public override void SessionLeaving(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
{
// Save state if first event.
if (!InitialStateSet)
{
InitialState = prevState;
InitialStateSet = true;
}
context.SetBuffering(session, false);
if (!context.IsBuffering())
{
if (ResumePlaying)
{
_logger.LogDebug("Session {SessionId} left group {GroupId}, notifying others to resume.", session.Id, context.GroupId.ToString());
// Client, that was buffering, left the group.
var playingState = new PlayingGroupState(LoggerFactory);
context.SetState(playingState);
var unpauseRequest = new UnpauseGroupRequest();
playingState.HandleRequest(unpauseRequest, context, Type, session, cancellationToken);
}
else
{
_logger.LogDebug("Session {SessionId} left group {GroupId}, returning to previous state.", session.Id, context.GroupId.ToString());
// Group is ready, returning to previous state.
var pausedState = new PausedGroupState(LoggerFactory);
context.SetState(pausedState);
}
}
}
public override void HandleRequest(IgnoreWaitGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
{
context.SetIgnoreGroupWait(session, request.IgnoreWait);
if (!context.IsBuffering())
{
_logger.LogDebug("Ignoring session {SessionId}, group {GroupId} is ready.", session.Id, context.GroupId.ToString());
if (ResumePlaying)
{
// Client, that was buffering, stopped following playback.
var playingState = new PlayingGroupState(LoggerFactory);
context.SetState(playingState);
var unpauseRequest = new UnpauseGroupRequest();
playingState.HandleRequest(unpauseRequest, context, Type, session, cancellationToken);
}
else
{
// Group is ready, returning to previous state.
var pausedState = new PausedGroupState(LoggerFactory);
context.SetState(pausedState);
}
}
}
public override void HandleRequest(ReadyGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
{
// Save state if first event.
if (!InitialStateSet)
{
InitialState = prevState;
InitialStateSet = true;
}
// Make sure the client is playing the correct item.
if (!request.PlaylistItemId.Equals(context.PlayQueue.GetPlayingItemPlaylistId()))
{
_logger.LogDebug("Session {SessionId} reported wrong playlist item in group {GroupId}.", session.Id, context.GroupId.ToString());
var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.SetCurrentItem);
var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
context.SendGroupUpdate(session, SyncPlayBroadcastType.CurrentSession, update, cancellationToken);
context.SetBuffering(session, true);
return;
}
// Compute elapsed time between the client reported time and now.
// Elapsed time is used to estimate the client position when playback is unpaused.
// Ideally, the request is received and handled without major delays.
// However, to avoid waiting indefinitely when a client is not reporting a correct time,
// the elapsed time is ignored after a certain threshold.
var currentTime = DateTime.UtcNow;
var elapsedTime = currentTime.Subtract(request.When);
var timeSyncThresholdTicks = TimeSpan.FromMilliseconds(context.TimeSyncOffset).Ticks;
if (Math.Abs(elapsedTime.Ticks) > timeSyncThresholdTicks)
{
_logger.LogWarning("Session {SessionId} is not time syncing properly. Ignoring elapsed time.", session.Id);
elapsedTime = TimeSpan.Zero;
}
// Ignore elapsed time if client is paused.
if (!request.IsPlaying)
{
elapsedTime = TimeSpan.Zero;
}
var requestTicks = context.SanitizePositionTicks(request.PositionTicks);
var clientPosition = TimeSpan.FromTicks(requestTicks) + elapsedTime;
var delayTicks = context.PositionTicks - clientPosition.Ticks;
var maxPlaybackOffsetTicks = TimeSpan.FromMilliseconds(context.MaxPlaybackOffset).Ticks;
_logger.LogDebug("Session {SessionId} is at {PositionTicks} (delay of {Delay} seconds) in group {GroupId}.", session.Id, clientPosition, TimeSpan.FromTicks(delayTicks).TotalSeconds, context.GroupId.ToString());
if (ResumePlaying)
{
// Handle case where session reported as ready but in reality
// it has no clue of the real position nor the playback state.
if (!request.IsPlaying && Math.Abs(delayTicks) > maxPlaybackOffsetTicks)
{
// Session not ready at all.
context.SetBuffering(session, true);
// Correcting session's position.
var command = context.NewSyncPlayCommand(SendCommandType.Seek);
context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
// Notify relevant state change event.
