/*

    kbs - Simple, easily fooled, POP3 spam filter

    Copyright (C) 2003  Ian Cowburn (ianc@noddybox.demon.co.uk)

    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    -------------------------------------------------------------------------

    Rules database

*/
static const char id[]="$Id$";

#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <stdio.h>
#include <ctype.h>

#include "global.h"
#include "dbase.h"
#include "dstring.h"
#include "config.h"
#include "debug.h"
#include "util.h"

static const char header_id[]=KBS_DBASE_H;


/* ---------------------------------------- TYPES
*/
struct Domain
    {
    RE_Expression	name;
    int			def_block;
    int			no_user;
    int			no_block;
    int			no_allow;
    int			no_allow_to;
    char		**user;
    RE_Expression	*block;
    RE_Expression	*allow;
    RE_Expression	*allow_to;
    Domain		*next;
    Domain		*prev;
    };


/* ---------------------------------------- GLOBALS
*/
static Domain		*head;
static Domain		*tail;

static int		no_trusted_users=0;
static int		no_trusted_domains=0;
static int		no_blacklist=0;

static char		**trusted_user=NULL;
static char		**trusted_domain=NULL;
static RE_Expression	*blacklist=NULL;

static DString		reason=NULL;


/* ---------------------------------------- PRVIVATE FUNCTIONS
*/
static int IsTrustedUser(const char *username, const char *domain)
{
    char *p;
    int f;
    int res=FALSE;

    p=CopyStr(username);
    p=CatStr(p,"@");
    p=CatStr(p,domain);

    for(f=0;f<no_trusted_users && !res;f++)
    {
    	if (strcasecmp(p,trusted_user[f])==0)
	{
	    res=TRUE;
	}
    }

    free(p);

    return res;
}


static int IsTrustedDomain(const char *domain)
{
    int f;

    for(f=0;f<no_trusted_domains;f++)
    {
    	if (strcasecmp(domain,trusted_domain[f])==0)
	    return TRUE;
    }

    return FALSE;
}


static const Domain *GetDomain(const char *domain)
{
    Domain *dom;

    dom=head;

    while(dom)
    {
    	if (RESearch(dom->name,domain))
	    return dom;

    	dom=dom->next;
    }

    return NULL;
}


static void DeJunk(DString ds, const char *p)
{
    int last_ws=FALSE;

    while(*p)
    {
    	if (isspace(*p))
	{
	    if (!last_ws)
	    	DSAddChar(ds,' ');

	    last_ws=TRUE;
	}
	else
	    last_ws=FALSE;

	if (isalnum(*p))
	{
	    DSAddChar(ds,*p);
	}

	p++;
    }
}


/* ---------------------------------------- INTERFACES
*/
Domain *DBNewDomain(RE_Expression name)
{
    Domain *dom;

    dom=Malloc(sizeof *dom);

    dom->name=name;
    dom->def_block=FALSE;

    dom->no_user=0;
    dom->no_block=0;
    dom->no_allow=0;

    dom->user=NULL;
    dom->block=NULL;
    dom->allow=NULL;
    dom->allow_to=NULL;

    if (tail)
    	tail->next=dom;
    else
    	head=tail=dom;

    dom->prev=tail;
    dom->next=NULL;

    return dom;
}


void DBDefault(Domain *domain, int block)
{
    domain->def_block=block;
}


void DBBlockUser(Domain *domain, const char *username)
{
    domain->no_user++;
    domain->user=Realloc(domain->user,sizeof(char *)*domain->no_user);
    domain->user[domain->no_user-1]=CopyStr(username);
}


void DBAllowSubject(Domain *domain, RE_Expression re)
{
    domain->no_allow++;
    domain->allow=Realloc(domain->allow,sizeof(RE_Expression)*domain->no_allow);
    domain->allow[domain->no_allow-1]=re;
}


void DBBlockSubject(Domain *domain, RE_Expression re)
{
    domain->no_block++;
    domain->block=Realloc(domain->block,sizeof(RE_Expression)*domain->no_block);
    domain->block[domain->no_block-1]=re;
}


void DBAllowTo(Domain *domain, RE_Expression re)
{
    domain->no_allow_to++;
    domain->allow_to=Realloc(domain->allow_to,
			     sizeof(RE_Expression)*domain->no_allow_to);
    domain->allow_to[domain->no_allow_to-1]=re;
}


void DBTrustedUser(const char *username)
{
    no_trusted_users++;
    trusted_user=Realloc(trusted_user,sizeof(char *)*no_trusted_users);
    trusted_user[no_trusted_users-1]=CopyStr(username);
}


void DBTrustedDomain(const char *domain)
{
    no_trusted_domains++;
    trusted_domain=Realloc(trusted_domain,sizeof(char *)*no_trusted_domains);
    trusted_domain[no_trusted_domains-1]=CopyStr(domain);
}


void DBBlacklist(RE_Expression re)
{
    no_blacklist++;
    blacklist=Realloc(blacklist,sizeof(RE_Expression)*no_blacklist);
    blacklist[no_blacklist-1]=re;
}


int DBBlockMessage(const POP3Message *msg)
{
    static const char *html="text/html";
    DString ds;
    const Domain *dom;
    int f;
    int show;

