path: root/include/zot.php

<?php

require_once('include/crypto.php');
require_once('include/items.php');

/**
 *
 * @function zot_new_uid($channel_nick)
 * @channel_id = unique nickname of controlling entity
 * @returns string
 *
 */

function zot_new_uid($channel_nick) {
	$rawstr = z_root() . '/' . $channel_nick . '.' . mt_rand();
	return(base64url_encode(hash('whirlpool',$rawstr,true),true));
}


/**
 *
 * Given an array of zot_uid(s), return all distinct hubs
 * If primary is true, return only primary hubs
 * Result is ordered by url to assist in batching.
 * Return only the first primary hub as there should only be one.
 *
 */

function zot_get_hubloc($arr,$primary = false) {

	$tmp = '';
	
	if(is_array($arr)) {
		foreach($arr as $e) {
			if(strlen($tmp))
				$tmp .= ',';
			$tmp .= "'" . dbesc($e) . "'" ;
		}
	}
	
	if(! strlen($tmp))
		return array();

	$sql_extra = (($primary) ? " and hubloc_flags & " . intval(HUBLOC_FLAGS_PRIMARY) : "" );
	$limit = (($primary) ? " limit 1 " : "");
	return q("select * from hubloc where hubloc_hash in ( $tmp ) $sql_extra order by hubloc_url $limit");

}
	 
function zot_notify($channel,$url,$type = 'notify',$recipients = null, $remote_key = null) {


// FIXME json encode all params
// build the packet externally so that here we really are doing just a zot of the packet. 

	$params = array(
		'type' => $type,
		'sender' => json_encode(array(
			'guid' => $channel['channel_guid'],
			'guid_sig' => base64url_encode(rsa_sign($channel['channel_guid'],$channel['channel_prvkey'])),
			'url' => z_root(),
			'url_sig' => base64url_encode(rsa_sign(z_root(),$channel['channel_prvkey']))
		)), 
		'callback' => '/post',
		'version' => ZOT_REVISION
	);


	if($recipients)
		$params['recipients'] = json_encode($recipients);

	// Hush-hush ultra top-secret mode

	if($remote_key) {
		$params = aes_encapsulate($params,$remote_key);
	}

	$x = z_post_url($url,$params);
	return($x);
}

/*
 *
 * zot_build_packet builds a notification packet that you can either
 * store in the queue with a message array or call zot_zot to immediately 
 * zot it to the other side
 *
 */

function zot_build_packet($channel,$type = 'notify',$recipients = null, $remote_key = null, $secret = null) {

	$data = array(
		'type' => $type,
		'sender' => array(
			'guid' => $channel['channel_guid'],
			'guid_sig' => base64url_encode(rsa_sign($channel['channel_guid'],$channel['channel_prvkey'])),
			'url' => z_root(),
			'url_sig' => base64url_encode(rsa_sign(z_root(),$channel['channel_prvkey']))
		), 
		'callback' => '/post',
		'version' => ZOT_REVISION
	);


	if($recipients)
		$data['recipients'] = $recipients;

	if($secret)
		$data['secret'] = $secret; 

	logger('zot_build_packet: ' . print_r($data,true));

	// Hush-hush ultra top-secret mode

	if($remote_key) {
		$data = aes_encapsulate(json_encode($data),$remote_key);
	}

	return json_encode($data);
}


function zot_zot($url,$data) {
	return z_post_url($url,array('data' => $data));
}

function zot_finger($webbie,$channel) {


	if(strpos($webbie,'@') === false) {
		$address = $webbie;
		$host = get_app()->get_hostname();
	}
	else {
		$address = substr($webbie,0,strpos($webbie,'@'));
		$host = substr($webbie,strpos($webbie,'@')+1);
	}

	$xchan_addr = $address . '@' . $host;

	$r = q("select xchan.*, hubloc.* from xchan 
			left join hubloc on xchan_hash = hubloc_hash
			where xchan_addr = '%s' and (hubloc_flags & %d) limit 1",
		dbesc($xchan_address),
		intval(HUBLOC_FLAGS_PRIMARY)
	);

	if($r) {
		$url = $r[0]['hubloc_url'];
	}
	else {
		$url = 'https://' . $host;
	}
	
