<?php
/**
 * Name: Facebook Connector
 * Version: 1.1
 * Author: Mike Macgirvin <http://macgirvin.com/profile/mike>
 *         Tobias Hößl <https://github.com/CatoTH/>
 */

/**
 * Installing the Friendica/Facebook connector
 *
 * 1. register an API key for your site from developer.facebook.com
 *   a. We'd be very happy if you include "Friendica" in the application name
 *      to increase name recognition. The Friendica icons are also present
 *      in the images directory and may be uploaded as a Facebook app icon.
 *      Use images/friendica-16.jpg for the Icon and images/friendica-128.jpg for the Logo.
 *   b. The url should be your site URL with a trailing slash.
 *      Friendica is a software application and does not require a Privacy Policy 
 *      or Terms of Service, though your installation of it might. Facebook may require
 *      that you provide a Privacy Policy, which we find ironic.  
 *   c. Set the following values in your .htconfig.php file
 *         $a->config['facebook']['appid'] = 'xxxxxxxxxxx';
 *         $a->config['facebook']['appsecret'] = 'xxxxxxxxxxxxxxx';
 *      Replace with the settings Facebook gives you.
 *   d. Navigate to Set Web->Site URL & Domain -> Website Settings.  Set 
 *      Site URL to yoursubdomain.yourdomain.com. Set Site Domain to your 
 *      yourdomain.com.
 * 2. (This step is now obsolete. Enable the plugin via the Admin panel.)
 *     Enable the facebook plugin by including it in .htconfig.php - e.g. 
 *     $a->config['system']['addon'] = 'plugin1,plugin2,facebook';
 * 3. Visit the Facebook Settings section of the "Settings->Plugin Settings" page.
 *    and click 'Install Facebook Connector'.
 * 4. This will ask you to login to Facebook and grant permission to the 
 *    plugin to do its stuff. Allow it to do so. 
 * 5. Optional step: If you want to use Facebook Real Time Updates (so new messages
 *    and new contacts are added ~1min after they are postet / added on FB), go to
 *    Settings -> plugins -> facebook and press the "Activate Real-Time Updates"-button.
 * 6. You're done. To turn it off visit the Plugin Settings page again and
 *    'Remove Facebook posting'.
 *
 * Vidoes and embeds will not be posted if there is no other content. Links 
 * and images will be converted to a format suitable for the Facebook API and 
 * long posts truncated - with a link to view the full post. 
 *
 * Facebook contacts will not be able to view private photos, as they are not able to
 * authenticate to your site to establish identity. We will address this 
 * in a future release.
 */

define('FACEBOOK_MAXPOSTLEN', 420);


function facebook_install() {
	register_hook('post_local',       'addon/facebook/facebook.php', 'facebook_post_local');
	register_hook('notifier_normal',  'addon/facebook/facebook.php', 'facebook_post_hook');
	register_hook('jot_networks',     'addon/facebook/facebook.php', 'facebook_jot_nets');
	register_hook('connector_settings',  'addon/facebook/facebook.php', 'facebook_plugin_settings');
	register_hook('cron',             'addon/facebook/facebook.php', 'facebook_cron');
	register_hook('queue_predeliver', 'addon/facebook/facebook.php', 'fb_queue_hook');
	
	if (get_config('facebook', 'realtime_active') == 1) facebook_subscription_add_users(); // Restore settings, if the plugin was installed before
}


function facebook_uninstall() {
	unregister_hook('post_local',       'addon/facebook/facebook.php', 'facebook_post_local');
	unregister_hook('notifier_normal',  'addon/facebook/facebook.php', 'facebook_post_hook');
	unregister_hook('jot_networks',     'addon/facebook/facebook.php', 'facebook_jot_nets');
	unregister_hook('connector_settings',  'addon/facebook/facebook.php', 'facebook_plugin_settings');
	unregister_hook('cron',             'addon/facebook/facebook.php', 'facebook_cron');
	unregister_hook('queue_predeliver', 'addon/facebook/facebook.php', 'fb_queue_hook');

	// hook moved
	unregister_hook('post_local_end',  'addon/facebook/facebook.php', 'facebook_post_hook');
	unregister_hook('plugin_settings',  'addon/facebook/facebook.php', 'facebook_plugin_settings');
	
	if (get_config('facebook', 'realtime_active') == 1) facebook_subscription_del_users();
}


/* declare the facebook_module function so that /facebook url requests will land here */

function facebook_module() {}


// If a->argv[1] is a nickname, this is a callback from Facebook oauth requests.
// If $_REQUEST["realtime_cb"] is set, this is a callback from the Real-Time Updates API

function facebook_init(&$a) {
	
	if (x($_REQUEST, "realtime_cb") && x($_REQUEST, "realtime_cb")) {
		logger("facebook_init: Facebook Real-Time callback called", LOGGER_DEBUG);
		
		if (x($_REQUEST, "hub_verify_token")) {
			// this is the verification callback while registering for real time updates
			
			$verify_token = get_config('facebook', 'cb_verify_token');
			if ($verify_token != $_REQUEST["hub_verify_token"]) {
				logger('facebook_init: Wrong Facebook Callback Verifier - expected ' . $verify_token . ', got ' . $_REQUEST["hub_verify_token"]);
				return;
			}
			
			if (x($_REQUEST, "hub_challenge")) {
				logger('facebook_init: Answering Challenge: ' . $_REQUEST["hub_challenge"], LOGGER_DATA);
				echo $_REQUEST["hub_challenge"];
				die();
			}
		}
		
		require_once('include/items.php');
		
		// this is a status update
		$content = file_get_contents("php://input");
		if (is_numeric($content)) $content = file_get_contents("php://input");
		$js = json_decode($content);
		logger(print_r($js, true), LOGGER_DATA);
		
		if (!isset($js->object) || $js->object != "user" || !isset($js->entry)) {
			logger('facebook_init: Could not parse Real-Time Update data', LOGGER_DEBUG);
			return;
		}
		
		$affected_users = array("feed" => array(), "friends" => array());
		
		foreach ($js->entry as $entry) {
			$fbuser = $entry->uid;
			foreach ($entry->changed_fields as $field) {
				if (!isset($affected_users[$field])) {
					logger('facebook_init: Unknown field "' . $field . '"');
					continue;
				}
				if (in_array($fbuser, $affected_users[$field])) continue;
				
				$r = q("SELECT `uid` FROM `pconfig` WHERE `cat` = 'facebook' AND `k` = 'self_id' AND `v` = '%s' LIMIT 1", dbesc($fbuser));
				if(! count($r))
					continue;
				$uid = $r[0]['uid'];
				
