Unicopia/src/main/java/com/minelittlepony/unicopia/item/SpellbookItem.java

package com.minelittlepony.unicopia.item;

import org.jetbrains.annotations.Nullable;

import com.minelittlepony.unicopia.EquinePredicates;
import com.minelittlepony.unicopia.entity.SpellbookEntity;
import com.minelittlepony.unicopia.entity.UEntities;
import com.minelittlepony.unicopia.util.Dispensable;

import net.minecraft.block.DispenserBlock;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.item.BookItem;
import net.minecraft.item.ItemStack;
import net.minecraft.item.ItemUsageContext;
import net.minecraft.nbt.NbtCompound;
import net.minecraft.util.ActionResult;
import net.minecraft.util.TypedActionResult;
import net.minecraft.util.math.BlockPointer;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.Direction;
import net.minecraft.world.World;

public class SpellbookItem extends BookItem implements Dispensable {
    public SpellbookItem(Settings settings) {
        super(settings);
        DispenserBlock.registerBehavior(this, createDispenserBehaviour());
    }

    @Override
    public TypedActionResult<ItemStack> dispenseStack(BlockPointer source, ItemStack stack) {
        Direction facing = source.getBlockState().get(DispenserBlock.FACING);
        BlockPos pos = source.getPos().offset(facing);

        float yaw = facing.getOpposite().asRotation();
        placeBook(stack, source.getWorld(), pos.getX(), pos.getY(), pos.getZ(), yaw);
        stack.decrement(1);

        return new TypedActionResult<>(ActionResult.SUCCESS, stack);
    }

    @Override
    public ActionResult useOnBlock(ItemUsageContext context) {

        @Nullable
        PlayerEntity player = context.getPlayer();

        if (!context.getWorld().isClient && EquinePredicates.PLAYER_UNICORN.test(player)) {
            BlockPos pos = context.getBlockPos().offset(context.getSide());

            placeBook(context.getStack(), context.getWorld(), pos.getX(), pos.getY(), pos.getZ(), context.getPlayerYaw() + 180);

            if (!player.getAbilities().creativeMode) {
                player.getStackInHand(context.getHand()).decrement(1);
            }

            return ActionResult.SUCCESS;
        }
        return ActionResult.PASS;
    }

    private static void placeBook(ItemStack stack, World world, int x, int y, int z, float yaw) {
        SpellbookEntity book = UEntities.SPELLBOOK.create(world);

        book.refreshPositionAndAngles(x + 0.5, y, z + 0.5, 0, 0);
        book.setHeadYaw(yaw);
        book.setYaw(yaw);

        @Nullable
        NbtCompound tag = stack.getSubNbt("spellbookState");
        if (tag != null) {
            book.getSpellbookState().fromNBT(tag);
        }

        world.spawnEntity(book);
    }
}