Fix drive viewer blockstate improperly updating

src/main/java/ru/dbotthepony/mc/otm/block/entity/BlockEntityDriveViewer.java

@@ -7,11 +7,13 @@ import net.minecraft.network.chat.TranslatableComponent;
 import net.minecraft.world.entity.player.Inventory;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
+import ru.dbotthepony.mc.otm.OverdriveThatMatters;
 import ru.dbotthepony.mc.otm.Registry;
 import ru.dbotthepony.mc.otm.block.BlockDriveViewer;
 import ru.dbotthepony.mc.otm.block.entity.worker.WorkerState;
@@ -30,37 +32,29 @@ public class BlockEntityDriveViewer extends BlockEntityMatteryPowered {
 		return energy.getBatteryLevel().compareTo(MTE_PER_OPERATION) >= 0;
 	}
 
-	@Override
+	private void updateState(Level level) {
-	public void setChanged() {
+		if (isRemoved())
-		super.setChanged();
+			return;
 
-		if (level != null) {
 		var state = getBlockState();
 
-			if (drive_slot.getItem(0).getCapability(MatteryCapability.DRIVE).isPresent()) {
-				if (!getBlockState().getValue(BlockDriveViewer.DRIVE_PRESENT)) {
-					state = state.setValue(BlockDriveViewer.DRIVE_PRESENT, true);
-				}
-			} else {
-				if (getBlockState().getValue(BlockDriveViewer.DRIVE_PRESENT)) {
-					state = state.setValue(BlockDriveViewer.DRIVE_PRESENT, false);
-				}
-			}
-
 		if (drive_slot.getItem(0).getCapability(MatteryCapability.DRIVE).isPresent() && canIOItems()) {
-				if (getBlockState().getValue(WorkerState.SEMI_WORKER_STATE) != WorkerState.WORKING) {
 			state = state.setValue(WorkerState.SEMI_WORKER_STATE, WorkerState.WORKING);
-				}
 		} else {
-				if (getBlockState().getValue(WorkerState.SEMI_WORKER_STATE) != WorkerState.IDLE) {
 			state = state.setValue(WorkerState.SEMI_WORKER_STATE, WorkerState.IDLE);
 		}
-			}
 
 		if (state != getBlockState()) {
 			level.setBlock(getBlockPos(), state, Block.UPDATE_CLIENTS);
 		}
 	}
+
+	@Override
+	public void setChanged() {
+		super.setChanged();
+
+		if (level != null)
+			OverdriveThatMatters.tickOnce(level, this::updateState);
 	}
 
 	public int getIOItemCount(int desired, boolean simulate) {
@@ -85,7 +79,29 @@ public class BlockEntityDriveViewer extends BlockEntityMatteryPowered {
 
 	private static final TranslatableComponent NAME = new TranslatableComponent("block.overdrive_that_matters.drive_viewer");
 
-	public final MatteryContainer drive_slot = new MatteryContainer(this::setChanged, 1);
+	public final MatteryContainer drive_slot = new MatteryContainer(this::setChanged, 1) {
+		@Override
+		public void setChanged(int slot, ItemStack new_state, ItemStack old_state) {
+			super.setChanged(slot, new_state, old_state);
+
+			if (level != null)
+				OverdriveThatMatters.tickOnce(level, (level) -> {
+					if (!isRemoved()) {
+						var state = getBlockState();
+
+						if (new_state.getCapability(MatteryCapability.DRIVE).isPresent()) {
+							state = state.setValue(BlockDriveViewer.DRIVE_PRESENT, true);
+						} else {
+							state = state.setValue(BlockDriveViewer.DRIVE_PRESENT, false);
+						}
+
+						if (state != getBlockState()) {
+							level.setBlock(getBlockPos(), state, Block.UPDATE_CLIENTS);
+						}
+					}
+				});
+		}
+	};
 
 	@Override
 	protected Component getDefaultDisplayName() {

src/main/java/ru/dbotthepony/mc/otm/container/MatteryContainer.java

@@ -284,7 +284,7 @@ public class MatteryContainer implements Container, Iterable<ItemStack> {
 
 	@Override
 	public ItemStack getItem(int slot) {
-		return slots[slot];
+		return slots[slot].isEmpty() ? ItemStack.EMPTY : slots[slot];
 	}
 
 	@Override