/***************************************************************************\
*                                                                           *
*  BitlBee - An IRC to IM gateway                                           *
*  Jabber module - SI packets                                               *
*                                                                           *
*  Copyright 2007 Uli Meis <a.sporto+bee@gmail.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 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.,  *
*  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.              *
*                                                                           *
\***************************************************************************/

#include "jabber.h"
#include "sha1.h"

void jabber_si_answer_request( file_transfer_t *ft );
int jabber_si_send_request(struct im_connection *ic, char *who, struct jabber_transfer *tf );

/* file_transfer free() callback */
void jabber_si_free_transfer( file_transfer_t *ft)
{
	struct jabber_transfer *tf = ft->data;
	struct jabber_data *jd = tf->ic->proto_data;

	if ( tf->watch_in )
		b_event_remove( tf->watch_in );

	jd->filetransfers = g_slist_remove( jd->filetransfers, tf );

	if( tf->fd != -1 )
	{
		closesocket( tf->fd );
		tf->fd = -1;
	}

	if( tf->disco_timeout )
		b_event_remove( tf->disco_timeout );
	
	g_free( tf->ini_jid );
	g_free( tf->tgt_jid );
	g_free( tf->iq_id );
	g_free( tf->sid );
	g_free( tf );
}

/* file_transfer canceled() callback */
void jabber_si_canceled( file_transfer_t *ft, char *reason )
{
	struct jabber_transfer *tf = ft->data;
	struct xt_node *reply, *iqnode;

	if( tf->accepted )
		return;
	
	iqnode = jabber_make_packet( "iq", "error", tf->ini_jid, NULL );
	xt_add_attr( iqnode, "id", tf->iq_id );
	reply = jabber_make_error_packet( iqnode, "forbidden", "cancel", "403" );
	xt_free_node( iqnode );
	
	if( !jabber_write_packet( tf->ic, reply ) )
		imcb_log( tf->ic, "WARNING: Error generating reply to file transfer request" );
	xt_free_node( reply );

}

int jabber_si_check_features( struct jabber_transfer *tf, GSList *features ) {
	int foundft = FALSE, foundbt = FALSE, foundsi = FALSE;

	while ( features )
	{
		if( !strcmp( features->data, XMLNS_FILETRANSFER ) )
			foundft = TRUE;
		if( !strcmp( features->data, XMLNS_BYTESTREAMS ) )
			foundbt = TRUE;
		if( !strcmp( features->data, XMLNS_SI ) )
			foundsi = TRUE;

		features = g_slist_next(features);
	}

	if( !foundft )
		imcb_file_canceled( tf->ic, tf->ft, "Buddy's client doesn't feature file transfers" );
	else if( !foundbt )
		imcb_file_canceled( tf->ic, tf->ft, "Buddy's client doesn't feature byte streams (required)" );
	else if( !foundsi )
		imcb_file_canceled( tf->ic, tf->ft, "Buddy's client doesn't feature stream initiation (required)" );
		
	return foundft && foundbt && foundsi;
}

void jabber_si_transfer_start( struct jabber_transfer *tf ) {

	if( !jabber_si_check_features( tf, tf->bud->features ) )
		return;
		
	/* send the request to our buddy */
	jabber_si_send_request( tf->ic, tf->bud->full_jid, tf );

	/* and start the receive logic */
	imcb_file_recv_start( tf->ic, tf->ft );

}

gboolean jabber_si_waitfor_disco( gpointer data, gint fd, b_input_condition cond )
{
	struct jabber_transfer *tf = data;
	struct jabber_data *jd = tf->ic->proto_data;

	tf->disco_timeout_fired++;

	if( tf->bud->features && jd->have_streamhosts==1 ) {
		tf->disco_timeout = 0;
		jabber_si_transfer_start( tf );
		return FALSE;
	}

