Updating a WooCommerce order status based on a $GET response? - wordpress

Question

I tried to look things up but I am unable to find anything quite similar.
So I have an external file. That file uses $_GET in order to enable bidirectional text order confirmations.
I am trying to modify order status based on that specific $_GET response, but I am now unable to generate any sort of error in my error logs and cannot quite tell what I am doing wrong. Please bear with me as I am not very experience with this.
Here's what I have done so far:
<?php
define( 'WP_USE_THEMES', false );
require_once( $_SERVER[ 'DOCUMENT_ROOT' ] . '/wp-load.php' );
/*
Receiving SMS using 2-Way SMS & PHP
if ((isset($_GET["sender"])) and
(isset($_GET["receiver"])) and
(isset($_GET["message"])) and
(isset($_GET["timestamp"])) and
(isset($_GET["network_id"])) and
(isset($_GET["network_name"]))
)
{
/*
The Sender of the SMS (ie. 07xyzzzzzz)
*/
$sender = $_GET["sender"];
/*
The Shortcode on which the SMS was sent (ie. 17xy, 18xy, 37xy, 38xy etc.)
*/
$receiver = $_GET["receiver"];
/*
The Message sent by the Sender to the Shortcode
*/
$message = $_GET["message"];
/*
The Timestamp in which the Message was received on the Shortcode, in UNIX Timestamp format.
*/
$timestamp = $_GET["timestamp"];
/*
The Network ID in which the Sender is located, with the following possible values:
1 for Vodafone Romania
2 for Orange Romania
3 for Telekom Romania Mobile / Telekom Romania
5 for Digimobil (RCS-RDS)
*/
$network_id = $_GET["network_id"];
/*
The Network Name corresponding to the Network ID
*/
$network_name = $_GET["network_name"];
/*
Write the SMS received to a text file
Please note that this is for example purpose only and the file(s) below must be not be publicly accessible. If you will
choose to store the SMS received to file(s) you must enable access restrictions and deny access from public to the respective
file(s) and you must disable directory listing on the directory where the files are stored.
We recommend you storing the SMS received to a database.
$handler = fopen("sms-mobile-originated-".date("d-m-Y", $timestamp)."txt", "a+");
fwrite($handler,
"SMS Received: From ".$sender.", ".
"Receiver ".$receiver.", ".
"Network ID: ".$network_id.", ".
"Network Name: ".$network_name.", ".
"Date / Time: ".date("d-m-Y H:i:s", $timestamp).", ".
"Message: ".$message.
"\r\n"
);
fclose($handler);
/*
Return the response to the request
For each received SMS you may send a SMS response to the sender (mobile subscriber) using any of the following methods:
(1) Using SMSLink - SMS Gateway API, such as SMS Gateway (HTTP), SMS Gateway (SOAP), SMS Gateway (JSON) or SMS Gateway (BULK)
(2) Using the output of this script, by writing the desired response below, if you enable this coresponding option in 2-Way SMS,
2-Way SMS Campaigns - Settings. In this case the SMSLink will read the script output and will send an SMS to the sender with
the output text. Please note that the output should be plain text (you should not output any HTML code).
*/
function sms_confirmation(){
if (substr(trim(urldecode($message)), 0, strlen("CF ETIN")) == "CF ETIN")
{
global $woocommerce;
$order = new WC_Order($order_id);
$phone = $order->get_billing_phone();
if (((strlen($phone) == 10) and ($phone == $sender)) or
((strlen($phone) == 9) and ("0".$phone == $sender)) or
((strlen($phone) == 11) and ($phone == "4".$sender)) or
((strlen($phone) == 13) and ($phone == "004".$sender)) or
((strlen($phone) == 12) and ($phone == "+4".$sender))
)
{
$order->update_status('confirm-sms', __('Approved by the customer', 'woocommerce') );
}
}
};
echo "Message Successfuly Received."
}
else
{
echo "Invalid Request.";
}
?>