Network energy cables (#2493)

src/main/java/techreborn/blockentity/cable/CableBlockEntity.java

@@ -24,7 +24,7 @@
 
 package techreborn.blockentity.cable;
 
-import net.fabricmc.fabric.api.transfer.v1.transaction.Transaction;
+import net.fabricmc.fabric.api.lookup.v1.block.BlockApiCache;
 import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.entity.BlockEntity;
@@ -34,6 +34,7 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NbtCompound;
 import net.minecraft.nbt.NbtHelper;
 import net.minecraft.network.packet.s2c.play.BlockEntityUpdateS2CPacket;
+import net.minecraft.server.world.ServerWorld;
 import net.minecraft.text.LiteralText;
 import net.minecraft.text.Text;
 import net.minecraft.text.TranslatableText;
@@ -49,45 +50,49 @@ import reborncore.common.network.NetworkManager;
 import reborncore.common.powerSystem.PowerSystem;
 import reborncore.common.util.StringUtils;
 import team.reborn.energy.api.EnergyStorage;
-import team.reborn.energy.api.EnergyStorageUtil;
 import team.reborn.energy.api.base.SimpleSidedEnergyContainer;
 import techreborn.blocks.cable.CableBlock;
 import techreborn.init.TRBlockEntities;
 import techreborn.init.TRContent;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
-/**
- * Created by modmuss50 on 19/05/2017.
- */
-
 public class CableBlockEntity extends BlockEntity
 		implements BlockEntityTicker<CableBlockEntity>, IListInfoProvider, IToolDrop {
-	private final SimpleSidedEnergyContainer energyContainer = new SimpleSidedEnergyContainer() {
+	// Can't use SimpleEnergyStorage because the cable type is not available when the BE is constructed.
+	final SimpleSidedEnergyContainer energyContainer = new SimpleSidedEnergyContainer() {
 		@Override
 		public long getCapacity() {
-			return getCableType().transferRate * 4;
+			return getCableType().transferRate * 4L;
 		}
 
 		@Override
-		public long getMaxInsert(@Nullable Direction side) {
-			if (!canAcceptEnergy(side)) {
-				return 0;
-			}
-			return getCableType().transferRate;
+		public long getMaxInsert(Direction side) {
+			if (allowTransfer(side)) return getCableType().transferRate;
+			else return 0;
 		}
 
 		@Override
-		public long getMaxExtract(@Nullable Direction side) {
-			return getCableType().transferRate;
+		public long getMaxExtract(Direction side) {
+			if (allowTransfer(side)) return getCableType().transferRate;
+			else return 0;
 		}
 	};
-	private double energy = 0;
 	private TRContent.Cables cableType = null;
-	private ArrayList<Direction> sendingFace = new ArrayList<>();
 	private BlockState cover = null;
+	long lastTick = 0;
+	// null means that it needs to be re-queried
+	List<CableTarget> targets = null;
+	/**
+	 * Bitmask to prevent input or output into/from the cable when the cable already transferred in the target direction.
+	 * This prevents double transfer rates, and back and forth between two cables.
+	 */
+	int blockedSides = 0;
+	/**
+	 * This is only used during the cable tick, whereas blockedOperations is used between ticks.
+	 */
+	boolean ioBlocked = false;
 
 	public CableBlockEntity(BlockPos pos, BlockState state) {
 		super(TRBlockEntities.CABLE, pos, state);
@@ -98,7 +103,7 @@ public class CableBlockEntity extends BlockEntity
 		this.cableType = type;
 	}
 
-	private TRContent.Cables getCableType() {
+	TRContent.Cables getCableType() {
 		if (cableType != null) {
 			return cableType;
 		}
@@ -113,6 +118,10 @@ public class CableBlockEntity extends BlockEntity
 		return TRContent.Cables.COPPER;
 	}
 
+	private boolean allowTransfer(Direction side) {
+		return !ioBlocked && (blockedSides & (1 << side.ordinal())) == 0;
+	}
+
 	public EnergyStorage getSideEnergyStorage(@Nullable Direction side) {
 		return energyContainer.getSideStorage(side);
 	}
@@ -128,13 +137,6 @@ public class CableBlockEntity extends BlockEntity
 		}
 	}
 
