In-memory order updater

Gemfile

@@ -21,7 +21,7 @@ gem 'pg', '~> 1.0', require: false if dbs.match?(/all|postgres/)
 gem 'fast_sqlite', require: false if dbs.match?(/all|sqlite/)
 gem 'sqlite3', '~> 1.4', require: false if dbs.match?(/all|sqlite/)
 
-
+gem 'db-query-matchers'
 gem 'database_cleaner', '~> 2.0', require: false
 gem 'rspec-activemodel-mocks', '~> 1.1', require: false
 gem 'rspec-rails', '~> 6.0.3', require: false

TODO.md

@@ -0,0 +1,20 @@
+In-Memory Order Updater TODO
+===
+
+- [x] Add additional cases to item_total_updater_spec (doesn't currently account for included adjustments)
+- [x] Consider Sofia's recommendation to break this class into POROs to simplify testing
+- [x] Add test coverage for `recalculate_item_total` when line item totals change
+- [ ] Handle persistence in `update_promotions`
+- [ ] Handle persistence in `update_taxes`
+- [ ] Scope handling of tax adjustments in `InMemoryOrderUpdater` and `OrderUpdater` to *not* marked for destruction
+- [ ] Write the `InMemoryOrderAdjuster` (also, should we rename this to `InMemoryOrderPromotionAdjuster`)
+
+- [ ] Test coverage to ensure state changes aren't persisted (if someone changes current implementation)
+- [ ] Should we blow up if something tries to persist?
+  - Some thoughts from the initial conservation
+   - "By calling this in memory order updater, we are making a contract with the user that it will be in memory"
+   - "This is really something which theoritically should be covered in tests"
+   - "Our inMemoryOrderUpdater probably shouldnt take a persist true flag"
+   - thinking about other changes to solidus deep in the stack
+   - thinking about users configuring all the configurable classes
+

