<?php
/**
 * A page that display's a user's friends' recent Twitter.com posts.
 *
 * Will display only the posts since the user's previous visit (plus one more).
 * There is HTML at the bottom of this file, with three PHP classes preceding it.
 * 
 * INSTALLATION
 * You will need to enter the email address and password of your Twitter account
 * below, where indicated.
 * Upload this file to your server and visit the page.
 * 
 * NOTE
 * Some of your friends may be only providing updates to friends. So they won't 
 * thank you if you allow other people to view this page. Keep it secret!
 * 
 * The first time you should see 24 hours of posts. The next time you'll only see 
 * new posts.
 *
 * Feel free to copy, edit and share this providing you:
 * a) Retain the original authorship credit.
 * b) Retain a link to this URL: http://www.gyford.com/phil/writing/2006/12/02/quick_twitter.php
 * c) If you make changes, document what's changed.
 * d) Don't charge anyone.
 * 
 * Changes:
 * v1.1 - URLs in posts are now truncated and clickable.
 * v1.2 - Added no-cache, and minimised navigation.
 * v1.3 - Fixing display by oldest first.
 * v1.31 - Better handling of errors with the curl stuff.
 * v1.4 - Added ability to post status updates.
 *
 * @author Phil Gyford (phil@gyford.com)
 * @version 1.4
 * @link http://www.gyford.com/phil/writing/2006/12/02/quick_twitter.php
 */


/**
 * Class for fetching a user's Twitter.com feed.
 *
 * Currently only gets the timeline of a user's friends' posts but 
 * could be expanded to get other things too.
 * 
 * @author Phil Gyford (phil@gyford.com)
 */
class TwitterFeed {

	
	///////////////////////////////////////////////////////////////////////
	// CONFIGURATION.
	
	// The email address you use to log in at Twitter.
	var $email = 'youremailaddress';
	
	// Your Twitter password.
	var $password = 'yourpassword';
	
	// Do you want the posts to be ordered by 'newest' or 'oldest' first?
	var $order_by = 'newest';
	
	// END CONFIGURATION.
	///////////////////////////////////////////////////////////////////////
	
	
	/**
	 * This will store the time that you last looked at this page.
	 * Fetched from the cookie. Unixtime.
	 * @var integer
	 */
	var $previous_look;
	
	
	/**
	 * Are we going to show 'all' or 'recent' posts?
	 * Will be changed if the 'show' GET var is set.
	 * @var string
	 */
	var $show = 'recent';
	
	
	/**
	 * Constructor.
	 * 
	 * Gets the time the user last visited this page and sets the current time.
	 * Sets how many posts we're going to show.
	 * @access public
	 */
	function TwitterFeed()
	{
		if (is_numeric($_COOKIE['twitter-lastlook'])) {
			$this->previous_look = $_COOKIE['twitter-lastlook'];
		} else {
			// First time here.
			$this->previous_look = 0;
		}

		header('Set-Cookie:twitter-lastlook=' . gmmktime() . ';expires=Friday, 16-Jan-2037 00:00:00 GMT;domain=' . $_SERVER['SERVER_NAME'] . ";path=/\n\n");
		
		// Do we need to change the default number of posts to show?
		if (isset($_GET['show'])) {
			if ($_GET['show'] == 'all') {
				$this->show = 'all';
			} elseif ($_GET['show'] == 'recent') {
				$this->show = 'recent';
			}
		}
	}
	
	
	/**
	 * Show the latest posts from the user's friends.
	 * @access public
	 * @return boolean
	 */
	function display()
	{
		// Fetch the XML feed.
		$xml_data = $this->_fetchFileContents('http://twitter.com/statuses/friends_timeline.xml');

		// Turn the XML into an array of TwitterPost objects.
		$parser = new TwitterParser();
		$posts = $parser->parse($xml_data);
		
		return $this->_displayPosts($posts);
		
	}
	
	
	/**
	 * Create a new status update.
	 * @access public
	 * @param string $text The status text to send.
	 * @return string
	 */
	function post($text)
	{
		return $this->_fetchFileContents(
			'http://twitter.com/statuses/update.xml',
			array (
				'status' => $text
			)
		);
	}
	
	
	/**
	 * Display a list of posts.
	 * @access private
	 * @param array $posts An array of TwitterPost objects.
	 * @return boolean
	 */
	function _displayPosts($posts)
	{

