How to use custom price table in open cart - opencart

Question

The concept of our project is, area wise products filtering, the products may be same or different. If the admin change the price of the product for particular area, then the price should change only that corresponding area.
For that, we have created new table as like oc_product_to_category with following new fields price,quantity,offer.
if the new table has the price value means then use that value for the process, if else means use default price value at the oc_product table. Upto category page we have successfully implemented this concept,
Category.php:
$this->load->model('mobile/product');
$price_by_category = $this->model_mobile_product->getpricebycategory($result['product_id'],$category_id);
if($price_by_category['price'] != ""){
$data['products'][] = array(
'product_id' => $result['product_id'],
'thumb' => $image,
'name' => $result['name'],
'description' => utf8_substr(strip_tags(html_entity_decode($result['description'], ENT_QUOTES, 'UTF-8')), 0, $this->config->get('config_product_description_length')) . '..',
'price' => "Rs.".$price_by_category['price'].".00",
'special' => $special,
'tax' => $tax,
'minimum' => $result['minimum'] > 0 ? $result['minimum'] : 1,
'rating' => $result['rating'],
'href' => $this->url->link('product/product', 'path=' . $this->request->get['path'] . '&product_id=' . $result['product_id'] . $url)
);;
}else{
$data['products'][] = array(
'product_id' => $result['product_id'],
'thumb' => $image,
'name' => $result['name'],
'description' => utf8_substr(strip_tags(html_entity_decode($result['description'], ENT_QUOTES, 'UTF-8')), 0, $this->config->get('config_product_description_length')) . '..',
'price' => $price,
'special' => $special,
'tax' => $tax,
'minimum' => $result['minimum'] > 0 ? $result['minimum'] : 1,
'rating' => $result['rating'],
'href' => $this->url->link('product/product', 'path=' . $this->request->get['path'] . '&product_id=' . $result['product_id'] . $url)
);
}
At cart , it takes the default price table value. If I create new function means, i have to change whole cart operation but i only want to change the price calculation, Based on the area id and product id.
I hope someone will give the solution.
Thanks..

Answer 1

There's no need to repeat the entire block for category.php. You can simply re-assign the price before adding to the array like $price = $price_by_category['price'] ?: $price.
To load your model in cart.php you can do it like this. In the __contruct block add:
public function __construct($registry) {
$this->registry = $registry;
Then in the getProducts() method you can load your model:
$this->load->model('mobile/product');
$mobileProduct = $this->registry->get('model_mobile_product');
$price_by_category = $mobileProduct->getpricebycategory($product_id,$category_id);
Of course the challenge here is you will need to add category data to the cart array when customer adds product to cart so you will be able to reference this later. My suggestion would be to encode it as a third slice in the cart session. Normally products look like this:
product-id:serialized-option-data:profile-id
So you can add another slice to store category id when adding to cart:
product-id:serialized-option-data:profile-id:category_id
Then afterward:
if (!empty($product[3])) {
$category_id = $product[3];
} else {
$category_id = 0;
}
You will also need to send category_id as POST data to controller/checkout/cart -> add() and then again pass it to system/library/cart.php to be encoded into the cart array.