ForgePatch/src/test/java/net/minecraftforge/debug/block/PistonEventTest.java

/*
 * Minecraft Forge
 * Copyright (c) 2016-2019.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation version 2.1
 * of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package net.minecraftforge.debug.block;

import java.util.List;

import net.minecraft.block.Block;
import net.minecraft.block.BlockState;
import net.minecraft.block.Blocks;
import net.minecraft.block.PistonBlock;
import net.minecraft.block.material.Material;
import net.minecraft.block.state.PistonBlockStructureHelper;
import net.minecraft.client.Minecraft;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.item.BlockItem;
import net.minecraft.item.Item;
import net.minecraft.item.ItemGroup;
import net.minecraft.util.Direction;
import net.minecraft.util.ResourceLocation;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.text.StringTextComponent;
import net.minecraft.world.World;
import net.minecraftforge.event.RegistryEvent;
import net.minecraftforge.event.world.PistonEvent;
import net.minecraftforge.event.world.PistonEvent.PistonMoveType;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;

/**
 * This test mod blocks pistons from moving cobblestone at all except indirectly
 * This test mod adds a block that moves upwards when pushed by a piston
 * This test mod informs the user what will happen the piston and affected blocks when changes are made
 * This test mod makes black wool pushed by a piston drop after being pushed.
 */
@Mod.EventBusSubscriber(modid = PistonEventTest.MODID)
@Mod(value = PistonEventTest.MODID)
public class PistonEventTest
{

    public static final String MODID = "piston_event_test";

    private static Block shiftOnMove = new BlockShiftOnMove();

    @SubscribeEvent
    public static void regItem(RegistryEvent.Register<Item> event)
    {
        event.getRegistry().register(new BlockItem(shiftOnMove, new Item.Properties().group(ItemGroup.BUILDING_BLOCKS)).setRegistryName(shiftOnMove.getRegistryName()));
    }

    @SubscribeEvent
    public static void regBlock(RegistryEvent.Register<Block> event)
    {
        event.getRegistry().register(shiftOnMove);
    }

    @SubscribeEvent
    public static void pistonPre(PistonEvent.Pre event)
    {
        if (event.getPistonMoveType() == PistonMoveType.EXTEND)
        {
            World world = (World) event.getWorld();
            PistonBlockStructureHelper pistonHelper = event.getStructureHelper();
            if (world.isRemote)
            {
                PlayerEntity player = Minecraft.getInstance().player;
                if (pistonHelper.canMove())
                {
                    player.sendMessage(new StringTextComponent(String.format("Piston will extend moving %d blocks and destroy %d blocks", pistonHelper.getBlocksToMove().size(), pistonHelper.getBlocksToDestroy().size())));
                }
                else
                {
                    player.sendMessage(new StringTextComponent("Piston won't extend"));
                }
            }

            if (pistonHelper.canMove())
            {
                List<BlockPos> posList = pistonHelper.getBlocksToMove();
                for (BlockPos newPos : posList)
                {
                    BlockState state = event.getWorld().getBlockState(newPos);
                    if (state.getBlock() == Blocks.BLACK_WOOL)
                    {
                        Block.spawnDrops(state, world, newPos);
                        world.setBlockState(newPos, Blocks.AIR.getDefaultState());
                    }
                }
            }

            // Make the block move up and out of the way so long as it won't replace the piston
            BlockPos pushedBlockPos = event.getFaceOffsetPos();
            if (world.getBlockState(pushedBlockPos).getBlock() == shiftOnMove && event.getDirection() != Direction.DOWN)
            {
                world.setBlockState(pushedBlockPos, Blocks.AIR.getDefaultState());
                world.setBlockState(pushedBlockPos.up(), shiftOnMove.getDefaultState());
            }

            // Block pushing cobblestone (directly, indirectly works)
            event.setCanceled(event.getWorld().getBlockState(event.getFaceOffsetPos()).getBlock() == Blocks.COBBLESTONE);
        }
        else
        {
            boolean isSticky = event.getWorld().getBlockState(event.getPos()).getBlock() == Blocks.STICKY_PISTON;
            if (event.getWorld().isRemote())
            {
                PlayerEntity player = Minecraft.getInstance().player;
                if (isSticky)
                {
                    BlockPos targetPos = event.getFaceOffsetPos().offset(event.getDirection());
                    boolean canPush = PistonBlock.canPush(event.getWorld().getBlockState(targetPos), (World) event.getWorld(), event.getFaceOffsetPos(), event.getDirection().getOpposite(), false, event.getDirection());
                    boolean isAir = event.getWorld().isAirBlock(targetPos);
                    player.sendMessage(new StringTextComponent(String.format("Piston will retract moving %d blocks", !isAir && canPush ? 1 : 0)));
                }
                else
                {
                    player.sendMessage(new StringTextComponent("Piston will retract"));
                }
            }
            // Offset twice to see if retraction will pull cobblestone
            event.setCanceled(event.getWorld().getBlockState(event.getFaceOffsetPos().offset(event.getDirection())).getBlock() == Blocks.COBBLESTONE && isSticky);
        }
    }

    public static class BlockShiftOnMove extends Block
    {
        public static String blockName = "shiftonmove";
        public static ResourceLocation blockId = new ResourceLocation(MODID, blockName);

        public BlockShiftOnMove()
        {
            super(Block.Properties.create(Material.ROCK));
            this.setRegistryName(blockId);
        }

    }

}