				$access_token = get_pconfig($uid,'facebook','access_token');
				if(! $access_token)
					return;
				
				switch ($field) {
					case "feed":
						logger('facebook_init: FB-User ' . $fbuser . ' / feed', LOGGER_DEBUG);
						
						if(! get_pconfig($uid,'facebook','no_wall')) {
							$private_wall = intval(get_pconfig($uid,'facebook','private_wall'));
							$s = fetch_url('https://graph.facebook.com/me/feed?access_token=' . $access_token);
							if($s) {
								$j = json_decode($s);
								logger('facebook_init: wall: ' . print_r($j,true), LOGGER_DATA);
								fb_consume_stream($uid,$j,($private_wall) ? false : true);
							}
						}
						
					break;
					case "friends":
						logger('facebook_init: FB-User ' . $fbuser . ' / friends', LOGGER_DEBUG);
						
						fb_get_friends($uid, false);
						set_pconfig($uid,'facebook','friend_check',time());
					break;
					default:
						logger('facebook_init: Unknown callback field for ' . $fbuser, LOGGER_NORMAL);
				}
				$affected_users[$field][] = $fbuser;
			}
		}
	}

	
	if($a->argc != 2)
		return;
	$nick = $a->argv[1];
	if(strlen($nick))
		$r = q("SELECT `uid` FROM `user` WHERE `nickname` = '%s' LIMIT 1",
				dbesc($nick)
		);
	if(! count($r))
		return;

	$uid           = $r[0]['uid'];
	$auth_code     = (x($_GET, 'code') ? $_GET['code'] : '');
	$error         = (x($_GET, 'error_description') ? $_GET['error_description'] : '');


	if($error)
		logger('facebook_init: Error: ' . $error);

	if($auth_code && $uid) {

		$appid = get_config('facebook','appid');
		$appsecret = get_config('facebook', 'appsecret');

		$x = fetch_url('https://graph.facebook.com/oauth/access_token?client_id='
			. $appid . '&client_secret=' . $appsecret . '&redirect_uri='
			. urlencode($a->get_baseurl() . '/facebook/' . $nick) 
			. '&code=' . $auth_code);

		logger('facebook_init: returned access token: ' . $x, LOGGER_DATA);

		if(strpos($x,'access_token=') !== false) {
			$token = str_replace('access_token=', '', $x);
 			if(strpos($token,'&') !== false)
				$token = substr($token,0,strpos($token,'&'));
			set_pconfig($uid,'facebook','access_token',$token);
			set_pconfig($uid,'facebook','post','1');
			if(get_pconfig($uid,'facebook','no_linking') === false)
				set_pconfig($uid,'facebook','no_linking',1);
			fb_get_self($uid);
			fb_get_friends($uid, true);
			fb_consume_all($uid);

		}

	}

}


function fb_get_self($uid) {
	$access_token = get_pconfig($uid,'facebook','access_token');
	if(! $access_token)
		return;
	$s = fetch_url('https://graph.facebook.com/me/?access_token=' . $access_token);
	if($s) {
		$j = json_decode($s);
		set_pconfig($uid,'facebook','self_id',(string) $j->id);
	}
}

function fb_get_friends_sync_new($uid, $access_token, $person) {
	$link = 'http://facebook.com/profile.php?id=' . $person->id;
	
	$r = q("SELECT * FROM `contact` WHERE `uid` = %d AND `url` = '%s' LIMIT 1",
		intval($uid),
		dbesc($link)
	);
	
	if (count($r) == 0) {
		logger('fb_get_friends: new contact found: ' . $link, LOGGER_DEBUG);
		
		fb_get_friends_sync_full($uid, $access_token, $person);
	}
}

function fb_get_friends_sync_full($uid, $access_token, $person) {
	$s = fetch_url('https://graph.facebook.com/' . $person->id . '?access_token=' . $access_token);
	if($s) {
		$jp = json_decode($s);
		logger('fb_get_friends: info: ' . print_r($jp,true), LOGGER_DATA);

		// always use numeric link for consistency

		$jp->link = 'http://facebook.com/profile.php?id=' . $person->id;

		// check if we already have a contact

		$r = q("SELECT * FROM `contact` WHERE `uid` = %d AND `url` = '%s' LIMIT 1",
			intval($uid),
			dbesc($jp->link)
		);			

		if(count($r)) {

			// check that we have all the photos, this has been known to fail on occasion

			if((! $r[0]['photo']) || (! $r[0]['thumb']) || (! $r[0]['micro'])) {  
				require_once("Photo.php");

				$photos = import_profile_photo('https://graph.facebook.com/' . $jp->id . '/picture', $uid, $r[0]['id']);

				$r = q("UPDATE `contact` SET `photo` = '%s', 
					`thumb` = '%s',
					`micro` = '%s', 
					`name-date` = '%s', 
					`uri-date` = '%s', 
					`avatar-date` = '%s'
					WHERE `id` = %d LIMIT 1
				",
					dbesc($photos[0]),
					dbesc($photos[1]),
					dbesc($photos[2]),
					dbesc(datetime_convert()),
					dbesc(datetime_convert()),
					dbesc(datetime_convert()),
					intval($r[0]['id'])
				);			
			}	
			return;
		}
		else {

			// create contact record 
			$r = q("INSERT INTO `contact` ( `uid`, `created`, `url`, `nurl`, `addr`, `alias`, `notify`, `poll`, 
				`name`, `nick`, `photo`, `network`, `rel`, `priority`,
				`writable`, `blocked`, `readonly`, `pending` )
				VALUES ( %d, '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', %d, %d, %d, 0, 0, 0 ) ",
				intval($uid),
				dbesc(datetime_convert()),
				dbesc($jp->link),
				dbesc(normalise_link($jp->link)),
				dbesc(''),
				dbesc(''),
				dbesc($jp->id),
				dbesc('facebook ' . $jp->id),
				dbesc($jp->name),
				dbesc(($jp->nickname) ? $jp->nickname : strtolower($jp->first_name)),
				dbesc('https://graph.facebook.com/' . $jp->id . '/picture'),
				dbesc(NETWORK_FACEBOOK),
				intval(CONTACT_IS_FRIEND),
				intval(1),
				intval(1)
			);
		}

		$r = q("SELECT * FROM `contact` WHERE `url` = '%s' AND `uid` = %d LIMIT 1",
			dbesc($jp->link),
			intval($uid)
		);

		if(! count($r)) {
			return;
		}

		$contact = $r[0];
		$contact_id  = $r[0]['id'];

		require_once("Photo.php");

		$photos = import_profile_photo($r[0]['photo'],$uid,$contact_id);

		$r = q("UPDATE `contact` SET `photo` = '%s', 
			`thumb` = '%s',
			`micro` = '%s', 
			`name-date` = '%s', 
			`uri-date` = '%s', 
			`avatar-date` = '%s'
			WHERE `id` = %d LIMIT 1
		",
			dbesc($photos[0]),
			dbesc($photos[1]),
			dbesc($photos[2]),
			dbesc(datetime_convert()),
			dbesc(datetime_convert()),
			dbesc(datetime_convert()),
			intval($contact_id)
		);			

	}
}

// if $fullsync is true, only new contacts are searched for

function fb_get_friends($uid, $fullsync = true) {

	$r = q("SELECT `uid` FROM `user` WHERE `uid` = %d AND `account_expired` = 0 LIMIT 1",
		intval($uid)
	);
	if(! count($r))
		return;