	/* 8 seconds should be enough for server and buddy to respond */
	if ( tf->disco_timeout_fired < 16 )
		return TRUE;
	
	if( !tf->bud->features && jd->have_streamhosts!=1 )
		imcb_log( tf->ic, "Couldn't get buddy's features nor discover all services of the server" );
	else if( !tf->bud->features )
		imcb_log( tf->ic, "Couldn't get buddy's features" );
	else
		imcb_log( tf->ic, "Couldn't discover some of the server's services" );
	
	tf->disco_timeout = 0;
	jabber_si_transfer_start( tf );
	return FALSE;
}

void jabber_si_transfer_request( struct im_connection *ic, file_transfer_t *ft, char *who ) 
{
	struct jabber_transfer *tf;
	struct jabber_data *jd = ic->proto_data;
	struct jabber_buddy *bud;
	char *server = jd->server, *s;

	if( ( s = strchr( who, '=' ) ) && jabber_chat_by_jid( ic, s + 1 ) )
		bud = jabber_buddy_by_ext_jid( ic, who, 0 );
	else
		bud = jabber_buddy_by_jid( ic, who, 0 );

	if( bud == NULL )
	{
		imcb_file_canceled( ic, ft, "Couldn't find buddy (BUG?)" );
		return;
	}
	
	imcb_log( ic, "Trying to send %s(%zd bytes) to %s", ft->file_name, ft->file_size, who );

	tf = g_new0( struct jabber_transfer, 1 );

	tf->ic = ic;
	tf->ft = ft;
	tf->fd = -1;
	tf->ft->data = tf;
	tf->ft->free = jabber_si_free_transfer;
	tf->bud = bud;
	ft->write = jabber_bs_send_write;

	jd->filetransfers = g_slist_prepend( jd->filetransfers, tf );

	/* query buddy's features and server's streaming proxies if neccessary */

	if( !tf->bud->features )
		jabber_iq_query_features( ic, bud->full_jid );

	/* If <auto> is not set don't check for proxies */
	if( ( jd->have_streamhosts!=1 ) && ( jd->streamhosts==NULL ) &&
	    ( strstr( set_getstr( &ic->acc->set, "proxy" ), "<auto>" ) != NULL ) ) {
		jd->have_streamhosts = 0;
		jabber_iq_query_server( ic, server, XMLNS_DISCO_ITEMS );
	} else if ( jd->streamhosts!=NULL )
		jd->have_streamhosts = 1;

	/* if we had to do a query, wait for the result. 
	 * Otherwise fire away. */
	if( !tf->bud->features || jd->have_streamhosts!=1 )
		tf->disco_timeout = b_timeout_add( 500, jabber_si_waitfor_disco, tf );
	else
		jabber_si_transfer_start( tf );
}

/*
 * First function that gets called when a file transfer request comes in.
 * A lot to parse.
 *
 * We choose a stream type from the options given by the initiator.
 * Then we wait for imcb to call the accept or cancel callbacks.
 */
int jabber_si_handle_request( struct im_connection *ic, struct xt_node *node, struct xt_node *sinode)
{
	struct xt_node *c, *d, *reply;
	char *sid, *ini_jid, *tgt_jid, *iq_id, *s, *ext_jid, *size_s;
	struct jabber_buddy *bud;
	int requestok = FALSE;
	char *name, *cmp;
	size_t size;
	struct jabber_transfer *tf;
	struct jabber_data *jd = ic->proto_data;
	file_transfer_t *ft;
	
