Code/net/minecraft/world/entity/ai/behavior/HarvestFarmland.java

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

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import java.util.List;
import javax.annotation.Nullable;
import net.minecraft.core.BlockPos;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.sounds.SoundEvents;
import net.minecraft.sounds.SoundSource;
import net.minecraft.tags.ItemTags;
import net.minecraft.world.SimpleContainer;
import net.minecraft.world.entity.ai.memory.MemoryModuleType;
import net.minecraft.world.entity.ai.memory.MemoryStatus;
import net.minecraft.world.entity.ai.memory.WalkTarget;
import net.minecraft.world.entity.npc.Villager;
import net.minecraft.world.entity.npc.VillagerProfession;
import net.minecraft.world.item.BlockItem;
import net.minecraft.world.item.ItemStack;
import net.minecraft.world.level.GameRules;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.CropBlock;
import net.minecraft.world.level.block.FarmBlock;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.gameevent.GameEvent;

public class HarvestFarmland extends Behavior<Villager> {
    private static final int HARVEST_DURATION = 200;
    public static final float SPEED_MODIFIER = 0.5F;
    @Nullable
    private BlockPos aboveFarmlandPos;
    private long nextOkStartTime;
    private int timeWorkedSoFar;
    private final List<BlockPos> validFarmlandAroundVillager = Lists.newArrayList();

    public HarvestFarmland() {
        super(
            ImmutableMap.of(
                MemoryModuleType.LOOK_TARGET,
                MemoryStatus.VALUE_ABSENT,
                MemoryModuleType.WALK_TARGET,
                MemoryStatus.VALUE_ABSENT,
                MemoryModuleType.SECONDARY_JOB_SITE,
                MemoryStatus.VALUE_PRESENT
            )
        );
    }

    protected boolean checkExtraStartConditions(ServerLevel p_23174_, Villager p_23175_) {
        if (!p_23174_.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) {
            return false;
        } else if (!p_23175_.getVillagerData().profession().is(VillagerProfession.FARMER)) {
            return false;
        } else {
            BlockPos.MutableBlockPos blockpos$mutableblockpos = p_23175_.blockPosition().mutable();
            this.validFarmlandAroundVillager.clear();

            for (int i = -1; i <= 1; i++) {
                for (int j = -1; j <= 1; j++) {
                    for (int k = -1; k <= 1; k++) {
                        blockpos$mutableblockpos.set(p_23175_.getX() + i, p_23175_.getY() + j, p_23175_.getZ() + k);
                        if (this.validPos(blockpos$mutableblockpos, p_23174_)) {
                            this.validFarmlandAroundVillager.add(new BlockPos(blockpos$mutableblockpos));
                        }
                    }
                }
            }

            this.aboveFarmlandPos = this.getValidFarmland(p_23174_);
            return this.aboveFarmlandPos != null;
        }
    }

    @Nullable
    private BlockPos getValidFarmland(ServerLevel p_23165_) {
        return this.validFarmlandAroundVillager.isEmpty() ? null : this.validFarmlandAroundVillager.get(p_23165_.getRandom().nextInt(this.validFarmlandAroundVillager.size()));
    }

    private boolean validPos(BlockPos p_23181_, ServerLevel p_23182_) {
        BlockState blockstate = p_23182_.getBlockState(p_23181_);
        Block block = blockstate.getBlock();
        Block block1 = p_23182_.getBlockState(p_23181_.below()).getBlock();
        return block instanceof CropBlock && ((CropBlock)block).isMaxAge(blockstate) || blockstate.isAir() && block1 instanceof FarmBlock;
    }

    protected void start(ServerLevel p_23177_, Villager p_23178_, long p_23179_) {
        if (p_23179_ > this.nextOkStartTime && this.aboveFarmlandPos != null) {
            p_23178_.getBrain().setMemory(MemoryModuleType.LOOK_TARGET, new BlockPosTracker(this.aboveFarmlandPos));
            p_23178_.getBrain().setMemory(MemoryModuleType.WALK_TARGET, new WalkTarget(new BlockPosTracker(this.aboveFarmlandPos), 0.5F, 1));
        }
    }

