Code/net/minecraft/world/entity/ai/goal/RemoveBlockGoal.java

package net.minecraft.world.entity.ai.goal;

import javax.annotation.Nullable;
import net.minecraft.core.BlockPos;
import net.minecraft.core.SectionPos;
import net.minecraft.core.particles.ItemParticleOption;
import net.minecraft.core.particles.ParticleTypes;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.util.RandomSource;
import net.minecraft.world.entity.Mob;
import net.minecraft.world.entity.PathfinderMob;
import net.minecraft.world.item.ItemStack;
import net.minecraft.world.item.Items;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.GameRules;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.LevelAccessor;
import net.minecraft.world.level.LevelReader;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.chunk.ChunkAccess;
import net.minecraft.world.level.chunk.status.ChunkStatus;
import net.minecraft.world.phys.Vec3;

public class RemoveBlockGoal extends MoveToBlockGoal {
    private final Block blockToRemove;
    private final Mob removerMob;
    private int ticksSinceReachedGoal;
    private static final int WAIT_AFTER_BLOCK_FOUND = 20;

    public RemoveBlockGoal(Block p_25840_, PathfinderMob p_25841_, double p_25842_, int p_25843_) {
        super(p_25841_, p_25842_, 24, p_25843_);
        this.blockToRemove = p_25840_;
        this.removerMob = p_25841_;
    }

    @Override
    public boolean canUse() {
        if (!getServerLevel(this.removerMob).getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) {
            return false;
        } else if (this.nextStartTick > 0) {
            this.nextStartTick--;
            return false;
        } else if (this.findNearestBlock()) {
            this.nextStartTick = reducedTickDelay(20);
            return true;
        } else {
            this.nextStartTick = this.nextStartTick(this.mob);
            return false;
        }
    }

    @Override
    public void stop() {
        super.stop();
        this.removerMob.fallDistance = 1.0;
    }

    @Override
    public void start() {
        super.start();
        this.ticksSinceReachedGoal = 0;
    }

    public void playDestroyProgressSound(LevelAccessor p_25847_, BlockPos p_25848_) {
    }

    public void playBreakSound(Level p_25845_, BlockPos p_25846_) {
    }

    @Override
    public void tick() {
        super.tick();
        Level level = this.removerMob.level();
        BlockPos blockpos = this.removerMob.blockPosition();
        BlockPos blockpos1 = this.getPosWithBlock(blockpos, level);
        RandomSource randomsource = this.removerMob.getRandom();
        if (this.isReachedTarget() && blockpos1 != null) {
            if (this.ticksSinceReachedGoal > 0) {
                Vec3 vec3 = this.removerMob.getDeltaMovement();
                this.removerMob.setDeltaMovement(vec3.x, 0.3, vec3.z);
                if (!level.isClientSide) {
                    double d0 = 0.08;
                    ((ServerLevel)level)
                        .sendParticles(
                            new ItemParticleOption(ParticleTypes.ITEM, new ItemStack(Items.EGG)),
                            blockpos1.getX() + 0.5,
                            blockpos1.getY() + 0.7,
                            blockpos1.getZ() + 0.5,
                            3,
                            (randomsource.nextFloat() - 0.5) * 0.08,
                            (randomsource.nextFloat() - 0.5) * 0.08,
                            (randomsource.nextFloat() - 0.5) * 0.08,
                            0.15F
                        );
                }
            }

            if (this.ticksSinceReachedGoal % 2 == 0) {
                Vec3 vec31 = this.removerMob.getDeltaMovement();
                this.removerMob.setDeltaMovement(vec31.x, -0.3, vec31.z);
                if (this.ticksSinceReachedGoal % 6 == 0) {
                    this.playDestroyProgressSound(level, this.blockPos);
                }
            }

            if (this.ticksSinceReachedGoal > 60) {
                level.removeBlock(blockpos1, false);
                if (!level.isClientSide) {
                    for (int i = 0; i < 20; i++) {
                        double d3 = randomsource.nextGaussian() * 0.02;
                        double d1 = randomsource.nextGaussian() * 0.02;
                        double d2 = randomsource.nextGaussian() * 0.02;
                        ((ServerLevel)level)
                            .sendParticles(
                                ParticleTypes.POOF, blockpos1.getX() + 0.5, blockpos1.getY(), blockpos1.getZ() + 0.5, 1, d3, d1, d2, 0.15F
                            );
                    }

                    this.playBreakSound(level, blockpos1);
                }
            }

            this.ticksSinceReachedGoal++;
        }
    }

    @Nullable
    private BlockPos getPosWithBlock(BlockPos p_25853_, BlockGetter p_25854_) {
        if (p_25854_.getBlockState(p_25853_).is(this.blockToRemove)) {
            return p_25853_;
        } else {
            BlockPos[] ablockpos = new BlockPos[]{
                p_25853_.below(), p_25853_.west(), p_25853_.east(), p_25853_.north(), p_25853_.south(), p_25853_.below().below()
            };

            for (BlockPos blockpos : ablockpos) {
                if (p_25854_.getBlockState(blockpos).is(this.blockToRemove)) {
                    return blockpos;
                }
            }

            return null;
        }
    }

    @Override
    protected boolean isValidTarget(LevelReader p_25850_, BlockPos p_25851_) {
        ChunkAccess chunkaccess = p_25850_.getChunk(
            SectionPos.blockToSectionCoord(p_25851_.getX()), SectionPos.blockToSectionCoord(p_25851_.getZ()), ChunkStatus.FULL, false
        );
        return chunkaccess == null
            ? false
            : chunkaccess.getBlockState(p_25851_).is(this.blockToRemove)
                && chunkaccess.getBlockState(p_25851_.above()).isAir()
                && chunkaccess.getBlockState(p_25851_.above(2)).isAir();
    }
}