	/* All this means we expect something like this: ( I think )
	 * <iq from=... to=... id=...>
	 * 	<si id=id xmlns=si profile=ft>
	 * 		<file xmlns=ft/>
	 * 		<feature xmlns=feature>
	 * 			<x xmlns=xdata type=submit>
	 * 				<field var=stream-method>
	 *
	 */
	if( !( ini_jid 		= xt_find_attr(   node, "from" ) 			) ||
	    !( tgt_jid 		= xt_find_attr(   node, "to" ) 				) ||
	    !( iq_id 		= xt_find_attr(   node, "id" ) 				) ||
	    !( sid 		= xt_find_attr( sinode, "id" ) 				) ||
	    !( cmp              = xt_find_attr( sinode, "profile" )                     ) ||
	    !( 0               == strcmp( cmp, XMLNS_FILETRANSFER )			) ||
	    !( d 		= xt_find_node( sinode->children, "file" ) 		) ||
	    !( cmp = xt_find_attr( d, "xmlns" )						) ||
	    !( 0               == strcmp( cmp, XMLNS_FILETRANSFER )			) ||
	    !( name 		= xt_find_attr( d, "name" ) 				) ||
	    !( size_s           = xt_find_attr( d, "size" )                             ) ||
	    !( 1               == sscanf( size_s, "%zd", &size )                        ) ||
	    !( d 		= xt_find_node( sinode->children, "feature" ) 		) ||
	    !( cmp              = xt_find_attr( d, "xmlns" )				) ||
	    !( 0               == strcmp( cmp, XMLNS_FEATURE )				) ||
	    !( d 		= xt_find_node( d->children, "x" ) 			) ||
	    !( cmp              = xt_find_attr( d, "xmlns" )				) ||
	    !( 0               == strcmp( cmp, XMLNS_XDATA )				) ||
	    !( cmp              = xt_find_attr( d, "type" )				) ||
	    !( 0               == strcmp( cmp, "form" )					) ||
	    !( d 		= xt_find_node( d->children, "field" ) 			) ||
	    !( cmp              = xt_find_attr( d, "var" )				) ||
	    !( 0               == strcmp( cmp, "stream-method" )			) )
	{
		imcb_log( ic, "WARNING: Received incomplete Stream Initiation request" );
	}
	else
	{
		/* Check if we support one of the options */

		c = d->children;
		while( ( c = xt_find_node( c, "option" ) ) )
			if( ( d = xt_find_node( c->children, "value" ) ) &&
			    ( d->text != NULL ) &&
			    ( strcmp( d->text, XMLNS_BYTESTREAMS ) == 0 ) )
			{
				requestok = TRUE;
				break;
			}
			else
			{
				c = c->next;
			}

		if ( !requestok )
			imcb_log( ic, "WARNING: Unsupported file transfer request from %s", ini_jid);
	}
	
	if( requestok )
	{
		/* Figure out who the transfer should come frome... */

		ext_jid = ini_jid;
		if( ( s = strchr( ini_jid, '/' ) ) )
		{
			if( ( bud = jabber_buddy_by_jid( ic, ini_jid, GET_BUDDY_EXACT ) ) )
			{
				bud->last_msg = time( NULL );
				ext_jid = bud->ext_jid ? : bud->bare_jid;
			}
			else
				*s = 0; /* We need to generate a bare JID now. */
		}

		if( !( ft = imcb_file_send_start( ic, ext_jid, name, size ) ) )
		{ 
			imcb_log( ic, "WARNING: Error handling transfer request from %s", ini_jid);
			requestok = FALSE;
		}

		if( s )
			*s = '/';
	}
	
	if( !requestok )
	{ 
		reply = jabber_make_error_packet( node, "item-not-found", "cancel", NULL );
		if (!jabber_write_packet( ic, reply ))
			imcb_log( ic, "WARNING: Error generating reply to file transfer request" );
		xt_free_node( reply );
		return XT_HANDLED;
	}

	/* Request is fine. */

	tf = g_new0( struct jabber_transfer, 1 );

	tf->ini_jid = g_strdup( ini_jid );
	tf->tgt_jid = g_strdup( tgt_jid );
	tf->iq_id = g_strdup( iq_id );
	tf->sid = g_strdup( sid );
	tf->ic = ic;
	tf->ft = ft;
	tf->fd = -1;
	tf->ft->data = tf;
	tf->ft->accept = jabber_si_answer_request;
	tf->ft->free = jabber_si_free_transfer;
	tf->ft->canceled = jabber_si_canceled;

	jd->filetransfers = g_slist_prepend( jd->filetransfers, tf );

	return XT_HANDLED;
}

/*
 * imc called the accept callback which probably means that the user accepted this file transfer.
 * We send our response to the initiator.
 * In the next step, the initiator will send us a request for the given stream type.
 * (currently that can only be a SOCKS5 bytestream)
 */
void jabber_si_answer_request( file_transfer_t *ft ) {
	struct jabber_transfer *tf = ft->data;
	struct xt_node *node, *sinode, *reply;

