src/game/java/net/minecraft/commands/arguments/EntityAnchorArgument.java

package net.minecraft.commands.arguments;

import com.google.common.collect.Maps;
import com.mojang.brigadier.StringReader;
import com.mojang.brigadier.arguments.ArgumentType;
import com.mojang.brigadier.context.CommandContext;
import com.mojang.brigadier.exceptions.CommandSyntaxException;
import com.mojang.brigadier.exceptions.DynamicCommandExceptionType;
import com.mojang.brigadier.suggestion.Suggestions;
import com.mojang.brigadier.suggestion.SuggestionsBuilder;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.function.BiFunction;
import javax.annotation.Nullable;
import net.minecraft.Util;
import net.minecraft.commands.CommandSourceStack;
import net.minecraft.commands.SharedSuggestionProvider;
import net.minecraft.network.chat.Component;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.phys.Vec3;

public class EntityAnchorArgument implements ArgumentType<EntityAnchorArgument.Anchor> {
    private static final Collection<String> EXAMPLES = Arrays.asList("eyes", "feet");
    private static final DynamicCommandExceptionType ERROR_INVALID = new DynamicCommandExceptionType(
        p_308348_ -> Component.translatableEscape("argument.anchor.invalid", p_308348_)
    );

    public static EntityAnchorArgument.Anchor getAnchor(CommandContext<CommandSourceStack> p_90354_, String p_90355_) {
        return p_90354_.getArgument(p_90355_, EntityAnchorArgument.Anchor.class);
    }

    public static EntityAnchorArgument anchor() {
        return new EntityAnchorArgument();
    }

    public EntityAnchorArgument.Anchor parse(StringReader p_90352_) throws CommandSyntaxException {
        int i = p_90352_.getCursor();
        String s = p_90352_.readUnquotedString();
        EntityAnchorArgument.Anchor entityanchorargument$anchor = EntityAnchorArgument.Anchor.getByName(s);
        if (entityanchorargument$anchor == null) {
            p_90352_.setCursor(i);
            throw ERROR_INVALID.createWithContext(p_90352_, s);
        } else {
            return entityanchorargument$anchor;
        }
    }

    @Override
    public <S> CompletableFuture<Suggestions> listSuggestions(CommandContext<S> p_90360_, SuggestionsBuilder p_90361_) {
        return SharedSuggestionProvider.suggest(EntityAnchorArgument.Anchor.BY_NAME.keySet(), p_90361_);
    }

    @Override
    public Collection<String> getExamples() {
        return EXAMPLES;
    }

    public static enum Anchor {
        FEET("feet", (p_90389_, p_90390_) -> p_90389_),
        EYES("eyes", (p_90382_, p_90383_) -> new Vec3(p_90382_.x, p_90382_.y + (double)p_90383_.getEyeHeight(), p_90382_.z));

        static final Map<String, EntityAnchorArgument.Anchor> BY_NAME = Util.make(Maps.newHashMap(), p_90387_ -> {
            for (EntityAnchorArgument.Anchor entityanchorargument$anchor : values()) {
                p_90387_.put(entityanchorargument$anchor.name, entityanchorargument$anchor);
            }
        });
        private final String name;
        private final BiFunction<Vec3, Entity, Vec3> transform;

        private Anchor(final String p_90374_, final BiFunction<Vec3, Entity, Vec3> p_90375_) {
            this.name = p_90374_;
            this.transform = p_90375_;
        }

        @Nullable
        public static EntityAnchorArgument.Anchor getByName(String p_90385_) {
            return BY_NAME.get(p_90385_);
        }

        public Vec3 apply(Entity p_90378_) {
            return this.transform.apply(p_90378_.position(), p_90378_);
        }

        public Vec3 apply(CommandSourceStack p_90380_) {
            Entity entity = p_90380_.getEntity();
            return entity == null ? p_90380_.getPosition() : this.transform.apply(p_90380_.getPosition(), entity);
        }
    }
}