EnergonRelics/src/main/java/com/thebrokenrail/energonrelics/block/entity/reactor/ReactorInputBlockEntity.java

package com.thebrokenrail.energonrelics.block.entity.reactor;

import net.minecraft.block.BlockState;
import net.minecraft.block.entity.BlockEntity;
import net.minecraft.block.entity.BlockEntityType;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.inventory.Inventories;
import net.minecraft.inventory.Inventory;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.util.collection.DefaultedList;

import java.util.Objects;

public class ReactorInputBlockEntity extends BlockEntity implements Inventory {
    public ReactorInputBlockEntity(BlockEntityType<?> type) {
        super(type);
    }

    private final int INVENTORY_SIZE = 5;

    private final DefaultedList<ItemStack> inv = DefaultedList.ofSize(INVENTORY_SIZE, ItemStack.EMPTY);

    @Override
    public int size() {
        return inv.size();
    }

    @Override
    public boolean isEmpty() {
        boolean empty = false;
        for (ItemStack stack : inv) {
            if (stack.isEmpty()) {
                empty = true;
                break;
            }
        }
        return empty;
    }

    @Override
    public ItemStack getStack(int slot) {
        return inv.get(slot);
    }

    @Override
    public ItemStack removeStack(int slot, int amount) {
        ItemStack stack = Inventories.splitStack(inv, slot, amount);
        if (!stack.isEmpty()) {
            markDirty();
        }
        return stack;
    }

    @Override
    public ItemStack removeStack(int slot) {
        return Inventories.removeStack(inv, slot);
    }

    @Override
    public void setStack(int slot, ItemStack stack) {
        inv.set(slot, stack);
        if (stack.getCount() > getMaxCountPerStack()) {
            stack.setCount(getMaxCountPerStack());
        }
    }

    @Override
    public boolean canPlayerUse(PlayerEntity player) {
        if (Objects.requireNonNull(getWorld()).getBlockEntity(getPos()) != this) {
            return false;
        } else {
            return player.squaredDistanceTo((double) getPos().getX() + 0.5D, (double) getPos().getY() + 0.5D, (double) getPos().getZ() + 0.5D) <= 64.0D;
        }
    }

    @Override
    public void clear() {
        inv.clear();
    }

    @Override
    public void fromTag(BlockState state, CompoundTag tag) {
        super.fromTag(state, tag);
        inv.clear();
        Inventories.fromTag(tag, inv);
    }

    @Override
    public CompoundTag toTag(CompoundTag tag) {
        super.toTag(tag);
        Inventories.toTag(tag, inv);
        return tag;
    }
}