/*
 *  eXist Open Source Native XML Database: Extension module
 *  Copyright (C) 2008 Josef Willenborg
 *  jwillenborg@mpiwg-berlin.mpg.de
 *  http://www.mpiwg-berlin.mpg.de
 *  
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *  
 *  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 Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *  
 *  $Id: TextModule.java $
 */
package org.exist.xquery.modules.mpdltext;

import java.util.ArrayList;

import org.exist.dom.QName;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;

import de.mpg.mpiwg.berlin.mpdl.exception.ApplicationException;
import de.mpg.mpiwg.berlin.mpdl.lt.doc.regularization.RegularizationManager;
import de.mpg.mpiwg.berlin.mpdl.lt.morph.app.Form;
import de.mpg.mpiwg.berlin.mpdl.lt.morph.app.MorphologyCache;

/**
 * @author Josef Willenborg (jwillenborg@mpiwg-berlin.mpg.de)
 */
public class GetQueryRegularizations extends BasicFunction {

	public final static FunctionSignature signature =
		new FunctionSignature(
			new QName("get-query-regularizations", MPDLTextModule.NAMESPACE_URI, MPDLTextModule.PREFIX),
			"A function which delivers regularizations (seperated by |) of a given Lucene query string of a given " +
			"language by the MPDL language technology",
			new SequenceType[] { new SequenceType(Type.STRING, Cardinality.ZERO_OR_MORE), 
			                     new SequenceType(Type.STRING, Cardinality.ZERO_OR_MORE) },
			new SequenceType(Type.STRING, Cardinality.ZERO_OR_MORE));

	public GetQueryRegularizations(XQueryContext context) {
		super(context, signature);
	}

	public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {
	  Sequence langSeq = args[0];
    Sequence luceneQueryStringSeq = args[1];
    String language = "";
    String luceneQueryString = "";
		if (langSeq.isEmpty() || luceneQueryStringSeq.isEmpty())
			return Sequence.EMPTY_SEQUENCE;
		language = langSeq.getStringValue();
		luceneQueryString = luceneQueryStringSeq.getStringValue();
    ValueSequence result = new ValueSequence();
    String resultStr = "";
    // add orig regularizations of all lucene query forms
    boolean regOrigFormsFound = false;
    try { 
      RegularizationManager regManager = RegularizationManager.getInstance();
      ArrayList<String> regOrigForms = regManager.getRegOrigsByNormLuceneQueryString(language, luceneQueryString);
      if (regOrigForms != null && regOrigForms.size() > 0) {
        regOrigFormsFound = true;
        for (int i=0; i<regOrigForms.size(); i++) {
          String regOrigForm = regOrigForms.get(i);
          resultStr = resultStr + regOrigForm + "|";
        }
      }
      MorphologyCache morphologyCache = MorphologyCache.getInstance();
      ArrayList<Form> resultVariants = morphologyCache.getFormsByLuceneQuery(language, luceneQueryString, true);
      for (int i=0; i<resultVariants.size(); i++) {
        Form form = resultVariants.get(i);
        String formName = form.getFormName();
        regOrigForms = regManager.getRegOrigsByNormLuceneQueryString(language, formName);
        if (regOrigForms != null && regOrigForms.size() > 0) {
          regOrigFormsFound = true;
          for (int j=0; j<regOrigForms.size(); j++) {
            String regOrigForm = regOrigForms.get(j);
            resultStr = resultStr + regOrigForm + "|";
          }
        }
      }
    } catch (ApplicationException e) {
      throw new XPathException(e);
    }
    if (! regOrigFormsFound) {
      result.add(new StringValue(""));
    } else {
      resultStr = resultStr.substring(0, resultStr.length() - 1); // without last | character
      result.add(new StringValue(resultStr));
    }
		return result;
	}
}