/// <summary>
///
/// </summary>
/// <param name="source"></param>
/// <param name="interpolation">相对于当前播放项的距离</param>
/// <returns></returns>
public async Task <PlaybackItem> PushToRelative(MusicUi source, int interpolation)
{
if (source.IsPlaying)
{
return(null);
}
if (!DbContext.PlaybackList.Any())
{
await PushGroup(new[] { source });
return(null);
}
MediaPlaybackItem playItem;
try
{
playItem = await source.GetPlaybackItem();
}
catch (Exception)
{
await _manageService.RemoveMusicData(new[] { source });
return(null);
}
var dbPlayList = DbContext.PlaybackList.OrderBy(pi => pi.TrackId).ToList();
int trackId = (int)_playbackList.CurrentItemIndex;
var dbPlayItem = await DbContext.PlaybackList.FirstOrDefaultAsync(pi => pi.MusicFileId == source.Id);
if (dbPlayItem != null)
{
_playbackList.Items.Remove(_playbackList.Items[dbPlayItem.TrackId]);
dbPlayList.Remove(dbPlayItem);
}
int targetId = trackId + interpolation;
if (targetId < 0)
{
targetId = 0;
}
else if (targetId > dbPlayList.Count)
{
targetId = dbPlayList.Count;
}
var newItem = dbPlayItem == null ? new PlaybackItem(source.Id) : dbPlayItem;
dbPlayList.Insert(targetId, newItem);
SetUpTrackId(dbPlayList, targetId);
DbContext.PlaybackList.UpdateRange(dbPlayList);
await DbContext.SaveChangesAsync();
_playbackList.Items.Insert(targetId, playItem);
return(newItem);
}
