private void AttemptSwap(InventorySlotUI destination, InventorySlotUI source)
{
// Provisionally remove item from both sides.
var removedSourceNumber = source.GetNumber();
var removedSourceItem = source.GetItem();
var removedDestinationNumber = destination.GetNumber();
var removedDestinationItem = destination.GetItem();
source.RemoveItems(removedSourceNumber);
destination.RemoveItems(removedDestinationNumber);
var sourceTakeBackNumber = CalculateTakeBack(removedSourceItem, removedSourceNumber, source, destination);
var destinationTakeBackNumber = CalculateTakeBack(removedDestinationItem, removedDestinationNumber, destination, source);
// Do take backs (if needed)
if (sourceTakeBackNumber > 0)
{
source.AddItems(removedSourceItem, sourceTakeBackNumber);
removedSourceNumber -= sourceTakeBackNumber;
}
if (destinationTakeBackNumber > 0)
{
destination.AddItems(removedDestinationItem, destinationTakeBackNumber);
removedDestinationNumber -= destinationTakeBackNumber;
}
// Abort if we can't do a successful swap
if (source.MaxAcceptable(removedDestinationItem) < removedDestinationNumber ||
destination.MaxAcceptable(removedSourceItem) < removedSourceNumber ||
removedSourceNumber == 0)
{
if (removedDestinationNumber > 0)
{
destination.AddItems(removedDestinationItem, removedDestinationNumber);
}
if (removedSourceNumber > 0)
{
source.AddItems(removedSourceItem, removedSourceNumber);
}
return;
}
// Do swaps
if (removedDestinationNumber > 0)
{
source.AddItems(removedDestinationItem, removedDestinationNumber);
}
if (removedSourceNumber > 0)
{
destination.AddItems(removedSourceItem, removedSourceNumber);
}
}
private bool AttemptSimpleTransfer(InventorySlotUI destination)
{
var draggingItem = startMoveSlot.GetItem();
var draggingNumber = startMoveSlot.GetNumber();
var acceptable = destination.MaxAcceptable(draggingItem);
var toTransfer = Mathf.Min(acceptable, draggingNumber);
if (toTransfer > 0)
{
startMoveSlot.RemoveItems(toTransfer);
destination.AddItems(draggingItem, toTransfer);
return(false);
}
return(true);
}
private int CalculateTakeBack(InventoryItem removedItem, int removedNumber, InventorySlotUI removeSource, InventorySlotUI destination)
{
var takeBackNumber = 0;
var destinationMaxAcceptable = destination.MaxAcceptable(removedItem);
if (destinationMaxAcceptable < removedNumber)
{
takeBackNumber = removedNumber - destinationMaxAcceptable;
var sourceTakeBackAcceptable = removeSource.MaxAcceptable(removedItem);
// Abort and reset
if (sourceTakeBackAcceptable < takeBackNumber)
{
return(0);
}
}
return(takeBackNumber);
}