package net.minecraft.util.datafix.fixes;

import com.mojang.datafixers.DSL;
import com.mojang.datafixers.OpticFinder;
import com.mojang.datafixers.Typed;
import com.mojang.datafixers.schemas.Schema;
import com.mojang.datafixers.types.Type;
import com.mojang.datafixers.util.Pair;
import com.mojang.serialization.Dynamic;

public class BlockEntityBlockStateFix extends NamedEntityFix {
	public BlockEntityBlockStateFix(final Schema outputSchema, final boolean changesType) {
		super(outputSchema, changesType, "BlockEntityBlockStateFix", References.BLOCK_ENTITY, "minecraft:piston");
	}

	@Override
	protected Typed<?> fix(final Typed<?> entity) {
		Type<?> newType = this.getOutputSchema().getChoiceType(References.BLOCK_ENTITY, "minecraft:piston");
		Type<?> blockStateType = newType.findFieldType("blockState");
		OpticFinder<?> blockStateF = DSL.fieldFinder("blockState", blockStateType);
		Dynamic<?> tag = entity.get(DSL.remainderFinder());
		int block = tag.get("blockId").asInt(0);
		tag = tag.remove("blockId");
		int data = tag.get("blockData").asInt(0) & 15;
		tag = tag.remove("blockData");
		Dynamic<?> blockStateTag = BlockStateData.getTag(block << 4 | data);
		Typed<?> output = (Typed<?>)newType.pointTyped(entity.getOps()).orElseThrow(() -> new IllegalStateException("Could not create new piston block entity."));
		return output.set(DSL.remainderFinder(), tag)
			.set(
				blockStateF,
				(Typed)((Pair)blockStateType.readTyped(blockStateTag)
						.result()
						.orElseThrow(() -> new IllegalStateException("Could not parse newly created block state tag.")))
					.getFirst()
			);
	}
}