SendGroupStateUpdate(context, request, session, cancellationToken);
_logger.LogWarning("Session {SessionId} got lost in time, correcting.", session.Id);
return;
}
// Session is ready.
context.SetBuffering(session, false);
if (context.IsBuffering())
{
// Others are still buffering, tell this client to pause when ready.
var command = context.NewSyncPlayCommand(SendCommandType.Pause);
command.When = currentTime.AddTicks(delayTicks);
context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
_logger.LogInformation("Session {SessionId} will pause when ready in {Delay} seconds. Group {GroupId} is waiting for all ready events.", session.Id, TimeSpan.FromTicks(delayTicks).TotalSeconds, context.GroupId.ToString());
}
else
{
// If all ready, then start playback.
// Let other clients resume as soon as the buffering client catches up.
if (delayTicks > context.GetHighestPing() * 2 * TimeSpan.TicksPerMillisecond)
{
// Client that was buffering is recovering, notifying others to resume.
context.LastActivity = currentTime.AddTicks(delayTicks);
var command = context.NewSyncPlayCommand(SendCommandType.Unpause);
var filter = SyncPlayBroadcastType.AllExceptCurrentSession;
if (!request.IsPlaying)
{
filter = SyncPlayBroadcastType.AllGroup;
}
context.SendCommand(session, filter, command, cancellationToken);
_logger.LogInformation("Session {SessionId} is recovering, group {GroupId} will resume in {Delay} seconds.", session.Id, context.GroupId.ToString(), TimeSpan.FromTicks(delayTicks).TotalSeconds);
}
else
{
// Client, that was buffering, resumed playback but did not update others in time.
delayTicks = context.GetHighestPing() * 2 * TimeSpan.TicksPerMillisecond;
delayTicks = Math.Max(delayTicks, context.DefaultPing);
context.LastActivity = currentTime.AddTicks(delayTicks);
var command = context.NewSyncPlayCommand(SendCommandType.Unpause);
context.SendCommand(session, SyncPlayBroadcastType.AllGroup, command, cancellationToken);
_logger.LogWarning("Session {SessionId} resumed playback, group {GroupId} has {Delay} seconds to recover.", session.Id, context.GroupId.ToString(), TimeSpan.FromTicks(delayTicks).TotalSeconds);
}
// Change state.
var playingState = new PlayingGroupState(LoggerFactory);
context.SetState(playingState);
playingState.HandleRequest(request, context, Type, session, cancellationToken);
}
}
else
{
// Check that session is really ready, tolerate player imperfections under a certain threshold.
if (Math.Abs(context.PositionTicks - requestTicks) > maxPlaybackOffsetTicks)
{
// Session still not ready.
context.SetBuffering(session, true);
// Session is seeking to wrong position, correcting.
var command = context.NewSyncPlayCommand(SendCommandType.Seek);
context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
// Notify relevant state change event.
SendGroupStateUpdate(context, request, session, cancellationToken);
_logger.LogWarning("Session {SessionId} is seeking to wrong position, correcting.", session.Id);
return;
}
else
{
// Session is ready.
context.SetBuffering(session, false);
}
if (!context.IsBuffering())
{
_logger.LogDebug("Session {SessionId} is ready, group {GroupId} is ready.", session.Id, context.GroupId.ToString());
// Group is ready, returning to previous state.
var pausedState = new PausedGroupState(LoggerFactory);
context.SetState(pausedState);
if (InitialState.Equals(GroupStateType.Playing))
{
// Group went from playing to waiting state and a pause request occured while waiting.
var pauseRequest = new PauseGroupRequest();
pausedState.HandleRequest(pauseRequest, context, Type, session, cancellationToken);
}
else if (InitialState.Equals(GroupStateType.Paused))
{
pausedState.HandleRequest(request, context, Type, session, cancellationToken);
}
}
}
}