crp_functions.php

<?php

function bit_crp_add_fields( $fields, $post_id ) {
	global $wpdb;

	$match_title = strip_tags( get_the_title( $post_id ) );
	$match_content = bit_get_the_matcher($post_id);

	$field_score = ", ( ( MATCH($wpdb->posts.post_title) AGAINST ('%s') *5 ) + ( MATCH($wpdb->postmeta.meta_value) AGAINST ('%s') *10 ) ) as score ";
	$field_score = $wpdb->prepare( $field_score, $match_title, $match_content ) ;
	
	return $fields . $field_score;
}
add_filter( 'crp_posts_fields', 'bit_crp_add_fields', 10, 2 );


function crp_add_join( $join, $id ) {
	global $wpdb;
	return $join . " LEFT JOIN $wpdb->postmeta ON $wpdb->postmeta.post_id = $wpdb->posts.ID ";
}
add_filter( 'crp_posts_join', 'crp_add_join', 10, 2 );


function crp_add_where( $where, $id ) {
	global $wpdb;
	return  $where . " AND $wpdb->postmeta.meta_key = '_yoast_wpseo_metadesc' ";
}
add_filter( 'crp_posts_where', 'crp_add_where', 10, 2 );


function bit_crp_add_matcher( $match, $stuff,  $post_id ) {
	global $wpdb;
	
	$matcher = " AND ( MATCH($wpdb->posts.post_title) AGAINST ('%s') ";	
	$matcher .= " OR MATCH($wpdb->postmeta.meta_value) AGAINST ('%s') ";
	$matcher .= " OR MATCH($wpdb->posts.post_title) AGAINST ('%s') ) ";	
	
	$match_title = strip_tags( get_the_title( $post_id ) );
	$match_content = bit_get_the_matcher($post_id);
	
	$matcher = $wpdb->prepare( $matcher, $match_title ,  $match_content, $match_title.' '. $match_content   );
	
	return  $matcher;

}
add_filter( 'crp_posts_match', 'bit_crp_add_matcher', 10, 3 );


function bit_crp_filter_orderby( $orderby ) {
   return 'score DESC';
}
add_filter( 'crp_posts_orderby', 'bit_crp_filter_orderby' ); 

// Function to get the match text
function bit_get_the_matcher($post_id){
	
	global $post;
	
	if(is_singular())
		$bit_post = $post;
	else
		$bit_post = get_post($post_id);
	
	$bit_content = get_post_meta($post_id , '_yoast_wpseo_metadesc', true);
	
	if(empty($bit_content)) $bit_content = get_post_meta($post_id , 'sf_custom_excerpt', true);	
	if(empty($bit_content)) $bit_content = $bit_post->post_content;
	
	$bit_content  = strip_tags( strip_shortcodes( $bit_content ));
	
	return wp_trim_words( $bit_content , 200, '' );
}