public async Task <int> Undo()
{
int count = this.getChangeCount();
count += mergeForwardOld();
this.IsCancelled = true;
// undoAction() just does extra things that may not be covered by the default one
undoAction();
removeFromPlayerActions();
Program.Controller.RemoveActionFromHash(this);
int depth = 0;
// recalculate future values
if (NextAction != null)
{
depth = await NextAction.ReCalculateNext();
}
// Unlink this node
var tempPrev = PrevAction;
var tempNext = NextAction;
if (PrevAction != null)
{
tempPrev.NextAction = tempNext;
}
if (NextAction != null)
{
tempNext.PrevAction = tempPrev;
}
Program.CurLeaderboard.InvokeChange(count);
await deleteMessage();
return(depth);
}