Start of new machine trait system

src/main/java/com/gregtechceu/gtceu/api/block/AppearanceBlock.java

@@ -8,8 +8,10 @@
 
 import org.jetbrains.annotations.Nullable;
 
-/// @deprecated Use normal Block class instead - replace `AppearanceBlock::getBlockAppearance` with
-/// `Block::getAppearance`
+/**
+ * @deprecated Use normal Block class instead - replace {@code AppearanceBlock::getBlockAppearance} with
+ *             {@code Block::getAppearance}
+ */
 @Deprecated(forRemoval = true)
 public class AppearanceBlock extends Block implements IAppearance {
 

src/main/java/com/gregtechceu/gtceu/api/block/MetaMachineBlock.java

@@ -10,6 +10,7 @@
 import com.gregtechceu.gtceu.api.machine.MetaMachine;
 import com.gregtechceu.gtceu.api.machine.MultiblockMachineDefinition;
 import com.gregtechceu.gtceu.api.machine.feature.*;
+import com.gregtechceu.gtceu.api.machine.trait.feature.IInteractionTrait;
 import com.gregtechceu.gtceu.common.data.GTItems;
 import com.gregtechceu.gtceu.common.machine.owner.MachineOwner;
 import com.gregtechceu.gtceu.syncsystem.ManagedSyncBlockEntity;
@@ -246,13 +247,8 @@ public void onRemove(BlockState pState, Level pLevel, BlockPos pPos, BlockState
         if (pState.hasBlockEntity()) {
             if (!pState.is(pNewState.getBlock())) { // new block
                 MetaMachine machine = MetaMachine.getMachine(pLevel, pPos);
-                if (machine instanceof IMachineLife machineLife) {
-                    machineLife.onMachineRemoved();
-                }
                 if (machine != null) {
-                    for (Direction direction : GTUtil.DIRECTIONS) {
-                        machine.getCoverContainer().removeCover(direction, null);
-                    }
+                    machine.onRemoved();
                 }
 
                 pLevel.updateNeighbourForOutputSignal(pPos, this);
@@ -274,16 +270,16 @@ public void onRemove(BlockState pState, Level pLevel, BlockPos pPos, BlockState
     public InteractionResult use(BlockState state, Level world, BlockPos pos, Player player, InteractionHand hand,
                                  BlockHitResult hit) {
         var machine = MetaMachine.getMachine(world, pos);
+        if (machine == null) return InteractionResult.FAIL;
         ItemStack itemStack = player.getItemInHand(hand);
         boolean shouldOpenUi = true;
 
-        if (machine != null && machine.getOwnerUUID() == null && player instanceof ServerPlayer sPlayer) {
+        if (machine.getOwnerUUID() == null && player instanceof ServerPlayer sPlayer) {
             machine.setOwnerUUID(sPlayer.getUUID());
         }
 
         Set<GTToolType> types = ToolHelper.getToolTypes(itemStack);
-        if (machine != null &&
-                (!types.isEmpty() && ToolHelper.canUse(itemStack) || types.isEmpty() && player.isShiftKeyDown())) {
+        if (!types.isEmpty() && ToolHelper.canUse(itemStack) || types.isEmpty() && player.isShiftKeyDown()) {
             var result = machine.onToolClick(types, itemStack, new UseOnContext(player, hand, hit));
             if (result.getSecond() == InteractionResult.CONSUME && player instanceof ServerPlayer serverPlayer) {
                 ToolHelper.playToolSound(result.getFirst(), serverPlayer);
@@ -303,6 +299,13 @@ public InteractionResult use(BlockState state, Level world, BlockPos pos, Player
             shouldOpenUi = gtToolItem.definition$shouldOpenUIAfterUse(new UseOnContext(player, hand, hit));
         }
 
+        for (var trait : machine.getTraitHolder().getAllTraits()) {
+            if (trait instanceof IInteractionTrait interactionTrait) {
+                InteractionResult result = interactionTrait.onUse(state, world, pos, player, hand, hit);
+                if (result != InteractionResult.PASS) return result;
+            }
+        }
+
         if (machine instanceof IInteractedMachine interactedMachine) {
             var result = interactedMachine.onUse(state, world, pos, player, hand, hit);
             if (result != InteractionResult.PASS) return result;

src/main/java/com/gregtechceu/gtceu/api/machine/MachineCoverContainer.java

@@ -27,7 +27,7 @@ public class MachineCoverContainer implements ICoverable, ISyncManaged {
     @SyncToClient
     @SaveField
     @RerenderOnChanged
-    private CoverBehavior up, down, north, south, west, east;
+    private @Nullable CoverBehavior up, down, north, south, west, east;
 
     public MachineCoverContainer(MetaMachine machine) {
         this.machine = machine;
@@ -67,7 +67,7 @@ public boolean shouldRenderBackSide() {
     }
 
     @Override
-    public CoverBehavior getCoverAtSide(Direction side) {
+    public @Nullable CoverBehavior getCoverAtSide(Direction side) {
         return switch (side) {
             case UP -> up;
             case SOUTH -> south;
@@ -92,12 +92,12 @@ public void setCoverAtSide(@Nullable CoverBehavior coverBehavior, Direction side
     }
 
     @Override
-    public IItemHandlerModifiable getItemHandlerCap(@Nullable Direction side, boolean useCoverCapability) {
+    public @Nullable IItemHandlerModifiable getItemHandlerCap(@Nullable Direction side, boolean useCoverCapability) {
         return machine.getItemHandlerCap(side, useCoverCapability);
     }
 
     @Override
-    public IFluidHandlerModifiable getFluidHandlerCap(@Nullable Direction side, boolean useCoverCapability) {
+    public @Nullable IFluidHandlerModifiable getFluidHandlerCap(@Nullable Direction side, boolean useCoverCapability) {
         return machine.getFluidHandlerCap(side, useCoverCapability);
     }
 }