/*
 *    Collection.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.collection;

import org.greenstone.gsdl3.util.*;
import org.greenstone.gsdl3.core.*;
import org.greenstone.gsdl3.service.*;


// java XML classes we're using
import org.w3c.dom.Document; 
import org.w3c.dom.Node; 
import org.w3c.dom.Element; 
import org.w3c.dom.NodeList; 

import java.io.File;
import java.util.HashMap;

import org.apache.log4j.*;

/**
 * Represents a collection in Greenstone. A collection is an extension of
 * a ServiceCluster - it has local data that the services use.
 *
 * @author <a href="mailto:kjdon@cs.waikato.ac.nz">Katherine Don</a>
 * @version $Revision: 13830 $
 * @see ModuleInterface
 */
public class Collection 
    extends ServiceCluster {

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.collection.Collection.class.getName());

    protected XMLTransformer transformer = null;
    /** same as setClusterName */
    public void setCollectionName(String name) {
	setClusterName(name);
    }

    public Collection() {
	super();
	this.description = this.doc.createElement(GSXML.COLLECTION_ELEM);
	
    }
	
    /**
     * Configures the collection.
     *
     * gsdlHome and collectionName must be set before configure is called.
     *
     * the file buildcfg.xml is located in gsdlHome/collect/collectionName
     * collection metadata is obtained, and services loaded.
     *
     * @return true/false on success/fail
     */
    public boolean configure() {
	
	if (this.site_home == null || this.cluster_name== null) {
	    logger.error("Collection: site_home and collection_name must be set before configure called!");
	    return false;
	}
	
	Element coll_config_xml = loadCollConfigFile();
	Element build_config_xml = loadBuildConfigFile();
	
	if (coll_config_xml==null||build_config_xml==null) {
	    return false;
	}
	// process the metadata and display items
	findAndLoadInfo(coll_config_xml, build_config_xml);
	
	// now do the services	
	Element service_list = (Element)GSXML.getChildByTagName(build_config_xml, GSXML.SERVICE_CLASS_ELEM+GSXML.LIST_MODIFIER);
	configureServiceRack(service_list, coll_config_xml);
	
	return true;
	
    }
    /** 
     * load in the collection config file into a DOM Element 
     */    
    protected Element loadCollConfigFile() {

	File coll_config_file = new File(GSFile.collectionConfigFile(this.site_home, this.cluster_name));
	
	if (!coll_config_file.exists()) {
	    logger.error("Collection: couldn't configure collection: "+this.cluster_name+", "+coll_config_file+" does not exist");
	    return null;
	}
	// get the xml for both files
	Document coll_config_doc = this.converter.getDOM(coll_config_file, CONFIG_ENCODING);
	Element coll_config_elem = null;
	if (coll_config_doc != null) {
	    coll_config_elem = coll_config_doc.getDocumentElement();
	}
	return coll_config_elem;

    }
    
    /** 
     * load in the collection build config file into a DOM Element 
     */        
    protected Element loadBuildConfigFile() {
	
	File build_config_file = new File(GSFile.collectionBuildConfigFile(this.site_home, this.cluster_name));
	if (!build_config_file.exists()) {
	    logger.error("Collection: couldn't configure collection: "+this.cluster_name+", "+build_config_file+" does not exist");
	    return null;
	}
	Document build_config_doc = this.converter.getDOM(build_config_file, CONFIG_ENCODING);
	Element build_config_elem = null;
	if (build_config_doc != null) {
	    build_config_elem = build_config_doc.getDocumentElement();
	}
	return build_config_elem;
    }

    /**
     * find the metadata and display elems from the two config files and add it to the appropriate lists
     */
    protected boolean findAndLoadInfo(Element coll_config_xml, 
				      Element build_config_xml){

	// metadata
	Element meta_list = (Element)GSXML.getChildByTagName(coll_config_xml, GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);
	addMetadata(meta_list);
	meta_list = (Element)GSXML.getChildByTagName(build_config_xml, GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);
	addMetadata(meta_list);

	meta_list = this.doc.createElement(GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER);
	GSXML.addMetadata(this.doc, meta_list, "httpPath", this.site_http_address+"/collect/"+this.cluster_name);
	addMetadata(meta_list);

	// display stuff
	Element display_list = (Element)GSXML.getChildByTagName(coll_config_xml, GSXML.DISPLAY_TEXT_ELEM+GSXML.LIST_MODIFIER);
	if (display_list != null) {
	    resolveMacros(display_list);
	    addDisplayItems(display_list);
	}
	return true;

    }

    protected boolean resolveMacros(Element display_list) {
	if (display_list==null) return false;
	NodeList displaynodes = display_list.getElementsByTagName(GSXML.DISPLAY_TEXT_ELEM);
	if (displaynodes.getLength()>0) { 
	    String http_site = this.site_http_address;
	    String http_collection = this.site_http_address +"/collect/"+this.cluster_name;
	    for(int k=0; k<displaynodes.getLength(); k++) {
		Element d = (Element) displaynodes.item(k);
		String text = GSXML.getNodeText(d);
		text = text.replaceAll("_httpsite_", http_site);
		text = text.replaceAll("_httpcollection_", http_collection);
		GSXML.setNodeText(d, text);
	    }
	}
	return true;
    }
    /** 
     * do a configure on only part of the collection
     */
    protected boolean configureSubset(String subset) {

	// need the coll config files
	Element coll_config_elem = loadCollConfigFile();
	Element build_config_elem = loadBuildConfigFile();
	if (coll_config_elem == null||build_config_elem == null) {
	    // wont be able to do any of teh requests
	    return false;
	}    
	
	if (subset.equals(GSXML.SERVICE_ELEM+GSXML.LIST_MODIFIER)) {
	    Element service_rack_list = (Element)GSXML.getChildByTagName(build_config_elem, GSXML.SERVICE_CLASS_ELEM+GSXML.LIST_MODIFIER);
	    
	    return configureServiceRack(service_rack_list, coll_config_elem);
	} 

	if (subset.equals(GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER) || subset.equals(GSXML.DISPLAY_TEXT_ELEM+GSXML.LIST_MODIFIER)) {
	    return findAndLoadInfo(coll_config_elem, build_config_elem);
	    
	}
	
	logger.error("Collection: cant process system request, configure "+subset);
	return false;
    } 

}