/*
 * Copyright (C) 2010 ZXing authors
 *
 * Licensed 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.
 */

/*
 * These authors would like to acknowledge the Spanish Ministry of Industry,
 * Tourism and Trade, for the support in the project TSI020301-2008-2
 * "PIRAmIDE: Personalizable Interactions with Resources on AmI-enabled
 * Mobile Dynamic Environments", led by Treelogic
 * ( http://www.treelogic.com/ ):
 *
 *   http://www.piramidepse.com/
 */

using System;
using System.Collections.Generic;
using System.Text;
using ZXing.Common;

namespace ZXing.OneD.RSS.Expanded.Decoders
{
    /// <summary>
    /// <author>Pablo Orduña, University of Deusto (pablo.orduna@deusto.es)</author>
    /// <author>Eduardo Castillejo, University of Deusto (eduardo.castillejo@deusto.es)</author>
    /// </summary>
    abstract class AI01decoder : AbstractExpandedDecoder
    {
        protected static int GTIN_SIZE = 40;

        internal AI01decoder(BitArray information)
           : base(information)
        {
        }

        protected void encodeCompressedGtin(StringBuilder buf, int currentPos)
        {
            buf.Append("(01)");
            int initialPosition = buf.Length;
            buf.Append('9');

            encodeCompressedGtinWithoutAI(buf, currentPos, initialPosition);
        }

        protected void encodeCompressedGtinWithoutAI(StringBuilder buf, int currentPos, int initialBufferPosition)
        {
            for (int i = 0; i < 4; ++i)
            {
                int currentBlock = this.getGeneralDecoder().extractNumericValueFromBitArray(currentPos + 10 * i, 10);
                if (currentBlock / 100 == 0)
                {
                    buf.Append('0');
                }
                if (currentBlock / 10 == 0)
                {
                    buf.Append('0');
                }
                buf.Append(currentBlock);
            }

            appendCheckDigit(buf, initialBufferPosition);
        }

        private static void appendCheckDigit(StringBuilder buf, int currentPos)
        {
            int checkDigit = 0;
            for (int i = 0; i < 13; i++)
            {
                int digit = buf[i + currentPos] - '0';
                checkDigit += (i & 0x01) == 0 ? 3 * digit : digit;
            }

            checkDigit = 10 - (checkDigit % 10);
            if (checkDigit == 10)
            {
                checkDigit = 0;
            }

            buf.Append(checkDigit);
        }
    }
}
