<?php
/**
 * Name: Facebook Post Connector
 * Version: 1.3
 * Author: Mike Macgirvin <http://macgirvin.com/profile/mike>
 * Author: Tobias Hößl <https://github.com/CatoTH/>
 *
 */

/**
 * Installing the Friendica/Facebook connector
 *
 * Detailed instructions how to use this plugin can be found at
 * https://github.com/friendica/friendica/wiki/How-to:-Friendica%E2%80%99s-Facebook-connector
 *
 * 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.
 */
 

require_once('include/security.php');

function fbpost_install() {
	register_hook('post_local',       'addon/fbpost/fbpost.php', 'fbpost_post_local');
	register_hook('notifier_normal',  'addon/fbpost/fbpost.php', 'fbpost_post_hook');
	register_hook('jot_networks',     'addon/fbpost/fbpost.php', 'fbpost_jot_nets');
	register_hook('connector_settings',  'addon/fbpost/fbpost.php', 'fbpost_plugin_settings');
	register_hook('enotify',          'addon/fbpost/fbpost.php', 'fbpost_enotify');
	register_hook('queue_predeliver', 'addon/fbpost/fbpost.php', 'fbpost_queue_hook');
}


function fbpost_uninstall() {
	unregister_hook('post_local',       'addon/fbpost/fbpost.php', 'fbpost_post_local');
	unregister_hook('notifier_normal',  'addon/fbpost/fbpost.php', 'fbpost_post_hook');
	unregister_hook('jot_networks',     'addon/fbpost/fbpost.php', 'fbpost_jot_nets');
	unregister_hook('connector_settings',  'addon/fbpost/fbpost.php', 'fbpost_plugin_settings');
	unregister_hook('enotify',          'addon/fbpost/fbpost.php', 'fbpost_enotify');
	unregister_hook('queue_predeliver', 'addon/fbpost/fbpost.php', 'fbpost_queue_hook');


}


/* declare the fbpost_module function so that /fbpost url requests will land here */

function fbpost_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

/**
 * @param App $a
 */
function fbpost_init(&$a) {

	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(!(isset($r) && count($r)))
		return;

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


	if($error)
		logger('fbpost_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() . '/fbpost/' . $nick)
			. '&code=' . $auth_code);

		logger('fbpost_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');
			fbpost_get_self($uid);
		}

	}

}


/**
 * @param int $uid
 */
function fbpost_get_self($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);
	}
}


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

/**
 * @param App $a
 */
function fbpost_post(&$a) {

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


		$fb_limited = get_config('facebook','crestrict');


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

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

		$value = ((x($_POST,'post_to_page')) ? $_POST['post_to_page'] : "0-0");
		$values = explode("-", $value);
		set_pconfig($uid,'facebook','post_to_page', $values[0]);
		set_pconfig($uid,'facebook','page_access_token', $values[1]);

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

	return;
}

// Facebook settings form

/**
 * @param App $a
 * @return string
 */
function fbpost_content(&$a) {

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


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


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

	$o = '';
	
	$fb_installed = false;
	if (get_pconfig(local_user(),'facebook','post')) {
		$access_token = get_pconfig(local_user(),'facebook','access_token');
		if ($access_token) {
			$s = fetch_url('https://graph.facebook.com/me/feed?access_token=' . $access_token);
			if($s) {
				$j = json_decode($s);
				if (isset($j->data)) $fb_installed = true;
			}
		}
	}
	
	$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/fbpost/fbpost.css' . '" media="all" />' . "\r\n";

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

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

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

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

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

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

		$o .= '<a href="https://www.facebook.com/dialog/oauth?client_id=' . $appid . '&redirect_uri=' 
			. $a->get_baseurl() . '/fbpost/' . $a->user['nickname'] . '&scope=publish_stream,manage_pages,photo_upload,user_groups,offline_access">' . t('Re-authenticate [This is necessary whenever your Facebook password is changed.]') . '</a>';
		$o .= '</div>';

