fabric-carpet/src/main/java/carpet/mixins/PistonBlock_movableTEMixin.java

package carpet.mixins;

import carpet.CarpetSettings;
import carpet.fakes.PistonBlockEntityInterface;
import com.google.common.collect.Lists;
import net.minecraft.block.*;
import net.minecraft.block.entity.BlockEntity;
import net.minecraft.block.piston.PistonHandler;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.Direction;
import net.minecraft.world.World;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.Inject;
import org.spongepowered.asm.mixin.injection.Redirect;
import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
import org.spongepowered.asm.mixin.injection.callback.LocalCapture;

import java.util.List;
import java.util.Set;

@Mixin(PistonBlock.class)
public abstract class PistonBlock_movableTEMixin extends FacingBlock
{
    protected PistonBlock_movableTEMixin(Settings block$Settings_1)
    {
        super(block$Settings_1);
    }
    
    private ThreadLocal<List<BlockEntity>> list1_BlockEntities = new ThreadLocal<>(); //Unneccessary ThreadLocal if client and server use different PistonBlock instances

    @Inject(method = "isMovable", at = @At("HEAD"), cancellable = true)
    private static void slimeHoney(BlockState blockState_1, World world_1, BlockPos blockPos_1, Direction direction_1, boolean boolean_1, Direction direction_2, CallbackInfoReturnable<Boolean> cir)
    {
        if (CarpetSettings.honeySlime && direction_1 != direction_2)
        {
            Block block = blockState_1.getBlock();
            if (block != Blocks.ORANGE_STAINED_GLASS && block != Blocks.SLIME_BLOCK) return;
            Block otherBlock = world_1.getBlockState(blockPos_1.offset(direction_2.getOpposite(),1)).getBlock();
            if (otherBlock != Blocks.ORANGE_STAINED_GLASS && otherBlock != Blocks.SLIME_BLOCK) return;
            cir.setReturnValue(block == otherBlock);
        }
    }

    @Inject(method = "isMovable", at = @At(value = "RETURN", ordinal = 3, shift = At.Shift.BEFORE))
    private static void movableCMD(BlockState blockState_1, World world_1, BlockPos blockPos_1,
            Direction direction_1, boolean boolean_1, Direction direction_2, CallbackInfoReturnable<Boolean> cir)
    {
        Block block_1 = blockState_1.getBlock();
        //Make CommandBlocks movable, either use instanceof CommandBlock or the 3 cmd block objects,
        if (CarpetSettings.movableBlockEntities && block_1 instanceof CommandBlock)
        {
            cir.setReturnValue(true);
        }
    }
    
    private static boolean isPushableBlockEntity(Block block)
    {
        //Making PISTON_EXTENSION (BlockPistonMoving) pushable would not work as its createNewTileEntity()-method returns null
        return block != Blocks.ENDER_CHEST && block != Blocks.ENCHANTING_TABLE &&
                       block != Blocks.END_GATEWAY && block != Blocks.END_PORTAL && block != Blocks.MOVING_PISTON  &&
                       block != Blocks.SPAWNER;
    }
    
    @Redirect(method = "isMovable", at = @At(value = "INVOKE", target = "Lnet/minecraft/block/Block;hasBlockEntity()Z"))
    private static boolean ifHasBlockEntity(Block block)
    {
        if (!block.hasBlockEntity())
        {
            return false;
        }
        else
        {
            return !(CarpetSettings.movableBlockEntities && isPushableBlockEntity(block));
        }
    }
    @Inject(method = "move", at = @At(value = "INVOKE", shift = At.Shift.BEFORE,
            target = "Ljava/util/List;size()I", ordinal = 4),locals = LocalCapture.CAPTURE_FAILHARD)
    private void onMove(World world_1, BlockPos blockPos_1, Direction direction_1, boolean boolean_1,
            CallbackInfoReturnable<Boolean> cir, BlockPos blockPos_2, PistonHandler pistonHandler_1,
            List<BlockPos> list_1, List<BlockState> list_2, List list_3, int int_2, BlockState blockStates_1[],
            Direction direction_2, Set set_1)
    {
        //Get the blockEntities and remove them from the world before any magic starts to happen
        if (CarpetSettings.movableBlockEntities)
        {
            list1_BlockEntities.set(Lists.<BlockEntity>newArrayList());
            for (int i = 0; i < list_1.size(); ++i)
            {
                BlockPos blockpos = list_1.get(i);
                BlockEntity blockEntity = (list_2.get(i).getBlock().hasBlockEntity()) ? world_1.getBlockEntity(blockpos) : null;
                list1_BlockEntities.get().add(blockEntity);
                if (blockEntity != null)
                {
                    //hopefully this call won't have any side effects in the future, such as dropping all the BlockEntity's items
                    //we want to place this same(!) BlockEntity object into the world later when the movement stops again
                    world_1.removeBlockEntity(blockpos);
                    blockEntity.markDirty();
                }
            }
        }
    }
    
    @Inject(method = "move", at = @At(value = "INVOKE", shift = At.Shift.BEFORE,
            target = "Lnet/minecraft/world/World;setBlockEntity(Lnet/minecraft/util/math/BlockPos;" +
                             "Lnet/minecraft/block/entity/BlockEntity;)V", ordinal = 0),
            locals = LocalCapture.CAPTURE_FAILHARD)
    private void setBlockEntityWithCarried(World world_1, BlockPos blockPos_1, Direction direction_1, boolean boolean_1,
            CallbackInfoReturnable<Boolean> cir, BlockPos blockPos_2, PistonHandler pistonHandler_1, List list_1,
            List list_2, List list_3, int int_2, BlockState blockStates_1[], Direction direction_2, Set set_1,
            int int_3, BlockPos blockPos_4, BlockState blockState_1)
    {
        BlockEntity blockEntityPiston = PistonExtensionBlock.createBlockEntityPiston((BlockState) list_2.get(int_3),
                direction_1, boolean_1, false);
        if (CarpetSettings.movableBlockEntities)
            ((PistonBlockEntityInterface) blockEntityPiston).setCarriedBlockEntity(list1_BlockEntities.get().get(int_3));
        world_1.setBlockEntity(blockPos_4, blockEntityPiston);
    }
    
    @Redirect(method = "move", at = @At(value = "INVOKE",
            target = "Lnet/minecraft/world/World;setBlockEntity(Lnet/minecraft/util/math/BlockPos;" +
                             "Lnet/minecraft/block/entity/BlockEntity;)V",
            ordinal = 0))
    private void dontDoAnything(World world, BlockPos blockPos_6, BlockEntity blockEntityPiston)
    {
    }
    
    @Redirect(method = "move", at = @At(value = "INVOKE",
            target = "Lnet/minecraft/block/PistonExtensionBlock;createBlockEntityPiston(Lnet/minecraft/block/BlockState;" +
                             "Lnet/minecraft/util/math/Direction;ZZ)Lnet/minecraft/block/entity/BlockEntity;",
            ordinal = 0))
    private BlockEntity returnNull(BlockState blockState_1, Direction direction_1, boolean boolean_1, boolean boolean_2)
    {
        return null;
    }
}