Show File Type and Size on Document Links

// Extensions to label, with the name shown to visitors.
$wpide_doc_types = array(
    'pdf'  => 'PDF',
    'doc'  => 'Word',
    'docx' => 'Word',
    'xls'  => 'Excel',
    'xlsx' => 'Excel',
    'ppt'  => 'PowerPoint',
    'pptx' => 'PowerPoint',
    'zip'  => 'ZIP',
);

add_filter( 'the_content', function ( $content ) use ( $wpide_doc_types ) {
    $pattern = '#<a\b([^>]*\bhref=["\']([^"\']+\.(' . implode( '|', array_keys( $wpide_doc_types ) ) . '))(?:\?[^"\']*)?["\'][^>]*)>(.*?)</a>#is';

    if ( ! preg_match( '#\.(' . implode( '|', array_keys( $wpide_doc_types ) ) . ')\b#i', $content ) ) {
        return $content;
    }

    $uploads = wp_get_upload_dir();

    return preg_replace_callback( $pattern, function ( $m ) use ( $wpide_doc_types, $uploads ) {
        if ( false !== strpos( $m[4], 'wpide-file-info' ) ) {
            return $m[0];
        }

        $type = $wpide_doc_types[ strtolower( $m[3] ) ];
        $info = $type;
        $url  = set_url_scheme( $m[2], 'https' );
        $base = set_url_scheme( $uploads['baseurl'], 'https' );

        if ( 0 === strpos( $url, $base ) ) {
            $path = $uploads['basedir'] . substr( $url, strlen( $base ) );
            if ( false === strpos( $path, '..' ) && is_readable( $path ) ) {
                $info .= ', ' . size_format( filesize( $path ), 1 );
            }
        }

        return '<a' . $m[1] . '>' . $m[4] . ' <span class="wpide-file-info">(' . esc_html( $info ) . ')</span></a>';
    }, $content );
}, 20 );