    protected void stop(ServerLevel p_23188_, Villager p_23189_, long p_23190_) {
        p_23189_.getBrain().eraseMemory(MemoryModuleType.LOOK_TARGET);
        p_23189_.getBrain().eraseMemory(MemoryModuleType.WALK_TARGET);
        this.timeWorkedSoFar = 0;
        this.nextOkStartTime = p_23190_ + 40L;
    }

    protected void tick(ServerLevel p_23196_, Villager p_23197_, long p_23198_) {
        if (this.aboveFarmlandPos == null || this.aboveFarmlandPos.closerToCenterThan(p_23197_.position(), 1.0)) {
            if (this.aboveFarmlandPos != null && p_23198_ > this.nextOkStartTime) {
                BlockState blockstate = p_23196_.getBlockState(this.aboveFarmlandPos);
                Block block = blockstate.getBlock();
                Block block1 = p_23196_.getBlockState(this.aboveFarmlandPos.below()).getBlock();
                if (block instanceof CropBlock && ((CropBlock)block).isMaxAge(blockstate)) {
                    p_23196_.destroyBlock(this.aboveFarmlandPos, true, p_23197_);
                }

                if (blockstate.isAir() && block1 instanceof FarmBlock && p_23197_.hasFarmSeeds()) {
                    SimpleContainer simplecontainer = p_23197_.getInventory();

                    for (int i = 0; i < simplecontainer.getContainerSize(); i++) {
                        ItemStack itemstack = simplecontainer.getItem(i);
                        boolean flag = false;
                        if (!itemstack.isEmpty() && itemstack.is(ItemTags.VILLAGER_PLANTABLE_SEEDS) && itemstack.getItem() instanceof BlockItem blockitem) {
                            BlockState blockstate1 = blockitem.getBlock().defaultBlockState();
                            p_23196_.setBlockAndUpdate(this.aboveFarmlandPos, blockstate1);
                            p_23196_.gameEvent(GameEvent.BLOCK_PLACE, this.aboveFarmlandPos, GameEvent.Context.of(p_23197_, blockstate1));
                            flag = true;
                        }

                        if (flag) {
                            p_23196_.playSound(
                                null,
                                this.aboveFarmlandPos.getX(),
                                this.aboveFarmlandPos.getY(),
                                this.aboveFarmlandPos.getZ(),
                                SoundEvents.CROP_PLANTED,
                                SoundSource.BLOCKS,
                                1.0F,
                                1.0F
                            );
                            itemstack.shrink(1);
                            if (itemstack.isEmpty()) {
                                simplecontainer.setItem(i, ItemStack.EMPTY);
                            }
                            break;
                        }
                    }
                }

                if (block instanceof CropBlock && !((CropBlock)block).isMaxAge(blockstate)) {
                    this.validFarmlandAroundVillager.remove(this.aboveFarmlandPos);
                    this.aboveFarmlandPos = this.getValidFarmland(p_23196_);
                    if (this.aboveFarmlandPos != null) {
                        this.nextOkStartTime = p_23198_ + 20L;
                        p_23197_.getBrain().setMemory(MemoryModuleType.WALK_TARGET, new WalkTarget(new BlockPosTracker(this.aboveFarmlandPos), 0.5F, 1));
                        p_23197_.getBrain().setMemory(MemoryModuleType.LOOK_TARGET, new BlockPosTracker(this.aboveFarmlandPos));
                    }
                }
            }

            this.timeWorkedSoFar++;
        }
    }

    protected boolean canStillUse(ServerLevel p_23204_, Villager p_23205_, long p_23206_) {
        return this.timeWorkedSoFar < 200;
    }
}