		// The URL of this page, so we can have a Refresh link.
		$url = $_SERVER['PHP_SELF'];
		if ($_SERVER['QUERY_STRING']) {
			$url .= '?' . $_SERVER['QUERY_STRING'];
		}
			
		print "<p><a href=\"$url\">Refresh</a> &nbsp; ";

		// Navigation for recent/24hours.
		if ($this->show == 'recent') {
			print '[ Recent | <a href="?show=all">24 hours</a> ]';
			
		} elseif ($this->show == 'all') {
			print '[ <a href="?show=recent">Recent</a> | 24 hours ]';
		}

		print "</p>\n";
		
		if (strtotime($posts[0]->created_at) < $this->previous_look) {
			print "<p><em>No new twitters.</em></p>\n";
		}
		
		
		$html = '';
		foreach ($posts as $n => $post) {
			
			if ($this->show == 'recent' && strtotime($post->created_at) < $this->previous_look) {
				// This post is older than when we last looked. 
				// So we're not going to show any more.
				break;
			}
			
			if ($this->order_by == 'newest') {
				$html .= $post->display(false);
			} else {
				$html = $post->display(false) . $html;
			}
		}
		
		print $html;
		
		return true;
	}
	

	/**
	 * Replacement for file_get_contents for when URL file-access is disabled.
	 * @access private
	 * @param string $url The URL of the file to fetch.
	 * @param array $post_args A hash of POST arguments.
	 * @return string The contents of the file or empty on failure.
	 */
	function _fetchFileContents($url, $post_args=array())
	{
		$ch = curl_init();

		curl_setopt($ch, CURLOPT_URL, $url);
		curl_setopt ($ch, CURLOPT_TIMEOUT, 10);
		curl_setopt($ch, CURLOPT_USERPWD, $this->email.':'.$this->password);
		curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);

		// Return the result instead of printing it
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
		
		if (count($post_args) > 0) {
			$postfields = array();
			foreach ($post_args as $key => $val) {
				$postfields[] = "$key=" . urlencode(utf8_encode($val));
			}
			curl_setopt ( $ch, CURLOPT_POST, 1);
			curl_setopt ( $ch, CURLOPT_POSTFIELDS, implode('&', $postfields));
		}

		$string = curl_exec ($ch);
		
		if (curl_errno($ch)) {
		   print "<p>ERROR: " . curl_error($ch) . "</p>\n";
		}
		
		curl_close ($ch);
	
		if (!is_string($string) || !strlen($string)) {
			// Something went wrong with the curl_exec and it returned false.
			return '';
		} else {
			return $string;
		}
	}
	
	
}


/**
 * Class describing a single post to Twitter.
 *
 * This is not complete - it only describes the data we need to display.
 *
 * @author Phil Gyford (phil@gyford.com)
 */
class TwitterPost {
	
	/**
	 * The time the post was created at, in a format like 'Fri Dec 01 23:25:35 +0000 2006'
	 * @var string
	 */
	var $created_at = '';

	/**
	 * The content of the post.
	 * @var string
	 */
	var $text = '';
	
	/**
	 * The name of the post's author.
	 * @var string
	 */
	var $name = '';

	/**
	 * The screen name of the post's author.
	 * @var string
	 */
	var $screen_name = '';
	
	
	/**
	 * Display the post.
	 * @access public
	 * @param boolean $print Print the results or return them?
	 * @return mixed True or the string if we're returning it.
	 */
	function display($print=true)
	{
		$string = "<p><b><a href=\"http://twitter.com/" . $this->screen_name . "\">".$this->name."</a>:</b> " . $this->_truncateLinks($this->text) . ' <span class="time">' .  $this->_relativeTime($this->created_at) ."</span></p>\n";
		
		if ($print) {
			print $string;
			return true;
		} else {
			return $string;
		}
	}
	
	
	/**
	 * Returns a relative date, eg "4 hrs ago".
	 *
	 * Assumes the passed-in can be parsed by strtotime.
	 * Precision could be one of:
	 * 	1	5 hours, 3 minutes, 2 seconds ago (not yet implemented).
	 * 	2	5 hours, 3 minutes
	 * 	3	5 hours
	 *
	 * This is all a little overkill, but copied from other places I've used it.
	 * Also superfluous, now I've noticed that the Twitter API includes something
	 * similar, but this version is more accurate and less verbose.
	 *
	 * @access private
	 * @param string date In a format parseable by strtotime().
	 * @param integer precision
	 * @return string
	 */
	function _relativeTime ($date, $precision=2)
	{
		$time = strtotime($date);
		$now = gmmktime();