-	public boolean canAcceptEnergy(@Nullable Direction direction) {
-		if (sendingFace.contains(direction)) {
-			return false;
-		}
-		return energyContainer.getCapacity() != getEnergy();
-	}
-
 	public long getEnergy() {
 		return energyContainer.amount;
 	}
@@ -160,7 +162,7 @@ public class CableBlockEntity extends BlockEntity
 	public void readNbt(NbtCompound compound) {
 		super.readNbt(compound);
 		if (compound.contains("energy")) {
-			energy = compound.getDouble("energy");
+			energyContainer.amount = compound.getLong("energy");
 		}
 		if (compound.contains("cover")) {
 			cover = NbtHelper.toBlockState(compound.getCompound("cover"));
@@ -172,13 +174,17 @@ public class CableBlockEntity extends BlockEntity
 	@Override
 	public NbtCompound writeNbt(NbtCompound compound) {
 		super.writeNbt(compound);
-		compound.putDouble("energy", energy);
+		compound.putLong("energy", energyContainer.amount);
 		if (cover != null) {
 			compound.put("cover", NbtHelper.fromBlockState(cover));
 		}
 		return compound;
 	}
 
+	public void neighborUpdate() {
+		targets = null;
+	}
+
 	// Tickable
 	@Override
 	public void tick(World world, BlockPos pos, BlockState state, CableBlockEntity blockEntity2) {
@@ -186,72 +192,7 @@ public class CableBlockEntity extends BlockEntity
 			return;
 		}
 
-		sendingFace.clear();
-
-		if (getEnergy() == 0) {
-			return;
-		}
-
-		ArrayList<EnergyStorage> acceptors = new ArrayList<>();
-		ArrayList<CableBlockEntity> cables = new ArrayList<>();
-
-		for (Direction face : Direction.values()) {
-			BlockPos adjPos = pos.offset(face);
-			BlockEntity blockEntity = world.getBlockEntity(adjPos);
-			EnergyStorage target = EnergyStorage.SIDED.find(world, adjPos, null, blockEntity, face.getOpposite());
-			if (target == null) {
-				continue;
-			}
-
-			if (blockEntity instanceof CableBlockEntity cableBlockEntity) {
-				if (cableBlockEntity.cableType != this.cableType) {
-					continue;
-				}
-				// Only need ones with energy stores less than ours
-				if (cableBlockEntity.getEnergy() < this.getEnergy()) {
-					cables.add(cableBlockEntity);
-				}
-
-
-			} else {
-				try (Transaction transaction = Transaction.openOuter()) {
-					if (target.insert(Long.MAX_VALUE, transaction) > 0) {
-						acceptors.add(target);
-						if (!sendingFace.contains(face)) {
-							sendingFace.add(face);
-						}
-					}
-				}
-			}
-		}
-
-		if (!acceptors.isEmpty()) {
-			Collections.shuffle(acceptors);
-
-			acceptors.forEach(t -> EnergyStorageUtil.move(
-					energyContainer.getSideStorage(null),
-					t,
-					Long.MAX_VALUE,
-					null
-			));
-		}
-
-
-		// Distribute energy between cables (TODO DIRTY FIX, until we game network cables)
-
-		if (!cables.isEmpty()) {
-
-			cables.add(this);
-			long energyTotal = cables.stream().mapToLong(CableBlockEntity::getEnergy).sum();
-			long remainingCount = cables.size();
-
-			for (CableBlockEntity cable : cables) {
-				long newEnergy = energyTotal / remainingCount;
-				cable.setEnergy(newEnergy);
-				energyTotal -= newEnergy;
-				remainingCount--;
-			}
-		}
+		CableTickManager.handleCableTick(this);
 	}
 