    KBSDEBUG(("msg.id=%d\n",msg->id));
    KBSDEBUG(("msg.to='%s'\n",msg->to));
    KBSDEBUG(("msg.from='%s'\n",msg->from));
    KBSDEBUG(("msg.from_uname='%s'\n",msg->from_uname));
    KBSDEBUG(("msg.from_domain='%s'\n",msg->from_domain));
    KBSDEBUG(("msg.subject='%s'\n",msg->subject));
    KBSDEBUG(("msg.content_type='%s'\n",msg->content_type));

    show=ConfigInt(CONFIG_SHOWMATCH);

    reason=DSReset(reason);

    if (IsTrustedDomain(msg->from_domain))
    	return FALSE;

    if (IsTrustedUser(msg->from_uname,msg->from_domain))
    	return FALSE;

    if (ConfigInt(CONFIG_BLOCKHTML) &&
	(strncmp(msg->content_type,html,strlen(html))==0 ||
	 strcmp(msg->content_type,"UNKNOWN")==0))
    {
	DSAddCP(reason,"HTML message or unknown content type");
    	return TRUE;
    }

    for(f=0;f<no_blacklist;f++)
    {
    	if (RESearch(blacklist[f],msg->from_domain))
	{
	    if (show)
	    {
		DSAddCP(reason,"blacklisted - ");
		DSAddCP(reason,REGetExpression(blacklist[f]));
	    }
	    else
		DSAddCP(reason,"blacklisted");

	    return TRUE;
	}
    }

    if (!(dom=GetDomain(msg->from_domain)))
	return FALSE;

    ds=DSInit();

    if (ConfigInt(CONFIG_DEJUNK))
    	DeJunk(ds,msg->subject);
    else
    	DSAddCP(ds,msg->subject);

    for(f=0;f<dom->no_allow;f++)
    {
    	if (RESearch(dom->allow[f],ds->text))
	{
	    DSFree(ds);
	    return FALSE;
	}
    }

    if (dom->no_allow_to)
    {
    	int found=FALSE;
	int f;

	for(f=0;f<dom->no_allow_to && !found;f++)
	    if (RESearch(dom->allow_to[f],msg->to))
	    	found=TRUE;

	if (!found)
	{
	    if (show)
	    {
	    	DSAddCP(reason,"disallowed to address - ");
		DSAddCP(reason,msg->to);
	    }
	    else
	    	DSAddCP(reason,"disallowed to address");

	    DSFree(ds);
	    return TRUE;
	}
    }

    for(f=0;f<dom->no_user;f++)
    {
	int res;

	if (ConfigInt(CONFIG_CASESENSE))
	    res=strcmp(dom->user[f],msg->from_uname);
	else
	    res=strcasecmp(dom->user[f],msg->from_uname);

	if (res==0)
	{
	    DSFree(ds);

	    if (show)
	    {
	    	DSAddCP(reason,"disallowed name - ");
		DSAddCP(reason,dom->user[f]);
	    }
	    else
	    	DSAddCP(reason,"disallowed name");
	    return TRUE;
	}
    }

    for(f=0;f<dom->no_block;f++)
    {
    	if (RESearch(dom->block[f],ds->text))
	{
	    if (show)
	    {
		DSAddCP(reason,"disallowed subject - ");
		DSAddCP(reason,REGetExpression(dom->block[f]));
	    }
	    else
		DSAddCP(reason,"disallowed subject");
	    DSFree(ds);
	    return TRUE;
	}
    }

    DSAddCP(reason,"default block");
    DSFree(ds);
    return dom->def_block;
}


const char *DBBlockReason(void)
{
    return reason->text;
}


void DBClose(void)
{
    Domain *d;
    int f;

    DSFree(reason);

    for(f=0;f<no_trusted_domains;f++)
    	free(trusted_domain[f]);

    free(trusted_domain);

    for(f=0;f<no_trusted_users;f++)
    	free(trusted_user[f]);

    free(trusted_user);

    for(f=0;f<no_blacklist;f++)
    	REFree(blacklist[f]);

    free(blacklist);

    d=head;

    while(d)
    {
    	Domain *t;

	t=d;

	d=d->next;

	for(f=0;f<t->no_user;f++)
	    free(t->user[f]);

	free(t->user);

	for(f=0;f<t->no_block;f++)
	    REFree(t->block[f]);

	free(t->block);

	for(f=0;f<t->no_allow;f++)
	    REFree(t->allow[f]);

	free(t->allow);

	for(f=0;f<t->no_allow_to;f++)
	    REFree(t->allow_to[f]);

	free(t->allow_to);

	free(t);
    }

    no_trusted_users=0;
    no_trusted_domains=0;

    head=tail=NULL;
    trusted_user=NULL;
    trusted_domain=NULL;
}


void DBDump(void)
{
    Domain *d;
    int f;

    for(f=0;f<no_trusted_domains;f++)
	KBSDEBUG(("trusted_domain[%d]='%s'\n",f,trusted_domain[f]));

    for(f=0;f<no_trusted_users;f++)
	KBSDEBUG(("trusted_user[%d]='%s'\n",f,trusted_user[f]));

    for(f=0;f<no_blacklist;f++)
	KBSDEBUG(("blacklist[%d]='%s'\n",f,blacklist[f]));

    d=head;

    while(d)
    {
    	KBSDEBUG(("DOMAIN '%s' default:%s\n",
			d->name,d->def_block ? "block":"allow"));

	for(f=0;f<d->no_user;f++)
	    KBSDEBUG(("  user[%d]='%s'\n",
	    			f,d->user[f]));

	for(f=0;f<d->no_block;f++)
	    KBSDEBUG(("  block[%d]='%s'\n",
	    			f,REGetExpression(d->block[f])));

	for(f=0;f<d->no_allow;f++)
	    KBSDEBUG(("  allow[%d]='%s'\n",
	    			f,REGetExpression(d->allow[f])));

	for(f=0;f<d->no_allow_to;f++)
	    KBSDEBUG(("  allow_to[%d]='%s'\n",
	    			f,REGetExpression(d->allow_to[f])));

	d=d->next;
    }
}


/* END OF FILE */