/*
 *    AbstractGS2DocumentRetrieve.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.gsdl3.core.GSException;
import org.greenstone.gsdl3.util.GSXML;
import org.greenstone.gsdl3.util.GSFile;
import org.greenstone.gsdl3.util.OID;
import org.greenstone.gsdl3.util.MacroResolver;
import org.greenstone.gsdl3.util.GS2MacroResolver;
import org.greenstone.gsdl3.util.GSConstants;
import org.greenstone.gsdl3.util.SimpleCollectionDatabase;
import org.greenstone.gsdl3.util.DBInfo;
// XML classes
import org.w3c.dom.Document;
import org.w3c.dom.Element; 
import org.w3c.dom.NodeList;

// General Java classes
import java.io.File;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.Set;
import java.util.Iterator;
import java.util.ArrayList;

import org.apache.log4j.*;

// Apache Commons
import org.apache.commons.lang3.*;

/** Implements the generic retrieval and classifier services for GS2 
 * collections.
 *
 * @author Katherine Don
 * @author Michael Dewsnip
 */

public abstract class AbstractGS2DocumentRetrieve
    extends AbstractDocumentRetrieve {

      static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.AbstractGS2DocumentRetrieve.class.getName());

    //    protected static final String EXTLINK_PARAM = "ext"; here or in base??    
    protected String index_stem = null;

    protected SimpleCollectionDatabase coll_db = null;


    /** constructor */
    protected AbstractGS2DocumentRetrieve()
    {
	this.macro_resolver = new GS2MacroResolver();
    }

    public void cleanUp() {
        super.cleanUp();
        this.coll_db.closeDatabase();
    }
    /** configure this service */
    public boolean configure(Element info, Element extra_info)
    {
	if (!super.configure(info, extra_info)){
	    return false;
	}
	
	logger.info("Configuring AbstractGS2DocumentRetrieve...");
	//this.config_info = info;
	
	// the index stem is either specified in the config file or is  the collection name
	Element index_stem_elem = (Element) GSXML.getChildByTagName(info, GSXML.INDEX_STEM_ELEM);
	if (index_stem_elem != null) {
	    this.index_stem = index_stem_elem.getAttribute(GSXML.NAME_ATT);
	}
	if (this.index_stem == null || this.index_stem.equals("")) {
	    logger.error("AbstractGS2DocumentRetrieve.configure(): indexStem element not found, stem will default to collection name");
	    this.index_stem = this.cluster_name;
	}

	// find out what kind of database we have
	Element database_type_elem = (Element) GSXML.getChildByTagName(info, GSXML.DATABASE_TYPE_ELEM);
	String database_type = null;
	if (database_type_elem != null) {
	  database_type = database_type_elem.getAttribute(GSXML.NAME_ATT);
	}
	if (database_type == null || database_type.equals("")) {
	  database_type = "gdbm"; // the default
	}
	coll_db = new SimpleCollectionDatabase(database_type);
	if (!coll_db.databaseOK()) {
	  logger.error("Couldn't create the collection database of type "+database_type);
	  return false;
	}
	
	// Open database for querying
	String coll_db_file = GSFile.collectionDatabaseFile(this.site_home, this.cluster_name, this.index_stem, database_type);
	if (!this.coll_db.openDatabase(coll_db_file, SimpleCollectionDatabase.READ)) {
	    logger.error("Could not open collection database!");
	    return false;
	}

	// we need to set the database for our GS2 macro resolver
	GS2MacroResolver gs2_macro_resolver = (GS2MacroResolver)this.macro_resolver;
	gs2_macro_resolver.setDB(this.coll_db);

	return true;
    }

    /** if id ends in .fc, .pc etc, then translate it to the correct id */
    protected String translateId(String node_id) {
	return OID.translateOID(this.coll_db, node_id); //return this.coll_db.translateOID(node_id);
    }
    
    /** if an id is not a greenstone id (an external id) then translate 
	it to a greenstone one*/
    protected String translateExternalId(String node_id){
	return this.coll_db.externalId2OID(node_id);
    }

