using System;
using iTextSharp.text;
/*
 * $Id: GreekAlphabetFactory.cs 106 2009-12-07 12:23:50Z psoares33 $
 * 
 *
 * This file is part of the iText project.
 * Copyright (c) 1998-2012 1T3XT BVBA
 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY 1T3XT,
 * 1T3XT DISCLAIMS THE WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * you must retain the producer line in every PDF that is created or manipulated
 * using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
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 * For more information, please contact iText Software Corp. at this
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 */
namespace iTextSharp.text.factories {

    /**
    * This class can produce String combinations representing a number built with
    * Greek letters (from alpha to omega, then alpha alpha, alpha beta, alpha gamma).
    * We are aware of the fact that the original Greek numbering is different;
    * See http://www.cogsci.indiana.edu/farg/harry/lan/grknum.htm#ancient
    * but this isn't implemented yet; the main reason being the fact that we
    * need a font that has the obsolete Greek characters qoppa and sampi.
    */
    public class GreekAlphabetFactory {
        /** 
        * Changes an int into a lower case Greek letter combination.
        * @param index the original number
        * @return the letter combination
        */
        public static String GetString(int index) {
            return GetString(index, true);
        }
        
        /** 
        * Changes an int into a lower case Greek letter combination.
        * @param index the original number
        * @return the letter combination
        */
        public static String GetLowerCaseString(int index) {
            return GetString(index);        
        }
        
        /** 
        * Changes an int into a upper case Greek letter combination.
        * @param index the original number
        * @return the letter combination
        */
        public static String GetUpperCaseString(int index) {
            return GetString(index).ToUpper(System.Globalization.CultureInfo.InvariantCulture);
        }

        /** 
        * Changes an int into a Greek letter combination.
        * @param index the original number
        * @return the letter combination
        */
        public static String GetString(int index, bool lowercase) {
            if (index < 1) return "";
            index--;
                
            int bytes = 1;
            int start = 0;
            int symbols = 24;  
            while (index >= symbols + start) {
                bytes++;
                start += symbols;
                symbols *= 24;
            }
                  
            int c = index - start;
            char[] value = new char[bytes];
            while (bytes > 0) {
                bytes--;
                value[bytes] = (char)(c % 24);
                if (value[bytes] > 16) value[bytes]++;
                value[bytes] += (char)(lowercase ? 945 : 913);
                value[bytes] = SpecialSymbol.GetCorrespondingSymbol(value[bytes]);
                c /= 24;
            }
            
            return new String(value);
        }
    }
}
