Add ComputerCraft integration to Train Observers

- Emit CC events train_passing & train_passed with the name of the train
  originating these events
- Add CC isTrainPassing() function to check passing train presence
- Add CC getPassingTrainName() function to get the passing train name,
  or nil failing that

src/main/java/com/simibubi/create/compat/computercraft/events/TrainPassEvent.java

@@ -0,0 +1,18 @@
+package com.simibubi.create.compat.computercraft.events;
+
+import org.jetbrains.annotations.NotNull;
+
+
+import com.simibubi.create.content.trains.entity.Train;
+
+public class TrainPassEvent implements ComputerEvent {
+
+	public @NotNull Train train;
+	public boolean passing;
+
+	public TrainPassEvent(@NotNull Train train, boolean passing) {
+		this.train = train;
+		this.passing = passing;
+	}
+
+}

src/main/java/com/simibubi/create/compat/computercraft/implementation/ComputerBehaviour.java

@@ -14,12 +14,14 @@ import com.simibubi.create.compat.computercraft.implementation.peripherals.Speed
 import com.simibubi.create.compat.computercraft.implementation.peripherals.StationPeripheral;
 import com.simibubi.create.compat.computercraft.implementation.peripherals.StressGaugePeripheral;
 import com.simibubi.create.compat.computercraft.implementation.peripherals.SyncedPeripheral;
+import com.simibubi.create.compat.computercraft.implementation.peripherals.TrackObserverPeripheral;
 import com.simibubi.create.content.kinetics.gauge.SpeedGaugeBlockEntity;
 import com.simibubi.create.content.kinetics.gauge.StressGaugeBlockEntity;
 import com.simibubi.create.content.kinetics.speedController.SpeedControllerBlockEntity;
 import com.simibubi.create.content.kinetics.transmission.sequencer.SequencedGearshiftBlockEntity;
 import com.simibubi.create.content.redstone.displayLink.DisplayLinkBlockEntity;
 import com.simibubi.create.content.redstone.nixieTube.NixieTubeBlockEntity;
+import com.simibubi.create.content.trains.observer.TrackObserverBlockEntity;
 import com.simibubi.create.content.trains.signal.SignalBlockEntity;
 import com.simibubi.create.content.trains.station.StationBlockEntity;
 import com.simibubi.create.foundation.blockEntity.SmartBlockEntity;
@@ -61,6 +63,8 @@ public class ComputerBehaviour extends AbstractComputerBehaviour {
 			return () -> new StressGaugePeripheral(sgbe);
 		if (be instanceof StationBlockEntity sbe)
 			return () -> new StationPeripheral(sbe);
+		if (be instanceof TrackObserverBlockEntity tobe)
+			return () -> new TrackObserverPeripheral(tobe);
 
 		throw new IllegalArgumentException("No peripheral available for " + be.getType()
 			.getRegistryName());

src/main/java/com/simibubi/create/compat/computercraft/implementation/peripherals/TrackObserverPeripheral.java

@@ -0,0 +1,45 @@
+package com.simibubi.create.compat.computercraft.implementation.peripherals;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+
+import com.simibubi.create.Create;
+import com.simibubi.create.compat.computercraft.events.ComputerEvent;
+import com.simibubi.create.compat.computercraft.events.TrainPassEvent;
+import com.simibubi.create.content.trains.entity.Train;
+import com.simibubi.create.content.trains.observer.TrackObserverBlockEntity;
+
+import dan200.computercraft.api.lua.LuaFunction;
+
+public class TrackObserverPeripheral extends SyncedPeripheral<TrackObserverBlockEntity> {
+
+	public TrackObserverPeripheral(TrackObserverBlockEntity blockEntity) {
+		super(blockEntity);
+	}
+
+	@LuaFunction
+	public boolean isTrainPassing() {
+		return Create.RAILWAYS.trains.containsKey(blockEntity.passingTrainUUID);
+	}
+
+	@LuaFunction
+	public @Nullable String getPassingTrainName() {
+		Train train = Create.RAILWAYS.trains.get(blockEntity.passingTrainUUID);
+		return train == null ? null : train.name.getString();
+	}
+
+	@Override
+	public void prepareComputerEvent(@NotNull ComputerEvent event) {
+		if (event instanceof TrainPassEvent tpe) {
+			queueEvent(tpe.passing ? "train_passing" : "train_passed", tpe.train.name.getString());
+		}
+	}
+
+	@NotNull
+	@Override
+	public String getType() {
+		return "Create_TrainObserver";
+	}
+
+}

src/main/java/com/simibubi/create/content/trains/observer/TrackObserverBlockEntity.java