	$access_token = get_pconfig($uid,'facebook','access_token');

	$no_linking = get_pconfig($uid,'facebook','no_linking');
	if($no_linking)
		return;

	if(! $access_token)
		return;
	$s = fetch_url('https://graph.facebook.com/me/friends?access_token=' . $access_token);
	if($s) {
		logger('facebook: fb_get_friends: ' . $s, LOGGER_DATA);
		$j = json_decode($s);
		logger('facebook: fb_get_friends: json: ' . print_r($j,true), LOGGER_DATA);
		if(! $j->data)
			return;
		foreach($j->data as $person)
			if ($fullsync)
				fb_get_friends_sync_full($uid, $access_token, $person);
			else
				fb_get_friends_sync_new($uid, $access_token, $person);
	}
}

// This is the POST method to the facebook settings page
// Content is posted to Facebook in the function facebook_post_hook() 

function facebook_post(&$a) {

	$uid = local_user();
	if($uid){

		$value = ((x($_POST,'post_by_default')) ? intval($_POST['post_by_default']) : 0);
		set_pconfig($uid,'facebook','post_by_default', $value);

		$no_linking = get_pconfig($uid,'facebook','no_linking');

		$no_wall = ((x($_POST,'facebook_no_wall')) ? intval($_POST['facebook_no_wall']) : 0);
		set_pconfig($uid,'facebook','no_wall',$no_wall);

		$private_wall = ((x($_POST,'facebook_private_wall')) ? intval($_POST['facebook_private_wall']) : 0);
		set_pconfig($uid,'facebook','private_wall',$private_wall);
	

		set_pconfig($uid,'facebook','blocked_apps',escape_tags(trim($_POST['blocked_apps'])));

		$linkvalue = ((x($_POST,'facebook_linking')) ? intval($_POST['facebook_linking']) : 0);
		set_pconfig($uid,'facebook','no_linking', (($linkvalue) ? 0 : 1));

		// FB linkage was allowed but has just been turned off - remove all FB contacts and posts

		if((! intval($no_linking)) && (! intval($linkvalue))) {
			$r = q("SELECT `id` FROM `contact` WHERE `uid` = %d AND `network` = '%s' ",
				intval($uid),
				dbesc(NETWORK_FACEBOOK)
			);
			if(count($r)) {
				require_once('include/Contact.php');
				foreach($r as $rr)
					contact_remove($rr['id']);
			}
		}
		elseif(intval($no_linking) && intval($linkvalue)) {
			// FB linkage is now allowed - import stuff.
			fb_get_self($uid);
			fb_get_friends($uid, true);
			fb_consume_all($uid);
		}

		info( t('Settings updated.') . EOL);
	} 

	return;		
}

// Facebook settings form

function facebook_content(&$a) {

	if(! local_user()) {
		notice( t('Permission denied.') . EOL);
		return '';
	}

	if($a->argc > 1 && $a->argv[1] === 'remove') {
		del_pconfig(local_user(),'facebook','post');
		info( t('Facebook disabled') . EOL);
	}

	if($a->argc > 1 && $a->argv[1] === 'friends') {
		fb_get_friends(local_user(), true);
		info( t('Updating contacts') . EOL);
	}


	$fb_installed = get_pconfig(local_user(),'facebook','post');

	$appid = get_config('facebook','appid');

	if(! $appid) {
		notice( t('Facebook API key is missing.') . EOL);
		return '';
	}

	$a->page['htmlhead'] .= '<link rel="stylesheet" type="text/css" href="' 
		. $a->get_baseurl() . '/addon/facebook/facebook.css' . '" media="all" />' . "\r\n";

	$o .= '<h3>' . t('Facebook Connect') . '</h3>';

	if(! $fb_installed) { 
		$o .= '<div id="facebook-enable-wrapper">';

		$o .= '<a href="https://www.facebook.com/dialog/oauth?client_id=' . $appid . '&redirect_uri=' 
			. $a->get_baseurl() . '/facebook/' . $a->user['nickname'] . '&scope=publish_stream,read_stream,offline_access">' . t('Install Facebook connector for this account.') . '</a>';
		$o .= '</div>';
	}

	if($fb_installed) {
		$o .= '<div id="facebook-disable-wrapper">';

		$o .= '<a href="' . $a->get_baseurl() . '/facebook/remove' . '">' . t('Remove Facebook connector') . '</a></div>';

		$o .= '<div id="facebook-enable-wrapper">';

		$o .= '<a href="https://www.facebook.com/dialog/oauth?client_id=' . $appid . '&redirect_uri=' 
			. $a->get_baseurl() . '/facebook/' . $a->user['nickname'] . '&scope=publish_stream,read_stream,offline_access">' . t('Re-authenticate [This is necessary whenever your Facebook password is changed.]') . '</a>';
		$o .= '</div>';
	
		$o .= '<div id="facebook-post-default-form">';
		$o .= '<form action="facebook" method="post" >';
		$post_by_default = get_pconfig(local_user(),'facebook','post_by_default');
		$checked = (($post_by_default) ? ' checked="checked" ' : '');
		$o .= '<input type="checkbox" name="post_by_default" value="1"' . $checked . '/>' . ' ' . t('Post to Facebook by default') . EOL;

		$no_linking = get_pconfig(local_user(),'facebook','no_linking');
		$checked = (($no_linking) ? '' : ' checked="checked" ');
		$o .= '<input type="checkbox" name="facebook_linking" value="1"' . $checked . '/>' . ' ' . t('Link all your Facebook friends and conversations on this website') . EOL ;

		$o .= '<p>' . t('Facebook conversations consist of your <em>profile wall</em> and your friend <em>stream</em>.');
		$o .= ' ' . t('On this website, your Facebook friend stream is only visible to you.');
		$o .= ' ' . t('The following settings determine the privacy of your Facebook profile wall on this website.') . '</p>';

		$private_wall = get_pconfig(local_user(),'facebook','private_wall');
		$checked = (($private_wall) ? ' checked="checked" ' : '');
		$o .= '<input type="checkbox" name="facebook_private_wall" value="1"' . $checked . '/>' . ' ' . t('On this website your Facebook profile wall conversations will only be visible to you') . EOL ;


		$no_wall = get_pconfig(local_user(),'facebook','no_wall');
		$checked = (($no_wall) ? ' checked="checked" ' : '');
		$o .= '<input type="checkbox" name="facebook_no_wall" value="1"' . $checked . '/>' . ' ' . t('Do not import your Facebook profile wall conversations') . EOL ;

		$o .= '<p>' . t('If you choose to link conversations and leave both of these boxes unchecked, your Facebook profile wall will be merged with your profile wall on this website and your privacy settings on this website will be used to determine who may see the conversations.') . '</p>';


		$blocked_apps = get_pconfig(local_user(),'facebook','blocked_apps');

		$o .= '<div><label id="blocked-apps-label" for="blocked-apps">' . t('Comma separated applications to ignore') . ' </label></div>';
    	$o .= '<div><textarea id="blocked-apps" name="blocked_apps" >' . htmlspecialchars($blocked_apps) . '</textarea></div>';

		$o .= '<input type="submit" name="submit" value="' . t('Submit') . '" /></form></div>';
	}

	return $o;
}


function facebook_cron($a,$b) {

	$last = get_config('facebook','last_poll');
	
	$poll_interval = intval(get_config('facebook','poll_interval'));
	if(! $poll_interval)
		$poll_interval = 3600;

	if($last) {
		$next = $last + $poll_interval;
		if($next > time()) 
			return;
	}

	logger('facebook_cron');


	// Find the FB users on this site and randomize in case one of them
	// uses an obscene amount of memory. It may kill this queue run
	// but hopefully we'll get a few others through on each run. 

