PHP CSV file upload and process

        if ( isset($_POST["csp_variation_submit"]) ) {

            if ( isset($_FILES["csp_variation_file"])) {
                //if there was an error uploading the file
                if ($_FILES["csp_variation_file"]["error"] > 0) {
                    echo "File Upload Error Code: " . $_FILES["csp_variation_file"]["error"] . "<br />";
                }
                else {
//                    Print file details
//                    echo "Uploaded File: " . $_FILES["file"]["name"] . "<br />";
//                    echo "Type: " . $_FILES["file"]["type"] . "<br />";
//                    echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
//                    echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";
                    $update_count = 0;
                    $tmpName = $_FILES["csp_variation_file"]["tmp_name"];
                    $variation_data = array_map('str_getcsv', file($tmpName));
                   array_shift($variation_data);

                    if (!empty($variation_data)):
                        foreach ($variation_data as $variation):
                            $variation_id = trim($variation[0]);
                            $regular_price = trim($variation[1]);
                            $minimum_price = trim($variation[2]);

                            if ( !$variation_id || $variation_id == '') {
                                continue;
                            }
                            $_product = wc_get_product( $variation_id );
                            if($_product){
                                update_post_meta($variation_id, '_regular_price', $regular_price);
                                update_post_meta($variation_id, 'minimum_price', $minimum_price);
                                $update_count++;
                            }
                            else{
                                echo 'Product Variation with ID '.$variation_id.' Not Exists <br>';
                            }
                        endforeach;
                            echo $update_count. ' total update done.';
                    endif;

                    //if file already exists
//                    if (file_exists(wp_upload_dir().'/variation_update/' . $_FILES["file"]["name"])) {
//                        echo $_FILES["file"]["name"] . " already exists. ";
//                    }
//                    else {
//                        //Store file in directory "upload" with the name of "uploaded_file.txt"
//                        $storagename = "uploaded_file.csv";
//                        move_uploaded_file($_FILES["file"]["tmp_name"], "upload/" . $storagename);
//                        echo "Stored in: " . wp_upload_dir().'/variation_update/' . $_FILES["file"]["name"] . "<br />";
//                    }
                }
            } else {
                echo "No file selected <br />";
            }
        }

        // Set class property
//        $this->product_carousal_setting = get_option( 'product_carousal_setting' );
        ?>
        <div class="wrap">
            <h2>Variation product CSV</h2>

            <form action="" method="post" enctype="multipart/form-data">
<!--                <input type="file" name="csp_variation_file" value="" />-->
<!--                <input type="submit" name="submit" value="Save" /></form>-->
           <?php

           
           submit_button(__( 'Process Update', 'textdomain' ),'primary','csp_variation_submit'); ?>
        </div>
        <?php