Changed method of checking if a computer attached

- After talking with SquidDev from CC: Tweaked I've changed to monitoring IPeripheral#attach and IPeripheral#detach for changes in the number of computers connected to the network, then updating the client using AttachedComputerPacket
- This works with wired full modems, wired cabled modems and directly connected computers
- Added SyncedPeripheralBase and SyncedComputerControllable for TE's and peripherals that want to be aware of attached computers

src/main/java/com/simibubi/create/compat/computercraft/AttachedComputerPacket.java

@@ -0,0 +1,35 @@
+package com.simibubi.create.compat.computercraft;
+
+import com.simibubi.create.foundation.networking.TileEntityDataPacket;
+import com.simibubi.create.foundation.tileEntity.SyncedTileEntity;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.network.FriendlyByteBuf;
+
+public class AttachedComputerPacket extends TileEntityDataPacket<SyncedTileEntity> {
+
+	private final boolean hasAttachedComputer;
+
+	public AttachedComputerPacket(BlockPos tilePos, boolean hasAttachedComputer) {
+		super(tilePos);
+		this.hasAttachedComputer = hasAttachedComputer;
+	}
+
+	public AttachedComputerPacket(FriendlyByteBuf buffer) {
+		super(buffer);
+		this.hasAttachedComputer = buffer.readBoolean();
+	}
+
+	@Override
+	protected void writeData(FriendlyByteBuf buffer) {
+		buffer.writeBoolean(hasAttachedComputer);
+	}
+
+	@Override
+	protected void handlePacket(SyncedTileEntity tile) {
+		if (tile instanceof SyncedComputerControllable computerControllable) {
+			computerControllable.setHasAttachedComputer(hasAttachedComputer);
+		}
+	}
+
+}

src/main/java/com/simibubi/create/compat/computercraft/ComputerControllable.java

@@ -2,14 +2,7 @@ package com.simibubi.create.compat.computercraft;
 
 import org.jetbrains.annotations.NotNull;
 
-import com.simibubi.create.compat.Mods;
-import com.simibubi.create.foundation.utility.Iterate;
-
 import dan200.computercraft.api.peripheral.IPeripheral;
-import net.minecraft.core.Direction;
-import net.minecraft.world.level.block.entity.BlockEntity;
-import net.minecraft.world.level.block.state.BlockState;
-import net.minecraft.world.level.block.state.properties.BooleanProperty;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.capabilities.CapabilityManager;
 import net.minecraftforge.common.capabilities.CapabilityToken;
@@ -24,7 +17,6 @@ public interface ComputerControllable {
 	void setPeripheral(LazyOptional<IPeripheral> peripheral);
 
 	LazyOptional<IPeripheral> getPeripheral();
-
 	default <T> LazyOptional<T> getPeripheralCapability(@NotNull Capability<T> cap) {
 		if (cap == PERIPHERAL_CAPABILITY) {
 			if (getPeripheral() == null || !getPeripheral().isPresent())
@@ -42,22 +34,4 @@ public interface ComputerControllable {
 		}
 	}
 
-	default boolean isComputerControlled(BlockEntity tile) {
-		if (tile.getLevel() == null || !(tile instanceof ComputerControllable))
-			return false;
-
-		for (Direction direction : Iterate.directions) {
-			BlockState state = tile.getLevel().getBlockState(tile.getBlockPos().relative(direction));
-
-			// TODO: Add a check for "cable" wired modem.
-			//  The difficulty comes since the "cable" wired modem uses an enum property instead of a boolean property.
-			//  This could possibly be surpassed with reflection. It would be good to find a more solid solution.
-			if (state.getBlock().equals(Mods.COMPUTERCRAFT.getBlock("wired_modem_full"))) {
-				return state.getOptionalValue(BooleanProperty.create("peripheral")).orElse(false);
-			}
-		}
-
-		return false;
-	}
-
 }

src/main/java/com/simibubi/create/compat/computercraft/SequencedGearshiftPeripheral.java

@@ -11,7 +11,7 @@ import dan200.computercraft.api.lua.IArguments;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.lua.LuaFunction;
 