    /** returns the id of the root node of the document containing node node_id. . may be the same as node_id */
    protected String getRootId(String node_id) {
	return OID.getTop(node_id);
    }
    /** returns a list of the child ids in order, null if no children */
    protected ArrayList getChildrenIds(String node_id) {
	DBInfo info = this.coll_db.getInfo(node_id);
	if (info == null) {
	    return null;
	}

	String contains = info.getInfo("contains");
	if (contains.equals("")) {
	    return null;
	}
	ArrayList children = new ArrayList();
	StringTokenizer st = new StringTokenizer(contains, ";");
	while (st.hasMoreTokens()) {
	    String child_id = StringUtils.replace(st.nextToken(), "\"", node_id);
	    children.add(child_id);
	}
	return children;

    }
    /** returns the node id of the parent node, null if no parent */
    protected String getParentId(String node_id){
	String parent = OID.getParent(node_id);
	if (parent.equals(node_id)) {
	    return null;
	}
	return parent;
    }

    /** get the metadata for the classifier node node_id
     * returns a metadataList element:
     * <metadataList><metadata name="xxx">value</metadata></metadataList>
     */
    // assumes only one value per metadata
    protected Element getMetadataList(String node_id, boolean all_metadata,
				      ArrayList metadata_names)  
	throws GSException {
	Element metadata_list = this.doc.createElement(GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);
	DBInfo info = this.coll_db.getInfo(node_id);
	if (info == null) {
	    return null;
	}
	String lang = "en"; // why do we need this??
	if (all_metadata) {
	    // return everything out of the database
	    Set keys = info.getKeys();
	    Iterator it = keys.iterator();
	    while(it.hasNext()) {
		String key = (String)it.next();
		//String value = info.getInfo(key);
		Vector values = info.getMultiInfo(key);
		for(int i=0; i<values.size(); i++) {
		    GSXML.addMetadata(this.doc, metadata_list, key, this.macro_resolver.resolve((String)values.elementAt(i), lang, MacroResolver.SCOPE_META, node_id));
		}
	    }
	    
	} else {
	    for (int i=0; i<metadata_names.size(); i++) {
                String meta_name = (String) metadata_names.get(i);
		String value = getMetadata(node_id, info, meta_name, lang);
		GSXML.addMetadata(this.doc, metadata_list, meta_name, value);
	    }
	}
	return metadata_list;
    }

    /** returns the structural information asked for.
     * info_type may be one of
     * INFO_NUM_SIBS, INFO_NUM_CHILDREN, INFO_SIB_POS
     */
    protected String getStructureInfo(String doc_id, String info_type) {
	String value="";
	if (info_type.equals(INFO_NUM_SIBS)) {
	    String parent_id = OID.getParent(doc_id);
	    if (parent_id.equals(doc_id)) {
		value="0";
	    } else {
		value = String.valueOf(getNumChildren(parent_id));
	    }
	    return value;
	}
	
	if (info_type.equals(INFO_NUM_CHILDREN)) {
	    return String.valueOf(getNumChildren(doc_id));
	}

	
	if (info_type.equals(INFO_SIB_POS)) {
	    String parent_id = OID.getParent(doc_id);
	    if (parent_id.equals(doc_id)) {
		return "-1";
	    }
	    
	    DBInfo info = this.coll_db.getInfo(parent_id);
	    if (info==null) {
		return "-1";
	    }
	    
	    String contains = info.getInfo("contains");
	    contains = StringUtils.replace(contains, "\"", parent_id);
	    String [] children = contains.split(";");
	    for (int i=0;i<children.length;i++) {
		String child_id = children[i];
		if (child_id.equals(doc_id)) {
		    return String.valueOf(i+1); // make it from 1 to length
			   
		}
	    }
	    
	    return "-1";
	} else {
	    return null;
	}

    }

    protected int getNumChildren(String node_id) {
	DBInfo info = this.coll_db.getInfo(node_id);
	if (info == null) {
	    return 0;
	}
	String contains = info.getInfo("contains");
	if (contains.equals("")) {
	    return 0;
	}
	String [] children = contains.split(";");
	return children.length;
    }
    