		$diff 	=  $now - $time;
		$months	=  floor($diff/2419200);
		$diff 	-= $months * 2419200;
		$weeks 	=  floor($diff/604800);
		$diff	-= $weeks*604800;
		$days 	=  floor($diff/86400);
		$diff 	-= $days * 86400;
		$hours 	=  floor($diff/3600);
		$diff 	-= $hours * 3600;
		$minutes = floor($diff/60);
		$diff 	-= $minutes * 60;
		$seconds = $diff;

		if ($days > 0) {
			// Over a day old, just show the actual date.
			// Probably won't happen as the feeds only have 24 hours of posts.
			return date('j M Y', $time);

		} else {
			$relative_date = '';
			if ($weeks > 0) {
				// Weeks and days
				$relative_date .= ($relative_date?', ':'').$weeks.' week'.($weeks>1?'s':'');
				if ($precision <= 2) {
					$relative_date .= $days>0?($relative_date?', ':'').$days.' day'.($days>1?'s':''):'';
					if ($precision == 1) {
						$relative_date .= $hours>0?($relative_date?', ':'').$hours.' hr'.($hours>1?'s':''):'';
					}
				}
			} elseif ($days > 0) {
				// days and hours
				$relative_date .= ($relative_date?', ':'').$days.' day'.($days>1?'s':'');
				if ($precision <= 2) {
					$relative_date .= $hours>0?($relative_date?', ':'').$hours.' hr'.($hours>1?'s':''):'';
					if ($precision == 1) {
						$relative_date .= $minutes>0?($relative_date?', ':'').$minutes.' min'.($minutes>1?'s':''):'';
					}
				}
			} elseif ($hours > 0) {
				// hours and minutes
				$relative_date .= ($relative_date?', ':'').$hours.' hr'.($hours>1?'s':'');
				if ($precision <= 2) {
					$relative_date .= $minutes>0?($relative_date?', ':'').$minutes.' min'.($minutes>1?'s':''):'';
					if ($precision == 1) {
						$relative_date .= $seconds>0?($relative_date?', ':'').$seconds.' sec'.($seconds>1?'s':''):'';
					}
				}
			} elseif ($minutes > 0) {
				// minutes only
				$relative_date .= ($relative_date?', ':'').$minutes.' min'.($minutes>1?'s':'');
				if ($precision == 1) {
					$relative_date .= $seconds>0?($relative_date?', ':'').$seconds.' sec'.($seconds>1?'s':''):'';
				}
			} else {
				// seconds only
				$relative_date .= ($relative_date?', ':'').$seconds.' sec'.($seconds>1?'s':'');
			}
		}

		// Return relative date and add proper verbiage
		return $relative_date.' ago';
	}
	
	
	/**
	 * Truncates any long links and makes them clickable.
	 * @access private
	 * @param string $text
	 * @param boolean $make_link_live Whether to make the links clickable.
	 * @return string The same text with short, possibly clickable links.
	 */
	function _truncateLinks($text, $make_link_live=true)
	{
		$link_length = 25;
		
		if ($make_link_live) {
			$replace = '(strlen(\'$0\')>$link_length) ? "<a href=\"$0\">".substr("$0",0,$link_length)."...</a>" : "<a href=\"$0\">$0</a>"';
		} else {
			$replace = '(strlen(\'$0\')>$link_length) ? substr("$0",0,$link_length)."..." : "$0"';
		}
		$text = preg_replace(
			"/((http(s?):\/\/))([a-zA-Z\d\_\.\+\,\;\?\%\~\-\/\#\='\*\$\!\(\)\&]+)([a-zA-Z\d\_\?\%\~\-\/\#\='\*\$\!\(\)\&])/e",
			$replace,
			$text);
	
		return $text;
	}
}


/**
 * A class for parsing a Twitter XML feed and creating an array of TwitterPost objects.
 *
 * @author Phil Gyford (phil@gyford.com)
 */
class TwitterParser {
	