-public class SequencedGearshiftPeripheral extends PeripheralBase<SequencedGearshiftTileEntity> {
+public class SequencedGearshiftPeripheral extends SyncedPeripheralBase<SequencedGearshiftTileEntity> {
 
 	public SequencedGearshiftPeripheral(SequencedGearshiftTileEntity tile) {
 		super(tile);

src/main/java/com/simibubi/create/compat/computercraft/SyncedComputerControllable.java

@@ -0,0 +1,7 @@
+package com.simibubi.create.compat.computercraft;
+
+public interface SyncedComputerControllable extends ComputerControllable {
+
+	void setHasAttachedComputer(boolean hasAttachedComputer);
+
+}

src/main/java/com/simibubi/create/compat/computercraft/SyncedPeripheralBase.java

@@ -0,0 +1,40 @@
+package com.simibubi.create.compat.computercraft;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.jetbrains.annotations.NotNull;
+
+import com.simibubi.create.foundation.networking.AllPackets;
+
+import dan200.computercraft.api.peripheral.IComputerAccess;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraftforge.network.PacketDistributor;
+
+public abstract class SyncedPeripheralBase<T extends BlockEntity & SyncedComputerControllable> extends PeripheralBase<T> {
+
+	private final AtomicInteger computers = new AtomicInteger();
+
+	public SyncedPeripheralBase(T tile) {
+		super(tile);
+	}
+
+	@Override
+	public void attach(@NotNull IComputerAccess computer) {
+		computers.incrementAndGet();
+		updateTile();
+	}
+
+	@Override
+	public void detach(@NotNull IComputerAccess computer) {
+		computers.decrementAndGet();
+		updateTile();
+	}
+
+	private void updateTile() {
+		boolean hasAttachedComputer = computers.get() > 0;
+
+		tile.setHasAttachedComputer(hasAttachedComputer);
+		AllPackets.channel.send(PacketDistributor.ALL.noArg(), new AttachedComputerPacket(tile.getBlockPos(), hasAttachedComputer));
+	}
+
+}

src/main/java/com/simibubi/create/content/contraptions/relays/advanced/sequencer/ConfigureSequencedGearshiftPacket.java

@@ -35,7 +35,7 @@ public class ConfigureSequencedGearshiftPacket extends TileEntityConfigurationPa
 
 	@Override
 	protected void applySettings(SequencedGearshiftTileEntity te) {
-		if (te.isComputerControlled(te))
+		if (te.hasAttachedComputer)
 			return;
 
 		te.run(-1);

src/main/java/com/simibubi/create/content/contraptions/relays/advanced/sequencer/SequencedGearshiftScreen.java

@@ -29,7 +29,7 @@ public class SequencedGearshiftScreen extends AbstractSimiScreen {
 	private ListTag compareTag;
 	private Vector<Instruction> instructions;
 	private BlockPos pos;
-	private final boolean isComputerControlled;
+	private final boolean hasAttachedComputer;
 
 	private Vector<Vector<ScrollInput>> inputs;
 
@@ -37,7 +37,7 @@ public class SequencedGearshiftScreen extends AbstractSimiScreen {
 		super(Lang.translateDirect("gui.sequenced_gearshift.title"));
 		this.instructions = te.instructions;
 		this.pos = te.getBlockPos();
-		this.isComputerControlled = te.isComputerControlled(te);
+		this.hasAttachedComputer = te.hasAttachedComputer;
 		compareTag = Instruction.serializeAll(instructions);
 	}
 
@@ -51,7 +51,7 @@ public class SequencedGearshiftScreen extends AbstractSimiScreen {
 		int y = guiTop;
 
 		inputs = new Vector<>(5);
-		if (!isComputerControlled) {
+		if (!hasAttachedComputer) {
 			for (int row = 0; row < inputs.capacity(); row++)
 				inputs.add(new Vector<>(3));
 
@@ -138,7 +138,7 @@ public class SequencedGearshiftScreen extends AbstractSimiScreen {
 
 		background.render(ms, x, y, this);
 
