<?php
/*
Plugin Name: Contextual Related Posts
Version: 1.1
Plugin URI: http://weblogtoolscollection.com/
Description: Show last 5 contextually related posts on single blog posts, increase exposure
Author: Mark Ghosh (LaughingLizard)
Author URI: http://weblogtoolscollection.com

Copyright (c) 2004
Released under the GPL license
http://www.gnu.org/licenses/gpl.txt

    This file is part of WordPress.
    WordPress is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

	INSTALL: 
	Just install the plugin in your blog and activate

*/

$max_related = 5; //Change this to show maximum related links
$RelatedText = "<h2>Related Posts from the Past:</h2>"; // THis is displayed before the related posts

// Make sure that the plugin is installed, if not, create the tables
$RelatedPosts = get_option('RelatedPosts'); 
if ($RelatedPosts == '') { 
	global $table_prefix;
	$sql = "ALTER TABLE ".$table_prefix."posts ADD FULLTEXT(post_content,post_title)";
	$wpdb->query($sql);
	update_option('RelatedPosts', "RelatedPostsver11");
}
add_action('comment_form','related');

function related($temppostid='') {
	global $wpdb, $table_prefix, $max_related, $post, $RelatedText, $single;
	if ($single && $post->post_title != "") {
		$stuff = addslashes($post->post_title);
		$sql = "SELECT ID,post_title,post_content,post_excerpt,post_date, MATCH(post_title,post_content) AGAINST ('$stuff') AS score FROM ".$table_prefix."posts WHERE MATCH (post_title,post_content) AGAINST ('$stuff') and post_status = 'publish' and id <> $temppostid LIMIT 0,$max_related";
		$search_counter = 0;
		$searches = $wpdb->get_results($sql);
		echo '<div>'.$RelatedText;
		if($searches){
			echo "<ul>";
			foreach($searches as $search){
		    		$title = trim(stripslashes($search->post_title));
			if ($search_counter <= $max_related) { ?>
			    <li><a href="<?php echo get_permalink($search->ID);?>" rel="bookmark"><?php echo $title;?></a></li>
			<?php } //end of search_counter loop
			$search_counter++; } //end of foreach loop
		}else{
			echo "<p>No results.</p>"; 
		}
		echo '</ul></div><br/><br/>';
	}
}

?>