Add Inventory.payItems() method

src/main/java/emu/grasscutter/game/inventory/Inventory.java

@@ -7,6 +7,7 @@ import java.util.List;
 
 import emu.grasscutter.GameConstants;
 import emu.grasscutter.data.GameData;
+import emu.grasscutter.data.common.ItemParamData;
 import emu.grasscutter.data.def.AvatarCostumeData;
 import emu.grasscutter.data.def.AvatarData;
 import emu.grasscutter.data.def.AvatarFlycloakData;
@@ -256,6 +257,52 @@ public class Inventory implements Iterable<GameItem> {
 					getPlayer().setCrystals(player.getCrystals() + count);
 		}
 	}
+
+	private int getVirtualItemCount(int itemId) {
+		switch (itemId) {
+			case 201:  // Primogem
+				return player.getPrimogems();
+			case 202:  // Mora
+				return player.getMora();
+			case 203:  // Genesis Crystals
+				return player.getCrystals();
+			default:
+				GameItem item = getInventoryTab(ItemType.ITEM_MATERIAL).getItemById(itemId);  // What if we ever want to operate on weapons/relics/furniture? :S
+				return (item == null) ? 0 : item.getCount();
+		}
+	}
+
+	public boolean payItems(Collection<ItemParamData> items) {
+		return payItems(items, null);
+	}
+	
+	public synchronized boolean payItems(Collection<ItemParamData> costItems, ActionReason reason) {
+		// Make sure player has requisite items
+		for (ItemParamData cost : costItems) {
+			if (getVirtualItemCount(cost.getId()) < cost.getCount()) {
+				return false;
+			}
+		}
+		// All costs are satisfied, now remove them all
+		for (ItemParamData cost : costItems) {
+			switch (cost.getId()) {
+				case 201 ->  // Primogem
+					player.setPrimogems(player.getPrimogems() - cost.getCount());
+				case 202 ->  // Mora
+					player.setMora(player.getMora() - cost.getCount());
+				case 203 ->  // Genesis Crystals
+					player.setCrystals(player.getCrystals() - cost.getCount());
+				default ->
+					removeItem(getInventoryTab(ItemType.ITEM_MATERIAL).getItemById(cost.getId()), cost.getCount());
+			}
+		}
+		
+		if (reason != null) {  // Do we need these?
+			// getPlayer().sendPacket(new PacketItemAddHintNotify(changedItems, reason));
+		}
+		// getPlayer().sendPacket(new PacketStoreItemChangeNotify(changedItems));
+		return true;
+	}
 	
 	public void removeItems(List<GameItem> items) {
 		// TODO Bulk delete