/*
 *    PhindServices.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;

import org.greenstone.gsdl3.util.*;

import org.greenstone.mgpp.*;
import org.w3c.dom.Document; 
import org.w3c.dom.Node; 
import org.w3c.dom.Element; 
import org.w3c.dom.Text; 

import java.util.Vector;
import java.util.HashMap;
import java.io.File;
/** 
 * PhindServices - the phind phrase browsing service
 * 
 * @author <a href="mailto:kjdon@cs.waikato.ac.nz">Katherine Don</a>
 * @version $Revision: 9798 $
 */
public class PhindPhraseBrowse
    extends ServiceRack {
    
    // the services on offer
    private static final String PHIND_SERVICE = "PhindApplet";

    private MGPPWrapper mgpp_src=null;
    private String basepath = null;

    private Element applet_description = null;
    
    public PhindPhraseBrowse() {
	this.mgpp_src = new MGPPWrapper();
	// set up the default params
	this.mgpp_src.setQueryLevel("Document");
	this.mgpp_src.setReturnLevel("Document");
	this.mgpp_src.setMaxDocs(5);
	this.mgpp_src.setStem(false);
	this.mgpp_src.setCase(true);
    }
    /** configure the service module
     *
     * @param info a DOM Element containing any config info for the service
     * @return true if configured
     */
    public boolean configure(Element info, Element extra_info) {

	System.out.println("configuring PhindPhraseBrowse");

	// set up short_service_info_ - for now just has name and type
	Element e = this.doc.createElement(GSXML.SERVICE_ELEM);
	e.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_APPLET);
	e.setAttribute(GSXML.NAME_ATT, PHIND_SERVICE);
	this.short_service_info.appendChild(e);

	// set up the static applet description

	applet_description = this.doc.createElement(GSXML.SERVICE_ELEM);
	applet_description.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_APPLET);
	applet_description.setAttribute(GSXML.NAME_ATT, PHIND_SERVICE);

	// add in the applet info for the phind applet
	// need to make this dynamic - library names etc
	// change the applet params - have a single param with the library name
	// this is left blank at this end, and must be filled in by applet action - if the library name is not needed, this param is left out
	// phindcgi param now is not complete - library must be prepended to it.
	String app_info = "<"+GSXML.APPLET_ELEM+" CODEBASE='lib' CODE='org.greenstone.applet.phind.Phind.class' ARCHIVE='phind.jar, xercesImpl.jar, xml-apis.jar' WIDTH='500' HEIGHT='400'><PARAM NAME='library' VALUE=''/> <PARAM NAME='phindcgi' VALUE='?";
	app_info += GSParams.ACTION +"=a&amp;"+GSParams.REQUEST_TYPE +"=r&amp;"+GSParams.SERVICE+"="+PHIND_SERVICE+"&amp;"+GSParams.OUTPUT+"=xml&amp;"+GSParams.RESPONSE_ONLY+"=1'/>";
	app_info +="<PARAM NAME='collection'   VALUE='";
	app_info += this.cluster_name;
	app_info += "'/> <PARAM NAME='classifier' VALUE='1'/>  <PARAM NAME='orientation'  VALUE='vertical'/> <PARAM NAME='depth' VALUE='2'/> <PARAM NAME='resultorder' VALUE='L,l,E,e,D,d'/> <PARAM NAME='backdrop' VALUE='interfaces/default/images/phindbg1.jpg'/><PARAM NAME='fontsize' VALUE='10'/> <PARAM NAME='blocksize'    VALUE='10'/>The Phind java applet.</"+GSXML.APPLET_ELEM+">";
	
