Problem

I would like to introduce catalogue promotions that are specific to certain customer groups. Those promotion rules should be considered as additional catalogue rule meaning that best of "standard" catalogue rules and "group specific" catalogue rules is applied.

Example 1:
Product X: price 100 EUR (from Category 1)
Promotion A: -10 EUR on product X
Promotion B: -15% on Category 1 for customer group LoyalCustomer

Price displayed in storefront: 90 EUR (100EUR minus discount from promotion A)
Price when LoyalCustomer adds product to the cart: 85 EUR (100EUR minus discount from promotion B which is better than A)

Example 2:
Product X: price 100 EUR (from Category 1)
Promotion A: -15 EUR on product X
Promotion B: -10% on Category 1 for customer group LoyalCustomer

Price displayed in storefront: 85 EUR (100EUR minus discount from promotion A)
Price when LoyalCustomer adds product to the cart: 85 EUR (100EUR minus discount from promotion A which is better than B)

Possible solutions with existing APIs

• Use separate channel for LoyalCustomer - possible for small e-commerce, but not for large international store. With many channels number of possible options for customer groups and regular channels would explode. It would also mean that all the channel settings need to be duplicated between "regular" channel and "customer group" channels
• Use middleware with price field from CheckoutLineUpdateInput. This solution does not allow to control for "regular" Promotions. I.e. if I use it to apply promotion B, promotion A will be applied on top of this (so final price in example 1 would be 76.5 EUR). This approach changes undiscountedPrice, so all the fields related to discounts in promotions become useless.

Discord Discussion Link

https://discord.com/channels/864066819866624010/1098185593160216666/1359481364004605985

General Assumptions

I propose:

• To introduce a concept of Customer Group for Users
• To allow for promotion rules to be specific for a Customer Group

Such promotion rule:

• Would not be applied to discontedPrice in Product/VariantChannelListing
• Would be applied in checkout if checkout user is assigned to given CustomerGroup
• Would be treated as additional CatalogueRule - meaning that it will be applied only if it is more beneficial than other CatalogueRules

API Changes

Mutations

mutation CustomerGroupCreate($name: String!) {
  customerGroupCreate(input: {name: $name}) {
    id
    name
  }
}

mutation AccountUpdate($customerId: ID!, $addGroups: [ID!], $removeGroups: [ID!]) {
    accountUpdate(customerId: $customerId, input: {addGroups: $addGroups, removeGroups: $deleteGroups}) {
      customerGroups {
        id
        name
        translation(languageCode: PL) {
         name
        }
      }
    }
}

Add field customerGroups ([ID!]) to PromotionRuleInput
Add fields addCustomerGroups ([ID!]) and removeCustomerGroups ([ID!]) to PromotionRuleUpdateInput

Database Changes

• Create new model CustomerGroup (fields: name)
• Create new model CustomerGroupTranslation
• Add field customer_groups (ManyToMany with CustomerGroup) to model User (

  saleor/saleor/account/models.py

  Line 160 in 36a9a14

  class User(

  )
• Add field customer_groups (ManyToMany with CustomerGroup) to model PromotionRule (

  saleor/saleor/discount/models.py

  Line 318 in e4f90c6

  class Promotion(ModelWithMetadata):

  )
• Add field customer_group_specific (Boolean) to easily filter Rules with no CustomerGroup constraints

UML Diagrams

No response

To Do List

Logic changes:

• Only consider PromotionRules with customer_group_specific=False in function get_product_promotion_discounts (possibly rename to something like get_public_product_promotion_discounts

  saleor/saleor/discount/utils/promotion.py

  Line 137 in 36a9a14

  def get_product_promotion_discounts(

• Filter rules_info in prepare_checkout_line_discount_objects_for_catalogue_promotions by customer_groups before taking first (i.e. best) one (

  saleor/saleor/discount/utils/checkout.py

  Line 147 in 5829c1f

  rule_info = line_info.rules_info[0]

  )

Testing Requirements

No response