/// <summary>
/// Gets the playlist specified for the user specified.
/// </summary>
public PlaylistDto GetPlaylistForUser(string username, string playlistName)
{
// Create a new empty playlist object
var playlist = new PlaylistDto {
Username = username, PlaylistName = playlistName
};
// Read the tracks from the database
PreparedStatement prepared =
_session.Prepare("SELECT username, playlist_name, sequence_no, artist, track_name, track_id, genre, track_length_in_seconds " +
"FROM playlist_tracks WHERE username = ? and playlist_name = ?");
BoundStatement bound = prepared.Bind(username, playlistName);
RowSet results = _session.Execute(bound);
foreach (Row row in results.GetRows())
{
PlaylistTrackDto track = MapRowToPlaylistTrack(row);
playlist.TrackList.Add(track);
// Pre-aggregate the playlist length in seconds;
playlist.PlaylistLengthInSeconds += track.TrackLengthInSeconds;
}
return(playlist);
}
/// <summary>
/// Deletes a track from a playlist by its sequence number.
/// </summary>
public void DeleteTrackFromPlaylist(PlaylistDto playlist, long sequenceNumber)
{
// Find the track to delete, and delete it from the list
// Find the track that has a matching sequence number
int index = playlist.TrackList.FindIndex(track => track.SequenceNumber == sequenceNumber);
// If the track was not found nothing to do
if (index < 0)
{
return;
}
// Get the track to delete, remove it from the playlist's track list
PlaylistTrackDto playlistTrackToDelete = playlist.TrackList[index];
playlist.TrackList.RemoveAt(index);
// Adjust the playlist length
playlist.PlaylistLengthInSeconds -= playlistTrackToDelete.TrackLengthInSeconds;
// Remove it from the database
PreparedStatement prepared = _session.Prepare("DELETE from playlist_tracks where username = ? and playlist_name = ? and sequence_no = ?");
BoundStatement bound = prepared.Bind(playlist.Username, playlist.PlaylistName,
SequenceToDateTimeOffset(playlistTrackToDelete.SequenceNumber));
_session.Execute(bound);
}
public ActionResult AddTrackToPlaylist(AddTrackToPlaylistModel model)
{
// Grab the PlaylistTrack information from the DB
TrackDto track = _tracksDao.GetTrackById(model.TrackId);
var playlistTrack = new PlaylistTrackDto(track);
var user = (UserDto)Session["user"];
PlaylistDto playlist = _playlistsDao.GetPlaylistForUser(user.Username, model.PlaylistName);
_playlistsDao.AddTrackToPlaylist(playlist, playlistTrack);
return(RedirectToAction("ListTracks", "PlaylistTracks", new { playlistName = model.PlaylistName }));
}
/// <summary>
/// Adds a track to a playlist.
/// </summary>
public void AddTrackToPlaylist(PlaylistDto playlist, PlaylistTrackDto playlistTrack)
{
PreparedStatement prepared = _session.Prepare("INSERT into playlist_tracks" +
" (username, playlist_name, sequence_no, artist, track_name, genre, track_id, track_length_in_seconds) " +
"VALUES (?, ?, ?, ?, ?, ?, ?, ?)");
// Since the playlistTrack sequence is like a time-series, set it's sequence to the current time
// Also update the total time for the playlist locally.
playlistTrack.SequenceNumber = DateTimeOffsetToSequence(DateTimeOffset.Now);
playlist.PlaylistLengthInSeconds += playlistTrack.TrackLengthInSeconds;
// TODO: If the C# driver adds support for binding parameters by name, use that here
BoundStatement bound = prepared.Bind(playlist.Username, playlist.PlaylistName,
SequenceToDateTimeOffset(playlistTrack.SequenceNumber), playlistTrack.Artist,
playlistTrack.TrackName, playlistTrack.Genre, playlistTrack.TrackId,
playlistTrack.TrackLengthInSeconds);
_session.Execute(bound);
playlist.TrackList.Add(playlistTrack);
}