		$o .= '<div id="fbpost-post-default-form">';
		$o .= '<form action="fbpost" 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;

		$suppress_view_on_friendica = get_pconfig(local_user(),'facebook','suppress_view_on_friendica');
		$checked = (($suppress_view_on_friendica) ? ' checked="checked" ' : '');
		$o .= '<input type="checkbox" name="suppress_view_on_friendica" value="1"' . $checked . '/>' . ' ' . t('Suppress "View on friendica"') . EOL;

		// List all pages
		$post_to_page = get_pconfig(local_user(),'facebook','post_to_page');
		$page_access_token = get_pconfig(local_user(),'facebook','page_access_token');
		$fb_token  = get_pconfig($a->user['uid'],'facebook','access_token');
		$url = 'https://graph.facebook.com/me/accounts';
		$x = file_get_contents($url."?access_token=".$fb_token);
		$accounts = json_decode($x);

		$o .= t("Post to page/group:")."<select name='post_to_page'>";
		if (intval($post_to_page) == 0)
			$o .= "<option value='0-0' selected>".t('None')."</option>";
		else
			$o .= "<option value='0-0'>".t('None')."</option>";

		foreach($accounts->data as $account) {
			if (is_array($account->perms))
				if ($post_to_page == $account->id)
					$o .= "<option value='".$account->id."-".$account->access_token."' selected>".$account->name."</option>";
				else
					$o .= "<option value='".$account->id."-".$account->access_token."'>".$account->name."</option>";
		}

		$url = 'https://graph.facebook.com/me/groups';
		$x = file_get_contents($url."?access_token=".$fb_token);
		$groups = json_decode($x);

		foreach($groups->data as $group) {
			if ($post_to_page == $group->id)
				$o .= "<option value='".$group->id."-0' selected>".$group->name."</option>";
			else
				$o .= "<option value='".$group->id."-0'>".$group->name."</option>";
		}

		$o .= "</select>";

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

	}

	return $o;
}

/**
 * @param App $a
 * @param null|object $b
 */
function fbpost_plugin_settings(&$a,&$b) {

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

}


/**
 * @param App $a
 * @param null|object $o
 */
function fbpost_plugin_admin(&$a, &$o){


	$o = '<input type="hidden" name="form_security_token" value="' . get_form_security_token("fbsave") . '">';
	
	$o .= '<h4>' . t('Facebook API Key') . '</h4>';
	
	$appid  = get_config('facebook', 'appid'  );
	$appsecret = get_config('facebook', 'appsecret' );
	
	$ret1 = q("SELECT `v` FROM `config` WHERE `cat` = 'facebook' AND `k` = 'appid' LIMIT 1");
	$ret2 = q("SELECT `v` FROM `config` WHERE `cat` = 'facebook' AND `k` = 'appsecret' LIMIT 1");
	if ((count($ret1) > 0 && $ret1[0]['v'] != $appid) || (count($ret2) > 0 && $ret2[0]['v'] != $appsecret)) $o .= t('Error: it appears that you have specified the App-ID and -Secret in your .htconfig.php file. As long as they are specified there, they cannot be set using this form.<br><br>');
	
	$o .= '<label for="fb_appid">' . t('App-ID / API-Key') . '</label><input id="fb_appid" name="appid" type="text" value="' . escape_tags($appid ? $appid : "") . '"><br style="clear: both;">';
	$o .= '<label for="fb_appsecret">' . t('Application secret') . '</label><input id="fb_appsecret" name="appsecret" type="text" value="' . escape_tags($appsecret ? $appsecret : "") . '"><br style="clear: both;">';

	$o .= '<input type="submit" name="fb_save_keys" value="' . t('Save') . '">';
	