	Document dom = this.converter.getDOM(app_info);
	if (dom==null) {
	    System.err.println("PhindPhraseBrowse.configure Error: Couldn't parse applet info");
	    return false;
	}
	Element app_elem = dom.getDocumentElement();
	applet_description.appendChild(this.doc.importNode(app_elem, true));

	return true;
    }

    protected Element getServiceDescription(String service, String lang, String subset) {
	if (!service.equals(PHIND_SERVICE)) {
	    return null;
	}
	Element describe = (Element) applet_description.cloneNode(true);
	describe.appendChild(GSXML.createDisplayTextElement(this.doc, GSXML.DISPLAY_TEXT_NAME,  getTextString(PHIND_SERVICE+".name", lang)));
	describe.appendChild(GSXML.createDisplayTextElement(this.doc, GSXML.DISPLAY_TEXT_DESCRIPTION,  getTextString(PHIND_SERVICE+".description", lang)));
	return describe;
    }

    protected Element processPhindApplet(Element request) {
	
	Element param_elem = (Element)GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
	HashMap params = GSXML.extractParams(param_elem, false);
	
	long first_e = Long.parseLong((String)params.get("pfe"));
	long last_e = Long.parseLong((String)params.get("ple"));
	long first_l = Long.parseLong((String)params.get("pfl"));
	long last_l = Long.parseLong((String)params.get("pll"));
	long first_d = Long.parseLong((String)params.get("pfd"));
	long last_d = Long.parseLong((String)params.get("pld"));
	
	long phrase;
	String phrase_str = (String)params.get("ppnum");
	if (phrase_str == null || phrase_str.equals("")) {
	    phrase=0;
	} else {
	    phrase = Long.parseLong(phrase_str);
	}
	String word = (String)params.get("pptext");
	String phind_index = (String)params.get("pc");
	// the location of the mgpp database files
	this.basepath = GSFile.phindBaseDir(this.site_home, this.cluster_name, phind_index);

	// the result element
	Element result = this.doc.createElement(GSXML.RESPONSE_ELEM);
	result.setAttribute(GSXML.FROM_ATT, PHIND_SERVICE);
	result.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);

	// applet result info must be in appletInfo element
	Element applet_data = this.doc.createElement(GSXML.APPLET_DATA_ELEM);
	result.appendChild(applet_data);
	Element phind_data = this.doc.createElement("phindData");
	applet_data.appendChild(phind_data);


	// if we dont know the phrase number, look it up
	if (phrase == 0) {
	    if (word==null || word.equals("")) {
		Element error = phindError("no word or phrase");
		phind_data.appendChild(error);
		return result;
	    }
	    phrase = findPhraseNumberFromWord( word);
	}
	if (phrase==0) {
	    // the word is not in the collection
	    // return a phind error string
	    Element error = phindError("the term "+word+" is not in the collection");
	    phind_data.appendChild(error);
	    return result;
	}
	
	// get the phrase data into the phind_data node
	getPhraseData(phind_data, phrase, first_l, last_l,
		      first_e, last_e,  first_d, last_d);
	return result;
	
	
    }// processPhindApplet
    
    protected long findPhraseNumberFromWord(String word) {

	// set the mgpp index data - we are looking up pword
	this.mgpp_src.loadIndexData(this.basepath+File.separatorChar+"pword");

	this.mgpp_src.runQuery(word);

	MGPPQueryResult res = this.mgpp_src.getQueryResult();
	Vector docs = res.getDocs();
	if (docs.size()==0) {
	    // phrase not found
	    return 0;
	}
	MGPPDocInfo doc = (MGPPDocInfo)docs.firstElement();
	return doc.num_;
    }

    protected boolean getPhraseData(Element phind_data,
				    long phrase, long first_l, long last_l,
				    long first_e, long last_e, long first_d, 
				    long last_d) {

	String record = this.mgpp_src.getDocument(this.basepath+File.separatorChar+"pdata", "Document",
					      phrase);
	if (record.equals("")) {
	    Element error = phindError("somethings gone wrong - we haven't got a record for phrase number "+phrase);
	    phind_data.appendChild(error);
	    return false;
	}
	
