private void MakeFriends( User first, User second, MongoCollection userCollection )
{
var firstFriend = new Friend( first );
var secondFriend = new Friend( second );
// Add permanently to model without saving
first.Friends.Add( secondFriend );
second.Friends.Add( firstFriend );
// Add atomically to database
userCollection.Update( Query.EQ( IdFieldName, first.Id ),
Update.AddToSet( FriendsFieldName,
secondFriend.ToBsonDocument() ) );
userCollection.Update( Query.EQ( IdFieldName, second.Id ),
Update.AddToSet( FriendsFieldName,
firstFriend.ToBsonDocument() ) );
// Update favorite movie collections for two users
userCollection.Update( Query.EQ( IdFieldName, first.Id ),
Update.AddToSetEachWrapped(
FriendsFavoriteMoviesFieldName,
(IEnumerable<MovieShortDetail>)second.FavoriteMovies ) ); /* We need this explicit type cast because driver
* wrong interpret ICollection and added whole
* collection as one element. */
userCollection.Update( Query.EQ( IdFieldName, second.Id ),
Update.AddToSetEachWrapped(
FriendsFavoriteMoviesFieldName,
(IEnumerable<MovieShortDetail>)first.FavoriteMovies ) );
}