[site-reviews] add external rating counts to summary

// Use these meta_keys in the Custom Fields metabox to add external rating values to your pages.
// If found, the values of these meta_keys will be added to the total rating counts of the Rating Summary.
// These meta keys will only work if you are assigning reviews to the page.

// external_rating_0
// external_rating_1
// external_rating_2
// external_rating_3
// external_rating_4
// external_rating_5

/**
 * Add external rating counts to the Rating Summary
 */
add_filter('site-reviews/ratings', function (array $ratings, array $args) {
    if (empty($ratings)) {
        $ratings = [0,0,0,0,0,0];
    }
    foreach ((array) $args['assigned_posts'] as $postId) {
        foreach ($ratings as $rating => $value) {
            $metaKey = 'external_rating_'.$rating;
            $ratings[$rating] += (int) get_post_meta($postId, $metaKey, true);
        }
    }
    return $ratings;
}, 10, 2);

/**
 * Add external rating counts when calculating the average rating,
 * ranking, and counts for assigned posts, users, and terms.
 */
add_filter('site-reviews/ratings/grouped', function (array $ratings, $metaKey) {
    if ('post' !== $metaKey) {
        return $ratings;
    }
    foreach ($ratings as $postId => $ratingValues) {
        foreach ($ratingValues as $rating => $value) {
            $metaKey = 'external_rating_'.$rating;
            $ratings[$postId][$rating] += (int) get_post_meta($postId, $metaKey, true);
        }
    }
    return $ratings;
}, 10, 2);