	$r = q("SELECT * FROM `pconfig` WHERE `cat` = 'facebook' AND `k` = 'post' AND `v` = '1' ORDER BY RAND() ");
	if(count($r)) {
		foreach($r as $rr) {
			if(get_pconfig($rr['uid'],'facebook','no_linking'))
				continue;
			$ab = intval(get_config('system','account_abandon_days'));
			if($ab > 0) {
				$z = q("SELECT `uid` FROM `user` WHERE `uid` = %d AND `login_date` > UTC_TIMESTAMP() - INTERVAL %d DAY LIMIT 1",
					intval($rr['uid']),
					intval($ab)
				);
				if(! count($z))
					continue;
			}

			// check for new friends once a day
			$last_friend_check = get_pconfig($rr['uid'],'facebook','friend_check');
			if($last_friend_check) 
				$next_friend_check = $last_friend_check + 86400;
			if($next_friend_check <= time()) {
				fb_get_friends($rr['uid'], true);
				set_pconfig($rr['uid'],'facebook','friend_check',time());
			}
			fb_consume_all($rr['uid']);
		}
	}
	
	if (get_config('facebook', 'realtime_active') == 1) {
		if (!facebook_check_realtime_active()) {
			
			logger('facebook_cron: Facebook is not sending Real-Time Updates any more, although it is supposed to. Trying to fix it...', LOGGER_NORMAL);
			facebook_subscription_add_users();
			
			if (facebook_check_realtime_active()) 
				logger('facebook_cron: Successful', LOGGER_NORMAL);
			else {
				logger('facebook_cron: Failed', LOGGER_NORMAL);
				
				if(strlen($a->config['admin_email']) && !get_config('facebook', 'realtime_err_mailsent')) {
					$res = mail($a->config['admin_email'], t('Problems with Facebook Real-Time Updates'), 
						"Hi!\n\nThere's a problem with the Facebook Real-Time Updates that cannob be solved automatically. Maybe an permission issue?\n\nThis e-mail will only be sent once.",
						'From: ' . t('Administrator') . '@' . $_SERVER['SERVER_NAME'] . "\n"
						. 'Content-type: text/plain; charset=UTF-8' . "\n"
						. 'Content-transfer-encoding: 8bit'
					);
					
					set_config('facebook', 'realtime_err_mailsent', 1);
				}
			}
		} else { // !facebook_check_realtime_active()
			del_config('facebook', 'realtime_err_mailsent');
		}
	}
	
	set_config('facebook','last_poll', time());

}


function facebook_plugin_settings(&$a,&$b) {

	$b .= '<div class="settings-block">';
	$b .= '<h3>' . t('Facebook') . '</h3>';
	$b .= '<a href="facebook">' . t('Facebook Connector Settings') . '</a><br />';
	$b .= '</div>';

}


function facebook_plugin_admin(&$a, &$o){
	
	$activated = facebook_check_realtime_active();
	if ($activated) {
		$o = t('Real-Time Updates are activated.') . '<br><br>';
		$o .= '<input type="submit" name="real_time_deactivate" value="' . t('Deactivate Real-Time Updates') . '">';
	} else {
		$o = t('Real-Time Updates not activated.') . '<br><input type="submit" name="real_time_activate" value="' . t('Activate Real-Time Updates') . '">';
	}
}

function facebook_plugin_admin_post(&$a, &$o){
	if (x($_REQUEST,'real_time_activate')) {
		facebook_subscription_add_users();
	}
	if (x($_REQUEST,'real_time_deactivate')) {
		facebook_subscription_del_users();
	}
}

function facebook_jot_nets(&$a,&$b) {
	if(! local_user())
		return;

	$fb_post = get_pconfig(local_user(),'facebook','post');
	if(intval($fb_post) == 1) {
		$fb_defpost = get_pconfig(local_user(),'facebook','post_by_default');
		$selected = ((intval($fb_defpost) == 1) ? ' checked="checked" ' : '');
		$b .= '<div class="profile-jot-net"><input type="checkbox" name="facebook_enable"' . $selected . ' value="1" /> ' 
			. t('Post to Facebook') . '</div>';	
	}
}


function facebook_post_hook(&$a,&$b) {


	if($b['deleted'] || ($b['created'] !== $b['edited']))
		return;

	/**
	 * Post to Facebook stream
	 */

	require_once('include/group.php');

	logger('Facebook post');

	$reply = false;
	$likes = false;

	$toplevel = (($b['id'] == $b['parent']) ? true : false);


	$linking = ((get_pconfig($b['uid'],'facebook','no_linking')) ? 0 : 1);

	if((! $toplevel) && ($linking)) {
		$r = q("SELECT * FROM `item` WHERE `id` = %d AND `uid` = %d LIMIT 1",
			intval($b['parent']),
			intval($b['uid'])
		);
		if(count($r) && substr($r[0]['uri'],0,4) === 'fb::')
			$reply = substr($r[0]['uri'],4);
		elseif(count($r) && substr($r[0]['extid'],0,4) === 'fb::')
			$reply = substr($r[0]['extid'],4);
		else
			return;

		$u = q("SELECT * FROM user where uid = %d limit 1",
			intval($b['uid'])
		);
		if(! count($u))
			return;

		// only accept comments from the item owner. Other contacts are unknown to FB.
 
		if(! link_compare($b['author-link'], $a->get_baseurl() . '/profile/' . $u[0]['nickname']))
			return;
		

		logger('facebook reply id=' . $reply);
	}

	if(strstr($b['postopts'],'facebook') || ($b['private']) || ($reply)) {

		if($b['private'] && $reply === false) {
			$allow_people = expand_acl($b['allow_cid']);
			$allow_groups = expand_groups(expand_acl($b['allow_gid']));
			$deny_people  = expand_acl($b['deny_cid']);
			$deny_groups  = expand_groups(expand_acl($b['deny_gid']));

			$recipients = array_unique(array_merge($allow_people,$allow_groups));
			$deny = array_unique(array_merge($deny_people,$deny_groups));

			$allow_str = dbesc(implode(', ',$recipients));
			if($allow_str) {
				$r = q("SELECT `notify` FROM `contact` WHERE `id` IN ( $allow_str ) AND `network` = 'face'"); 
				$allow_arr = array();
				if(count($r)) 
					foreach($r as $rr)
						$allow_arr[] = $rr['notify'];
			}

