// Drag events by nature only matters when they affect the top inventory.
// What you are holding in the cursor is already yours.
// If you drag it into your own inventory you are not really taking anything.
// If you drag into the top inventory however, you may both give and take.
// You "take" by dragging over an existing item (since we don't do any math).
protected static List<Entry<ItemStack, Integer>> getChangesDrag(InventoryDragEvent event) {
// Create
List<Entry<ItemStack, Integer>> ret = new MassiveList<>();
// Fill
final Inventory inventory = event.getInventory();
for (Entry<Integer, ItemStack> entry : event.getNewItems().entrySet()) {
int rawSlot = entry.getKey();
if (InventoryUtil.isBottomInventory(rawSlot, inventory)) continue;
ItemStack take = inventory.getItem(rawSlot);
if (isSomething(take)) ret.add(new SimpleEntry<ItemStack, Integer>(take, +take.getAmount()));
ItemStack give = entry.getValue();
if (isSomething(give)) ret.add(new SimpleEntry<ItemStack, Integer>(give, -give.getAmount()));
}
// Return
return ret;
}
