Thread: Could someone guide me in the right direction please?

// Add categories to a post based on keywords in the title.
// Modify the $title_keywords array.  Use one keyword => one category name
// Categories MUST exist first.  The Post title keywords will match regardless of case.
function test_add_category ($post_id = 0) {
   if (!$post_id) return;
if ( $post->post_type != 'ad_listing' )
    return;
   $title_keywords = array ( // The keywords and the corresponding category name to add
     'new iphone 5' => 'IPHONE 5',
     'iphone 6' => 'IPHONE 6'
   );

   $title = get_the_title($post_id);
   foreach ( $title_keywords as $keyword => $cat ) {
      if ( stripos($title, $keyword) !== false ) {
         $cat_id = get_cat_ID($cat);
      }
      if ($cat_id) {
         $result =  wp_set_post_terms( $post_id, $tags = $cat_id, $taxonomy = 'ad_cat', $append = true );
      }
   }
}
add_action('publish_post','test_add_category');