			$deny_str = dbesc(implode(', ',$deny));
			if($deny_str) {
				$r = q("SELECT `notify` FROM `contact` WHERE `id` IN ( $deny_str ) AND `network` = 'face'"); 
				$deny_arr = array();
				if(count($r)) 
					foreach($r as $rr)
						$deny_arr[] = $rr['notify'];
			}

			if(count($deny_arr) && (! count($allow_arr))) {

				// One or more FB folks were denied access but nobody on FB was specifically allowed access.
				// This might cause the post to be open to public on Facebook, but only to selected members
				// on another network. Since this could potentially leak a post to somebody who was denied, 
				// we will skip posting it to Facebook with a slightly vague but relevant message that will 
				// hopefully lead somebody to this code comment for a better explanation of what went wrong.

				notice( t('Post to Facebook cancelled because of multi-network access permission conflict.') . EOL);
				return;
			}


			// if it's a private message but no Facebook members are allowed or denied, skip Facebook post

			if((! count($allow_arr)) && (! count($deny_arr)))
				return;
		}

		if($b['verb'] == ACTIVITY_LIKE)
			$likes = true;				


		$appid  = get_config('facebook', 'appid'  );
		$secret = get_config('facebook', 'appsecret' );

		if($appid && $secret) {

			logger('facebook: have appid+secret');

			$fb_token  = get_pconfig($b['uid'],'facebook','access_token');


			// post to facebook if it's a public post and we've ticked the 'post to Facebook' box, 
			// or it's a private message with facebook participants
			// or it's a reply or likes action to an existing facebook post			

			if($fb_token && ($toplevel || $b['private'] || $reply)) {
				logger('facebook: able to post');
				require_once('library/facebook.php');
				require_once('include/bbcode.php');	

				$msg = $b['body'];

				logger('Facebook post: original msg=' . $msg, LOGGER_DATA);

				// make links readable before we strip the code

				// unless it's a dislike - just send the text as a comment

				if($b['verb'] == ACTIVITY_DISLIKE)
					$msg = trim(strip_tags(bbcode($msg)));

				$search_str = $a->get_baseurl() . '/search';

				if(preg_match("/\[url=(.*?)\](.*?)\[\/url\]/is",$msg,$matches)) {

					// don't use hashtags for message link

					if(strpos($matches[2],$search_str) === false) {
						$link = $matches[1];
						if(substr($matches[2],0,5) != '[img]')
							$linkname = $matches[2];
					}
				}

				// strip tag links to avoid link clutter, this really should be 
				// configurable because we're losing information

				$msg = preg_replace("/\#\[url=(.*?)\](.*?)\[\/url\]/is",'#$2',$msg);

				// provide the link separately for normal links
				$msg = preg_replace("/\[url=(.*?)\](.*?)\[\/url\]/is",'$2 $1',$msg);

				if(preg_match("/\[img\](.*?)\[\/img\]/is",$msg,$matches))
					$image = $matches[1];

				$msg = preg_replace("/\[img\](.*?)\[\/img\]/is", t('Image: ') . '$1', $msg);

				if((strpos($link,z_root()) !== false) && (! $image))
					$image = $a->get_baseurl() . '/images/friendica-64.jpg';

				$msg = trim(strip_tags(bbcode($msg)));
				$msg = html_entity_decode($msg,ENT_QUOTES,'UTF-8');

				// add any attachments as text urls

			    $arr = explode(',',$b['attach']);

			    if(count($arr)) {
					$msg .= "\n";
        			foreach($arr as $r) {
            			$matches = false;
						$cnt = preg_match('|\[attach\]href=\"(.*?)\" size=\"(.*?)\" type=\"(.*?)\" title=\"(.*?)\"\[\/attach\]|',$r,$matches);
						if($cnt) {
							$msg .= $matches[1];
						}
					}
				}

				if (strlen($msg) > FACEBOOK_MAXPOSTLEN) {
					$shortlink = "";
					require_once('library/slinky.php');

					$display_url = $b['plink'];

					$slinky = new Slinky( $display_url );
					// setup a cascade of shortening services
					// try to get a short link from these services
					// in the order ur1.ca, trim, id.gd, tinyurl
					$slinky->set_cascade( array( new Slinky_UR1ca(), new Slinky_Trim(), new Slinky_IsGd(), new Slinky_TinyURL() ) );
					$shortlink = $slinky->short();
					// the new message will be shortened such that "... $shortlink"
					// will fit into the character limit
					$msg = substr($msg, 0, FACEBOOK_MAXPOSTLEN - strlen($shortlink) - 4);
					$msg .= '... ' . $shortlink;
				}
				if(! strlen($msg))
					return;

				logger('Facebook post: msg=' . $msg, LOGGER_DATA);

				if($likes) { 
					$postvars = array('access_token' => $fb_token);
				}
				else {
					$postvars = array(
						'access_token' => $fb_token, 
						'message' => $msg
					);
					if(isset($image))
						$postvars['picture'] = $image;
					if(isset($link))
						$postvars['link'] = $link;
					if(isset($linkname))
						$postvars['name'] = $linkname;
				}

				if(($b['private']) && ($toplevel)) {
					$postvars['privacy'] = '{"value": "CUSTOM", "friends": "SOME_FRIENDS"';
					if(count($allow_arr))
						$postvars['privacy'] .= ',"allow": "' . implode(',',$allow_arr) . '"';
					if(count($deny_arr))
						$postvars['privacy'] .= ',"deny": "' . implode(',',$deny_arr) . '"';
					$postvars['privacy'] .= '}';

				}

				if($reply) {
					$url = 'https://graph.facebook.com/' . $reply . '/' . (($likes) ? 'likes' : 'comments');
				}
				else { 
					$url = 'https://graph.facebook.com/me/feed';
					if($b['plink'])
						$postvars['actions'] = '{"name": "' . t('View on Friendica') . '", "link": "' .  $b['plink'] . '"}';
				}

				logger('facebook: post to ' . $url);
				logger('facebook: postvars: ' . print_r($postvars,true));

				// "test_mode" prevents anything from actually being posted.
				// Otherwise, let's do it.

				if(! get_config('facebook','test_mode')) {
					$x = post_url($url, $postvars);

					$retj = json_decode($x);
					if($retj->id) {
						q("UPDATE `item` SET `extid` = '%s' WHERE `id` = %d LIMIT 1",
							dbesc('fb::' . $retj->id),
							intval($b['id'])
						);
					}
					else {
						if(! $likes) {
							$s = serialize(array('url' => $url, 'item' => $b['id'], 'post' => $postvars));
							require_once('include/queue_fn.php');
							add_to_queue($a->contact,NETWORK_FACEBOOK,$s);
							notice( t('Facebook post failed. Queued for retry.') . EOL);
						}
					}
					
					logger('Facebook post returns: ' . $x, LOGGER_DEBUG);
				}
			}
		}
	}
}


function facebook_post_local(&$a,&$b) {

	// Figure out if Facebook posting is enabled for this post and file it in 'postopts'
	// where we will discover it during background delivery.

