WordPress Media Library rename files

wp.php

<?php
if ( !defined( 'ABSPATH' ) ) {
    exit;
}
add_action( 'init', 'rename_media_files_init' );
function rename_media_files_init() {
    add_filter( 'attachment_fields_to_edit', 'rename_media_files_fields_to_edit', 11, 2 );
    add_filter( 'attachment_fields_to_save', 'rename_media_files_attachment_fields_to_save', 11, 2 );
}

/**
 * Add field on media edit screen
 * @since 0.1
 * @param array $form_fields Existing form fields
 * @param object $post Current attachment post object
 * @return array $form_fields New form fields
 */
function rename_media_files_fields_to_edit( $form_fields, $post ) {
    /* Only show if not in Thickbox iframe */
    if ( defined( 'IFRAME_REQUEST' ) && true === IFRAME_REQUEST ) {
        return $form_fields;
    }
    rename_media_files_load_textdomain();
    $orig_file                                 = get_attached_file( $post->ID );
    $orig_filename                             = basename( $orig_file );
    $form_fields[ 'rename_media_files_input' ] = array( 'label' => __( 'New file name:', 'rename-media-files' ),
                                                        'value' => '',
                                                        'helps' => sprintf( __( 'Enter a new file name in the field above. (current filename is <strong>%1$s</strong>)', 'rename-media-files' ), $orig_filename ) );
    return $form_fields;
}

/**
 * Save form field value on media edit screen
 * @since 0.1
 * @param array $post Current attachment post data
 * @param array $attachment Data submitted via form
 * @return array $post Current attachment post data
 */
function rename_media_files_attachment_fields_to_save( $post, $attachment ) {
    /* Only proceed if new filename is submitted */
    if ( $attachment[ 'rename_media_files_input' ] ) {
        /* Get original filename */
        $orig_file     = get_attached_file( $post[ 'ID' ] );
        $orig_filename = basename( $orig_file );
        /* Get original path of file */
        $orig_dir_path = substr( $orig_file, 0, ( strrpos( $orig_file, "/" ) ) );
        /* Get image sizes */
        $image_sizes = array_merge( get_intermediate_image_sizes(), array( 'full' ) );
        /* If image, get URLs to original sizes */
        if ( wp_attachment_is_image( $post[ 'ID' ] ) ) {
            $orig_image_urls = array();
            foreach ( $image_sizes as $image_size ) {
                $orig_image_data                = wp_get_attachment_image_src( $post[ 'ID' ], $image_size );
                $orig_image_urls[ $image_size ] = $orig_image_data[ 0 ];
            }
            /* Otherwise, get URL to original file */
        } else {
            $orig_attachment_url = wp_get_attachment_url( $post[ 'ID' ] );
        }
        /* Make new filename and path */
        $new_filename = wp_unique_filename( $orig_dir_path, $attachment[ 'rename_media_files_input' ] );
        $new_file     = $orig_dir_path . "/" . $new_filename;
        copy( $orig_file, $new_file );
        update_attached_file( $post[ 'ID' ], $new_file );
        $post_for_guid = get_post( $post[ 'ID' ] );
        $guid          = str_replace( $orig_filename, $new_filename, $post_for_guid->guid );
        wp_update_post( array( 'ID'   => $post[ 'ID' ],
                               'guid' => $guid ) );
        /* Update attachment's metadata */
        wp_update_attachment_metadata( $post[ 'ID' ], wp_generate_attachment_metadata( $post[ 'ID' ], $new_file ) );
        global $wpdb;
        if ( wp_attachment_is_image( $post[ 'ID' ] ) ) {
            foreach ( $image_sizes as $image_size ) {
                $orig_image_url = $orig_image_urls[ $image_size ];
                $new_image_data = wp_get_attachment_image_src( $post[ 'ID' ], $image_size );
                $new_image_url  = $new_image_data[ 0 ];
                $wpdb->query( $wpdb->prepare( "UPDATE $wpdb->posts SET post_content = REPLACE(post_content, '$orig_image_url', '$new_image_url');" ) );
            }
        } else {
            $new_attachment_url = wp_get_attachment_url( $post[ 'ID' ] );
            $wpdb->query( $wpdb->prepare( "UPDATE $wpdb->posts SET post_content = REPLACE(post_content, '$orig_attachment_url', '$new_attachment_url');" ) );
        }
    }
    return $post;
}