	/**
	 * Holds a TwitterPost object when we're cycling through the XML.
	 * @var object
	 */
	var $current_post;
	
	/**
	 * Keeps track of which element in the XML we're currently within.
	 * @var string
	 */
	var $current_tag;
	
	/**
	 * Where we store an array of TwitterPosts gathered from the feed.
	 * @var array
	 */
	var $posts = array();
	
	
	/**
	 * Pass in some XML data, as a string, and it returns an array of TwitterPost objects.
	 * @access public
	 * @param string $xml_data A Twitter XML feed's contents.
	 * @return An array of TwitterPost objects.
	 */
	function parse ($xml_data)
	{
		$this->xml_parser = xml_parser_create();
		xml_set_object($this->xml_parser, $this);
		xml_set_element_handler($this->xml_parser, '_tagOpen', '_tagClose');
		xml_set_character_data_handler($this->xml_parser, '_characterData');
		xml_parser_set_option($this->xml_parser, XML_OPTION_CASE_FOLDING, false);
		
		// Start going through the data, calling the methods specified above for each bit.
		xml_parse($this->xml_parser, $xml_data);
		
		xml_parser_free($this->xml_parser);
		
		return $this->posts;
	}
	
	
	/**
	 * When we reach a new XML tag, what do we do?
	 * @access private
	 * @param object $parser An xml_parser object.
	 * @param string $tag A tag name.
	 * @param array $attributes
	 */
	function _tagOpen($parser, $tag, $attributes)
	{
		if ($tag == 'status') {
			// Starting a new post.
			$this->current_post = new TwitterPost;
			
		} elseif (!empty($this->current_post)) {
			// Inside a 'status' element, so record the tag's name.
			$this->current_tag = $tag;
		}
	}
	
	
	/**
	 * When we reach a closing XML tag, what do we do?
	 * @access private
	 * @param object $parser An xml_parser object.
	 * @param string $tag A tag name
	 */
	function _tagClose($parser, $tag)
	{
		if ($tag == 'status') {
			// Finished a post, add this one to our store.
			$this->posts[] = $this->current_post;
			// Re-set our post object ready for a new one.
			unset($this->current_post);
		}
	}
	
	
	/**
	 * What do we do with the contents of a tag?
	 * @access private
	 * @param object $parser An xml_parser object.
	 * @param string $cdata The contents of the tag.
	 */
	function _characterdata($parser, $cdata)
	{
		if (!empty($this->current_post)) {
			// Inside a 'status' element.
			if (isset($this->current_post->{$this->current_tag})) {
				// This is a property of the TwitterPost class, so save the data.
				$this->current_post->{$this->current_tag} .= trim($cdata);
			}
		}
	}	
}


// Below here is the HTML of the page...
?><html>
<head>
	<meta http-equiv="content-type" content="text/html; charset=utf-8" />
	<title>Your Recent Twitters</title>
	<style type="text/css">
		body {background: #fff; font-family:Arial,Helvetica,sans-serif; font-size:0.75em;}
		p {margin: 0 0 0.5em 0;}
		span.time {color: #999; font-size: 0.833em;}
		input.submit {font-size: 1em;}
	</style>
	<meta http-equiv="Pragma" content="no-cache" />
	<script type="text/javascript">
	<!--
		function countText() {
			f = document.statusForm;
			if (f.status.value.length > 140) {
				f.status.value = f.status.value.substring(0, 140);
			} else {
				document.getElementById('counter').innerHTML = 140 - f.status.value.length;
			}
		}
	//-->
	</script>
</head>
<body>

<?php 

$twitter = new TwitterFeed;
$status = '';

if (array_key_exists('status', $_POST) && strlen(trim($_POST['status'])) > 0) {
	$result = $twitter->post(trim($_POST['status']));
	if ($result) {
		print "<p>Update posted.</p>\n";
	} else {
		print "<p>Looks like the update didn't post.</p>\n";
		$status = $_POST['status'];
	}
}


?>
<form name="statusForm" method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<p><textarea name="status" cols="36" rows="4" onkeydown="countText();" onkeyup="countText();"><?php echo $status; ?></textarea><br />
	<a href="#" onclick="countText();">Characters left:</a> <span id="counter">140</span> <input class="submit" type="submit" value="Submit" /></p>
</form>

<?php 
$twitter->display(); 
?>

</body>
</html>