Add 'no-content' and 'has-banner' classes to BODY.

[ghost]

There are many instances for the purposes of design/styles (especially when using BULP) when it becomes necessary to identify if the content editor is empty or if there is a Banner being used on the page. This function would add classes to the body if either is true.

 * Add 'no-banner' and/or 'has-bu-banner' class to BODY to the page.
 *
 * @param string $classes The class or classes to be added to the body.
 * @param number $_post The post ID.
 * @param string $content The post content from the editor.
 * @param bool $banner_visible Check if there is a BU Banner.
 * @return string $classes The class or classes to be added to the body.
 */
function responsi_banner_content_class( $classes ) {
    // Get post ID. Return if none.
    $_post = get_post();

    if ( empty( $_post ) ) {
        return;
    }

    // Get Post Content from content editor.
    $content = $_post->post_content;

    // If no content, add class to Body.
    if ( empty( $content ) ) {
        $classes[] = 'no-content';
    }

    // Check that BU Banners is installed and if there is a banner on the current page.
    $banner_visible = false;
    if ( function_exists( 'bu_has_banner' ) ) {
        $banner_visible = bu_has_banner();
    }

    // If there is a banner, add class to Body.
    if ( $banner_visible ) {
        $classes[] = 'has-bu-banner';
    }

    // Add $classes array to body.
    return $classes;
}
add_filter( 'body_class', 'responsi_banner_content_class' );```

[acketon]

this should probably be done in two repos: bu-banners and bu-landing pages