	$rhs = '/.well-known/zot-info';

	if($channel) {
		$postvars = array(
			'address'    => $address,
			'target'     => $channel['channel_guid'],
			'target_sig' => $channel['channel_guid_sig'],
			'key'        => $channel['channel_pubkey']
		);
		$result = z_post_url($url . $rhs,$postvars);
		if(! $result['success'])
			$result = z_post_url('http://' . $host . $rhs,$postvars);
	}		
	else {
		$rhs .= 'address=' . urlencode($address);

		$result =  z_fetch_url($url . $rhs);
		if(! $result['success'])
			$result = z_fetch_url('http://' . $host . $rhs);
	}
	
	return $result;	 

}

function zot_refresh($them,$channel = null) {

	if($them['hubloc_url'])
		$url = $them['hubloc_url'];
	else {
		$r = q("select hubloc_url from hubloc where hubloc_hash = '%s' and hubloc_flags & %d limit 1",
			dbesc($them['xchan_hash']),
			intval(HUBLOC_FLAGS_PRIMARY)
		);
		if($r)
			$url = $r[0]['hubloc_url'];
	}
	if(! $url)
		return;

	$postvars = array();

	if($channel) {
		$postvars['target']     = $channel['channel_guid'];
		$postvars['target_sig'] = $channel['channel_guid_sig'];
		$postvars['key']        = $channel['channel_pubkey'];
	}

	if(array_key_exists('xchan_addr',$them) && $them['xchan_addr'])
		$postvars['address'] = $them['xchan_addr'];
	if(array_key_exists('xchan_hash',$them) && $them['xchan_hash'])
		$postvars['guid_hash'] = $them['xchan_hash'];
	if(array_key_exists('xchan_guid',$them) && $them['xchan_guid'] 
		&& array_key_exists('xchan_guid_sig',$them) && $them['xchan_guid_sig']) {
		$postvars['guid'] = $them['xchan_guid'];
		$postvars['guid_sig'] = $them['xchan_guid_sig'];
	}

	$rhs = '/.well-known/zot-info';

	$result = z_post_url($url . $rhs,$postvars);
	
	if($result['success']) {

		$j = json_decode($result['body'],true);

		$x = import_xchan($j);

		if(! $x['success']) 
			return $x;

		$xchan_hash = $x['hash'];

		$their_perms = 0;


		if($channel) {
			$global_perms = get_perms();
			if($j['permissions']['data']) {
				$permissions = aes_unencapsulate(array(
					'data' => $j['permissions']['data'],
					'key'  => $j['permissions']['key'],
					'iv'   => $j['permissions']['iv']),
					$channel['channel_prvkey']);
				if($permissions)
					$permissions = json_decode($permissions,true);
				logger('decrypted permissions: ' . print_r($permissions,true), LOGGER_DATA);
			}
			else
				$permissions = $j['permissions'];

			foreach($permissions as $k => $v) {
				if($v) {
					$their_perms = $their_perms | intval($global_perms[$k][1]);
				}
			}

			$r = q("select * from abook where abook_xchan = '%s' and abook_channel = %d and not (abook_flags & %d) limit 1",
				dbesc($x['hash']),
				intval($channel['channel_id']),
				intval(ABOOK_FLAG_SELF)
			);
			if($r) {		
				$y = q("update abook set abook_their_perms = %d 
					where abook_xchan = '%s' and abook_channel = %d 
					and not (abook_flags & %d) limit 1",
					intval($their_perms),
					dbesc($x['hash']),
					intval($channel['channel_id']),
					intval(ABOOK_FLAG_SELF)
				);
				if(! $y)
					logger('abook update failed');
			}
			else {
				$default_perms = 0;
				// look for default permissions to apply in return - e.g. auto-friend
				$z = q("select * from abook where abook_channel = %d and (abook_flags & %d) limit 1",
					intval($channel['channel_id']),
					intval(ABOOK_FLAG_SELF)
				);
				if($z)
					$default_perms = intval($z[0]['my_perms']);		