	// This can only be triggered by a local user posting to their own wall.

	if((local_user()) && (local_user() == $b['uid'])) {

		$fb_post   = intval(get_pconfig(local_user(),'facebook','post'));
		$fb_enable = (($fb_post && x($_REQUEST,'facebook_enable')) ? intval($_REQUEST['facebook_enable']) : 0);

		// if API is used, default to the chosen settings
		if($_REQUEST['api_source'] && intval(get_pconfig(local_user(),'facebook','post_by_default')))
			$fb_enable = 1;

		if(! $fb_enable)
			return;

		if(strlen($b['postopts']))
			$b['postopts'] .= ',';
		$b['postopts'] .= 'facebook';
	}
}


function fb_queue_hook(&$a,&$b) {

	$qi = q("SELECT * FROM `queue` WHERE `network` = '%s'",
		dbesc(NETWORK_FACEBOOK)
	);
	if(! count($qi))
		return;

	require_once('include/queue_fn.php');

	foreach($qi as $x) {
		if($x['network'] !== NETWORK_FACEBOOK)
			continue;

		logger('facebook_queue: run');

		$r = q("SELECT `user`.* FROM `user` LEFT JOIN `contact` on `contact`.`uid` = `user`.`uid` 
			WHERE `contact`.`self` = 1 AND `contact`.`id` = %d LIMIT 1",
			intval($x['cid'])
		);
		if(! count($r))
			continue;

		$user = $r[0];

		$appid  = get_config('facebook', 'appid'  );
		$secret = get_config('facebook', 'appsecret' );

		if($appid && $secret) {
			$fb_post   = intval(get_pconfig($user['uid'],'facebook','post'));
			$fb_token  = get_pconfig($user['uid'],'facebook','access_token');

			if($fb_post && $fb_token) {
				logger('facebook_queue: able to post');
				require_once('library/facebook.php');

				$z = unserialize($x['content']);
				$item = $z['item'];
				$j = post_url($z['url'],$z['post']);

				$retj = json_decode($j);
				if($retj->id) {
					q("UPDATE `item` SET `extid` = '%s' WHERE `id` = %d LIMIT 1",
						dbesc('fb::' . $retj->id),
						intval($item)
					);
					logger('facebook_queue: success: ' . $j); 
					remove_queue_item($x['id']);
				}
				else {
					logger('facebook_queue: failed: ' . $j);
					update_queue_time($x['id']);
				}
			}
		}
	}
}

function fb_consume_all($uid) {

	require_once('include/items.php');

	$access_token = get_pconfig($uid,'facebook','access_token');
	if(! $access_token)
		return;
	
	if(! get_pconfig($uid,'facebook','no_wall')) {
		$private_wall = intval(get_pconfig($uid,'facebook','private_wall'));
		$s = fetch_url('https://graph.facebook.com/me/feed?access_token=' . $access_token);
		if($s) {
			$j = json_decode($s);
			logger('fb_consume_stream: wall: ' . print_r($j,true), LOGGER_DATA);
			fb_consume_stream($uid,$j,($private_wall) ? false : true);
		}
	}
	$s = fetch_url('https://graph.facebook.com/me/home?access_token=' . $access_token);
	if($s) {
		$j = json_decode($s);
		logger('fb_consume_stream: feed: ' . print_r($j,true), LOGGER_DATA);
		fb_consume_stream($uid,$j,false);
	}

}

function fb_get_photo($uid,$link) {
	$access_token = get_pconfig($uid,'facebook','access_token');
	if(! $access_token || (! stristr($link,'facebook.com/photo.php')))
		return "\n" . '[url=' . $link . ']' . t('link') . '[/url]';
	$ret = preg_match('/fbid=([0-9]*)/',$link,$match);
	if($ret)
		$photo_id = $match[1];
	$x = fetch_url('https://graph.facebook.com/' . $photo_id . '?access_token=' . $access_token);
	$j = json_decode($x);
	if($j->picture)
		return "\n\n" . '[url=' . $link . '][img]' . $j->picture . '[/img][/url]';
	else
		return "\n" . '[url=' . $link . ']' . t('link') . '[/url]';
}

function fb_consume_stream($uid,$j,$wall = false) {

	$a = get_app();


	$user = q("SELECT `nickname`, `blockwall` FROM `user` WHERE `uid` = %d AND `account_expired` = 0 LIMIT 1",
		intval($uid)
	);
	if(! count($user))
		return;

	$my_local_url = $a->get_baseurl() . '/profile/' . $user[0]['nickname'];

	$no_linking = get_pconfig($uid,'facebook','no_linking');
	if($no_linking)
		return;

	$self = q("SELECT * FROM `contact` WHERE `self` = 1 AND `uid` = %d LIMIT 1",
		intval($uid)
	);

	$blocked_apps = get_pconfig($uid,'facebook','blocked_apps');
	$blocked_apps_arr = explode(',',$blocked_apps);

	$self_id = get_pconfig($uid,'facebook','self_id');
	if(! count($j->data) || (! strlen($self_id)))
		return;

	foreach($j->data as $entry) {
		logger('fb_consume: entry: ' . print_r($entry,true), LOGGER_DATA);
		$datarray = array();

		$r = q("SELECT * FROM `item` WHERE ( `uri` = '%s' OR `extid` = '%s') AND `uid` = %d LIMIT 1",
				dbesc('fb::' . $entry->id),
				dbesc('fb::' . $entry->id),
				intval($uid)
		);
		if(count($r)) {
			$post_exists = true;
			$orig_post = $r[0];
			$top_item = $r[0]['id'];
		}
		else {
			$post_exists = false;
			$orig_post = null;
		}

		if(! $orig_post) {
			$datarray['gravity'] = 0;
			$datarray['uid'] = $uid;
			$datarray['wall'] = (($wall) ? 1 : 0);
			$datarray['uri'] = $datarray['parent-uri'] = 'fb::' . $entry->id;
			$from = $entry->from;
			if($from->id == $self_id)
				$datarray['contact-id'] = $self[0]['id'];
			else {
				$r = q("SELECT * FROM `contact` WHERE `notify` = '%s' AND `uid` = %d AND `blocked` = 0 AND `readonly` = 0 LIMIT 1",
					dbesc($from->id),
					intval($uid)
				);
				if(count($r))
					$datarray['contact-id'] = $r[0]['id'];
			}

			// don't store post if we don't have a contact

			if(! x($datarray,'contact-id')) {
				logger('no contact: post ignored');
				continue;
			}

			$datarray['verb'] = ACTIVITY_POST;
			if($wall) {
				$datarray['owner-name'] = $self[0]['name'];
				$datarray['owner-link'] = $self[0]['url'];
				$datarray['owner-avatar'] = $self[0]['thumb'];
			}
			if(isset($entry->application) && isset($entry->application->name) && strlen($entry->application->name))
				$datarray['app'] = strip_tags($entry->application->name);
			else
				$datarray['app'] = 'facebook';

