Fix shift clicking server error/desync (fixes GH-6)

src/main/java/pm/c7/scout/ScoutMixin.java

@@ -39,7 +39,7 @@ public class ScoutMixin extends AutoMixin {
 			try {
 				transformers.put(name, (ClassNodeTransformer) Class.forName(type.getClassName()).getDeclaredConstructor().newInstance());
 			} catch (Exception e) {
-				LOGGER.error("Transformer class for mixin {} not found", name, e);
+				LOGGER.error("[Scout] Transformer class for mixin {} not found", name, e);
 			}
 		}
 		return super.shouldAnnotationSkipMixin(name, an);

src/main/java/pm/c7/scout/mixin/server/DefaultedListMixin.java

@@ -0,0 +1,28 @@
+package pm.c7.scout.mixin.server;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+import net.minecraft.util.collection.DefaultedList;
+import pm.c7.scout.ScoutUtil;
+import pm.c7.scout.server.ScoutUtilServer;
+
+@Environment(EnvType.SERVER)
+@Mixin(DefaultedList.class)
+public class DefaultedListMixin {
+	@Inject(method = "get", at = @At("HEAD"), cancellable = true)
+	public void scout$fixIndexingSlots(int index, CallbackInfoReturnable<Object> cir) {
+		var currentPlayer = ScoutUtilServer.getCurrentPlayer();
+		if (ScoutUtil.isBagSlot(index)) {
+			if (currentPlayer != null) {
+				cir.setReturnValue(ScoutUtil.getBagSlot(index, currentPlayer.playerScreenHandler));
+			} else {
+				cir.setReturnValue(null);
+			}
+		}
+	}
+}

src/main/java/pm/c7/scout/mixin/server/ScreenHandlerMixin.java

@@ -0,0 +1,26 @@
+package pm.c7.scout.mixin.server;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.item.ItemStack;
+import net.minecraft.screen.ScreenHandler;
+import net.minecraft.screen.slot.SlotActionType;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import pm.c7.scout.server.ScoutUtilServer;
+
+@Environment(EnvType.SERVER)
+@Mixin(value = ScreenHandler.class)
+public abstract class ScreenHandlerMixin {
+	@Redirect(method = "internalOnSlotClick", at = @At(value = "INVOKE", target = "Lnet/minecraft/screen/ScreenHandler;quickMove(Lnet/minecraft/entity/player/PlayerEntity;I)Lnet/minecraft/item/ItemStack;"))
+	public ItemStack scout$fixQuickMove(ScreenHandler self, PlayerEntity player, int index, int slotIndex, int button, SlotActionType actionType, PlayerEntity playerAgain) {
+		ScoutUtilServer.setCurrentPlayer(player);
+		ItemStack ret = self.quickMove(player, index);
+		ScoutUtilServer.clearCurrentPlayer();
+
+		return ret;
+	}
+}

src/main/java/pm/c7/scout/server/ScoutUtilServer.java

@@ -0,0 +1,25 @@
+package pm.c7.scout.server;
+
+import org.jetbrains.annotations.Nullable;
+
+import net.minecraft.entity.player.PlayerEntity;
+import pm.c7.scout.ScoutUtil;
+
+public class ScoutUtilServer {
+	private static PlayerEntity currentPlayer = null;
+
+	public static void setCurrentPlayer(PlayerEntity player) {
+		if (currentPlayer != null) {
+			ScoutUtil.LOGGER.warn("[Scout] New player set during existing quick move, expect players getting wrong items!");
+		}
+		currentPlayer = player;
+	}
+
+	public static void clearCurrentPlayer() {
+		currentPlayer = null;
+	}
+
+	public static @Nullable PlayerEntity getCurrentPlayer() {
+		return currentPlayer;
+	}
+}