    /** returns the document type of the doc that the specified node 
	belongs to. should be one of 
	GSXML.DOC_TYPE_SIMPLE, 
	GSXML.DOC_TYPE_PAGED, 
	GSXML.DOC_TYPE_HIERARCHY
    */
    protected String getDocType(String node_id) {
	DBInfo info = this.coll_db.getInfo(node_id);
	if (info == null) {
	    return GSXML.DOC_TYPE_SIMPLE;
	}
	String doc_type = info.getInfo("doctype");
	if (!doc_type.equals("")&&!doc_type.equals("doc")) {
	    return doc_type;
	}

	String top_id = OID.getTop(node_id);
	boolean is_top = (top_id.equals(node_id) ? true : false);
	
	String children = info.getInfo("contains");
	boolean is_leaf = (children.equals("") ? true : false);

	if (is_top && is_leaf) { // a single section document
	    return GSXML.DOC_TYPE_SIMPLE;
	}

	// now we just check the top node
	if (!is_top) { // we need to look at the top info
	    info = this.coll_db.getInfo(top_id);
	}
	if (info == null) {
	    return GSXML.DOC_TYPE_HIERARCHY;
	}
 
	String childtype = info.getInfo("childtype");
	if (childtype.equals("Paged")) {
	    return GSXML.DOC_TYPE_PAGED;
	}
	return GSXML.DOC_TYPE_HIERARCHY;
    }

    /** returns the content of a node
     * should return a nodeContent element:
     * <nodeContent>text content or other elements</nodeContent>
     */
    abstract protected Element getNodeContent(String doc_id, String lang) throws GSException;

    protected String getMetadata(String node_id, DBInfo info, 
				 String metadata, String lang) {
	boolean multiple = false;
	String relation = "";
	String separator = ", ";
	int pos = metadata.indexOf(GSConstants.META_RELATION_SEP);
	if (pos ==-1) {
              Vector values = info.getMultiInfo(metadata);        
	      if (values !=null){      
		  // just a plain meta entry eg dc.Title
		  StringBuffer result = new StringBuffer(); 
		  boolean first = true;
		  for (int i=0; i<values.size(); i++) {
		      if (first) {
			  first = false;
		      } else {
			  result.append(separator);
		      }
		      result.append(this.macro_resolver.resolve((String)values.elementAt(i), lang, MacroResolver.SCOPE_META, node_id)); 
		  }
                   return result.toString();
	      }
	      else{
                String result  = info.getInfo(metadata);
                return this.macro_resolver.resolve(result, lang, MacroResolver.SCOPE_META, node_id);
	      }
	}

	String temp = metadata.substring(0, pos);
	metadata = metadata.substring(pos+1);
	// check for all on the front
	if (temp.equals("all")) {
	    multiple=true;	    
	    pos = metadata.indexOf(GSConstants.META_RELATION_SEP);
	    if (pos ==-1) {
		temp = "";
	    } else {
		temp = metadata.substring(0, pos);
		metadata = metadata.substring(pos+1);
	    }
	}
	
	// now check for relational info
	if (temp.equals("parent") || temp.equals("root") || temp.equals( "ancestors")) { // "current" "siblings" "children" "descendants"
	    relation = temp;
	    pos = metadata.indexOf(GSConstants.META_RELATION_SEP);
	    if (pos == -1) {
		temp = "";
	    } else {
		temp = metadata.substring(0, pos);
		metadata = metadata.substring(pos+1);
	    }
	}
	
	// now look for separator info
	if (temp.startsWith(GSConstants.META_SEPARATOR_SEP) && temp.endsWith(GSConstants.META_SEPARATOR_SEP)) {
	    separator = temp.substring(1, temp.length()-1);
	    
	}
	
	String relation_id = node_id;
	if (relation.equals("parent") || relation.equals("ancestors")) {
	    relation_id = OID.getParent(node_id);
	    // parent or ancestor does not include self
	    if (relation_id.equals(node_id)){
		return "";
	    }
	} else if (relation.equals("root")) {
	    relation_id = OID.getTop(node_id);
	}
	
