public async Task AddRandomSongAsync()
{
var song = await SelectRandomSongAsync().ConfigureAwait(false);
// if for some reason could not find new song to play
// then just add currently playing track to upcoming songs
// (the same logic is implemented in synchronous version as well)
UpcomingSongs.Add(song ?? CurrentSong);
}
public async Task MoveToNextSongAsync()
{
if (SongArchive.Count >= MaxSongs)
{
SongArchive.RemoveAt(0);
}
SongArchive.Add(CurrentSong);
CurrentSong = UpcomingSongs.First();
UpcomingSongs.RemoveAt(0);
await AddRandomSongAsync().ConfigureAwait(false);
}
public async Task RemoveSongAsync(int songId)
{
for (var i = 0; i < MaxSongs; i++)
{
if (UpcomingSongs[i].Id != songId)
{
continue;
}
await AddRandomSongAsync().ConfigureAwait(false);
UpcomingSongs.RemoveAt(i);
return;
}
}
/// <summary>
/// Method removes song by its ID from the list of upcoming songs
/// and adds new randonly selected song to the list (to keep its size constant)
/// </summary>
public void RemoveSong(int songId)
{
for (var i = 0; i < MaxSongs; i++)
{
if (UpcomingSongs[i].Id != songId)
{
continue;
}
UpcomingSongs.RemoveAt(i);
UpcomingSongs.Add(SelectRandomSong());
return;
}
}
public void MoveToPrevSong()
{
if (!SongArchive.Any())
{
return;
}
// shrink list of upcoming songs
UpcomingSongs.Insert(0, CurrentSong);
UpcomingSongs.Remove(UpcomingSongs.Last());
// reassign current song (take last song from archive)
CurrentSong = SongArchive.Last();
// update archive
SongArchive.Remove(SongArchive.Last());
}
public void MoveToNextSong()
{
// update archive
if (SongArchive.Count >= MaxSongs)
{
SongArchive.RemoveAt(0);
}
SongArchive.Add(CurrentSong);
// reassign current song (take first item from list of upcoming songs)
CurrentSong = UpcomingSongs.First();
// update the list of upcoming songs
UpcomingSongs.RemoveAt(0);
AddRandomSong();
}
public void MoveUpcomingSong(int from, int to)
{
if (from == to)
{
return;
}
if (from < 0 || to < 0 || from >= UpcomingSongs.Count || to >= UpcomingSongs.Count)
{
return;
}
var song = UpcomingSongs[from];
UpcomingSongs.Remove(song);
UpcomingSongs.Insert(to, song);
}
/// <summary>
/// Switching to previous song is done synchronously
/// since his operation is very cheap (just recombinate songs in collections)
/// </summary>
public Task MoveToPrevSongAsync()
{
if (SongArchive.Any())
{
// shrink list of upcoming songs
UpcomingSongs.Insert(0, CurrentSong);
UpcomingSongs.Remove(UpcomingSongs.Last());
// reassign current song (take last song from archive)
CurrentSong = SongArchive.Last();
// update archive
SongArchive.Remove(SongArchive.Last());
}
return(Task.CompletedTask);
}
/// <summary>
/// Same as synchronous version but with async calls to EF
/// </summary>
private async Task <Song> SelectRandomSongAsync(int maxAttempts = 15)
{
var attempts = 0;
Song song;
// keep selecting song randomly until the song file is actually present in the file system...
// ...and while it isn't present in archive of recently played songs and upcoming songs
do
{
if (attempts++ == maxAttempts)
{
return(_songSelector.DefaultSong());
}
song = await _songSelector.SelectSongAsync().ConfigureAwait(false);
}while (SongArchive.Any(s => s.Id == song.Id) || // true, if the archive already contains this song
UpcomingSongs.Any(s => s.Id == song.Id) || // true, if it is already in songlist
song.Id == CurrentSong.Id || // true, if it's currently playing
FileLocator.FindSongPath(song) == ""); // true, if the file with this song doesn't exist
return(song);
}
public void AddRandomSong() => UpcomingSongs.Add(SelectRandomSong() ?? CurrentSong);
