Automatically Generate and Email unique voucher code for every sale - magento

Question

I have been hunting around for a solution to this problem I am trying to resolve.
Here is the scenario:
I want to issue a single use voucher code for every purchase made between two specified dates. The voucher is to be redeemed between another two specified dates. The voucher must be single use only, but could potentially be given away if the original purchaser doesn't want/need it.
Each customer can be assigned any number of individual voucher codes - one to be issued per purchase.
The voucher code should be automatically generated and emailed to them with their order confirmation, so there is no manual work required.
Can someone help either with usable code for Magento 1.6.2, or point me towards a plugin that might do the job?
I have contacted MageStore about their offering to ask if it fits my needs, but thought I would ask the question here in case I can get an answer/solution faster, as they are not available at this time.
=== Final working solution ===
I found code in various places that each had bits that helped, but not one overall working solution for me. Eventually, I managed to hack this together into a module - here is the observer.php part of that module (the crux of the beast). I hope it helps someone!
Note - this code worked for ME in MY scenario. I cannot offer any support on this, and take no responsibility for it's use in your application - please make use of it as you see fit.
<?php
/**
* Our class name should follow the directory structure of
* our Observer.php model, starting from the namespace,
* replacing directory separators with underscores.
* i.e. app/code/local/SmashingMagazine/
* LogProductUpdate/Model/Observer.php
*/
class Robgt_AutoVoucher_Model_Observer
{
/**
* Magento passes a Varien_Event_Observer object as
* the first parameter of dispatched events.
*/
public function autoVoucher(Varien_Event_Observer $observer)
{
// Should we run this code at all?
// Between 17th at midnight and 24th at midday December 2012 ONLY
$from = strtotime('2012-12-17 00:00:01');
$to = strtotime('2012-12-24 11:59:59');
$now = time();
if($from <= $now && $to >= $now) {
//Get the Order ID
$order = $observer->getEvent()->getOrder();
$orderEntityId = $order->getId();
$orderid = $order->getIncrementId();
//$orderid = Mage::getSingleton('checkout/session')->getLastRealOrderId();
if(empty($orderid))
{
$orderid = '999999999';
}
// Grab the last 3 digits of the Order number for use in the voucher code
$last_orderNumberDigits = substr($orderid, -3, 3);;
// Create coupon code random part
$codeLength = 7;
$chars = "ABCDEFGHIJKLMNPQRSTUVWXYZ1234567890";
srand((double)microtime()*1000000);
$i = 0;
$code = '' ;
while ($i <= $codeLength)
{
$num = rand() % 33;
$tmp = substr($chars, $num, 1);
$code = $code . $tmp;
$i++;
}
$couponRandomCode = $code;
// Build coupon code
// Format is: MH[Last 3 Digits of Order number]-[5 Random digits]
$couponCode = 'MH'.$last_orderNumberDigits.'-'.$couponRandomCode;
$couponName = 'Xmas2012 - '.$couponCode;
// Build the coupon rule
$rule = Mage::getModel('salesrule/rule');
$rule->setName($couponName);
$rule->setDescription('Xmas 2012 Discount coupon');
$rule->setFromDate('2013-01-01'); // Jan 1st
$rule->setToDate('2013-01-31'); // Jan 31st
$rule->setCouponType(2);
$rule->setCouponCode($couponCode);
$rule->setUsesPerCoupon(1);
$rule->setUsesPerCustomer(1);
$rule->setCustomerGroupIds('0,1,3,4');
$rule->setIsActive(1);
$conditions = array(
"1" => array(
'type' => 'salesrule/rule_condition_combine',
'aggregator' => 'all',
'value' => 1,
'new_child' => false
),
"1--1" => array(
'type' => 'salesrule/rule_condition_product_found',
'value' => 1,
'aggregator' => 'all',
'new_child' => false
),
"1--1--1" => array(
'type' => 'salesrule/rule_condition_product',
'attribute' => 'category_ids',
'operator' => '!()',
'value' => '932,341,800,1116'
)
);
$actions = array(
"1" => array(
"type" => "salesrule/rule_condition_product",
"aggregator" => "all",
"value" => "1",
"new_child" => false
),
"1--1" => array(
"type" => "salesrule/rule_condition_product",
"attribute" => "category_ids",
'operator' => '!()',
'value' => '932,341,800,1116'
)
);
$rule->setData('conditions',$conditions);
$rule->setData("actions",$actions);
$rule->setStopRulesProcessing(1);
$rule->setIsAdvanced(1);
$rule->setProductIds('');
$rule->setSortOrder(0);
$rule->setSimpleAction('by_percent');
$rule->setDiscountAmount(10);
$rule->setDiscountStep(0);
$rule->setSimpleFreeShipping(0);
$rule->setTimesUsed(0);
$rule->setIsRss(0);
$rule->setWebsiteIds('1');
$rule->loadPost($rule->getData());
$rule->save();
// Email the details to Trev
$to = 'trevor.wallinger#gmail.com';
//$to = 'robgt.com#gmail.com';
$subject = 'New Xmas 2012 Voucher Code';
$message = '<body style="background:#F6F6F6; font-family:Verdana, Arial, Helvetica, sans-serif; font-size:12px; margin:0; padding:0;">
<div style="background:#F6F6F6; font-family:Verdana, Arial, Helvetica, sans-serif; font-size:12px; margin:0; padding:0;">
<table cellspacing="0" cellpadding="0" border="0" height="100%" width="100%">
<tr>
<td align="center" valign="top" style="padding:20px 0 20px 0">
<!-- [ header starts here] -->
<table bgcolor="FFFFFF" cellspacing="0" cellpadding="10" border="0" width="650" style="border:1px solid #E0E0E0;">
<tr>
<td valign="top">
<h1 style="font-size:22px; font-weight:normal; line-height:22px; margin:0 0 11px 0;">A new coupon code was generated, as follows:</h1>
<p style="font-size:12px; line-height:16px; margin:0 0 8px 0;"><strong>Order Number:</strong> '.$orderid.'</p>
<p style="font-size:12px; line-height:16px; margin:0 0 8px 0;"><strong>Coupon Code:</strong> '.$couponCode.'</p>
</td>
</tr>
</table>
</td>
</tr>
</table>
</div>
</body>
';
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
try {
mail($to, $subject, $message, $headers);
$mailReport = 'Mail sent!';
}
catch(Exception $ex) {
$mailReport = "Mail failed to send!";
}
// Log the voucher code generated
// Saved to /var/log/coupons.log
Mage::log(
"Coupon created: {$couponCode} | Order ID: {$orderid} | Mail Report: {$mailReport}\n\r",
null,
'coupons.log'
);
} // End If Date check.
}
}