 	// IListInfoProvider
@@ -286,4 +227,67 @@ public class CableBlockEntity extends BlockEntity
 	public ItemStack getToolDrop(PlayerEntity playerIn) {
 		return new ItemStack(getCableType().block);
 	}
+
+	void appendTargets(List<OfferedEnergyStorage> targetStorages) {
+		ServerWorld serverWorld = (ServerWorld) world;
+
+		// Update our targets if necessary.
+		if (targets == null) {
+			BlockState newBlockState = getCachedState();
+
+			targets = new ArrayList<>();
+			for (Direction direction : Direction.values()) {
+				boolean foundSomething = false;
+
+				BlockPos adjPos = getPos().offset(direction);
+				BlockEntity adjBe = serverWorld.getBlockEntity(adjPos);
+
+				if (adjBe instanceof CableBlockEntity adjCable && adjCable.getCableType() == getCableType()) {
+					// Make sure cables are not used as regular targets.
+					foundSomething = true;
+				} else if (EnergyStorage.SIDED.find(serverWorld, adjPos, null, adjBe, direction.getOpposite()) != null) {
+					foundSomething = true;
+					targets.add(new CableTarget(
+							direction,
+							BlockApiCache.create(EnergyStorage.SIDED, serverWorld, adjPos)
+					));
+				}
+
+				newBlockState = newBlockState.with(CableBlock.PROPERTY_MAP.get(direction), foundSomething);
+			}
+
+			serverWorld.setBlockState(getPos(), newBlockState);
+		}
+
+		// Fill the list.
+		for (CableTarget target : targets) {
+			EnergyStorage storage = target.find();
+
+			if (storage == null) {
+				// Schedule a rebuild next tick.
+				// This is just a reference change, the iterator remains valid.
+				targets = null;
+			} else {
+				targetStorages.add(new OfferedEnergyStorage(this, target.directionTo, storage));
+			}
+		}
+
+		// Reset blocked sides.
+		blockedSides = 0;
+	}
+
+	private static final class CableTarget {
+		private final Direction directionTo;
+		private final BlockApiCache<EnergyStorage, Direction> cache;
+
+		CableTarget(Direction directionTo, BlockApiCache<EnergyStorage, Direction> cache) {
+			this.directionTo = directionTo;
+			this.cache = cache;
+		}
+
+		@Nullable
+		EnergyStorage find() {
+			return cache.find(directionTo.getOpposite());
+		}
+	}
 }