				$y = q("insert into abook ( abook_account, abook_channel, abook_xchan, abook_their_perms, abook_my_perms, abook_created, abook_updated, abook_flags ) values ( %d, %d, '%s', %d, '%s', '%s', %d )",
					intval($channel['channel_account_id']),
					intval($channel['channel_id']),
					dbesc($x['hash']),
					intval($their_perms),
					intval($default_perms),
					dbesc(datetime_convert()),
					dbesc(datetime_convert()),
					intval(($default_perms) ? 0 : ABOOK_FLAG_BLOCKED|ABOOK_FLAG_IGNORED|ABOOK_FLAG_PENDING)
				);
				if($y) {
					logger("New introduction received for {$channel['channel_name']}");
					if($default_perms) {
						// send back a permissions update for auto-friend/auto-permissions
						$z = q("select * from abook where abook_xchan = '%s' and abook_channel = %d and not (abook_flags & %d) limit 1",
							dbesc($x['hash']),
							intval($channel['channel_id']),
							intval(ABOOK_FLAG_SELF)
						);
						if($z)
							proc_run('php','include/notifier.php','permissions_update',$z[0]['abook_id']);
					}
				}
			}
		}
		return true;
	}
	return false;

}

		
function zot_gethub($arr) {

	if($arr['guid'] && $arr['guid_sig'] && $arr['url'] && $arr['url_sig']) {
		$r = q("select * from hubloc 
				where hubloc_guid = '%s' and hubloc_guid_sig = '%s' 
				and hubloc_url = '%s' and hubloc_url_sig = '%s'
				limit 1",
			dbesc($arr['guid']),
			dbesc($arr['guid_sig']),
			dbesc($arr['url']),
			dbesc($arr['url_sig'])
		);
		if($r && count($r))
			return $r[0];
	}
	return null;
}

function zot_register_hub($arr) {

	$result = array('success' => false);

	if($arr['hub'] && $arr['hub_sig'] && $arr['guid'] && $arr['guid_sig']) {

		$guid_hash = base64url_encode(hash('whirlpool',$arr['guid'] . $arr['guid_sig'], true));

		$x = z_fetch_url($arr['hub'] . '/.well-known/zot-info/?f=&hash=' . $guid_hash);

		if($x['success']) {
			$record = json_decode($x['body'],true);
			$c = import_xchan($record);
			if($c['success'])
				$result['success'] = true;			
		}
	}
	return $result;
}


// Takes a json array from zot_finger and imports the xchan and hublocs
// If the xchan already exists, update the name and photo if these have changed.
// 


function import_xchan_from_json($j) {

	$ret = array('success' => false);

	$xchan_hash = base64url_encode(hash('whirlpool',$j->guid . $j->guid_sig, true));
	$import_photos = false;

	if(! rsa_verify($j->guid,base64url_decode($j->guid_sig),$j->key)) {
		logger('import_xchan_from_json: Unable to verify channel signature for ' . $j->address);
		$ret['message'] = t('Unable to verify channel signature');
		return $ret;
	}

	$r = q("select * from xchan where xchan_hash = '%s' limit 1",
		dbesc($xchan_hash)
	);	

	if($r) {
		if($r[0]['xchan_photo_date'] != $j->photo_updated)
			$update_photos = true;
		if($r[0]['xchan_name_date'] != $j->name_updated) {
			$r = q("update xchan set xchan_name = '%s', xchan_name_date = '%s' where xchan_hash = '%s' limit 1",
				dbesc($j->name),
				dbesc($j->name_updated),
				dbesc($xchan_hash)
			);
		}
	}
	else {
		$import_photos = true;
		$x = q("insert into xchan ( xchan_hash, xchan_guid, xchan_guid_sig, xchan_pubkey, xchan_photo_mimetype,
				xchan_photo_l, xchan_addr, xchan_url, xchan_name, xchan_network, xchan_photo_date, xchan_name_date)
				values ( '%s', '%s', '%s', '%s' , '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s') ",
			dbesc($xchan_hash),
			dbesc($j->guid),
			dbesc($j->guid_sig),
			dbesc($j->key),
			dbesc($j->photo_mimetype),
			dbesc($j->photo),
			dbesc($j->address),
			dbesc($j->url),
			dbesc($j->name),
			dbesc('zot'),
			dbesc($j->photo_updated),
			dbesc($j->name_updated)
		);

	}				


	if($import_photos) {

		require_once("Photo.php");

