Esta es esencialmente una funcionalidad de una clase, de verdad. Necesitarías una interfaz de clase que se vería así
class ProductDiscount {
/**
* Create a NEW discount code and return the instance of
*
* @param $code string the discount code
* @param $discount float price adjustment in % (ex:
* @param $options array (optional) an array of options :
* 'expire' => timestamp (optional)
* 'limited' => int (optional)
* @return ProductDiscount
*/
static public function create($code, $discount, $options = NULL);
/**
* This essentially validate the code, and return the instance of the
* discount if the code exists. The method returns null if the discount
* is not valid for any reason. If an instance is returned, to apply
* the discount, one should invoke the "consume()" method of the instance.
*
* @param $code string
*
* @return ProductDiscount|null
*/
static public function validate($code);
private $_code; // string
private $_discount; // float
private $_expire; // unix timestamp (see time()) or null if unlimited
private $_count; // int or null if unlimited
private function __construct();
public function getCode(); // return string
public function getDiscount(); // return float
public function isLimited(); // return bool; true if $_count || $_expire is not null
public function getCount(); // returns int; how many of this discount is left or null if unlimited
public function getExpireDate();// returns int (unix timestamp) or null if unlimited
public function consume(); // apply this discount now
public function consumeAll(); // invalidate this discount for future use
}
La tabla DB podría verse así
id UNSIGNED INT(10) NOT NULL AUTOINCREMENT -- (Primary Key)
code VARCHAR(12) NOT NULL -- (Indexed, unique)
discount UNSIGNED INT(3) NOT NULL -- percent value 0..100
expire DATETIME DEFAULT NULL -- unlimited by default
count INT(10) DEFAULT 1 -- can be NULL
Nota: El proceso de validación podría ser simplemente SELECT declaración :
SELECT *
FROM tblproductdiscount
WHERE code = {$code} -- $code = mysql_real_escape_string($code)
AND (count IS NULL OR count > 0)
AND (expire IS NULL or expire > NOW())
Luego, solo use esta clase al validar el formulario de pago. Por ejemplo,
if (!empty($discountCode)) {
$discount = ProductDiscount::validate($discountCode);
if ($discount !== null) {
$price *= (1 - $discount->getDiscount());
$discount->consume();
}
}
Bueno, así es como yo lo haría.
