Class: Spree::Promotion::Actions::CreateQuantityAdjustments
- Inherits:
-
CreateItemAdjustments
- Object
- ActiveRecord::Base
- Base
- Spree::PromotionAction
- CreateItemAdjustments
- Spree::Promotion::Actions::CreateQuantityAdjustments
- Defined in:
- app/models/spree/promotion/actions/create_quantity_adjustments.rb
Defined Under Namespace
Classes: PartialLineItem
Instance Method Summary collapse
-
#compute_amount(line_item) ⇒ Object
Computes the amount for the adjustment based on the line item and any other applicable items in the order.
Methods inherited from CreateItemAdjustments
#perform, #preload_relations, #remove_from
Methods included from AdjustmentSource
#remove_adjustments_from_incomplete_orders
Methods included from CalculatedAdjustments
#calculator_type, #calculator_type=
Methods inherited from Spree::PromotionAction
#perform, #preload_relations, #remove_from, #to_partial_path
Methods inherited from Base
Methods included from Core::Permalinks
#generate_permalink, #save_permalink
Instance Method Details
#compute_amount(line_item) ⇒ Object
Computes the amount for the adjustment based on the line item and any other applicable items in the order. The rules for this specific adjustment are as follows:
Setup
We have a quantity group promotion on t-shirts. If a user orders 3 t-shirts, they get $5 off of each. The shirts come in one size and three colours: red, blue, and white.
Scenario 1
User has 2 red shirts, 1 white shirt, and 1 blue shirt in their order. We want to compute the adjustment amount for the white shirt.
Result: -$5
Reasoning: There are a total of 4 items that are eligible for the promotion. Since that is greater than 3, we can discount the items. The white shirt has a quantity of 1, therefore it will get discounted by adjustment_amount * 1 or $5.
Scenario 1-1
What about the blue shirt? How much does it get discounted?
Result: $0
Reasoning: We have a total quantity of 4. However, we only apply the adjustment to groups of 3. Assuming the white and red shirts have already had their adjustment calculated, that means 3 units have been discounted. Leaving us with a lonely blue shirt that isn’t part of a group of 3. Therefore, it does not receive the discount.
Scenario 2
User has 4 red shirts in their order. What is the amount?
Result: -$15
Reasoning: The total quantity of eligible items is 4, so we the adjustment will be non-zero. However, we only apply it to groups of 3, therefore there is one extra item that is not eligible for the adjustment. adjustment_amount * 3 or $15.
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# File 'app/models/spree/promotion/actions/create_quantity_adjustments.rb', line 58 def compute_amount(line_item) adjustment_amount = calculator.compute(PartialLineItem.new(line_item)) adjustment_amount ||= BigDecimal(0) adjustment_amount = adjustment_amount.abs order = line_item.order line_items = actionable_line_items(order) actioned_line_items = order.line_item_adjustments.reload. select { |adjustment| adjustment.source == self && adjustment.amount < 0 }. map(&:adjustable) other_line_items = actioned_line_items - [line_item] applicable_quantity = total_applicable_quantity(line_items) used_quantity = total_used_quantity(other_line_items) usable_quantity = [ applicable_quantity - used_quantity, line_item.quantity ].min persist_quantity(usable_quantity, line_item) amount = adjustment_amount * usable_quantity [line_item.amount, amount].min * -1 end |