private async Task SyncPostCategories(Post post, IList <int> categoryIds)
{
var current = await GetCategoryIdsInPostAsync(post);
var needRemoveIds = current.Where(i => !categoryIds.Contains(i));
if (!needRemoveIds.IsNullOrEmpty())
{
var spec = new PostCategoryFilterSpecification(post, needRemoveIds.ToList());
var removeItems = await postsCategoriesRepository.ListAsync(spec);
postsCategoriesRepository.DeleteRange(removeItems);
}
var needToAdd = categoryIds.Where(i => !current.Contains(i));
if (!needToAdd.IsNullOrEmpty())
{
foreach (var newCategoryId in needToAdd)
{
await postsCategoriesRepository.AddAsync(new PostCategory { PostId = post.Id, CategoryId = newCategoryId });
}
}
}