/*
* Licensed to the Apache Software Foundation (ASF) Under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for Additional information regarding copyright ownership.
* The ASF licenses this file to You Under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed Under the License is distributed on an "AS Is" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations Under the License.
*/
/*
 * Created on May 15, 2005
 *
 */
namespace HH.WMS.Utils.NPOI.SS.Formula.Functions
{
    using System;
    using HH.WMS.Utils.NPOI.SS.Formula.Eval;

    /**
     * @author Amol S. Deshmukh < amolweb at ya hoo dot com >
     *
     */
    public class LeftRight : Var1or2ArgFunction
    {
        private static ValueEval DEFAULT_ARG1 = new NumberEval(1.0);
        private bool _isLeft;
        public LeftRight(bool isLeft)
        {
            _isLeft = isLeft;
        }
        public override ValueEval Evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0)
        {
            return Evaluate(srcRowIndex, srcColumnIndex, arg0, DEFAULT_ARG1);
        }
        public override ValueEval Evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0,
				ValueEval arg1)
        {
            String arg;
            int index;
            try
            {
                arg = TextFunction.EvaluateStringArg(arg0, srcRowIndex, srcColumnIndex);
                index = TextFunction.EvaluateIntArg(arg1, srcRowIndex, srcColumnIndex);
            }
            catch (EvaluationException e)
            {
                return e.GetErrorEval();
            }

            if (index < 0)
            {
                return ErrorEval.VALUE_INVALID;
            }

            String result;
            if (_isLeft)
            {
                result = arg.Substring(0, Math.Min(arg.Length, index));
            }
            else
            {
                result = arg.Substring(Math.Max(0, arg.Length - index));
            }
            return new StringEval(result);
        }
    }
}