public Operation <PlaylistModel> CreatePlaylist(PlaylistModel model)
{
// 1. create a playlist if it doesn't already exist,
// 2. create the tracks if they don't exist
// 3. add tracks to playlisttracks
var operation = Operation.Create(() =>
{
// 1. create a playlist if it doesn't already exist,
var playlist = (from plist in _db.Playlists where plist.Name == model.Name select plist).FirstOrDefault();
if (playlist != null)
{
throw new Exception(string.Format("A playlist named {0} already exists", model.Name));
}
var newPlaylist = model.Create();
_db.Playlists.Add(newPlaylist);
// 2. create the tracks if they don't exist TODO: requires enhancement
var newTracks = model.Tracks.Select(t => t.Create()).ToList();
_db.Tracks.AddRange(newTracks);
// persist changes to database
_db.SaveChanges();
// 3. add tracks to playlisttracks
var playlistTracks = newTracks.Select(t =>
{
var playlistTrack = new PlaylistTrack()
{
PlaylistID = newPlaylist.PlaylistID,
TrackID = t.TrackID
};
return(playlistTrack);
}).ToList();
_db.PlaylistTracks.AddRange(playlistTracks);
// persist changes to database
_db.SaveChanges();
// assign id of newly created playlist to the model
model.PlaylistID = newPlaylist.PlaylistID;
model.Tracks = newTracks.Select(t => { return(new TrackModel(t)); }).ToList();
return(model);
});
return(operation);
}