How to add a product thumbnail and product galery from a images URL using php script in WordPress Woocommerce.

function.php

<?php 

function downloadAndUploadImages($post_id,$post_title,$img,$sku){
    ini_set('max_execution_time', 300); //300 seconds = 5 minutes
    ini_set('memory_limit','1024M');
    $ext = substr(strrchr($img,'.'),1);
    // WordPress Upload Directory to Copy to (must be CHMOD to 777)
    $uploads = wp_upload_dir();
    $copydir = $uploads['path']."/";
    // Code to Copy Image to WordPress Upload Directory (Server Must Support file_get_content/fopen/fputs)
    $data = @file_get_contents($img);
    $filetitle = strtolower(str_replace(array(' ', '-', '.', '(', ')', '!', '@', '#', '$', '%', '^', '&', '*', '_', '=', '+', '/', '"'), "-", $post_title));
    $file = fopen($copydir . "$filetitle-$sku-$post_id.$ext", "w+");
    fputs($file, $data);
    fclose($file);
    // Insert Image to WordPress Media Libarby
    $filepath = $uploads['path']."/$filetitle-$sku-$post_id.$ext";         
    $wp_filetype = wp_check_filetype(basename($filepath), null );
    $attachment = array(
     'guid' =>$filepath,
     'post_mime_type' => $wp_filetype['type'],
     'post_title' => $post_title,
     'post_content' => 'Image for '.$post_title,
     'post_status' => 'inherit'
    );
    $attachment_id = wp_insert_attachment( $attachment, $filepath, $post_id);
    // Include image.php
    require_once( ABSPATH . 'wp-admin/includes/image.php' );
    // Define attachment metadata
    $attach_data = wp_generate_attachment_metadata( $attachment_id, $filepath );
    // Assign metadata to attachment
    wp_update_attachment_metadata( $attachment_id,  $attach_data );
    return $attachment_id;
}


//How to use this function

$product_id = 1;
$sku = 'ASDF';
$product_title = 'Test Product';

/#1 For product thumbnail
$thumbnail_url = 'http://placehold.it/120x120&text=image1';
$attachment_id = downloadAndUploadImages($product_id,$product_title,$thumbnail_url,'Thumbnail-'.$sku ); // We adding Thumbnail to sku for providing a unique name to each image on Wordpress
add_post_meta($product_id, '_thumbnail_id', $attachment_id); 

//#2 For galery
$images = array(
                'http://placehold.it/120x120&text=image1',
                'http://placehold.it/120x120&text=image2',
                'http://placehold.it/120x120&text=image3',
                'http://placehold.it/120x120&text=image4'
            );

$prd_img_galery = array();
$count = 1;
foreach($images as $image){  
    $attachment_id = downloadAndUploadImages($product_id,$product_title,$image,$count.'-'.$sku ); // We adding $count to sku for providing a unique name to each image on Wordpress
    $prd_img_galery[] = $attachment_id;
    $count ++;
}
if(count($prd_img_galery)>1){
    update_post_meta($product_id, "_product_image_gallery", implode(',', $prd_img_galery));
}elseif(count($prd_img_galery)==1){    
   update_post_meta($product_id, "_product_image_gallery",trim($prd_img_galery[0]));
}