@@ -1,11 +1,18 @@
 package com.simibubi.create.content.trains.observer;
 
 import java.util.List;
+import java.util.UUID;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
-import javax.annotation.Nullable;
 
 import com.jozufozu.flywheel.util.transform.TransformStack;
 import com.mojang.blaze3d.vertex.PoseStack;
+import com.simibubi.create.Create;
+import com.simibubi.create.compat.computercraft.AbstractComputerBehaviour;
+import com.simibubi.create.compat.computercraft.ComputerCraftProxy;
+import com.simibubi.create.compat.computercraft.events.TrainPassEvent;
 import com.simibubi.create.content.contraptions.ITransformableBlockEntity;
 import com.simibubi.create.content.contraptions.StructureTransform;
 import com.simibubi.create.content.redstone.displayLink.DisplayLinkBlock;
@@ -18,11 +25,14 @@ import com.simibubi.create.foundation.blockEntity.behaviour.filtering.FilteringB
 import com.simibubi.create.foundation.utility.Lang;
 
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.phys.AABB;
 import net.minecraft.world.phys.Vec3;
+import net.minecraftforge.common.capabilities.Capability;
+import net.minecraftforge.common.util.LazyOptional;
 
 public class TrackObserverBlockEntity extends SmartBlockEntity implements ITransformableBlockEntity {
 
@@ -30,6 +40,9 @@ public class TrackObserverBlockEntity extends SmartBlockEntity implements ITrans
 
 	private FilteringBehaviour filtering;
 
+	public AbstractComputerBehaviour computerBehaviour;
+	public @Nullable UUID passingTrainUUID;
+
 	public TrackObserverBlockEntity(BlockEntityType<?> type, BlockPos pos, BlockState state) {
 		super(type, pos, state);
 	}
@@ -38,6 +51,7 @@ public class TrackObserverBlockEntity extends SmartBlockEntity implements ITrans
 	public void addBehaviours(List<BlockEntityBehaviour> behaviours) {
 		behaviours.add(edgePoint = new TrackTargetingBehaviour<>(this, EdgePointType.OBSERVER));
 		behaviours.add(filtering = createFilter().withCallback(this::onFilterChanged));
+		behaviours.add(computerBehaviour = ComputerCraftProxy.behaviour(this));
 		filtering.setLabel(Lang.translateDirect("logistics.train_observer.cargo_filter"));
 	}
 
@@ -63,6 +77,17 @@ public class TrackObserverBlockEntity extends SmartBlockEntity implements ITrans
 		if (isBlockPowered() == shouldBePowered)
 			return;
 
+		if (observer != null && computerBehaviour.hasAttachedComputer()) {
+			if (shouldBePowered)
+				passingTrainUUID = observer.getCurrentTrain();
+			if (passingTrainUUID != null) {
+				computerBehaviour.prepareComputerEvent(
+						new TrainPassEvent(Create.RAILWAYS.trains.get(passingTrainUUID), shouldBePowered));
+				if (!shouldBePowered)
+					passingTrainUUID = null;
+			}
+		}
+
 		BlockState blockState = getBlockState();
 		if (blockState.hasProperty(TrackObserverBlock.POWERED))
 			level.setBlock(worldPosition, blockState.setValue(TrackObserverBlock.POWERED, shouldBePowered), 3);
@@ -110,4 +135,17 @@ public class TrackObserverBlockEntity extends SmartBlockEntity implements ITrans
 		});
 	}
 
+	@Override
+	public <T> @NotNull LazyOptional<T> getCapability(@NotNull Capability<T> cap, Direction side) {
+		if (computerBehaviour.isPeripheralCap(cap))
+			return computerBehaviour.getPeripheralCapability();
+		return super.getCapability(cap, side);
+	}
+
+	@Override
+	public void invalidateCaps() {
+		super.invalidateCaps();
+		computerBehaviour.removePeripheral();
+	}
+
 }