core/app/models/spree/in_memory_order_updater.rb

@@ -0,0 +1,252 @@
+# frozen_string_literal: true
+
+module Spree
+  class InMemoryOrderUpdater
+    attr_reader :order
+
+    delegate :payments, :line_items, :adjustments, :all_adjustments, :shipments, :quantity, to: :order
+
+    def initialize(order)
+      @order = order
+    end
+
+    # This is a multi-purpose method for processing logic related to changes in the Order.
+    # It is meant to be called from various observers so that the Order is aware of changes
+    # that affect totals and other values stored in the Order.
+    #
+    # This method should never do anything to the Order that results in a save call on the
+    # object with callbacks (otherwise you will end up in an infinite recursion as the
+    # associations try to save and then in turn try to call +update!+ again.)
+    def recalculate(persist: true)
+      order.transaction do
+        recalculate_item_count
+        update_shipment_amounts(persist:)
+        update_totals(persist:)
+        if order.completed?
+          recalculate_payment_state
+          update_shipments
+          recalculate_shipment_state
+        end
+
+        Spree::Bus.publish(:order_recalculated, order:)
+
+        persist_totals if persist
+      end
+    end
+    alias_method :update, :recalculate
+    deprecate update: :recalculate, deprecator: Spree.deprecator
+
+    # Recalculates the +shipment_state+ attribute according to the following logic:
+    #
+    # shipped   when all Shipments are in the "shipped" state
+    # partial   when at least one Shipment has a state of "shipped" and there is another Shipment with a state other than "shipped"
+    #           or there are InventoryUnits associated with the order that have a state of "sold" but are not associated with a Shipment.
+    # ready     when all Shipments are in the "ready" state
+    # backorder when there is backordered inventory associated with an order
+    # pending   when all Shipments are in the "pending" state
+    #
+    # The +shipment_state+ value helps with reporting, etc. since it provides a quick and easy way to locate Orders needing attention.
+    def recalculate_shipment_state
+      log_state_change('shipment') do
+        order.shipment_state = determine_shipment_state
+      end
+
+      order.shipment_state
+    end
+    alias_method :update_shipment_state, :recalculate_shipment_state
+    deprecate update_shipment_state: :recalculate_shipment_state, deprecator: Spree.deprecator
+
+    # Recalculates the +payment_state+ attribute according to the following logic:
+    #
+    # paid          when +payment_total+ is equal to +total+
+    # balance_due   when +payment_total+ is less than +total+
+    # credit_owed   when +payment_total+ is greater than +total+
+    # failed        when most recent payment is in the failed state
+    # void          when the order has been canceled and the payment total is 0
+    #
+    # The +payment_state+ value helps with reporting, etc. since it provides a quick and easy way to locate Orders needing attention.
+    def recalculate_payment_state
+      log_state_change('payment') do
+        order.payment_state = determine_payment_state
+      end
+
+      order.payment_state
+    end
+    alias_method :update_payment_state, :recalculate_shipment_state
+    deprecate update_payment_state: :recalculate_shipment_state, deprecator: Spree.deprecator
+
+    private
+
+    def determine_payment_state
+      if payments.present? && payments.valid.empty? && order.outstanding_balance != 0
+        'failed'
+      elsif order.state == 'canceled' && order.payment_total.zero?
+        'void'
+      elsif order.outstanding_balance > 0
+        'balance_due'
+      elsif order.outstanding_balance < 0
+        'credit_owed'
+      else
+        # outstanding_balance == 0
+        'paid'
+      end
+    end
+
+    def determine_shipment_state
+      if order.backordered?
+        'backorder'
+      else
+        # get all the shipment states for this order
+        shipment_states = shipments.states
+        if shipment_states.size > 1
+          # multiple shiment states means it's most likely partially shipped
+          'partial'
+        else
+          # will return nil if no shipments are found
+          shipment_states.first
+        end
+      end
+    end
+
+    # This will update and select the best promotion adjustment, update tax
+    # adjustments, update cancellation adjustments, and then update the total
+    # fields (promo_total, included_tax_total, additional_tax_total, and
+    # adjustment_total) on the item.
+    # @return [void]
+    def update_adjustments(persist:)
+      # Promotion adjustments must be applied first, then tax adjustments.
+      # This fits the criteria for VAT tax as outlined here:
+      # http://www.hmrc.gov.uk/vat/managing/charging/discounts-etc.htm#1
+      # It also fits the criteria for sales tax as outlined here:
+      # http://www.boe.ca.gov/formspubs/pub113/
+      update_promotions(persist:)
+      update_tax_adjustments
+      recalculate_item_totals
+      # FIXME: Write Persist changes to items
+      # persist_changes_to_items if persist
+    end
+
+    # Updates the following Order total values:
+    #
+    # +payment_total+      The total value of all finalized Payments (NOTE: non-finalized Payments are excluded)
+    # +item_total+         The total value of all LineItems
+    # +adjustment_total+   The total value of all adjustments (promotions, credits, etc.)
+    # +promo_total+        The total value of all promotion adjustments
+    # +total+              The so-called "order total."  This is equivalent to +item_total+ plus +adjustment_total+.
+    def update_totals(persist:)
+      recalculate_payment_total
+      recalculate_item_total
+      recalculate_shipment_total
+      update_adjustment_total(persist:)
+    end
+
+    def update_shipment_amounts(persist:)
+      shipments.each { _1.update_amounts(persist:) }
+    end
+
+    def update_adjustment_total(persist:)
+      update_adjustments(persist:)
+
+      all_items = line_items + shipments
+      # FIXME: We will need to ignore tax adjustments marked for destruction here and maybe elsewhere
+      order_tax_adjustments = adjustments.select(&:tax?)
+
+      order.adjustment_total = all_items.sum(&:adjustment_total) + adjustments.sum(&:amount)
+      order.included_tax_total = all_items.sum(&:included_tax_total) + order_tax_adjustments.select(&:included?).sum(&:amount)
+      order.additional_tax_total = all_items.sum(&:additional_tax_total) + order_tax_adjustments.reject(&:included?).sum(&:amount)
+
+      recalculate_order_total
+    end
+
+    def update_promotions(persist:)
+      if persist
+        Spree::Config.promotions.order_adjuster_class
+      else
+        InMemoryOrderAdjuster
+      end.new(order).call
+    end
+
+    # TODO: split implementation based on 'persist'
+    def update_tax_adjustments
+      Spree::Config.tax_adjuster_class.new(order).adjust!
+    end
+
+    def update_cancellations
+    end
+    deprecate :update_cancellations, deprecator: Spree.deprecator
+
+    def recalculate_item_totals
+      [*line_items, *shipments].each do |item|
+        Spree::ItemTotal.new(item).recalculate!
+      end
+    end
+
+    def persist_item_changes
+      [*line_items, *shipments].each do |item|
+        next unless item.changed?
+
+        item.update_columns(
+          promo_total:          item.promo_total,
+          included_tax_total:   item.included_tax_total,
+          additional_tax_total: item.additional_tax_total,
+          adjustment_total:     item.adjustment_total,
+          updated_at:           Time.current,
+        )
+      end
+    end
+
+    # give each of the shipments a chance to update themselves
+    def update_shipments
+      shipments.each(&:update_state)
+    end
+
+    def recalculate_payment_total
+      order.payment_total = payments.completed.includes(:refunds).sum { |payment| payment.amount - payment.refunds.sum(:amount) }
+    end
+
+    def recalculate_shipment_total
+      order.shipment_total = shipments.to_a.sum(&:cost)
+      recalculate_order_total
+    end
+
+    def recalculate_order_total
+      order.total = order.item_total + order.shipment_total + order.adjustment_total
+    end
+
+    def recalculate_item_count
+      order.item_count = line_items.to_a.sum(&:quantity)
+    end
+
+    def recalculate_item_total
+      order.item_total = line_items.to_a.sum(&:amount)
+      recalculate_order_total
+    end
+
+    def persist_totals
+      order.save!
+    end
+
+    def log_state_change(name)
+      state = "#{name}_state"
+      old_state = order.public_send(state)
+      yield
+      new_state = order.public_send(state)
+      if old_state != new_state
+        order.state_changes.new(
+          previous_state: old_state,
+          next_state:     new_state,
+          user_id:        order.user_id,
+          name:
+        )
+      end
+    end
+
+    class InMemoryOrderAdjuster
+      def initialize(order)
+      end
+
+      def call
+      end
+    end
+  end
+end