}

/**
 * @param App $a
 */

function fbpost_plugin_admin_post(&$a){
	check_form_security_token_redirectOnErr('/admin/plugins/fbpost', 'fbsave');
	
	if (x($_REQUEST,'fb_save_keys')) {
		set_config('facebook', 'appid', $_REQUEST['appid']);
		set_config('facebook', 'appsecret', $_REQUEST['appsecret']);

		info(t('The new values have been saved.'));
	}

}

/**
 * @param App $a
 * @param object $b
 * @return mixed
 */
function fbpost_jot_nets(&$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 fbpost_ShareAttributes($match) {

        $attributes = $match[1];

        $author = "";
        preg_match("/author='(.*?)'/ism", $attributes, $matches);
        if ($matches[1] != "")
                $author = $matches[1];

        preg_match('/author="(.*?)"/ism', $attributes, $matches);
        if ($matches[1] != "")
                $author = $matches[1];

        $headline = '<div class="shared_header">';

        $headline .= sprintf(t('%s:'), $author);

        $headline .= "</div>";

        $text = "<br />".$headline."</strong><blockquote>".$match[2]."</blockquote>";

        return($text);
}


/**
 * @param App $a
 * @param object $b
 * @return mixed
 */
function fbpost_post_hook(&$a,&$b) {


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

	/**
	 * Post to Facebook stream
	 */

	require_once('include/group.php');
	require_once('include/html2plain.php');

	logger('Facebook post');

	$reply = false;
	$likes = false;

	$deny_arr = array();
	$allow_arr = array();

	$toplevel = (($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 ( $allow_str ) AND `network` = 'face'"); 
				if(count($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 ( $deny_str ) AND `network` = 'face'"); 
				if(count($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)));

				// Old code
				/*$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)));*/

				// New code

				// Looking for the first image
				$image = '';
				if(preg_match("/\[img\=([0-9]*)x([0-9]*)\](.*?)\[\/img\]/is",$b['body'],$matches))
					$image = $matches[3];

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

				// When saved into the database the content is sent through htmlspecialchars
				// That means that we have to decode all image-urls
				$image = htmlspecialchars_decode($image);

				// Checking for a bookmark element
				$body = $b['body'];
				if (strpos($body, "[bookmark") !== false) {
					// splitting the text in two parts:
					// before and after the bookmark
					$pos = strpos($body, "[bookmark");
					$body1 = substr($body, 0, $pos);
					$body2 = substr($body, $pos);

					// Removing the bookmark and all quotes after the bookmark
					// they are mostly only the content after the bookmark.
					$body2 = preg_replace("/\[bookmark\=([^\]]*)\](.*?)\[\/bookmark\]/ism",'',$body2);
					$body2 = preg_replace("/\[quote\=([^\]]*)\](.*?)\[\/quote\]/ism",'',$body2);
					$body2 = preg_replace("/\[quote\](.*?)\[\/quote\]/ism",'',$body2);

					$body = $body1.$body2;
				}

				// Convert recycle signs
				$body = str_replace("\t", " ", $body);
				// recycle 1
				$recycle = html_entity_decode("&#x2672; ", ENT_QUOTES, 'UTF-8');
				$body = preg_replace( '/'.$recycle.'\[url\=(\w+.*?)\](\w+.*?)\[\/url\]/i', "\n\t$2:\t", $body);
				// recycle 2 (Test)
				$recycle = html_entity_decode("&#x25CC; ", ENT_QUOTES, 'UTF-8');
				$body = preg_replace( '/'.$recycle.'\[url\=(\w+.*?)\](\w+.*?)\[\/url\]/i', "\n\t$2:\t", $body);

				// share element
				$body = preg_replace_callback("/\[share(.*?)\]\s?(.*?)\s?\[\/share\]/ism","fbpost_ShareAttributes", $body);

