How to Create an OpenCart Extension to Send SMS

<?php
// Heading
$_['heading_title']    = 'MTS Exolve send SMS';

// Text
$_['text_extension']   = 'Extensions';
$_['text_success']     = 'Success: You have modified show menu module!';
$_['text_edit']        = 'Edit Show Menu Module';

// Entry
$_['entry_status']     = 'Status';
$_['entry_api_token']  = 'MTS Exolve API Key';
$_['entry_api_phone']  = 'MTS Exolve sender phone';
$_['entry_text']       = 'SMS text template';

// Error
$_['error_permission'] = 'Warning: You do not have permission to modify this module!';
$_['error_api_token']  = 'MTS Exolve API Key Required';
$_['error_api_phone']  = 'MTS Exolve sender phone Required';

{{ header }}{{ column_left }}
<div id="content">
   <div class="page-header">
      <div class="container-fluid">
     <div class="float-end">
        <button type="submit" form="form-module" data-bs-toggle="tooltip" title="{{ button_save }}" class="btn btn-primary">
               <i class="fa-solid fa-save"></i>
            </button>
         
            <a href="https://habr.com/ru/companies/exolve/articles/827168/{{ back }}" data-bs-toggle="tooltip" title="{{ button_back }}" class="btn btn-light">
               <i class="fa-solid fa-reply"></i>
            </a>
         </div>
         
         <h1>{{ heading_title }}</h1>
        
         <ol class="breadcrumb">
        {% for breadcrumb in breadcrumbs %}
          <li class="breadcrumb-item">
                 <a href="https://habr.com/ru/companies/exolve/articles/827168/{{ breadcrumb.href }}">{{ breadcrumb.text }}</a>               
              </li>
        {% endfor %}
     </ol>
      </div>
   </div>
   <div class="container-fluid">
      <div class="card">
     <div class="card-header">
            <i class="fa-solid fa-pencil"></i> {{ text_edit }}
         </div>

     <div class="card-body">
            <form id="form-module" action="{{ save }}" method="post" data-oc-toggle="ajax">
        <div class="row mb-3">
                   <label for="input-status" class="col-sm-2 col-form-label">
                     {{ entry_status }}
                   </label>
           <div class="col-sm-10">
              <div class="form-check form-switch form-switch-lg">
              <input type="hidden" name="module_opc_send_sms_status" value="0"/>
               <input type="checkbox" name="module_opc_send_sms_status" value="1" 
               id="input-status" class="form-check-input"{% if module_opc_send_sms_status %} checked{% endif %}/>
              </div>
           </div>
        </div>

        <div class="row mb-3 required">
         <label class="col-sm-2 col-form-label" for="input-api_token">{{ entry_api_token }}</label>
         <div class="col-sm-10">
           <input type="text" class="form-control" placeholder="{{ entry_api_token }}"
            name="module_opc_send_sms_token" value="{{ module_opc_send_sms_token }}">
           <div id="error-api-token" class="invalid-feedback"></div>
         </div>
       </div>


       <div class="row mb-3 required">
         <label class="col-sm-2 col-form-label" for="input-api_phone">{{ entry_api_phone }}</label>
         <div class="col-sm-10">
           <input type="text" class="form-control" placeholder="{{ entry_api_phone }}"
            name="module_opc_send_sms_phone" value="{{ module_opc_send_sms_phone }}">
           <div id="error-api-phone" class="invalid-feedback"></div>
         </div>
       </div>


       <div class="row mb-3 required">
         <label class="col-sm-2 col-form-label" for="input-text">{{ entry_text }}</label>
         <div class="col-sm-10">
           <input type="text" class="form-control" placeholder="{{ entry_text }}"
            name="module_opc_send_sms_text" value="{{ module_opc_send_sms_text }}">
          <p>Use %order_id% to place varible. <br> E.g. Your order %order_id% created.</p>
         </div>
       </div>

        </form>
     </div>
      </div>
   </div>
</div>
{{ footer }}

<?php
/**
 * Extension name: Send SMS
 * Descrption: Using this extension we will a send sms via MTS Exolve API after make order.
 * Author: BosonBeard. 
 * 
 */
namespace Opencart\Catalog\Controller\Extension\OpcSendSms\Event;

class Event extends \Opencart\System\Engine\Controller
{
    /**
     * index
     * Event trigger: catalog/model/checkout/order/addHistory/before
     * @param  mixed $route
     * @param  mixed $data
     * @param  mixed $output
     * @return void
     */
    public function index(&$route = false, &$data = array(), &$output = array()): void {

        // get data from OpenCart

        $order_id = "none";
        $this->load->model('setting/setting');

        if (isset($this->session->data['order_id']))
            {
                    $order_id = $this->session->data['order_id'];
            }
        
         // get data from OpenCart
        $customer_phone = $this->customer->getTelephone(); 
 
        // get data from extension opc_send_sms 
        $sender_phone =  $this->config->get('module_opc_send_sms_phone');
        $token =  $this->config->get('module_opc_send_sms_token');
        $text_raw =  $this->config->get('module_opc_send_sms_text');
        
        if (!$text_raw)
        {
            $text_raw = "Order $order_id created.";
        }    
        $text = str_replace('%order_id%',$order_id,$text_raw);

        // send request to MTS Exolve API
        $curl = curl_init();

        curl_setopt_array($curl, array(
        CURLOPT_URL => 'https://api.exolve.ru/messaging/v1/SendSMS',
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_ENCODING => '',
        CURLOPT_MAXREDIRS => 10,
        CURLOPT_TIMEOUT => 0,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
        CURLOPT_CUSTOMREQUEST => 'POST',
        CURLOPT_POSTFIELDS =>'{
        "number": "'.$sender_phone.'",
        "destination": "'.$customer_phone.'",
        "text": "'.$text.'" 
        }
        ',
        CURLOPT_HTTPHEADER => array(
            'Content-Type: application/json',
            "Authorization: Bearer $token"
            ),
        ));
        $response = curl_exec($curl);
        curl_close($curl);
        
    }

    /**
     * getTemplateBuffer
     *
     * @param  mixed $route
     * @param  mixed $event_template_buffer
     * @return string
     */
    protected function getTemplateBuffer($route, $event_template_buffer) {

        // if there already is a modified template from view/*/before events use that one
        if ($event_template_buffer) {
            return $event_template_buffer;
        }
    }
}