		$photos = import_profile_photo($j->photo,0,$xchan_hash);
		$r = q("update xchan set xchan_photo_date = '%s', xchan_photo_l = '%s', xchan_photo_m = '%s', xchan_photo_s = '%s', xchan_photo_mimetype = '%s'
				where xchan_hash = '%s' limit 1",
				dbesc($j->photo_updated),
				dbesc($photos[0]),
				dbesc($photos[1]),
				dbesc($photos[2]),
				dbesc($photos[3]),
				dbesc($xchan_hash)
		);
	}

	if($j->locations) {
		foreach($j->locations as $location) {
			if(! rsa_verify($location->url,base64url_decode($location->url_sig),$j->key)) {
				logger('import_xchan_from_json: Unable to verify site signature for ' . $location->url);
				$ret['message'] .= sprintf( t('Unable to verify site signature for %s'), $location->url) . EOL;
				continue;
			}

			$r = q("select * from hubloc where hubloc_hash = '%s' and hubloc_url = '%s' limit 1",
				dbesc($xchan_hash),
				dbesc($location->url)
			);
			if($r) {
				if(($r[0]['hubloc_flags'] & HUBLOC_FLAGS_PRIMARY) && (! $location->primary)) {
					$r = q("update hubloc set hubloc_flags = (hubloc_flags ^ %d) where hubloc_id = %d limit 1",
						intval(HUBLOC_FLAGS_PRIMARY),
						intval($r[0]['hubloc_id'])
					);
				}
				continue;
			}

			$r = q("insert into hubloc ( hubloc_guid, hubloc_guid_sig, hubloc_hash, hubloc_addr, hubloc_flags, hubloc_url, hubloc_url_sig, hubloc_host, hubloc_callback, hubloc_sitekey)
					values ( '%s','%s','%s','%s', %d ,'%s','%s','%s','%s','%s')",
				dbesc($j->guid),
				dbesc($j->guid_sig),
				dbesc($xchan_hash),
				dbesc($location->address),
				intval((intval($location->primary)) ? HUBLOC_FLAGS_PRIMARY : 0),
				dbesc($location->url),
				dbesc($location->url_sig),
				dbesc($location->host),
				dbesc($location->callback),
				dbesc($location->sitekey)
			);

		}

	}

	if(! x($ret,'message')) {
		$ret['success'] = true;
		$ret['hash'] = $xchan_hash;
	}
	return $ret;
}

// Takes a json associative array from zot_finger and imports the xchan and hublocs
// If the xchan already exists, update the name and photo if these have changed.
// 


function import_xchan($arr) {

	$ret = array('success' => false);

	$xchan_hash = base64url_encode(hash('whirlpool',$arr['guid'] . $arr['guid_sig'], true));
	$import_photos = false;

	if(! rsa_verify($arr['guid'],base64url_decode($arr['guid_sig']),$arr['key'])) {
		logger('import_xchan_from_json: Unable to verify channel signature for ' . $arr['address']);
		$ret['message'] = t('Unable to verify channel signature');
		return $ret;
	}

	$r = q("select * from xchan where xchan_hash = '%s' limit 1",
		dbesc($xchan_hash)
	);	

	if($r) {
		if($r[0]['xchan_photo_date'] != $arr['photo_updated'])
			$update_photos = true;
		if($r[0]['xchan_name_date'] != $arr['name_updated']) {
			$r = q("update xchan set xchan_name = '%s', xchan_name_date = '%s' where xchan_hash = '%s' limit 1",
				dbesc($arr['name']),
				dbesc($arr['name_updated']),
				dbesc($xchan_hash)
			);
		}
	}
	else {
		$import_photos = true;
		$x = q("insert into xchan ( xchan_hash, xchan_guid, xchan_guid_sig, xchan_pubkey, xchan_photo_mimetype,
				xchan_photo_l, xchan_addr, xchan_url, xchan_name, xchan_network, xchan_photo_date, xchan_name_date)
				values ( '%s', '%s', '%s', '%s' , '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s') ",
			dbesc($xchan_hash),
			dbesc($arr['guid']),
			dbesc($arr['guid_sig']),
			dbesc($arr['key']),
			dbesc($arr['photo_mimetype']),
			dbesc($arr['photo']),
			dbesc($arr['address']),
			dbesc($arr['url']),
			dbesc($arr['name']),
			dbesc('zot'),
			dbesc($arr['photo_updated']),
			dbesc($arr['name_updated'])
		);

