/// <summary>
/// Checks the subscriptions for the device and removes all tracks still referred to by other playlists from the proposed deletes.
/// </summary>
/// <param name="library">The libray that can be used to access tracks. (for iTunes, the XML library is preferred, COM access is slow for enumeration)</param>
/// <param name="actions">The actions generated by diff.</param>
/// <returns>A subset of actions with all damaging deletes removed.</returns>
public IEnumerable<SyncAction> FixProposedDeletes(iTunesLibrary library, IEnumerable<SyncAction> actions)
{
// We don't have anything to compare to = return the proposed actions as-is.
if (Subscription == null) return actions;
HashSet<string> subscribedTracks = GetSubscribedTracks(library);
// Pick all tracks that are set to be deleted.
HashSet<string> proposedDeletions = new HashSet<string>(
from a in actions
where a.Type == SyncType.Remove
select a.DeviceLocation
);
// Remove all proposed deletions that are still referenced by other playlists
proposedDeletions.ExceptWith(subscribedTracks);
// Create a new list without the excluded deletes
return new List<SyncAction>(
from a in actions
where (a.Type == SyncType.Add) || ((a.Type == SyncType.Remove) && (proposedDeletions.Contains(a.DeviceLocation)))
select a
);
}
static HashSet<string> GetSubscribedTracks(IEnumerable<string> playlists, iTunesLibrary library, string root)
{
HashSet<string> tracks = new HashSet<string>();
foreach (string playlistName in playlists)
{
IPlaylist playlist = library.GetFirstPlaylistByName(playlistName);
if(playlist == null)
{
Log.WarnFormat("Subscribed playlist {0} not found.", playlistName);
continue;
}
foreach (ITrack track in playlist.Tracks)
{
tracks.Add(track.GetPlaylistLine(root));
}
}
return tracks;
}
/// <summary>
/// Compares current subscription to a new subscription and retrieves a list of all tracks that will no longer be referred to by any playlists.
/// </summary>
/// <param name="library">The libray that can be used to access tracks. (for iTunes, the XML library is preferred, COM access is slow for enumeration)</param>
/// <param name="newSubscription">The new subscription request from the client.</param>
/// <returns>A list of all tracks that will no longer be referred to by any playlists.</returns>
public IEnumerable<string> GetGarbageTracks(iTunesLibrary library, ISubscription newSubscription)
{
// We don't have anything to compare to = nothing to clean up.
if ((Subscription == null) ||
(Subscription.Playlists == null) ||
(Subscription.Playlists.Length <= 0)) return new List<string>();
HashSet<string> currentTracks = GetSubscribedTracks(library);
HashSet<string> newTracks = GetSubscribedTracks(newSubscription.Playlists, library, newSubscription.DeviceMediaRoot);
currentTracks.ExceptWith(newTracks);
return currentTracks;
}
/// <summary>
/// Returns a list of all unique tracks in subscribed playlists.
/// </summary>
/// <returns>A list of all unique tracks in subscribed playlists.</returns>
public HashSet<string> GetSubscribedTracks(iTunesLibrary library)
{
return GetSubscribedTracks(Subscription.Playlists, library, Subscription.DeviceMediaRoot);
}
/// <summary>
/// Compares current subscription to a new subscription and retrieves a list of all tracks that will no longer be referred to by any playlists.
/// </summary>
/// <param name="library">The libray that can be used to access tracks. (for iTunes, the XML library is preferred, COM access is slow for enumeration)</param>
/// <param name="newSubscription">The new subscription request from the client.</param>
/// <returns>A list of all tracks that will no longer be referred to by any playlists as SyncActions of type Remove.</returns>
public SyncAction[] GetGarbageActions(iTunesLibrary library, ISubscription newSubscription)
{
// Do some lambda magic...
return GetGarbageTracks(library, newSubscription).Select(
s => new SyncAction {DeviceLocation = s, Type = SyncType.Remove}
).ToArray();
}