	// parse the record - its in gordons cryptic form
	// ":word:tf:ef:df:el:dl:lf:ll"
	// el: e,e,e
	// dl: d;f,d;f,
	// lf and ll may be null
	// l: type,dest, dest; type,dest,dest

	// ignore everything up to and including first colon (has
	// <Document>3505: at the start)
	record = record.substring(record.indexOf(':')+1);

	// split on ':'
	String [] fields = record.split(":");
	String word = fields[0];
	String tf = fields[1];
	String ef = fields[2];
	String df = fields[3];

	
	String expansions = fields[4];
	String documents = fields[5];
	String lf = "0";
	String linklist = "";
	if (fields.length > 7) {// have thesaurus stuff
	    lf =fields[6];
	    linklist = fields[7];
	}
	
	// the phindData attributes and phrase
	phind_data.setAttribute("id", Long.toString(phrase));
	phind_data.setAttribute("df", df);
	phind_data.setAttribute("ef", ef);
	phind_data.setAttribute("lf", lf);
	phind_data.setAttribute("tf", tf);
	GSXML.createTextElement(this.doc, "phrase", word);

	addExpansionList(phind_data, expansions, word, ef, first_e, last_e);
	addDocumentList(phind_data, documents, word, df, first_d, last_d);
	if (!lf.equals("0")) {
	    addThesaurusList(phind_data, linklist, word, lf, first_l, last_l);
	}
	return true;
    }

    protected boolean addExpansionList( Element phind_data, String record, 
				       String word,
				       String freq,
				       long first, long last) {

	Element expansion_list = this.doc.createElement("expansionList");
	phind_data.appendChild(expansion_list);
	expansion_list.setAttribute("length", freq);
	expansion_list.setAttribute("start", Long.toString(first));
	expansion_list.setAttribute("end", Long.toString(last));

	// get the list of strings
	String [] expansions = record.split(",");
	int length = expansions.length;
	if (length < last) last = length;
	for (long i = first; i < last; i++) {
	    long num  = Long.parseLong(expansions[(int)i]);
	    Element expansion = getExpansion( num, word);
	    expansion.setAttribute("num", Long.toString(i));
	    expansion_list.appendChild(expansion);
	}
	return true;
    }
    
    protected Element getExpansion(long phrase_num, 
				   String orig_phrase) {
	
	// look up the phrase in the pdata thingy
	String record = this.mgpp_src.getDocument(this.basepath+File.separatorChar+"pdata", "Document",
					      phrase_num);

	if (record ==null || record.equals("")) return null;

	// ignore everything up to and including first colon 
	record = record.substring(record.indexOf(':')+1);

	String [] fields = record.split(":");
	String phrase = fields[0];
	String tf = fields[1];
	//String ef = fields[2]; dont use this
	String df = fields[3];

	Element expansion = this.doc.createElement("expansion");
	expansion.setAttribute("tf", tf);
	expansion.setAttribute("df", df);
	expansion.setAttribute("id", Long.toString(phrase_num));

	// get teh suffix and prefix
	String [] ends = splitPhraseOnWord(phrase, orig_phrase);
	if (!ends[0].equals("")) {
	    expansion.appendChild(GSXML.createTextElement(this.doc, "prefix", ends[0]));
	}
	if (!ends[1].equals("")) {
	    expansion.appendChild(GSXML.createTextElement(this.doc, "suffix", ends[1]));
	}

	return expansion;

    }

    protected boolean addDocumentList(Element phind_data, String record, 
				      String word,
				      String freq,
				      long first, long last) {

	Element document_list = this.doc.createElement("documentList");
	phind_data.appendChild(document_list);
	document_list.setAttribute("length", freq);
	document_list.setAttribute("start", Long.toString(first));
	document_list.setAttribute("end", Long.toString(last));

