/*
 *    GS2MGPPRetrieve.java
 *    Copyright (C) 2002 New Zealand Digital Library, http://www.nzdl.org
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU 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 General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package org.greenstone.gsdl3.service;


// Greenstone classes
import org.greenstone.mgpp.*;
import org.greenstone.gsdl3.util.*;

// XML classes
import org.w3c.dom.Element; 

// General Java classes
import java.io.File;


/**
 * A ServiceRack class for retrieval in greenstone 2 MGPP collections
 *
 * @author <a href="mailto:kjdon@cs.waikato.ac.nz">Katherine Don</a>
 * @version $Revision: 8674 $
 * @see ServiceRack
 */
public class GS2MGPPRetrieve 
    extends GS2Retrieve {

    // Parameters used
    private static final String LEVEL_PARAM = "level";

    // Elements used in the config file that are specific to this class
    private static final String DEFAULT_LEVEL_ELEM = "defaultLevel";

    private MGPPWrapper mgpp_src = null;
    
    private String default_level = null;


    /** constructor */
    public GS2MGPPRetrieve()
    {
	this.mgpp_src = new MGPPWrapper();
    }


    /** configure this service */
    public boolean configure(Element info, Element extra_info)
    {
	// Do specific configuration
	System.out.println("Configuring GS2MGPPRetrieve...");

	// Get the default level out of <defaultLevel> (buildConfig.xml)
	Element def = (Element) GSXML.getChildByTagName(info, DEFAULT_LEVEL_ELEM);
	if (def != null) {
	    this.default_level = def.getAttribute(GSXML.NAME_ATT);
	}
	if (this.default_level == null || this.default_level.equals("")) {
	    System.err.println("Error: default level not specified!");
	    return false;
	}
	// System.out.println("Default level: " + default_level_);

	// Do generic configuration
	return super.configure(info, extra_info);
    }

    
    /** Retrieve the content of a document */
    protected Element processDocumentContentRetrieve(Element request)
    {
	// Create a new (empty) result message
	Element result = this.doc.createElement(GSXML.RESPONSE_ELEM);
	result.setAttribute(GSXML.FROM_ATT,DOCUMENT_CONTENT_RETRIEVE_SERVICE );
	result.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);

	// Get the parameters of the request 
	Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
	Element extlink_param = GSXML.getNamedElement(param_list, GSXML.PARAM_ELEM, GSXML.NAME_ATT, EXTLINK_PARAM);
	boolean extlink = false;
	if (extlink_param != null && GSXML.getValue(extlink_param).equals("1")) {
	    extlink = true;
	}

	// Get the request doc_list
	Element query_doc_list = (Element) GSXML.getChildByTagName(request, GSXML.DOC_NODE_ELEM+GSXML.LIST_MODIFIER);
	if (query_doc_list == null) {
	    System.err.println("Error: DocumentContentRetrieve request specified no doc nodes.\n");
	    return result;
	}
	String lang = request.getAttribute(GSXML.LANG_ATT);
	Element doc_list = this.doc.createElement(GSXML.DOC_NODE_ELEM+GSXML.LIST_MODIFIER);
	result.appendChild(doc_list);

	// The location of the MGPP text files
	String textdir = GSFile.collectionBaseDir(this.site_home, this.cluster_name) +
	    File.separatorChar + GSFile.collectionTextPath(this.cluster_name);

	// Get the documents
	String[] doc_ids = GSXML.getAttributeValuesFromList(query_doc_list, 
						     GSXML.NODE_ID_ATT);
	for (int i = 0; i < doc_ids.length; i++) {
	    String doc_id = doc_ids[i];
	    if (extlink) {
		doc_id = this.gdbm_src.extlink2OID(doc_id);
	    }
	    else if (OID.needsTranslating(doc_id)) {
		doc_id = this.gdbm_src.translateOID(doc_id);
	    }

	    long doc_num = this.gdbm_src.OID2Docnum(doc_id);
	    String doc_content = this.mgpp_src.getDocument(textdir, this.default_level, doc_num);
	    doc_content = resolveTextMacros(doc_content, doc_id, lang);

	    // For now, stick it in a text node - eventually should be parsed as xml??

	    Element doc = this.doc.createElement(GSXML.DOC_NODE_ELEM);
	    doc.setAttribute(GSXML.NODE_ID_ATT, doc_id);
	    GSXML.addDocText(this.doc, doc, doc_content);
	    doc_list.appendChild(doc);

	}
	
	return result;
    }
}