				$bodyparts = explode("\t", $body);
				// Doesn't help with multiple repeats - the problem has to be solved later
				if (sizeof($bodyparts) == 3) {
					$html = bbcode($bodyparts[2], false, false);
					$test = trim(html2plain($html, 0, true));

					if (trim($bodyparts[0]) == "")
						$body = trim($bodyparts[2]);
					else if (trim($test) == "")
						$body = trim($bodyparts[0]);
					else
						$body = trim($bodyparts[0])."\n\n".trim($bodyparts[1])."[quote]".trim($bodyparts[2])."[/quote]";
				} else
					$body = str_replace("\t", "", $body);

				// At first convert the text to html
				$html = bbcode($body, false, false);

				// Then convert it to plain text
				$msg = trim($b['title']." \n\n".html2plain($html, 0, true));

				// Removing useless spaces
				if (substr($msg, -2) == "«")
					$msg = trim(substr($msg, 0, -2))."«";

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

				// Removing multiple newlines
				while (strpos($msg, "\n\n\n") !== false)
					$msg = str_replace("\n\n\n", "\n\n", $msg);

				// 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) {
							$msg .= "\n".$matches[1];
						}
					}
				}

				$link = '';
				$linkname = '';
				// look for bookmark-bbcode and handle it with priority
				if(preg_match("/\[bookmark\=([^\]]*)\](.*?)\[\/bookmark\]/is",$b['body'],$matches)) {
					$link = $matches[1];
					$linkname = $matches[2];
				}

				// If there is no bookmark element then take the first link
				if ($link == '') {
					$links = collecturls($html);
					if (sizeof($links) > 0) {
						reset($links);
						$link = current($links);
					}
				}

				// Remove trailing and leading spaces
				$msg = trim($msg);


				// Fallback - if message is empty
				if(!strlen($msg))
					$msg = $linkname;

				if(!strlen($msg))
					$msg = $link;

				if(!strlen($msg))
					$msg = $image;

				// If there is nothing to post then exit
				if(!strlen($msg))
					return;

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

				$video = "";

				if($likes) {
					$postvars = array('access_token' => $fb_token);
				} else {
					// message, picture, link, name, caption, description, source, place, tags
					if(trim($link) != "")
						if (@exif_imagetype($link) != 0) {
							$image = $link;
							$link = "";
						}

					$postvars = array(
						'access_token' => $fb_token,
						'message' => $msg
					);
					if(trim($image) != "")
						$postvars['picture'] = $image;

					if(trim($link) != "") {
						$postvars['link'] = $link;

						if ((stristr($link,'youtube')) || (stristr($link,'youtu.be')) || (stristr($link,'vimeo'))) {
							$video = $link;
						}
					}
					if(trim($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'] .= '}';

				}

				$post_to_page = get_pconfig($b['uid'],'facebook','post_to_page');
				$page_access_token = get_pconfig($b['uid'],'facebook','page_access_token');
				if ((intval($post_to_page) != 0) and ($page_access_token != ""))
					$target = $post_to_page;
				else
					$target = "me";

				if($reply) {
					$url = 'https://graph.facebook.com/' . $reply . '/' . (($likes) ? 'likes' : 'comments');
				} else if (($video != "") or (($image == "") and ($link != ""))) {
					// If it is a link to a video or a link without a preview picture then post it as a link
					if ($video != "")
						$link = $video;

					$postvars = array(
						'access_token' => $fb_token,
						'link' => $link,
					);
					if ($msg != $video)
						$postvars['message'] = $msg;

					$url = 'https://graph.facebook.com/'.$target.'/links';
				} else if (($link == "") and ($image != "")) {
					// If it is only an image without a page link then post this image as a photo
					$postvars = array(
						'access_token' => $fb_token,
						'url' => $image,
					);
					if ($msg != $image)
						$postvars['message'] = $msg;