	/* generate response, start with the SI tag */
	sinode = xt_new_node( "si", NULL, NULL );
	xt_add_attr( sinode, "xmlns", XMLNS_SI );
	xt_add_attr( sinode, "profile", XMLNS_FILETRANSFER );
	xt_add_attr( sinode, "id", tf->sid );

	/* now the file tag */
	node = xt_new_node( "file", NULL, NULL );
	xt_add_attr( node, "xmlns", XMLNS_FILETRANSFER );

	xt_add_child( sinode, node );

	/* and finally the feature tag */
	node = xt_new_node( "field", NULL, NULL );
	xt_add_attr( node, "var", "stream-method" );
	xt_add_attr( node, "type", "list-single" );

	/* Currently all we can do. One could also implement in-band (IBB) */
	xt_add_child( node, xt_new_node( "value", XMLNS_BYTESTREAMS, NULL ) );

	node = xt_new_node( "x", NULL, node );
	xt_add_attr( node, "xmlns", XMLNS_XDATA );
	xt_add_attr( node, "type", "submit" );

	node = xt_new_node( "feature", NULL, node );
	xt_add_attr( node, "xmlns", XMLNS_FEATURE );

	xt_add_child( sinode, node );

	reply = jabber_make_packet( "iq", "result", tf->ini_jid, sinode );
	xt_add_attr( reply, "id", tf->iq_id );
	
	if( !jabber_write_packet( tf->ic, reply ) )
		imcb_log( tf->ic, "WARNING: Error generating reply to file transfer request" );
	else
		tf->accepted = TRUE;
	xt_free_node( reply );
}

static xt_status jabber_si_handle_response(struct im_connection *ic, struct xt_node *node, struct xt_node *orig )
{
	struct xt_node *c, *d;
	char *ini_jid = NULL, *tgt_jid, *iq_id, *cmp;
	GSList *tflist;
	struct jabber_transfer *tf=NULL;
	struct jabber_data *jd = ic->proto_data;

	if( !( tgt_jid = xt_find_attr( node, "from" ) ) ||
	    !( ini_jid = xt_find_attr( node, "to" ) ) )
	{
		imcb_log( ic, "Invalid SI response from=%s to=%s", tgt_jid, ini_jid );
		return XT_HANDLED;
	}
	
	/* All this means we expect something like this: ( I think )
	 * <iq from=... to=... id=...>
	 * 	<si xmlns=si>
	 * 	[	<file xmlns=ft/>    ] <-- not neccessary
	 * 		<feature xmlns=feature>
	 * 			<x xmlns=xdata type=submit>
	 * 				<field var=stream-method>
	 * 					<value>
	 */
	if( !( tgt_jid = xt_find_attr( node, "from" ) ) ||
	    !( ini_jid = xt_find_attr( node, "to" ) ) ||
	    !( iq_id   = xt_find_attr( node, "id" ) ) ||
	    !( c = xt_find_node( node->children, "si" ) ) ||
	    !( cmp = xt_find_attr( c, "xmlns" ) ) ||
	    !( strcmp( cmp, XMLNS_SI ) == 0 ) ||
	    !( d = xt_find_node( c->children, "feature" ) ) ||
	    !( cmp = xt_find_attr( d, "xmlns" ) ) ||
	    !( strcmp( cmp, XMLNS_FEATURE ) == 0 ) ||
	    !( d = xt_find_node( d->children, "x" ) ) ||
	    !( cmp = xt_find_attr( d, "xmlns" ) ) ||
	    !( strcmp( cmp, XMLNS_XDATA ) == 0 ) ||
	    !( cmp = xt_find_attr( d, "type" ) ) ||
	    !( strcmp( cmp, "submit" ) == 0 ) ||
	    !( d = xt_find_node( d->children, "field" ) ) ||
	    !( cmp = xt_find_attr( d, "var" ) ) ||
	    !( strcmp( cmp, "stream-method" ) == 0 ) ||
	    !( d = xt_find_node( d->children, "value" ) ) )
	{
		imcb_log( ic, "WARNING: Received incomplete Stream Initiation response" );
		return XT_HANDLED;
	}