			$found_blocked = false;

			if(count($blocked_apps_arr)) {
				foreach($blocked_apps_arr as $bad_appl) {
					if(strlen(trim($bad_appl)) && (stristr($datarray['app'],trim($bad_appl)))) {
						$found_blocked = true;
					}
				}
			}
				
			if($found_blocked) {
				logger('facebook: blocking application: ' . $datarray['app']);
				continue;
			}

			$datarray['author-name'] = $from->name;
			$datarray['author-link'] = 'http://facebook.com/profile.php?id=' . $from->id;
			$datarray['author-avatar'] = 'https://graph.facebook.com/' . $from->id . '/picture';
			$datarray['plink'] = $datarray['author-link'] . '&v=wall&story_fbid=' . substr($entry->id,strpos($entry->id,'_') + 1);

			$datarray['body'] = escape_tags($entry->message);

			if($entry->picture && $entry->link) {
				$datarray['body'] .= "\n\n" . '[url=' . $entry->link . '][img]' . $entry->picture . '[/img][/url]';
			}
			else {
				if($entry->picture)
					$datarray['body'] .= "\n\n" . '[img]' . $entry->picture . '[/img]';
				// if just a link, it may be a wall photo - check
				if($entry->link)
					$datarray['body'] .= fb_get_photo($uid,$entry->link);
			}
			if($entry->name)
				$datarray['body'] .= "\n" . $entry->name;
			if($entry->caption)
				$datarray['body'] .= "\n" . $entry->caption;
			if($entry->description)
				$datarray['body'] .= "\n" . $entry->description;
			$datarray['created'] = datetime_convert('UTC','UTC',$entry->created_time);
			$datarray['edited'] = datetime_convert('UTC','UTC',$entry->updated_time);

			// If the entry has a privacy policy, we cannot assume who can or cannot see it,
			// as the identities are from a foreign system. Mark it as private to the owner.

			if($entry->privacy && $entry->privacy->value !== 'EVERYONE') {
				$datarray['private'] = 1;
				$datarray['allow_cid'] = '<' . $uid . '>';
			}
			
			$top_item = item_store($datarray);
			$r = q("SELECT * FROM `item` WHERE `id` = %d AND `uid` = %d LIMIT 1",
				intval($top_item),
				intval($uid)
			);			
			if(count($r)) {
				$orig_post = $r[0];
				logger('fb: new top level item posted');
			}
		}

		if(isset($entry->likes) && isset($entry->likes->data))
			$likers = $entry->likes->data;
		else
			$likers = null;

		if(isset($entry->comments) && isset($entry->comments->data))
			$comments = $entry->comments->data;
		else
			$comments = null;

		if(is_array($likers)) {
			foreach($likers as $likes) {

				if(! $orig_post)
					continue;

				// If we posted the like locally, it will be found with our url, not the FB url.

				$second_url = (($likes->id == $self_id) ? $self[0]['url'] : 'http://facebook.com/profile.php?id=' . $likes->id); 

				$r = q("SELECT * FROM `item` WHERE `parent-uri` = '%s' AND `uid` = %d AND `verb` = '%s' 
					AND ( `author-link` = '%s' OR `author-link` = '%s' ) LIMIT 1",
					dbesc($orig_post['uri']),
					intval($uid),
					dbesc(ACTIVITY_LIKE),
					dbesc('http://facebook.com/profile.php?id=' . $likes->id),
					dbesc($second_url)
				);

				if(count($r))
					continue;
					
				$likedata = array();
				$likedata['parent'] = $top_item;
				$likedata['verb'] = ACTIVITY_LIKE;
				$likedata['gravity'] = 3;
				$likedata['uid'] = $uid;
				$likedata['wall'] = (($wall) ? 1 : 0);
				$likedata['uri'] = item_new_uri($a->get_baseurl(), $uid);
				$likedata['parent-uri'] = $orig_post['uri'];
				if($likes->id == $self_id)
					$likedata['contact-id'] = $self[0]['id'];
				else {
					$r = q("SELECT * FROM `contact` WHERE `notify` = '%s' AND `uid` = %d AND `blocked` = 0 AND `readonly` = 0 LIMIT 1",
						dbesc($likes->id),
						intval($uid)
					);
					if(count($r))
						$likedata['contact-id'] = $r[0]['id'];
				}
				if(! x($likedata,'contact-id'))
					$likedata['contact-id'] = $orig_post['contact-id'];

				$likedata['app'] = 'facebook';
				$likedata['verb'] = ACTIVITY_LIKE;						
				$likedata['author-name'] = $likes->name;
				$likedata['author-link'] = 'http://facebook.com/profile.php?id=' . $likes->id;
				$likedata['author-avatar'] = 'https://graph.facebook.com/' . $likes->id . '/picture';
				
				$author  = '[url=' . $likedata['author-link'] . ']' . $likedata['author-name'] . '[/url]';
				$objauthor =  '[url=' . $orig_post['author-link'] . ']' . $orig_post['author-name'] . '[/url]';
				$post_type = t('status');
        		$plink = '[url=' . $orig_post['plink'] . ']' . $post_type . '[/url]';
				$likedata['object-type'] = ACTIVITY_OBJ_NOTE;

				$likedata['body'] = sprintf( t('%1$s likes %2$s\'s %3$s'), $author, $objauthor, $plink);
				$likedata['object'] = '<object><type>' . ACTIVITY_OBJ_NOTE . '</type><local>1</local>' . 
					'<id>' . $orig_post['uri'] . '</id><link>' . xmlify('<link rel="alternate" type="text/html" href="' . xmlify($orig_post['plink']) . '" />') . '</link><title>' . $orig_post['title'] . '</title><content>' . $orig_post['body'] . '</content></object>';  

				$item = item_store($likedata);			
			}
		}
		if(is_array($comments)) {
			foreach($comments as $cmnt) {

				if(! $orig_post)
					continue;

				$r = q("SELECT * FROM `item` WHERE `uid` = %d AND ( `uri` = '%s' OR `extid` = '%s' ) LIMIT 1",
					intval($uid),
					dbesc('fb::' . $cmnt->id),
					dbesc('fb::' . $cmnt->id)
				);
				if(count($r))
					continue;

				$cmntdata = array();
				$cmntdata['parent'] = $top_item;
				$cmntdata['verb'] = ACTIVITY_POST;
				$cmntdata['gravity'] = 6;
				$cmntdata['uid'] = $uid;
				$cmntdata['wall'] = (($wall) ? 1 : 0);
				$cmntdata['uri'] = 'fb::' . $cmnt->id;
				$cmntdata['parent-uri'] = $orig_post['uri'];
				if($cmnt->from->id == $self_id) {
					$cmntdata['contact-id'] = $self[0]['id'];
				}
				else {
					$r = q("SELECT * FROM `contact` WHERE `notify` = '%s' AND `uid` = %d LIMIT 1",
						dbesc($cmnt->from->id),
						intval($uid)
					);
					if(count($r)) {
						$cmntdata['contact-id'] = $r[0]['id'];
						if($r[0]['blocked'] || $r[0]['readonly'])
							continue;
					}
				}
				if(! x($cmntdata,'contact-id'))
					$cmntdata['contact-id'] = $orig_post['contact-id'];

