/**
 * LiveTube: Allow FB crawler to receive cached HTML for selected static paths
 * Place in /wp-content/mu-plugins/allow-fb-cache.php
 */

if ( defined( 'WPINC' ) ) {

    // Run only on site with blog ID 1 (livetube.tv)
    if ( function_exists( 'get_current_blog_id' ) && (int) get_current_blog_id() !== 1 ) {
        return;
    }

    add_filter( 'rocket_cache_reject_ua', 'lt_allow_facebook_for_static_paths' );
    function lt_allow_facebook_for_static_paths( $ua ) {
        $allowed_paths = array(
            '/', '/about', '/about/app', '/about/contact-us',
            '/legal/privacy', '/legal/tos', '/cookie-policy-eu',
            '/help', '/media', '/de', '/es', '/ja', '/ko', '/ru', '/uk', '/zh-hans', '/zh-hant'
        );

        $req = isset( $_SERVER['REQUEST_URI'] ) ? strtolower( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '';

        foreach ( $allowed_paths as $p ) {
            if ( strpos( $req, strtolower( $p ) ) !== false ) {
                // remove Facebook tokens from reject list
                $tokens = array( 'facebookexternalhit', 'facebot', 'facebookcatalog' );
                foreach ( $tokens as $t ) {
                    $key = array_search( $t, $ua, true );
                    if ( $key !== false ) {
                        unset( $ua[ $key ] );
                    }
                }
                $ua = array_values( $ua );
                break;
            }
        }
        return $ua;
    }
}