MVP for main projector collecting items for catalysts (ender eye)

Currently hardcoded to a range near the center of two projector blocks. Will swallow all ender eye items and exchange them for diamonds to the nearest player.

Author: robotgryphon

src/main/java/com/robotgryphon/compactcrafting/blocks/tiles/FieldProjectorTile.java

@@ -1,13 +1,133 @@
 package com.robotgryphon.compactcrafting.blocks.tiles;
 
+import com.robotgryphon.compactcrafting.CompactCrafting;
+import com.robotgryphon.compactcrafting.blocks.FieldProjectorBlock;
 import com.robotgryphon.compactcrafting.core.Registration;
+import net.minecraft.block.BlockState;
+import net.minecraft.entity.item.ItemEntity;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+import net.minecraft.item.Items;
+import net.minecraft.particles.ParticleTypes;
+import net.minecraft.tileentity.ITickableTileEntity;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.tileentity.TileEntityType;
+import net.minecraft.util.Direction;
+import net.minecraft.util.math.AxisAlignedBB;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.vector.Vector3f;
+import net.minecraftforge.items.ItemHandlerHelper;
 
-public class FieldProjectorTile extends TileEntity {
+import java.util.List;
+import java.util.Optional;
+
+public class FieldProjectorTile extends TileEntity implements ITickableTileEntity  {
 
     public FieldProjectorTile() {
         super(Registration.FIELD_PROJECTOR_TILE.get());
     }
 
+    public Optional<BlockPos> getCenter() {
+        BlockState bs = this.getBlockState();
+        Direction facing = bs.get(FieldProjectorBlock.FACING);
+
+
+        Optional<BlockPos> location = getOppositeProjector();
+        if(location.isPresent()) {
+            BlockPos opp = location.get();
+            int centerOffset = opp.manhattanDistance(pos);
+
+            BlockPos center = pos.offset(facing, centerOffset / 2);
+            return Optional.of(center);
+        } else {
+            // No center -- no found opposite
+            return Optional.empty();
+        }
+    }
+
+    /**
+     * Gets the location of the opposite field projector.
+     * @return
+     */
+    public Optional<BlockPos> getOppositeProjector() {
+        BlockState bs = this.getBlockState();
+        Direction facing = bs.get(FieldProjectorBlock.FACING);
+
+        for(int i = 1; i <= 13; i++) {
+            // check block exists in offset position
+            BlockPos offsetInDirection = pos.offset(facing, i);
+            BlockState stateInPos = world.getBlockState(offsetInDirection);
+
+            if(stateInPos.getBlock() instanceof FieldProjectorBlock) {
+                // We have a field projector
+                Direction otherFpDirection = stateInPos.get(FieldProjectorBlock.FACING);
+                if(otherFpDirection == facing.getOpposite())
+                    return Optional.of(offsetInDirection);
+            }
+        }
+
+        return Optional.empty();
+    }
+
+    public Direction getProjectorSide() {
+        BlockState bs = this.getBlockState();
+        Direction facing = bs.get(FieldProjectorBlock.FACING);
+
+        return facing.getOpposite();
+    }
+
+    public boolean isMainProjector() {
+        Direction side = getProjectorSide();
+
+        // We're the main projector if we're to the NORTH
+        return side == Direction.NORTH;
+    }
+
+    @Override
+    public void tick() {
+        if(!isMainProjector())
+            return;
+
+        Optional<BlockPos> center = getCenter();
+        if(center.isPresent()) {
+            BlockPos c = center.get();
+            world.addParticle(ParticleTypes.SMOKE, c.getX() + 0.5f, c.getY() + 0.5f, c.getZ() + 0.5f, 0.0D, 0.0D, 0.0D);
+        }
+
+        searchForCatalyst();
+    }
+
+    private void searchForCatalyst() {
+        Optional<BlockPos> center = getCenter();
+
+        // No center area - no other projector present
+        if(!center.isPresent())
+            return;
+
+        BlockPos centerPos = center.get();
+        AxisAlignedBB itemSuckBounds = new AxisAlignedBB(centerPos).grow(2);
+
+        try {
+            List<ItemEntity> itemsInRange = world.getEntitiesWithinAABB(ItemEntity.class, itemSuckBounds);
+            collectItems(centerPos, itemsInRange);
+        }
+
+        catch(NullPointerException npe) {
+
+        }
+    }
+
+    private void collectItems(BlockPos center, List<ItemEntity> itemsInRange) {
+        itemsInRange.forEach(item -> {
+            if(item.getItem().getItem() == Items.ENDER_PEARL) {
+                PlayerEntity closestPlayer = world.getClosestPlayer(center.getX(), center.getY(), center.getZ(), 5, false);
+
+                item.remove(false);
+
+                ItemStack output = new ItemStack(Items.DIAMOND, 1);
+                closestPlayer.addItemStackToInventory(output);
+            }
+        });
+    }
 }