				$cmntdata['app'] = 'facebook';
				$cmntdata['created'] = datetime_convert('UTC','UTC',$cmnt->created_time);
				$cmntdata['edited']  = datetime_convert('UTC','UTC',$cmnt->created_time);
				$cmntdata['verb'] = ACTIVITY_POST;						
				$cmntdata['author-name'] = $cmnt->from->name;
				$cmntdata['author-link'] = 'http://facebook.com/profile.php?id=' . $cmnt->from->id;
				$cmntdata['author-avatar'] = 'https://graph.facebook.com/' . $cmnt->from->id . '/picture';
				$cmntdata['body'] = $cmnt->message;
				$item = item_store($cmntdata);			
			}
		}
	}
}


function fb_get_app_access_token() {
	
	$acc_token = get_config('facebook','app_access_token');
	
	if ($acc_token !== false) return $acc_token;
	
	$appid = get_config('facebook','appid');
	$appsecret = get_config('facebook', 'appsecret');
	
	if ($appid === false || $appsecret === false) {
		logger('fb_get_app_access_token: appid and/or appsecret not set', LOGGER_DEBUG);
		return false;
	}
	
	$x = fetch_url('https://graph.facebook.com/oauth/access_token?client_id=' . $appid . '&client_secret=' . $appsecret . "&grant_type=client_credentials");
	
	if(strpos($x,'access_token=') !== false) {
		logger('fb_get_app_access_token: returned access token: ' . $x, LOGGER_DATA);
	
		$token = str_replace('access_token=', '', $x);
 		if(strpos($token,'&') !== false)
			$token = substr($token,0,strpos($token,'&'));
		
		if ($token == "") {
			logger('fb_get_app_access_token: empty token: ' . $x, LOGGER_DEBUG);
			return false;
		}
		set_config('facebook','app_access_token',$token);
		return $token;
	} else {
		logger('fb_get_app_access_token: response did not contain an access_token: ' . $x, LOGGER_DATA);
		return false;
	}
}

function facebook_subscription_del_users() {
	$a = get_app();
	$access_token = fb_get_app_access_token();
	
	$url = "https://graph.facebook.com/" . get_config('facebook', 'appid'  ) . "/subscriptions?access_token=" . $access_token;
	facebook_delete_url($url);
	
	del_config('facebook', 'realtime_active');
}

function facebook_subscription_add_users() {
	
	$a = get_app();
	$access_token = fb_get_app_access_token();
	
	$url = "https://graph.facebook.com/" . get_config('facebook', 'appid'  ) . "/subscriptions?access_token=" . $access_token;
	
	list($usec, $sec) = explode(" ", microtime());
	$verify_token = sha1($usec . $sec . rand(0, 999999999));
	set_config('facebook', 'cb_verify_token', $verify_token);
	
	$cb = $a->get_baseurl() . '/facebook/?realtime_cb=1';
	
	$j = post_url($url,array(
		"object" => "user",
		"fields" => "feed,friends",
		"callback_url" => $cb,
		"verify_token" => $verify_token,
	));
	del_config('facebook', 'cb_verify_token');
	
	if ($j) {
		logger("Facebook reponse: " . $j, LOGGER_DATA);
		
		if (facebook_check_realtime_active()) set_config('facebook', 'realtime_active', 1);
	};
}

function facebook_subscriptions_get() {
	
	$access_token = fb_get_app_access_token();
	if (!$access_token) return null;
	
	$url = "https://graph.facebook.com/" . get_config('facebook', 'appid'  ) . "/subscriptions?access_token=" . $access_token;
	$j = fetch_url($url);
	$ret = null;
	if ($j) {
		$x = json_decode($j);
		if (isset($x->data)) $ret = $x->data;
	}
	return $ret;
}


function facebook_check_realtime_active() {
	$ret = facebook_subscriptions_get();
	if (is_null($ret)) return false;
	if (is_array($ret)) foreach ($ret as $re) if (is_object($re) && $re->object == "user") return true;
	return false;
}


// DELETE-request to $url

if(! function_exists('facebook_delete_url')) {
function facebook_delete_url($url,$headers = null, &$redirects = 0, $timeout = 0) {
	$a = get_app();
	$ch = curl_init($url);
	if(($redirects > 8) || (! $ch)) 
		return false;

	curl_setopt($ch, CURLOPT_HEADER, true);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER,true);
	curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "DELETE");
	curl_setopt($ch, CURLOPT_USERAGENT, "Friendica");

	if(intval($timeout)) {
		curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
	}
	else {
		$curl_time = intval(get_config('system','curl_timeout'));
		curl_setopt($ch, CURLOPT_TIMEOUT, (($curl_time !== false) ? $curl_time : 60));
	}

	if(defined('LIGHTTPD')) {
		if(!is_array($headers)) {
			$headers = array('Expect:');
		} else {
			if(!in_array('Expect:', $headers)) {
				array_push($headers, 'Expect:');
			}
		}
	}
	if($headers)
		curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

	$check_cert = get_config('system','verifyssl');
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, (($check_cert) ? true : false));
	$prx = get_config('system','proxy');
	if(strlen($prx)) {
		curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 1);
		curl_setopt($ch, CURLOPT_PROXY, $prx);
		$prxusr = get_config('system','proxyuser');
		if(strlen($prxusr))
			curl_setopt($ch, CURLOPT_PROXYUSERPWD, $prxusr);
	}

	$a->set_curl_code(0);

	// don't let curl abort the entire application
	// if it throws any errors.

	$s = @curl_exec($ch);

	$base = $s;
	$curl_info = curl_getinfo($ch);
	$http_code = $curl_info['http_code'];

	$header = '';

	// Pull out multiple headers, e.g. proxy and continuation headers
	// allow for HTTP/2.x without fixing code

	while(preg_match('/^HTTP\/[1-2].+? [1-5][0-9][0-9]/',$base)) {
		$chunk = substr($base,0,strpos($base,"\r\n\r\n")+4);
		$header .= $chunk;
		$base = substr($base,strlen($chunk));
	}

	if($http_code == 301 || $http_code == 302 || $http_code == 303) {
        $matches = array();
        preg_match('/(Location:|URI:)(.*?)\n/', $header, $matches);
        $url = trim(array_pop($matches));
        $url_parsed = @parse_url($url);
        if (isset($url_parsed)) {
            $redirects++;
            return delete_url($url,$headers,$redirects,$timeout);
        }
    }
	$a->set_curl_code($http_code);
	$body = substr($s,strlen($header));

	$a->set_curl_headers($header);

	curl_close($ch);
	return($body);
}}