Assorted taxonomy filter functions

gistfile1.php

<?php 
/**
 * Updates the count property of an array of term objects to reflect the number of posts in the 
 * current query that have the term. 
 * 
 * WordPress's default count comes from all posts in the DB, not the current query. 
 * 
 * @author Brent Shepherd <brent@findingsimple.com>
 * @since 1.0
 */
function eg_update_term_counts( $terms, $taxonomy ) {

  $post_ids = eex_get_all_post_ids_in_query();

	if( empty( $post_ids ) )
		return $terms;

	// Get all the term IDs that apply to the current query's posts
	$object_terms = wp_get_object_terms( $post_ids, $taxonomy, array( 'fields' => 'ids' ) );

	$term_counts = array_count_values( $object_terms );

	// Update the counts for each term
	foreach( $terms as $key => $term )
		if ( isset( $term_counts[$term->term_id] ) ) 
			$term->count = $term_counts[$term->term_id];
		else 
			unset( $terms[$key] );

	return $terms;
}

/**
 * Returns a search URI with the current filters.
 * 
 * If the $filter parameter is set with $value parameter in the current query, then it is 
 * removed from the return URI, otherwise it is added.
 * 
 * @param $filter string The filter's rewrite slug. eg. post_type
 * @param $value string The value for the filter eg. event
 * 
 * @author Brent Shepherd <brent@findingsimple.com>
 * @since 1.0
 */
function eg_get_search_filter_uri( $filter, $value ) {
	global $wp_query;

	$search_link = ( empty( $wp_query->query_vars['s'] ) || $wp_query->query_vars['s'] == '~' ) ? get_search_link( '~' ) : get_search_link();
	$search_link = add_query_arg( $_GET, $search_link );

	$filter_query = '';

	if( isset( $wp_query->query_vars[$filter] ) ) { // Results already being filtered by this filter type
		$taxonomies = get_taxonomies( array( 'query_var' => $filter ) );
			// If we are filtering by a post_type, replace it with the new post type
		if( 'post_type' == $filter ) {
			$filter_query = ( $wp_query->query_vars[$filter] == $value ) ?  remove_query_arg( $filter, $search_link ) : add_query_arg( $filter, $value, $search_link );
		// If we are filtering by taxonomy
		} elseif( ! empty( $taxonomies ) ) {
			// Loop over the taxonomies being used to filter
			foreach( $wp_query->tax_query->queries as $query ) {
				$tax = get_taxonomy( $query['taxonomy'] );
				// If this taxonomy is not the filter in question, ignore it
				if( $tax->query_var != $filter )
					continue;
				// If the term for this URL is not already being used to filter the taxonomy
				if( strpos( $wp_query->query_vars[$filter], $value ) === false ) {
					// Append the term to the taxonomy filter string
					$filter_query = add_query_arg( $filter, $wp_query->query_vars[$filter] . '+' . $value, $search_link );
				} else {
					// Otherwise, remove the term
					if( $wp_query->query_vars[$filter] == $value ) {
						$filter_query = remove_query_arg( $filter, $search_link );
					} else {
						$filter_value = str_replace( $value, '', $wp_query->query_vars[$filter] );
						// Remove any residual + symbols left behind
						$filter_value = str_replace( '++', '+', $filter_value );
						$filter_value = preg_replace( '/(^\+|\+$)/', '', $filter_value );
						$filter_query = add_query_arg( $filter, $filter_value, $search_link );
					}
				}
			}
		}
	} else {
		$filter_query = add_query_arg( $filter, $value, $search_link );
	}

	return $filter_query;
}


/**
 * Sets the count property of an array of post type objects to reflect the number of posts 
 * of that type in the current query. If a post type is not in the current query, it is 
 * removed from the $post_types array. 
 * 
 * @author Brent Shepherd <brent@findingsimple.com>
 * @since 1.0
 */
function eg_get_post_types_with_counts( $post_type_names = array() ) {
  global $wp_query;

	if( empty( $post_type_names ) )
		$post_type_names = array( 
							'eex_opportunity', 
							'eex_case_study', 
							'eex_event', 
							'eex_resources', 
							'eex_contact', 
							'eex_program',
							'page'
						);

	foreach( $post_type_names as $post_type )
		$post_types[$post_type] = get_post_type_object( $post_type );

	$post_counts = array();

	$post_ids = eex_get_all_post_ids_in_query( 'any' );

	// Count the posts of each type
	foreach( $post_ids as $post_id ) {

		$post = get_post( $post_id );

		if( ! in_array( $post->post_type, $post_type_names ) )
			continue;

		$post_counts[$post->post_type] = ( ! isset( $post_counts[$post->post_type] ) ) ? 1 : ++$post_counts[$post->post_type];
	}

	// If all post type counts are 0, calculate total post type counts and return full post types array
	if( array_sum( $post_counts ) == 0 ) {
		foreach( $post_types as $post_type_name => $post_type )
			$post_types[$post_type_name]->count = wp_count_posts( $post_type_name )->publish;
	} else {
		foreach( $post_counts as $post_type_name => $count )
			$post_types[$post_type_name]->count = $count;
	}

	// Remove any post types with a count of 0
	foreach( $post_types as $post_type_name => $post_type )
		if ( !isset( $post_type->count ) || $post_type->count == 0 )
			unset( $post_types[$post_type_name] );

	return $post_types;
}