using Lucene.Net.Analysis.Util;
using System.IO;

namespace Lucene.Net.Analysis.Sv
{
    /*
	 * 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.
	 */

    /* 
	 * This algorithm is updated based on code located at:
	 * http://members.unine.ch/jacques.savoy/clef/
	 * 
	 * Full copyright for that code follows:
	 */

    /*
	 * Copyright (c) 2005, Jacques Savoy
	 * All rights reserved.
	 *
	 * Redistribution and use in source and binary forms, with or without 
	 * modification, are permitted provided that the following conditions are met:
	 *
	 * Redistributions of source code must retain the above copyright notice, this 
	 * list of conditions and the following disclaimer. Redistributions in binary 
	 * form must reproduce the above copyright notice, this list of conditions and
	 * the following disclaimer in the documentation and/or other materials 
	 * provided with the distribution. Neither the name of the author nor the names 
	 * of its contributors may be used to endorse or promote products derived from 
	 * this software without specific prior written permission.
	 * 
	 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
	 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
	 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
	 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
	 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
	 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
	 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
	 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
	 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
	 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	 * POSSIBILITY OF SUCH DAMAGE.
	 */

    /// <summary>
    /// Light Stemmer for Swedish.
    /// <para>
    /// This stemmer implements the algorithm described in:
    /// <c>Report on CLEF-2003 Monolingual Tracks</c>
    /// Jacques Savoy
    /// </para>
    /// </summary>
    public class SwedishLightStemmer
    {
        public virtual int Stem(char[] s, int len)
        {
            if (len > 4 && s[len - 1] == 's')
            {
                len--;
            }

            if (len > 7 && (StemmerUtil.EndsWith(s, len, "elser") || StemmerUtil.EndsWith(s, len, "heten")))
            {
                return len - 5;
            }

            if (len > 6 && (StemmerUtil.EndsWith(s, len, "arne") || StemmerUtil.EndsWith(s, len, "erna") || StemmerUtil.EndsWith(s, len, "ande") || StemmerUtil.EndsWith(s, len, "else") || StemmerUtil.EndsWith(s, len, "aste") || StemmerUtil.EndsWith(s, len, "orna") || StemmerUtil.EndsWith(s, len, "aren")))
            {
                return len - 4;
            }

            if (len > 5 && (StemmerUtil.EndsWith(s, len, "are") || StemmerUtil.EndsWith(s, len, "ast") || StemmerUtil.EndsWith(s, len, "het")))
            {
                return len - 3;
            }

            if (len > 4 && (StemmerUtil.EndsWith(s, len, "ar") || StemmerUtil.EndsWith(s, len, "er") || StemmerUtil.EndsWith(s, len, "or") || StemmerUtil.EndsWith(s, len, "en") || StemmerUtil.EndsWith(s, len, "at") || StemmerUtil.EndsWith(s, len, "te") || StemmerUtil.EndsWith(s, len, "et")))
            {
                return len - 2;
            }

            if (len > 3)
            {
                switch (s[len - 1])
                {
                    case 't':
                    case 'a':
                    case 'e':
                    case 'n':
                        return len - 1;
                }
            }

            return len;
        }
    }
}