/*
 * Copyright (C) 2016-2022 ActionTech.
 * License: http://www.gnu.org/licenses/gpl.html GPL version 2 or higher.
 */

package com.actiontech.dble.plan.common.item.function.strfunc;

import com.actiontech.dble.plan.common.item.Item;
import com.actiontech.dble.plan.common.item.function.ItemFunc;

import java.util.List;


public class ItemFuncElt extends ItemStrFunc {

    public ItemFuncElt(List<Item> args, int charsetIndex) {
        super(args, charsetIndex);
    }

    @Override
    public final String funcName() {
        return "elt";
    }

    @Override
    public String valStr() {
        long l = args.get(0).valInt().longValue();
        if (l < 1 || l >= args.size()) {
            this.nullValue = true;
            return EMPTY;
        }
        Item arg = args.get((int) l);
        if (arg.isNull()) {
            this.nullValue = true;
            return EMPTY;
        } else {
            return arg.valStr();
        }
    }

    @Override
    public ItemFunc nativeConstruct(List<Item> realArgs) {
        return new ItemFuncElt(realArgs, charsetIndex);
    }
}
