/*
 *  relations.c
 *
 *  Copyright (C) 2003 Nadav Rotem <nadav256@hotmail.com>
 *
 *  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 Library 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "grader-tc.h"

#include "libots.h"
/*
The Inner product of two texts is defined as the number of topics they
share. This set of functions implements this relations using the ots
api.

Application: a relation between a slashdot article and a comment made
usage: ots_text_relations(story,"en",comment,"en",n);
where n is the max number of most important topics to consider; safe to give a high number (ex: 20);

returns: 
	0 - off topic
	n - number of topics they share

*/

#define OTS_MAX_TOPIC_WORD_SIZE 256

/*Returns the number of topics that two blocks of text share*/
int ots_text_relations(
const unsigned char *text1,const unsigned char *lang_code1,
const unsigned char *text2,const unsigned char *lang_code2,const int topic_num)
{
GList* top1;
GList* top2;
int score;

top1=ots_text_stem_list(text1,lang_code1,topic_num);
top2=ots_text_stem_list(text2,lang_code2,topic_num);

score=ots_topic_list_score(top1,top2);

if (top1){g_list_foreach (top1, (GFunc) g_free, NULL);g_list_free (top1);}
if (top2){g_list_foreach (top2, (GFunc) g_free, NULL);g_list_free (top2);}

return score;
}




/*For a given text, return the list of the topics*/
char* ots_text_topics(
const unsigned char *text,const unsigned char *lang_code,int topic_num)
{
int i;
GString *word;
unsigned char *str;
unsigned char *tmp;
OtsArticle *Art;

if (NULL==text) return NULL;
word = g_string_new (NULL);

Art = ots_new_article ();

ots_load_xml_dictionary(Art,lang_code); /*Load the dictionary*/
if (text!=NULL) ots_parse_stream (text,strlen(text), Art);   /* read text , put it in struct Article */
ots_grade_doc (Art);


for (i=0;i<=topic_num;i++)
{
tmp=ots_word_in_list(Art->ImpWords,i);
if ((tmp!=NULL)&&(strlen(tmp)>0)) {g_string_append(word,tmp);
		g_string_append(word," "); }
}


str=word->str;
g_string_free (word, FALSE);
ots_free_article (Art);

return str;
}



/*For a given text, return the list of the stemmed topics*/
GList* ots_text_stem_list(const unsigned char *text, const unsigned char *lang_code, int topic_num)
{
int i;
GList *topics=NULL;
unsigned char *tmp;
OtsArticle *Art;

if (NULL==text) return NULL;

Art = ots_new_article ();

ots_load_xml_dictionary(Art,lang_code); 
if (text!=NULL) ots_parse_stream (text,strlen(text), Art);   
ots_grade_doc (Art);


for (i=0;i<=topic_num;i++)
{
tmp=ots_stem_in_list(Art->ImpWords,i);
if ((tmp)&&(strlen(tmp)>0))
topics=g_list_append(topics,g_strdup(tmp));
}


ots_free_article (Art);
return topics;
}		

/*Gives a score on the relations between two lists of topics; simmilar to the inner product*/
int ots_topic_list_score(
const GList *topic_list1,
const GList *topic_list2)
{
	int count=0;
	GList *tmplist1;
	GList *tmplist2;
	
	if (!(topic_list1)) return 0;
	if (!(topic_list2)) return 0;
	
	tmplist1 = g_list_first(topic_list1);
	while(tmplist1)
	{
	tmplist2 = g_list_first(topic_list2);
	while(tmplist2)
		{
		
		if ((tmplist1->data)&&(tmplist2->data)&&(strlen(tmplist2->data)>1)) 
			if (0==strncmp(tmplist1->data,tmplist2->data,OTS_MAX_TOPIC_WORD_SIZE)) 
							{count++;}
		
		tmplist2 = g_list_next(tmplist2);
		}
	tmplist1 = g_list_next(tmplist1);
	}

return count;
}