src/main/java/techreborn/blockentity/cable/CableTickManager.java

@@ -0,0 +1,164 @@
+package techreborn.blockentity.cable;
+
+import net.fabricmc.fabric.api.event.lifecycle.v1.ServerTickEvents;
+import net.fabricmc.fabric.api.transfer.v1.transaction.Transaction;
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import team.reborn.energy.api.EnergyStorage;
+import techreborn.init.TRContent;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.Deque;
+import java.util.List;
+
+@SuppressWarnings("UnstableApiUsage")
+class CableTickManager {
+	private static long tickCounter = 0;
+	private static final List<CableBlockEntity> cableList = new ArrayList<>();
+	private static final List<OfferedEnergyStorage> targetStorages = new ArrayList<>();
+	private static final Deque<CableBlockEntity> bfsQueue = new ArrayDeque<>();
+
+	static void handleCableTick(CableBlockEntity startingCable) {
+		if (!(startingCable.getWorld() instanceof ServerWorld)) throw new IllegalStateException();
+
+		try {
+			gatherCables(startingCable);
+			if (cableList.size() == 0) return;
+
+			// Group all energy into the network.
+			long networkCapacity = 0;
+			long networkAmount = 0;
+
+			for (CableBlockEntity cable : cableList) {
+				networkAmount += cable.energyContainer.amount;
+				networkCapacity += cable.energyContainer.getCapacity();
+
+				// Update cable connections.
+				cable.appendTargets(targetStorages);
+				// Block any cable I/O while we access the network amount directly.
+				// Some things might try to access cables, for example a p2p tunnel pointing back at a cable.
+				// If the cables and the network go out of sync, we risk duping or voiding energy.
+				cable.ioBlocked = true;
+			}
+
+			// Just in case.
+			if (networkAmount > networkCapacity) {
+				networkAmount = networkCapacity;
+			}
+
+			// Pull energy from storages.
+			networkAmount += dispatchTransfer(startingCable.getCableType(), EnergyStorage::extract, networkCapacity - networkAmount);
+			// Push energy into storages.
+			networkAmount -= dispatchTransfer(startingCable.getCableType(), EnergyStorage::insert, networkAmount);
+
+			// Split energy evenly across cables.
+			int cableCount = cableList.size();
+			for (CableBlockEntity cable : cableList) {
+				cable.energyContainer.amount = networkAmount / cableCount;
+				networkAmount -= cable.energyContainer.amount;
+				cableCount--;
+				cable.markDirty();
+				cable.ioBlocked = false;
+			}
+		} finally {
+			cableList.clear();
+			targetStorages.clear();
+			bfsQueue.clear();
+		}
+	}
+
+	private static boolean shouldTickCable(CableBlockEntity current) {
+		// Make sure we only gather and tick each cable once per tick.
+		if (current.lastTick == tickCounter) return false;
+		// Make sure we ignore cables in non-ticking chunks.
+		if (!(current.getWorld() instanceof ServerWorld sw) || !sw.method_37117(current.getPos())) return false;
+
+		return true;
+	}
+
+	/**
+	 * Perform a BFS to gather all connected ticking cables.
+	 */
+	private static void gatherCables(CableBlockEntity start) {
+		if (!shouldTickCable(start)) return;
+
+		bfsQueue.add(start);
+		start.lastTick = tickCounter;
+		cableList.add(start);
+
+		while (!bfsQueue.isEmpty()) {
+			CableBlockEntity current = bfsQueue.removeFirst();
+
+			for (Direction direction : Direction.values()) {
+				BlockPos adjPos = current.getPos().offset(direction);
+
+				if (current.getWorld().getBlockEntity(adjPos) instanceof CableBlockEntity adjCable && current.getCableType() == adjCable.getCableType()) {
+					if (shouldTickCable(adjCable)) {
+						bfsQueue.add(adjCable);
+						adjCable.lastTick = tickCounter;
+						cableList.add(adjCable);
+					}
+				}
+			}
+		}
+	}
+
+	/**
+	 * Perform a transfer operation across a list of targets.
+	 */
+	private static long dispatchTransfer(TRContent.Cables cableType, TransferOperation operation, long maxAmount) {
+		// Build target list.
+		List<SortableStorage> sortedTargets = new ArrayList<>();
+		for (var storage : targetStorages) {
+			sortedTargets.add(new SortableStorage(operation, storage));
+		}
+		// Shuffle for better average transfer.
+		Collections.shuffle(sortedTargets);
+		// Sort by lowest simulation target.
+		sortedTargets.sort(Comparator.comparingLong(sortableStorage -> sortableStorage.simulationResult));
+		// Actually perform the transfer.
+		try (Transaction transaction = Transaction.openOuter()) {
+			long transferredAmount = 0;
+			for (int i = 0; i < sortedTargets.size(); ++i) {
+				SortableStorage target = sortedTargets.get(i);
+				int remainingTargets = sortedTargets.size() - i;
+				long remainingAmount = maxAmount - transferredAmount;
+				// Limit max amount to the cable transfer rate.
+				long targetMaxAmount = Math.min(remainingAmount / remainingTargets, cableType.transferRate);
+
+				long localTransferred = operation.transfer(target.storage.storage, targetMaxAmount, transaction);
+				if (localTransferred > 0) {
+					transferredAmount += localTransferred;
+					// Block duplicate operations.
+					target.storage.afterTransfer();
+				}
+			}
+			transaction.commit();
+			return transferredAmount;
+		}
+	}
+
+	private interface TransferOperation {
+		long transfer(EnergyStorage storage, long maxAmount, Transaction transaction);
+	}
+
+	private static class SortableStorage {
+		private final OfferedEnergyStorage storage;
+		private final long simulationResult;
+
+		SortableStorage(TransferOperation operation, OfferedEnergyStorage storage) {
+			this.storage = storage;
+			try (Transaction tx = Transaction.openOuter()) {
+				this.simulationResult = operation.transfer(storage.storage, Long.MAX_VALUE, tx);
+			}
+		}
+	}
+
+	static {
+		ServerTickEvents.START_SERVER_TICK.register(server -> tickCounter++);
+	}
+}

