/*
Plugin Name: Add Meta Keyword Tag
Plugin URI: http://www.projectarcanum.com/archive/2006/03/05/wordpress-plugin-add-meta-keyword-tag/
Description: Outputs meta keyword tags. For single posts it can create keywords from categories names or Bunny's Technorati Tags (or any custom field with keywords/tags).
Version: 1.0
Author: Cody Williams
Author URI: http://www.projectarcanum.com/

Copyright (c) 2006 Cody Williams
Released under the GNU General Public License (GPL)
http://www.gnu.org/licenses/gpl.txt
*/

/* Settings */
$use_categories = true;  // use category names as keywords
$categories_first = true;  // categories go first in keyword list. set to false to put categories after tags
$use_bunny = true;  // use Bunny's Technorati Tags as keywords, or basically any custom field with seperated tags

$single_only = true; // set to true to only output keywords on single posts.
$defaultkeywords = 'your, keywords, here'; // if $single_only is false, these keywords will be output on any page that is not a single post.

/* More Advanced Settings */
$bunny_custom_field = 'tags'; // the custom field of you bunny tags, by default is 'tags'.
$bunny_tag_seperator = ' '; // the tag seperator that seperates tags in the custom field. In Bunny's tags this defaults to space
/* End Settings */

function add_meta_keyword_tag() {
	global $use_categories, $categories_first, $use_bunny, $bunny_custom_field, $bunny_tag_seperator, $defaultkeywords, $single_only, $posts;
	
	$keywords = '';
	
	if (is_single()) {

		if (($use_categories) and ($categories_first)) {
			// create keywords from categories
			$categories = get_the_category($posts[0]->ID);
			$categorycount = count($categories);
			$count = 1;
			foreach( $categories as $cat ) {
				
				if ($count == $categorycount) {
					// last one, dont need a seperator
					$keywords .= $cat->category_nicename;
				} else {
					$keywords .= $cat->category_nicename . ', ';
				}
				
				$count = $count + 1;
			}
		}
		
		if ($use_bunny) {
			// create keywords from Bunny's Technorati Tags or something similair
			$gettags = get_post_custom($posts[0]->ID);
			$tags = $gettags[$bunny_custom_field][0];
			
			if(!empty($tags))
			{
				if (($categories_first) and ($use_categories)) {
					$keywords .= ', ';
				}
				$tags = str_replace($bunny_tag_seperator,', ',$tags);
				$keywords .= $tags;
				if (!($categories_first) and ($use_categories)) {
					$keywords .= ', ';
				}
			}
		}
		
		if (($use_categories) and !($categories_first)) {
			// create keywords from categories
			$categories = get_the_category($posts[0]->ID);
			$categorycount = count($categories);
			$count = 1;
			foreach( $categories as $cat ) {
				
				if ($count == $categorycount) {
					// last one, dont need a seperator
					$keywords .= $cat->category_nicename;
				} else {
					$keywords .= $cat->category_nicename . ', ';
				}
				
				$count = $count + 1;
			}
		}

	} else {
		if (!($single_only)) {
			$keywords = $defaultkeywords;
		}
	}
	// output meta keyword tag
	echo '<meta name="keywords" content="' . $keywords . '" />' . "\n";
}

add_action('wp_head', 'add_meta_keyword_tag');
?>