	}				


	if($import_photos) {

		require_once("Photo.php");

		$photos = import_profile_photo($arr['photo'],0,$xchan_hash);
		$r = q("update xchan set xchan_photo_date = '%s', xchan_photo_l = '%s', xchan_photo_m = '%s', xchan_photo_s = '%s', xchan_photo_mimetype = '%s'
				where xchan_hash = '%s' limit 1",
				dbesc($arr['photo_updated']),
				dbesc($photos[0]),
				dbesc($photos[1]),
				dbesc($photos[2]),
				dbesc($photos[3]),
				dbesc($xchan_hash)
		);
	}

	if($arr['locations']) {
		foreach($arr['locations'] as $location) {
			if(! rsa_verify($location['url'],base64url_decode($location['url_sig']),$arr['key'])) {
				logger('import_xchan_from_json: Unable to verify site signature for ' . $location['url']);
				$ret['message'] .= sprintf( t('Unable to verify site signature for %s'), $location['url']) . EOL;
				continue;
			}

			$r = q("select * from hubloc where hubloc_hash = '%s' and hubloc_url = '%s' limit 1",
				dbesc($xchan_hash),
				dbesc($location['url'])
			);
			if($r) {
				if(($r[0]['hubloc_flags'] & HUBLOC_FLAGS_PRIMARY) && (! $location['primary'])) {
					$r = q("update hubloc set hubloc_flags = (hubloc_flags ^ %d) where hubloc_id = %d limit 1",
						intval(HUBLOC_FLAGS_PRIMARY),
						intval($r[0]['hubloc_id'])
					);
				}
				continue;
			}

			$r = q("insert into hubloc ( hubloc_guid, hubloc_guid_sig, hubloc_hash, hubloc_addr, hubloc_flags, hubloc_url, hubloc_url_sig, hubloc_host, hubloc_callback, hubloc_sitekey)
					values ( '%s','%s','%s','%s', %d ,'%s','%s','%s','%s','%s')",
				dbesc($arr['guid']),
				dbesc($arr['guid_sig']),
				dbesc($xchan_hash),
				dbesc($location['address']),
				intval((intval($location['primary'])) ? HUBLOC_FLAGS_PRIMARY : 0),
				dbesc($location['url']),
				dbesc($location['url_sig']),
				dbesc($location['host']),
				dbesc($location['callback']),
				dbesc($location['sitekey'])
			);

		}

	}

	if(! x($ret,'message')) {
		$ret['success'] = true;
		$ret['hash'] = $xchan_hash;
	}
	return $ret;
}

function zot_process_response($arr,$outq) {
	if(! $arr['success'])
		return;

	$x = json_decode($arr['body'],true);

	// synchronous message types are handled immediately
	// async messages remain in the queue until processed.

	if(intval($outq['outq_async'])) {
		$r = q("update outq set outq_delivered = 1, outq_updated = '%s' where outq_hash = '%s' and outq_channel = %d limit 1",
			dbesc(datetime_convert()),
			dbesc($outq['outq_hash']),
			intval($outq['outq_channel'])
		);
	}
	else {
		$r = q("delete from outq where outq_hash = '%s' and outq_channel = %d limit 1",
			dbesc($outq['outq_hash']),
			intval($outq['outq_channel'])
		);
	}

	logger('zot_process_response: ' . print_r($x,true), LOGGER_DATA);
}

function zot_fetch($arr) {

	logger('zot_fetch: ' . print_r($arr,true), LOGGER_DATA);

	$url = $arr['sender']['url'] . $arr['callback'];

	$ret_hub = zot_gethub($arr['sender']);
	if(! $ret_hub) {
		logger('zot_fetch: not ret_hub');
		return;
	}
	

	$ret_secret = json_encode(array($arr['secret'],'secret_sig' => base64url_encode(rsa_sign($arr['secret'],get_config('system','prvkey')))));
	

