WordPress Post Grid - Yoast Primary Category Support

rtp-post-grid-yoast-primary-category.php

<?php
/*
Plugin Name: Post Grid Yoast Primary Category
Plugin URI: https://runthings.dev/
Description: Bring the primary category to the start of the list
Version: 1.0.0
Author: runthings.dev
Author URI: https://runthings.dev/
*/

if ( ! defined('ABSPATH')) exit;  // if direct access 

add_action( 'plugins_loaded', 'rtp_category_override' );

function rtp_category_override() {
    remove_action('post_grid_layout_element_categories', 'post_grid_layout_element_categories');
    add_action('post_grid_layout_element_categories', 'rtp_post_grid_layout_element_categories');
}

function rtp_post_grid_layout_element_categories($args){

    $element  = isset($args['element']) ? $args['element'] : array();
    $elementIndex  = isset($args['index']) ? $args['index'] : '';
    $post_id = isset($args['post_id']) ? $args['post_id'] : '';

    if(empty($post_id)) return;

    $custom_class = isset($element['custom_class']) ? $element['custom_class'] : '';
    $custom_class = do_shortcode($custom_class);
    $link_target = isset($element['link_target']) ? $element['link_target'] : '';
    $max_count = isset($element['max_count']) ? (int) $element['max_count'] : 3;
    $wrapper_html = !empty($element['wrapper_html']) ? $element['wrapper_html'] : '%s';
    $separator = isset($element['separator']) ? $element['separator'] : ', ';

    $term_list = rtp_get_categories_list($post_id);

    $categories_html = '';
    $term_total_count = count($term_list);
    $max_term_limit = ($term_total_count < $max_count) ? $term_total_count : $max_count ;

    $i = 0;
    foreach ($term_list as $term){
        if($i >= $max_count) continue;

        $term_id = isset($term->term_id) ? $term->term_id : '';
        $term_name = isset($term->name) ? $term->name : '';
        $term_link = get_term_link($term_id);

        $categories_html .= '<a target="'.esc_attr($link_target).'" href="'.esc_url($term_link).'">'.esc_html($term_name).'</a>';
        if( $i+1 < $max_term_limit){ $categories_html .= $separator;}

        $i++;
    }

    //var_dump($categories_html);

    ?>
    <div class="element element_<?php echo esc_attr($elementIndex); ?> <?php echo esc_attr($custom_class); ?> categories ">
        <?php echo sprintf($wrapper_html, $categories_html); ?>
    </div>
    <?php
}

/**
 * Get the categories, and reorder if Yoast plugin is installed, to put
 * primary category first
 * 
 * @source https://www.lab21.gr/blog/wordpress-get-primary-category-post/
 */
function rtp_get_categories_list($post_id)
{
    $term = "category";
    $all_terms = wp_get_post_terms( $post_id, $term, array( 'fields' => 'all' ) );

    // default behaviour if Yoast not installed
    if (!class_exists('WPSEO_Primary_Term')){
        return $all_terms;
    }

    // try to get Yoast primary category
    $wpseo_primary_term = new WPSEO_Primary_Term( $term, $post_id );
    $primary_term = get_term($wpseo_primary_term->get_primary_term());

    if (is_wp_error($primary_term)){
        return $all_terms;
    }
    
    // bring primary term to start of array
    foreach ($all_terms as $key => $object) {
        if ($object->term_id === $primary_term->term_id) {
            // remove it from its current location
            array_splice($all_terms, $key, 1);

            // add primary term to start of array
            array_unshift($all_terms, $primary_term);
            break;
        }
    }

    return $all_terms;
}