core/app/models/spree/item_total.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class Spree::ItemTotal
+  def initialize(item)
+    @item = item
+  end
+
+  def recalculate!
+    tax_adjustments = item.adjustments.select(&:tax?)
+
+    # Included tax adjustments are those which are included in the price.
+    # These ones should not affect the eventual total price.
+    #
+    # Additional tax adjustments are the opposite, affecting the final total.
+    item.included_tax_total   = tax_adjustments.select(&:included?).sum(&:amount)
+    item.additional_tax_total = tax_adjustments.reject(&:included?).sum(&:amount)
+
+    item.adjustment_total = item.adjustments.reject(&:included?).sum(&:amount)
+  end
+
+  private
+
+  attr_reader :item
+end

core/app/models/spree/line_item.rb

@@ -16,7 +16,7 @@ class LineItem < Spree::Base
 
     has_one :product, through: :variant
 
-    has_many :adjustments, as: :adjustable, inverse_of: :adjustable, dependent: :destroy
+    has_many :adjustments, as: :adjustable, inverse_of: :adjustable, dependent: :destroy, autosave: true
     has_many :inventory_units, inverse_of: :line_item
 
     before_validation :normalize_quantity

core/app/models/spree/order_taxation.rb

@@ -56,7 +56,8 @@ def update_adjustments(item, taxed_items)
 
       # Remove any tax adjustments tied to rates which no longer match.
       unmatched_adjustments = tax_adjustments - active_adjustments
-      item.adjustments.destroy(unmatched_adjustments)
+
+      unmatched_adjustments.each(&:mark_for_destruction)
     end
 
     # Update or create a new tax adjustment on an item.
@@ -76,7 +77,8 @@ def update_adjustment(item, tax_item)
         label: tax_item.label,
         included: tax_item.included_in_price
       )
-      tax_adjustment.update!(amount: tax_item.amount)
+
+      tax_adjustment.amount = tax_item.amount
       tax_adjustment
     end
   end

core/app/models/spree/order_updater.rb

@@ -202,6 +202,7 @@ def update_taxes
       Spree::Config.tax_adjuster_class.new(order).adjust!
 
       [*line_items, *shipments].each do |item|
+        # FIXME: We will need to ignore tax adjustments marked for destruction here and maybe elsewhere
         tax_adjustments = item.adjustments.select(&:tax?)
         # Tax adjustments come in not one but *two* exciting flavours:
         # Included & additional

core/app/models/spree/shipment.rb

@@ -258,10 +258,10 @@ def tracking_url
       @tracking_url ||= shipping_method.build_tracking_url(tracking)
     end
 
-    def update_amounts
+    def update_amounts(persist: true)
       if selected_shipping_rate
         self.cost = selected_shipping_rate.cost
-        if changed?
+        if changed? && persist
           update_columns(
             cost:,
             updated_at: Time.current