	$data = array(
		'type'    => 'pickup',
		'url'     => z_root(),
		'callback_sig' => base64url_encode(rsa_sign(z_root() . '/post',get_config('system','prvkey'))),
		'callback' => z_root() . '/post',
		'secret' => $arr['secret'],
		'secret_sig' => base64url_encode(rsa_sign($arr['secret'],get_config('system','prvkey')))
	);


	$datatosend = json_encode(aes_encapsulate(json_encode($data),$ret_hub['hubloc_sitekey']));
	
	$fetch = zot_zot($url,$datatosend);

	$result = zot_import($fetch);

}


function zot_import($arr) {

	logger('zot_import: ' . print_r($arr,true), LOGGER_DATA);

	$data = json_decode($arr['body'],true);

	logger('zot_import: data1: ' . print_r($data,true));

	if(array_key_exists('iv',$data)) {
		$data = json_decode(aes_unencapsulate($data,get_config('system','prvkey')),true);
    }

	logger('zot_import: data' . print_r($data,true), LOGGER_DATA);

	$incoming = $data['pickup'];
	if(is_array($incoming)) {
		foreach($incoming as $i) {

			if(array_key_exists('iv',$i['notify'])) {
				$i['notify'] = json_decode(aes_unencapsulate($i['notify'],get_config('system','prvkey')),true);
    		}

			logger('zot_import: notify: ' . print_r($i['notify'],true));

			$i['notify']['sender']['hash'] = base64url_encode(hash('whirlpool',$i['notify']['sender']['guid'] . $i['notify']['sender']['guid_sig'], true));
			$deliveries = null;

			if(array_key_exists('recipients',$i['notify']) && count($i['notify']['recipients'])) {
				logger('specific recipients');
				$recip_arr = array();
				foreach($i['notify']['recipients'] as $recip) {
					$recip_arr[] =  base64url_encode(hash('whirlpool',$recip['guid'] . $recip['guid_sig'], true));
				}
				logger('recip_arr: ' . print_r($recip_arr,true));
				stringify_array_elms($recip_arr);
				logger('recip_arr: ' . print_r($recip_arr,true));
				$recips = implode(',',$recip_arr);
				logger('recips: ' . $recips);
				$r = q("select channel_hash as hash from channel where channel_hash in ( " . $recips . " ) ");
				if(! $r)
					continue;

				$deliveries = $r;

				// We found somebody on this site that's in the recipient list. 


			}
			else {
				logger('public post');

				// Public post. look for any site members who are accepting posts from this sender
				$deliveries = public_recips($i);
			}
			if(! $deliveries)
				continue;
			
			if($i['message']) { 
				if($i['message']['type'] === 'activity') {
					$arr = get_item_elements($i['message']);

					logger('Activity received: ' . print_r($arr,true));
					logger('Activity recipients: ' . print_r($deliveries,true));

					$relay = ((array_key_exists('flags',$i['message']) && in_array('relay',$i['message']['flags'])) ? true : false);
					process_delivery($i['notify']['sender'],$arr,$deliveries,$relay);

				}
				elseif($i['message']['type'] === 'mail') {
					$arr = get_mail_elements($i['message']);

					logger('Mail received: ' . print_r($arr,true));
					logger('Mail recipients: ' . print_r($deliveries,true));


					process_mail_delivery($i['notify']['sender'],$arr,$deliveries);

				}
			}

		}
	}
}


// A public message with no listed recipients can be delivered to anybody who
// has PERMS_NETWORK for that type of post, or PERMS_SITE and is one the same
// site, or PERMS_SPECIFIC and the sender is a contact who is granted 
// permissions via their connection permissions in the address book.
// Here we take a given message and construct a list of hashes of everybody
// on the site that we should deliver to.  



function public_recips($msg) {

	logger('public_recips: ' . print_r($msg,true));

	if($msg['message']['type'] === 'activity') {
		if(array_key_exists('flags',$msg['message']) && in_array('thread_parent', $msg['message']['flags'])) {
			$col = 'channel_w_stream';
			$field = PERMS_W_STREAM;
		}
		else {
			$col = 'channel_w_comment';
			$field = PERMS_W_COMMENT;
		}
	}
	elseif($msg['message']['type'] === 'mail') {
		$col = 'channel_w_mail';
		$field = PERMS_W_MAIL;
	}

	if(! $col)
		return NULL;

	if($msg['notify']['sender']['url'] === z_root())
		$sql = " where (( " . $col . " & " . PERMS_NETWORK . " )  or ( " . $col . " & " . PERMS_SITE . " )) ";				
	else
		$sql = " where ( " . $col . " & " . PERMS_NETWORK . " ) " ;