	// now we either have a single node, or we have ancestors	
	DBInfo relation_info;
	if (relation_id.equals(node_id)) {
	    relation_info = info;
	} else {
	    relation_info = this.coll_db.getInfo(relation_id);
	}
	if (relation_info == null) {
	    return "";
	}

	StringBuffer result = new StringBuffer();

	if (!multiple) {
	    result.append(this.macro_resolver.resolve(relation_info.getInfo(metadata), lang, MacroResolver.SCOPE_META, relation_id));
	} else {
	    // we have multiple meta
	    Vector values = relation_info.getMultiInfo(metadata);
  	    if (values != null) {
		boolean first = true;
		for (int i=0; i<values.size(); i++) {
		    if (first) {
			first = false;
		    } else {
			result.append(separator);
		    }
		    result.append(this.macro_resolver.resolve((String)values.elementAt(i), lang, MacroResolver.SCOPE_META, relation_id));
		}
	    }
          logger.info(result); 
	}
	// if not ancestors, then this is all we do
	if (!relation.equals("ancestors")) {
	    return result.toString();
	}
	
	// now do the ancestors 
	String current_id = relation_id;
	relation_id = OID.getParent(current_id);
	while (!relation_id.equals(current_id)) {
	    relation_info = this.coll_db.getInfo(relation_id);
	    if (relation_info == null) return result.toString();
	    if (!multiple) {
		result.insert(0, separator);
		result.insert(0, this.macro_resolver.resolve(relation_info.getInfo(metadata), lang, MacroResolver.SCOPE_META, relation_id));
	    } else {
		Vector values = relation_info.getMultiInfo(metadata);
		if (values != null) {
		    for (int i=values.size()-1; i>=0; i--) {
			result.insert(0, separator);
			result.insert(0, this.macro_resolver.resolve((String)values.elementAt(i), lang, MacroResolver.SCOPE_META, relation_id));
		    }
		}
		
	    }
	    current_id = relation_id;
	    relation_id = OID.getParent(current_id);
	} 
	return result.toString();
    }
    

    /** needs to get info from collection database - if the calling code gets it already it may pay to pass it in instead */
    protected String resolveTextMacros(String doc_content, String doc_id, String lang)
    {
	// resolve any collection specific macros
	doc_content = macro_resolver.resolve(doc_content, lang, MacroResolver.SCOPE_TEXT, doc_id);
	return doc_content;
    }

    protected Element getInfo(String doc_id, String info_type) {

	String value="";
	if (info_type.equals(INFO_NUM_SIBS)) {
	    String parent_id = OID.getParent(doc_id);
	    if (parent_id.equals(doc_id)) {
		value="0";
	    } else {
		value = String.valueOf(getNumChildren(parent_id));
	    }
	} else if (info_type.equals(INFO_NUM_CHILDREN)) {
	    value = String.valueOf(getNumChildren(doc_id));
	} else if (info_type.equals(INFO_SIB_POS)) {
	    String parent_id = OID.getParent(doc_id);
	    if (parent_id.equals(doc_id)) {
		value="-1";
	    } else {
		DBInfo info = this.coll_db.getInfo(parent_id);
		if (info==null) {
		    value ="-1";
		} else {
		    String contains = info.getInfo("contains");
		    contains = StringUtils.replace(contains, "\"", parent_id);
		    String [] children = contains.split(";");
		    for (int i=0;i<children.length;i++) {
			String child_id = children[i];
			if (child_id.equals(doc_id)) {
			    value = String.valueOf(i+1); // make it from 1 to length
			    break;
			}
		    }
		}
	    }
	} else {
	    return null;
	}
	Element info_elem = this.doc.createElement("info");
	info_elem.setAttribute(GSXML.NAME_ATT, info_type);
	info_elem.setAttribute(GSXML.VALUE_ATT, value);
	return info_elem;
    }

    protected String getHrefOID(String href_url){
        return this.coll_db.docnum2OID(href_url);
    }

}