	if( !( strcmp( d->text, XMLNS_BYTESTREAMS ) == 0 ) ) { 
		/* since we should only have advertised what we can do and the peer should
		 * only have chosen what we offered, this should never happen */
		imcb_log( ic, "WARNING: Received invalid Stream Initiation response, method %s", d->text );
			
		return XT_HANDLED;
	}
	
	/* Let's see if we can find out what this bytestream should be for... */

	for( tflist = jd->filetransfers ; tflist; tflist = g_slist_next(tflist) )
	{
		struct jabber_transfer *tft = tflist->data;
		if( ( strcmp( tft->iq_id, iq_id ) == 0 ) )
		{
		    	tf = tft;
			break;
		}
	}

	if (!tf) 
	{
		imcb_log( ic, "WARNING: Received bytestream request from %s that doesn't match an SI request", ini_jid );
		return XT_HANDLED;
	}

	tf->ini_jid = g_strdup( ini_jid );
	tf->tgt_jid = g_strdup( tgt_jid );

	imcb_log( ic, "File %s: %s accepted the transfer!", tf->ft->file_name, tgt_jid );

	jabber_bs_send_start( tf );

	return XT_HANDLED;
}

int jabber_si_send_request(struct im_connection *ic, char *who, struct jabber_transfer *tf )
{
	struct xt_node *node, *sinode;
	struct jabber_buddy *bud;

	/* who knows how many bits the future holds :) */
	char filesizestr[ 1 + ( int ) ( 0.301029995663981198f * sizeof( size_t ) * 8 ) ];

	const char *methods[] = 
	{  	
		XMLNS_BYTESTREAMS,
		//XMLNS_IBB,
		NULL 
	};
	const char **m;
	char *s;

	/* Maybe we should hash this? */
	tf->sid = g_strdup_printf( "BitlBeeJabberSID%d", tf->ft->local_id );
	
	if( ( s = strchr( who, '=' ) ) && jabber_chat_by_jid( ic, s + 1 ) )
		bud = jabber_buddy_by_ext_jid( ic, who, 0 );
	else
		bud = jabber_buddy_by_jid( ic, who, 0 );

	/* start with the SI tag */
	sinode = xt_new_node( "si", NULL, NULL );
	xt_add_attr( sinode, "xmlns", XMLNS_SI );
	xt_add_attr( sinode, "profile", XMLNS_FILETRANSFER );
	xt_add_attr( sinode, "id", tf->sid );

/*	if( mimetype ) 
		xt_add_attr( node, "mime-type", mimetype ); */

	/* now the file tag */
/*	if( desc )
 		node = xt_new_node( "desc", descr, NULL ); */
	node = xt_new_node( "range", NULL, NULL );

	sprintf( filesizestr, "%zd", tf->ft->file_size );
	node = xt_new_node( "file", NULL, node );
	xt_add_attr( node, "xmlns", XMLNS_FILETRANSFER );
	xt_add_attr( node, "name", tf->ft->file_name );
	xt_add_attr( node, "size", filesizestr );
/*	if (hash)
		xt_add_attr( node, "hash", hash );
	if (date)
		xt_add_attr( node, "date", date ); */

	xt_add_child( sinode, node );

	/* and finally the feature tag */
	node = xt_new_node( "field", NULL, NULL );
	xt_add_attr( node, "var", "stream-method" );
	xt_add_attr( node, "type", "list-single" );

	for ( m = methods ; *m ; m ++ )
		xt_add_child( node, xt_new_node( "option", NULL, xt_new_node( "value", (char *)*m, NULL ) ) );

	node = xt_new_node( "x", NULL, node );
	xt_add_attr( node, "xmlns", XMLNS_XDATA );
	xt_add_attr( node, "type", "form" );

	node = xt_new_node( "feature", NULL, node );
	xt_add_attr( node, "xmlns", XMLNS_FEATURE );

	xt_add_child( sinode, node );

	/* and we are there... */
	node = jabber_make_packet( "iq", "set", bud ? bud->full_jid : who, sinode );
	jabber_cache_add( ic, node, jabber_si_handle_response );
	tf->iq_id = g_strdup( xt_find_attr( node, "id" ) );
	
	return jabber_write_packet( ic, node );
}