public void TagPost(int postId, string tag)
{
if (string.IsNullOrEmpty(tag))
{
throw new ArgumentException("Tag name is invalid");
}
var post = _postRepository.AsQuery().FirstOrDefault(p => p.Id == postId);
if (post == null)
{
throw new ArgumentException(string.Format("Specified post (id={0}) does not exist", postId));
}
var tagEntity = _tagRepository.AsQuery().FirstOrDefault(t => t.Name == tag);
// check if a given post is already tagged with tag specified
if (tagEntity == null || !post.Tags.Any(pt => pt.Id == tagEntity.Id))
{
if (tagEntity == null)
{
tagEntity = new Repositories.Entities.Tag
{
Name = tag
};
_tagRepository.Add(tagEntity);
}
post.Tags.Add(tagEntity);
}
}
