<?php

$data = array(
    'product_ids' => null,
    'name' => sprintf('Success Purchase Discount: 10 percent discount',$_customerId),
    'description' => null,
    'is_active' => 1,
    'website_ids' => array(1),
    'customer_group_ids' => array(1),
    'coupon_type' => 2,
    'coupon_code' => $order->getShippingAddress()->getFirstname().'-'.Mage::helper('core')->getRandomString(4),
    'uses_per_coupon' => 1,
    'uses_per_customer' => 1,
    'from_date' => time(),
    'to_date' => null,
    'sort_order' => null,
    'is_rss' => 1,
    'rule' => array(
        'conditions' => array(
                                array(  'type' => 'salesrule/rule_condition_combine','aggregator' => 'all','value' => 1,'new_child' => null  )
                              )
    ),
    'simple_action' => 'by_percent',
    'discount_amount' => 10,
    'discount_qty' => 0,
    'discount_step' => null,
    'apply_to_shipping' => 0,
    'simple_free_shipping' => 0,
    'stop_rules_processing' => 0,
    'rule' => array(
        'actions' => array(
            array('type' => 'salesrule/rule_condition_product_combine','aggregator' => 'all','value' => 1,'new_child' => null  )
        )
    ),
    'store_labels' => array('Purchase Discount')
);

$model = Mage::getModel('salesrule/rule');
//$data = $this->_filterDates($data, array('from_date', 'to_date'));

$validateResult = $model->validateData(new Varien_Object($data));

if ($validateResult == true) {

    if (isset($data['simple_action']) && $data['simple_action'] == 'by_percent'
            && isset($data['discount_amount'])) {
        $data['discount_amount'] = min(100, $data['discount_amount']);
    }

    if (isset($data['rule']['conditions'])) {
        $data['conditions'] = $data['rule']['conditions'];
    }

    if (isset($data['rule']['actions'])) {
        $data['actions'] = $data['rule']['actions'];
    }

    unset($data['rule']);

    $model->loadPost($data);

    $model->save();
}

 //send email

$emailTemplate = Mage::getModel('core/email_template')->loadDefault('coupon_email_template');

//Variables for Confirmation Mail.
$customerName=$order->getShippingAddress()->getName();
$customerEmail=$order->getShippingAddress()->getEmail();
$emailTemplateVariables = array();
$emailTemplateVariables['name'] = $customerName;
$emailTemplateVariables['coupon'] = $model->acquireCoupon()->getCode();

//Appending the Custom Variables to Template.
$processedTemplate = $emailTemplate->getProcessedTemplate($emailTemplateVariables);

$senderEmail=Mage::getStoreConfig('trans_email/ident_general/email');
$senderName=Mage::getStoreConfig('trans_email/ident_general/name');

//Sending E-Mail to Customers.
$mail = Mage::getModel('core/email')
 ->setToName($senderName)
 ->setToEmail($customerEmail)
 ->setBody($processedTemplate)
 ->setSubject('Subject :')
 ->setFromEmail($senderEmail)
 ->setFromName($senderName)
 ->setType('html');
 try{
 //Confimation E-Mail Send
 $mail->send();
 }
 catch(Exception $error)
 {
 Mage::getSingleton('core/session')->addError($error->getMessage());
 return false;
 }

?>

function coupon_gen(){
  jQuery.ajax({
                type: 'POST',
                url: 'coupon.php',
                success: function(data) {
                    alert(data);

                },
                error: function(){
                alert("Url not found");
                }
            });
};