src/main/java/techreborn/blockentity/cable/OfferedEnergyStorage.java

@@ -0,0 +1,24 @@
+package techreborn.blockentity.cable;
+
+import net.minecraft.util.math.Direction;
+import team.reborn.energy.api.EnergyStorage;
+
+/**
+ * EnergyStorage adjacent to an energy cable, with some additional info.
+ */
+class OfferedEnergyStorage {
+	final CableBlockEntity sourceCable;
+	final Direction direction;
+	final EnergyStorage storage;
+
+	OfferedEnergyStorage(CableBlockEntity sourceCable, Direction direction, EnergyStorage storage) {
+		this.sourceCable = sourceCable;
+		this.direction = direction;
+		this.storage = storage;
+	}
+
+	void afterTransfer() {
+		// Block insertions from this side.
+		sourceCable.blockedSides |= 1 << direction.ordinal();
+	}
+}

src/main/java/techreborn/blocks/cable/CableBlock.java

@@ -105,42 +105,6 @@ public class CableBlock extends BlockWithEntity implements Waterloggable {
 		cableShapeUtil = new CableShapeUtil(this);
 	}
 
-	public BooleanProperty getProperty(Direction facing) {
-		return switch (facing) {
-			case WEST -> WEST;
-			case NORTH -> NORTH;
-			case SOUTH -> SOUTH;
-			case UP -> UP;
-			case DOWN -> DOWN;
-			default -> EAST;
-		};
-	}
-
-	private BlockState makeConnections(World world, BlockPos pos) {
-		Boolean down = canConnectTo(world, pos, Direction.DOWN);
-		Boolean up = canConnectTo(world, pos, Direction.UP);
-		Boolean north = canConnectTo(world, pos, Direction.NORTH);
-		Boolean east = canConnectTo(world, pos, Direction.EAST);
-		Boolean south = canConnectTo(world, pos, Direction.SOUTH);
-		Boolean west = canConnectTo(world, pos, Direction.WEST);
-
-		return this.getDefaultState().with(DOWN, down).with(UP, up).with(NORTH, north).with(EAST, east)
-				.with(SOUTH, south).with(WEST, west);
-	}
-
-	private Boolean canConnectTo(WorldAccess world, BlockPos currentPos, Direction side) {
-		BlockPos adjPos = currentPos.offset(side);
-		BlockEntity adjBe = world.getBlockEntity(adjPos);
-		if (adjBe instanceof CableBlockEntity) {
-			return Boolean.TRUE;
-		}
-		// TODO: this doesn't work at all, fix this
-		else if (world instanceof ServerWorld sw && EnergyStorage.SIDED.find(sw, adjPos, null, adjBe, side.getOpposite()) != null) {
-			return Boolean.TRUE;
-		}
-		return Boolean.FALSE;
-	}
-
 	// BlockContainer
 	@Override
 	public BlockRenderType getRenderType(BlockState state) {
@@ -210,7 +174,7 @@ public class CableBlock extends BlockWithEntity implements Waterloggable {
 
 	@Override
 	public BlockState getPlacementState(ItemPlacementContext context) {
-		return makeConnections(context.getWorld(), context.getBlockPos())
+		return getDefaultState()
 				.with(WATERLOGGED, context.getWorld().getFluidState(context.getBlockPos()).getFluid() == Fluids.WATER);
 	}
 
@@ -221,8 +185,16 @@ public class CableBlock extends BlockWithEntity implements Waterloggable {
 		if (ourState.get(WATERLOGGED)) {
 			worldIn.getFluidTickScheduler().schedule(ourPos, Fluids.WATER, Fluids.WATER.getTickRate(worldIn));
 		}
-		Boolean value = canConnectTo(worldIn, otherPos, direction);
-		return ourState.with(getProperty(direction), value);
+		return ourState;
+	}
+
+	@SuppressWarnings("deprecation")
+	@Override
+	public void neighborUpdate(BlockState state, World world, BlockPos pos, Block block, BlockPos fromPos, boolean notify) {
+		if (world.getBlockEntity(pos) instanceof CableBlockEntity cable) {
+			cable.neighborUpdate();
+		}
+		super.neighborUpdate(state, world, pos, block, fromPos, notify);
 	}
 
 	@SuppressWarnings("deprecation")