	$r = q("select channel_hash as hash from channel " . $sql );

	if(! $r)
		$r = array();

	$x = q("select channel_hash as hash from channel left join abook on abook_channel = channel_id where abook_xchan = '%s'
		and ( " . $col . " & " . PERMS_SPECIFIC . " )  and ( abook_my_perms & " . $field . " ) ",
		dbesc($msg['notify']['sender']['hash'])
	); 

	if(! $x)
		$x = array();

	$r = array_merge($r,$x);


	return $r;
}


function process_delivery($sender,$arr,$deliveries,$relay) {

	
	foreach($deliveries as $d) {
		$r = q("select * from channel where channel_hash = '%s' limit 1",
			dbesc($d['hash'])
		);

		if(! $r)
			continue;

		$channel = $r[0];

		$perm = (($arr['uri'] == $arr['parent_uri']) ? 'send_stream' : 'post_comments');

		if(! perm_is_allowed($channel['channel_id'],$sender['hash'],$perm)) {
			logger("permission denied for delivery {$channel['channel_id']}");
			continue;
		}
	

		if($arr['item_restrict'] & ITEM_DELETED) {
			delete_imported_item($sender,$arr,$channel['channel_id']);
			continue;
		}

		$r = q("select id, edited from item where uri = '%s' and uid = %d limit 1",
			dbesc($arr['uri']),
			intval($channel['channel_id'])
		);
		if($r) {
			if($arr['edited'] > $r[0]['edited'])
				update_imported_item($sender,$arr,$channel['channel_id']);
			$item_id = $r[0]['id'];
		}
		else {
			$arr['aid'] = $channel['channel_account_id'];
			$arr['uid'] = $channel['channel_id'];
			$item_id = item_store($arr);
		}

		if($relay && $item_id) {
			logger('process_delivery: invoking relay');
			proc_run('php','include/notifier.php','relay',intval($item_id));
		}
	}
}


function update_imported_item($sender,$item,$uid) {
// FIXME
	logger('update_imported_item');

}

function delete_imported_item($sender,$item,$uid) {

	$r = q("select id from item where author_xchan = '%s' or owner_xchan = '%s'
		and uri = '%s' and uid = %d limit 1",
		dbesc($sender['hash']),
		dbesc($sender['hash']),
		dbesc($item['uri']),
		intval($uid)
	);
	if(! $r) {
		logger('delete_imported_item: failed: ownership issue');
		return;
	}
		
	$r = q("update item set body = '', title = '', item_restrict = %d, edited = '%s', changed = '%s'
		where ( thr_parent = '%s' or parent_uri = '%s' ) and uid = %d",
		intval(ITEM_DELETED),
		dbesc(datetime_convert()),
		dbesc(datetime_convert()),
		dbesc($item['uri']),
		dbesc($item['uri']),
		intval($uid)
	);

	if(! $r)
		logger("delete_imported_item: db update failed. Item = {$item['uri']} uid = $uid");

}

function process_mail_delivery($sender,$arr,$deliveries) {

	
	foreach($deliveries as $d) {
		$r = q("select * from channel where channel_hash = '%s' limit 1",
			dbesc($d['hash'])
		);

		if(! $r)
			continue;

		$channel = $r[0];

		if(! perm_is_allowed($channel['channel_id'],$sender['hash'],'post_mail')) {
			logger("permission denied for mail delivery {$channel['channel_id']}");
			continue;
		}
	
		$r = q("select id from mail where uri = '%s' and channel_id = %d limit 1",
			dbesc($arr['uri']),
			intval($channel['channel_id'])
		);
		if($r) {
			logger('duplicate mail received');
			continue;
		}
		else {
			$arr['account_id'] = $channel['channel_account_id'];
			$arr['channel_id'] = $channel['channel_id'];
			$item_id = mail_store($arr);
		}
	}
}