/*
 *    GS2LuceneRetrieve.java
 *    Copyright (C) 2005 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.gsdl3.core.GSException;
import org.greenstone.gsdl3.util.GSFile;
import org.greenstone.gsdl3.util.GSXML;
import org.greenstone.gsdl3.util.DBInfo;
import org.greenstone.gsdl3.util.GSHTML;
import org.greenstone.gsdl3.util.OID;
// XML classes
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Text;

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

import org.apache.log4j.Logger;

/** Retrieve documents from a gs2 lucene collection. Note that this doesn't 
    actually use lucene, as the documents are stored in XML files */
public class GS2LuceneRetrieve
    extends AbstractGS2DocumentRetrieve
{
    
    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.GS2LuceneRetrieve.class.getName());
    
    
    protected static final String DOC_LEVEL="Doc";
    protected static final String SEC_LEVEL="Sec";
    protected static final String ID_ATT = "gs2:docOID";

    // 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 String default_level = null;
    private String text_dir = null;

    private boolean text_available = true;
    
    public GS2LuceneRetrieve() {
    }
    
    public void cleanUp() {
	super.cleanUp();
    }
    
    /** configure this service */
    public boolean configure(Element info, Element extra_info)
    {
	if (!super.configure(info, extra_info)){
	    return false;
	}
	
	// Do specific configuration
	logger.info("Configuring GS2LuceneRetrieve...");
	
	text_dir = GSFile.collectionIndexDir(this.site_home, this.cluster_name) + File.separatorChar+"text"+File.separatorChar;
	if (!(new File(text_dir).isDirectory())) {
	    logger.error("Text directory "+text_dir+" does not exist, will be unable to retrieve text for "+cluster_name);
	    text_available = false;
	    return true; // return true so that we still get the other services for the collection
	}
	// 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.SHORTNAME_ATT);
	}
	if (this.default_level == null || this.default_level.equals("")) {
	    logger.error("Default level not specified for "+this.cluster_name+", assuming "+DOC_LEVEL);
	    this.default_level = DOC_LEVEL;
 	}
	
	return true;
	
    }
    
    /** returns the content of a node
     * should return a nodeContent element:
     * <nodeContent>text content or other elements</nodeContent>
     */
    protected Element getNodeContent(String doc_id, String lang) throws GSException {	
      String [] args = new String[1];
      args[0] = doc_id;
      String doc_content = getTextString("TextRetrievalError", lang, args);
	try {
	    if (!text_available) {
		throw new Exception("No text directory available");
	    }
	    	
	    DBInfo info=this.coll_db.getInfo(OID.getTop(doc_id));
	    if (info == null) {
		throw new Exception("Couldn't get database entry for "+OID.getTop(doc_id));
	    }
	    
	    String archivedir=info.getInfo("archivedir");
	    File doc_xml_file = new File(text_dir+archivedir+File.separatorChar+"doc.xml");
	    if (!doc_xml_file.isFile()) {
		throw new Exception("Doc XML file "+doc_xml_file.getPath()+" does not exist");
	    }
	    Document doc_xml_doc = this.converter.getDOM(doc_xml_file, "utf-8");
	    if (doc_xml_doc == null) {
		throw new Exception("Couldn't parse file "+doc_xml_file.getPath());
	    }
	    Element full_document = doc_xml_doc.getDocumentElement();
	    if (full_document == null) {
		throw new Exception("Couldn't parse file "+doc_xml_file.getPath());
	    }
	    Element current_section = null;
	    if (default_level.equals(DOC_LEVEL)) {
		current_section = full_document;
	    } else {
		current_section = GSXML.getNamedElement(full_document, SEC_LEVEL, ID_ATT, doc_id);
	    }
	    if (current_section == null) {
		throw new Exception("Couldn't find section "+ doc_id+" in file "+doc_xml_file.getPath());
	    }
	    doc_content = GSXML.getNodeText(current_section);
	    if (doc_content == null) {
		doc_content = "";
	    } else {
 		doc_content = resolveTextMacros(doc_content, doc_id, lang);
 	    } 
	} catch (Exception e) {
	    logger.error("Error trying to get document text for "+doc_id+" in collection "+this.cluster_name+": "+e);
	}
	
	Element content_node = this.doc.createElement(GSXML.NODE_CONTENT_ELEM);
	Text t = this.doc.createTextNode(doc_content);
	content_node.appendChild(t);
	return content_node;
    }
}