App Shopify - Recibir dato de Api y aplicar respuesta como descuento en el carrito de una tienda

Hola les dejo en ingles la funcionalidad que se necesita, necesito urgentemente alguien que desarrolle una app que pueda ser inicialmente instalada en cualquier tienda Shopify y a futuro publicada en el App store. Lo unico que hace la App es que cuando estas en la pagina de carrito, que haya un campo donde puedas ingresar un numero y presionar "Aplicar". Lo que se hara aqui es usar ese numero para hacer una llamada de API y recibir un numero de respuesta.

Este numero que se recibe del callback se debe de aplicar como descuento en el carrito.


STEP 1: When a user in the Shopify store gets to Checkout (during the entire checkout process there is a pane with total amount on the right side) we need to add an input field and a button. This input field will allow a user to input a Client Number, when the 'Apply' button is clicked, the plugin will send a POST call to X endpoint with the following data:
{
  "storeId": 1,
  "companyYClientNumber": 12345678,
  "origin":"web",
  "totalOrderPrice":"500",
  "products":[
    {
      "sku": 412424,
      "quantity": 4
    },
    {
      "sku": 535255,
      "quantity": 1
    }
  ]
}

** storeId = a fixed number that I will provide
    companyYClientNumber = the number that was provided by the user in the input field in the Checkout
    origin = Will always be 'web'
    totalOrderPrice = The Subtotal of the order in checkout (this excludes shipping fees if any)
    products = an array of all the products in the order in which every product includes sku of that product and the quantity of bought products

step 2:
the /post request sent  in step 1 will return a response like the one below:
{"status":"success","apitoken":"amppd6ju1mhsm","grant":{"cash":200,"paymentinkind":0,"volunteer":100,"prize":300},"redeem":{"prize":0, "prizeallow":0},"invalidproducts":["product x", "product y"]}

here we are only looking for the value of redeem.prize, if it is greater than 0 the value will be applied as a discount to the subtotal. We don't need to store or interact in any way with the rest.

If the response returns status:failed we will disaplay a small message that says "It appears that your client number is not valid or the products in your cart are not part of an active promotion".

STEP 3:
When the order is processed and is successful we will send a /post request to X endpoint with the following data:
{
  "typeOperation":"Sale",
  "apiToken":"AmPPd6jU1mHSm",
  "status":"Done",
  "folio":"F12"
}

Where typeOperation, apiToken and folio: will be provided and will never change.
And 'status' will be "Done" if order was completed successfully or "Unsuccessful" if it wasn't