	// get the list of doc,freq
	String [] doc_freqs = record.split(";");
	int length = doc_freqs.length;
	if (length<last) last=length;

	for (long i = first; i < last; i++) {
	    String doc_elem = doc_freqs[(int)i];
	    int p = doc_elem.indexOf(',');
	    long doc_num;
	    String doc_freq;
	    if (p == -1) { // there is no freq in the record
		doc_num =Long.parseLong(doc_elem);
		doc_freq = "1";
	    } else {
		doc_num = Long.parseLong(doc_elem.substring(0,p));
		doc_freq = doc_elem.substring(p+1);
	    }
	    Element document = getDocument( doc_num);
	    document.setAttribute("freq", doc_freq);
	    document.setAttribute("num", Long.toString(i));
	    document_list.appendChild(document);
	}

	
	return true;
    }


    protected Element getDocument(long doc_num) {
	
	// look up the phrase in the docs thingy
	String record = this.mgpp_src.getDocument(this.basepath+File.separatorChar+"docs", "Document",
					      doc_num);
	
	if (record ==null || record.equals("")) return null;
	
	// ignore everything up to and including first \t
	record = record.substring(record.indexOf('\t')+1);

	String [] fields = record.split("\t");
	String hash = fields[0];
	String title = fields[1];

	Element d = this.doc.createElement("document");
	d.setAttribute("hash", hash);
	d.appendChild(GSXML.createTextElement(this.doc, "title", title));
	
	return d;

    }
    protected boolean addThesaurusList(Element phind_data, String record,
				       String word,
				       String freq,
				       long first, long last) {


	Element thesaurus_list = this.doc.createElement("thesaurusList");
	phind_data.appendChild(thesaurus_list);
	thesaurus_list.setAttribute("length", freq);
	thesaurus_list.setAttribute("start", Long.toString(first));
	thesaurus_list.setAttribute("end", Long.toString(last));
	
	// get the list of type,dest,dest
	String [] links = record.split(";");
	int length = links.length;
	long index = 0;
	for (int i = 0; i < length; i++) { // go through the entries
	    String link_info = links[(int)i];
	    String [] items = link_info.split(",");
	    // the first entry is teh type
	    String type = items[0];
	    for (int j = 1; j<items.length; j++, index++) {
		if (index >= first && index < last) { // only output the ones we want
		    long phrase = Long.parseLong(items[j]);
		    Element t = getThesaurus(phrase);
		    t.setAttribute("type", type);
		    thesaurus_list.appendChild(t);
		}
	    }
	}

	return true;
    }

    protected Element getThesaurus(long phrase_num) {

	// look up the phrase in the pdata thingy
	String record = this.mgpp_src.getDocument(this.basepath+File.separatorChar+"pdata", "Document",
					      phrase_num);

	if (record ==null || record.equals("")) return null;

	// ignore everything up to and including first colon 
	record = record.substring(record.indexOf(':')+1);

	String [] fields = record.split(":");
	String phrase = fields[0];
	String tf = fields[1];
	//String ef = fields[2]; dont use this
	String df = fields[3];

	Element thesaurus = this.doc.createElement("thesaurus");
	thesaurus.setAttribute("tf", tf);
	thesaurus.setAttribute("df", df);
	thesaurus.setAttribute("id", Long.toString(phrase_num));
	thesaurus.appendChild(GSXML.createTextElement(this.doc, "phrase", phrase));
	return thesaurus;

    }

    /** returns an array of two elements - the prefix and the suffix*/
    protected String [] splitPhraseOnWord(String phrase, String word) {
	
	if (word.equals("")) {
	    
	    String [] res =  {phrase, ""};
	    return res;
	}
	// use 2 so that we only split on the first occurrance. trailing empty strings should be included 
	String [] result = phrase.split(word, 2);
	return result;
	
    }

    protected Element phindError(String message) {
	Element e = this.doc.createElement("phindError");
	Text t = this.doc.createTextNode(message);
	e.appendChild(t);
	return e;
    }
    
}