-		if (isComputerControlled) {
+		if (hasAttachedComputer) {
 			for (int row = 0; row < instructions.capacity(); row++) {
 				AllGuiTextures toDraw = AllGuiTextures.SEQUENCER_EMPTY;
 				int yOffset = toDraw.height * row;
@@ -183,7 +183,7 @@ public class SequencedGearshiftScreen extends AbstractSimiScreen {
 	}
 
 	public void sendPacket() {
-		if (isComputerControlled)
+		if (hasAttachedComputer)
 			return;
 
 		ListTag serialized = Instruction.serializeAll(instructions);

src/main/java/com/simibubi/create/content/contraptions/relays/advanced/sequencer/SequencedGearshiftTileEntity.java

@@ -5,8 +5,8 @@ import java.util.Vector;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import com.simibubi.create.compat.computercraft.ComputerControllable;
 import com.simibubi.create.compat.computercraft.SequencedGearshiftPeripheral;
+import com.simibubi.create.compat.computercraft.SyncedComputerControllable;
 import com.simibubi.create.content.contraptions.relays.encased.SplitShaftTileEntity;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
@@ -19,7 +19,7 @@ import net.minecraft.world.level.block.state.BlockState;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.util.LazyOptional;
 
-public class SequencedGearshiftTileEntity extends SplitShaftTileEntity implements ComputerControllable {
+public class SequencedGearshiftTileEntity extends SplitShaftTileEntity implements SyncedComputerControllable {
 
 	Vector<Instruction> instructions;
 	int currentInstruction;
@@ -29,6 +29,7 @@ public class SequencedGearshiftTileEntity extends SplitShaftTileEntity implement
 	boolean poweredPreviously;
 
 	LazyOptional<IPeripheral> peripheral;
+	boolean hasAttachedComputer;
 
 	public SequencedGearshiftTileEntity(BlockEntityType<?> type, BlockPos pos, BlockState state) {
 		super(type, pos, state);
@@ -38,6 +39,7 @@ public class SequencedGearshiftTileEntity extends SplitShaftTileEntity implement
 		currentInstructionProgress = 0;
 		timer = 0;
 		poweredPreviously = false;
+		hasAttachedComputer = false;
 	}
 
 	@Override
@@ -82,7 +84,7 @@ public class SequencedGearshiftTileEntity extends SplitShaftTileEntity implement
 	}
 
 	public void onRedstoneUpdate(boolean isPowered, boolean isRunning) {
-		if (isComputerControlled(this))
+		if (hasAttachedComputer)
 			return;
 		if (!poweredPreviously && isPowered)
 			risingFlank();
@@ -197,6 +199,11 @@ public class SequencedGearshiftTileEntity extends SplitShaftTileEntity implement
 		return this.peripheral;
 	}
 
+	@Override
+	public void setHasAttachedComputer(boolean hasAttachedComputer) {
+		this.hasAttachedComputer = hasAttachedComputer;
+	}
+
 	@Override
 	public float getRotationSpeedModifier(Direction face) {
 		if (isVirtual())

src/main/java/com/simibubi/create/foundation/networking/AllPackets.java

@@ -8,6 +8,7 @@ import java.util.function.Function;
 import java.util.function.Supplier;
 
 import com.simibubi.create.Create;
+import com.simibubi.create.compat.computercraft.AttachedComputerPacket;
 import com.simibubi.create.content.contraptions.components.structureMovement.ContraptionBlockChangedPacket;
 import com.simibubi.create.content.contraptions.components.structureMovement.ContraptionDisassemblyPacket;
 import com.simibubi.create.content.contraptions.components.structureMovement.ContraptionRelocationPacket;
@@ -184,7 +185,7 @@ public enum AllPackets {
 	S_TRAIN_PROMPT(TrainPromptPacket.class, TrainPromptPacket::new, PLAY_TO_CLIENT),
 	CONTRAPTION_RELOCATION(ContraptionRelocationPacket.class, ContraptionRelocationPacket::new, PLAY_TO_CLIENT),
 	TRACK_GRAPH_ROLL_CALL(TrackGraphRollCallPacket.class, TrackGraphRollCallPacket::new, PLAY_TO_CLIENT),
-
+	ATTACHED_COMPUTER(AttachedComputerPacket.class, AttachedComputerPacket::new, PLAY_TO_CLIENT),
 	;
 
 	public static final ResourceLocation CHANNEL_NAME = Create.asResource("main");