					$url = 'https://graph.facebook.com/'.$target.'/photos';
				} else if (($link != "") or ($image != "") or ($b['title'] == '') or (strlen($msg) < 500)) {
					$url = 'https://graph.facebook.com/'.$target.'/feed';
					if (!get_pconfig($b['uid'],'facebook','suppress_view_on_friendica') and $b['plink'])
						$postvars['actions'] = '{"name": "' . t('View on Friendica') . '", "link": "' .  $b['plink'] . '"}';
				} else {
					// if its only a message and a subject and the message is larger than 500 characters then post it as note
					$postvars = array(
						'access_token' => $fb_token,
						'message' => bbcode($b['body'], false, false),
						'subject' => $b['title'],
					);
					$url = 'https://graph.facebook.com/'.$target.'/notes';
				}

				// Post to page?
				if (!$reply and ($target != "me") and $page_access_token)
					$postvars['access_token'] = $page_access_token;

				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);
					logger('Facebook post returns: ' . $x, LOGGER_DEBUG);

					$retj = json_decode($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);
						}

						if (isset($retj->error) && $retj->error->type == "OAuthException" && $retj->error->code == 190) {
							logger('Facebook session has expired due to changed password.', LOGGER_DEBUG);

							$last_notification = get_pconfig($b['uid'], 'facebook', 'session_expired_mailsent');
							if (!$last_notification || $last_notification < (time() - FACEBOOK_SESSION_ERR_NOTIFICATION_INTERVAL)) {
								require_once('include/enotify.php');

								$r = q("SELECT * FROM `user` WHERE `uid` = %d LIMIT 1", intval($b['uid']) );
								notification(array(
									'uid' => $b['uid'],
									'type' => NOTIFY_SYSTEM,
									'system_type' => 'facebook_connection_invalid',
									'language'     => $r[0]['language'],
									'to_name'      => $r[0]['username'],
									'to_email'     => $r[0]['email'],
									'source_name'  => t('Administrator'),
									'source_link'  => $a->config["system"]["url"],
									'source_photo' => $a->config["system"]["url"] . '/images/person-80.jpg',
								));

								set_pconfig($b['uid'], 'facebook', 'session_expired_mailsent', time());
							} else logger('Facebook: No notification, as the last one was sent on ' . $last_notification, LOGGER_DEBUG);
						}
					}
				}
			}
		}
	}
}

/**
 * @param App $app
 * @param object $data
 */
function fbpost_enotify(&$app, &$data) {
	if (x($data, 'params') && $data['params']['type'] == NOTIFY_SYSTEM && x($data['params'], 'system_type') && $data['params']['system_type'] == 'facebook_connection_invalid') {
		$data['itemlink'] = '/facebook';
		$data['epreamble'] = $data['preamble'] = t('Your Facebook connection became invalid. Please Re-authenticate.');
		$data['subject'] = t('Facebook connection became invalid');
		$data['body'] = sprintf( t("Hi %1\$s,\n\nThe connection between your accounts on %2\$s and Facebook became invalid. This usually happens after you change your Facebook-password. To enable the connection again, you have to %3\$sre-authenticate the Facebook-connector%4\$s."), $data['params']['to_name'], "[url=" . $app->config["system"]["url"] . "]" . $app->config["sitename"] . "[/url]", "[url=" . $app->config["system"]["url"] . "/facebook]", "[/url]");
	}
}

/**
 * @param App $a
 * @param object $b
 */
function fbpost_post_local(&$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
		// but allow a specific override

		if($_REQUEST['api_source'] && intval(get_pconfig(local_user(),'facebook','post_by_default'))) {
			if(! x($_REQUEST,'facebook_enable'))
				$fb_enable = 1;
		}

		if(! $fb_enable)
			return;

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


/**
 * @param App $a
 * @param object $b
 */
function fbpost_queue_hook(&$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']);
				}
			}
		}
	}
}


/**
 * @return bool|string
 */
function fbpost_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;
	}
	logger('https://graph.facebook.com/oauth/access_token?client_id=' . $appid . '&client_secret=' . $appsecret . '&grant_type=client_credentials', LOGGER_DATA);
	$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;
	}
}