Calculate campaign price

The task is to write functionality for calculating campaign price when a customer is doing a checkout. We have the following campaign types Campaigns based on product combination Campaigns based on volume, for example 2 for amount or 3 for x amount

Combo campaigns

For the combo campaign to work, the customer must combine a minimum of two products to get the campaign price. A combo campaign contains a list of products that the customer can combine, here is an example:

EAN	Combo Price
5000112637922	30
5000112637939	30
7310865004703	30
7340005404261	30
7310532109090	50
7611612222105	50

Here are some combination examples a customer can make, a product can be combined with itself.

5000112637922 + 7310865004703 = 30
7310532109090 + 7611612222105 + 5000112637922 + 7310865004703 = 80

Note: If the customer adds three products to their basket and all of them are in a campaign, the customer only pays the campaign price for two of them and will pay original price for the third product

Volume campaigns

The volume campaigns are based on number of items the customer needs to add to their basket to trigger the campaign price. For example, you can setup a campaign for Coca-Cola and the customer needs to buy two to get the campaign price.

EAN	Price	Quantity
8711000530085	85	2
7310865004703	20	2

Note: If the customer adds a third item to the basket, the customer needs to pay regular price for the third item and campaign price for the rest