[DFC Orders] Backorder stock controlled products

app/controllers/cart_controller.rb

@@ -11,6 +11,8 @@ def populate
       order.cap_quantity_at_stock!
       order.recreate_all_fees!
 
+      StockSyncJob.sync_linked_catalogs(order)
+
       render json: { error: false, stock_levels: stock_levels(order) }, status: :ok
     else
       render json: { error: cart_service.errors.full_messages.join(",") },

app/jobs/backorder_job.rb

@@ -13,17 +13,9 @@ class BackorderJob < ApplicationJob
   sidekiq_options retry: 0
 
   def self.check_stock(order)
-    variants_needing_stock = order.variants.select do |variant|
-      # TODO: scope variants to hub.
-      # We are only supporting producer stock at the moment.
-      variant.on_hand&.negative?
-    end
+    links = SemanticLink.where(variant_id: order.line_items.select(:variant_id))
 
-    linked_variants = variants_needing_stock.select do |variant|
-      variant.semantic_links.present?
-    end
-
-    perform_later(order, linked_variants) if linked_variants.present?
+    perform_later(order) if links.exists?
   rescue StandardError => e
     # Errors here shouldn't affect the checkout. So let's report them
     # separately:
@@ -32,44 +24,60 @@ def self.check_stock(order)
     end
   end
 
-  def perform(order, linked_variants)
+  def perform(order)
     OrderLocker.lock_order_and_variants(order) do
-      place_backorder(order, linked_variants)
+      place_backorder(order)
     end
   rescue StandardError
     # If the backordering fails, we need to tell the shop owner because they
     # need to organgise more stock.
-    BackorderMailer.backorder_failed(order, linked_variants).deliver_later
+    BackorderMailer.backorder_failed(order).deliver_later
 
     raise
   end
 
-  def place_backorder(order, linked_variants)
+  def place_backorder(order)
     user = order.distributor.owner
+    items = backorderable_items(order)
 
     # We are assuming that all variants are linked to the same wholesale
     # shop and its catalog:
-    urls = FdcUrlBuilder.new(linked_variants[0].semantic_links[0].semantic_id)
+    reference_link = items[0].variant.semantic_links[0].semantic_id
+    urls = FdcUrlBuilder.new(reference_link)
     orderer = FdcBackorderer.new(user, urls)
 
     backorder = orderer.find_or_build_order(order)
     broker = load_broker(order.distributor.owner, urls)
     ordered_quantities = {}
 
-    linked_variants.each do |variant|
-      retail_quantity = add_item_to_backorder(variant, broker, backorder, orderer)
-      ordered_quantities[variant] = retail_quantity
+    items.each do |item|
+      retail_quantity = add_item_to_backorder(item, broker, backorder, orderer)
+      ordered_quantities[item] = retail_quantity
     end
 
     place_order(user, order, orderer, backorder)
 
-    linked_variants.each do |variant|
-      variant.on_hand += ordered_quantities[variant]
+    items.each do |item|
+      variant = item.variant
+      variant.on_hand += ordered_quantities[item] if variant.on_demand
     end
   end
 
-  def add_item_to_backorder(variant, broker, backorder, orderer)
-    needed_quantity = -1 * variant.on_hand
+  # We look at linked variants which are either stock controlled or
+  # are on demand with negative stock.
+  def backorderable_items(order)
+    order.line_items.select do |item|
+      # TODO: scope variants to hub.
+      # We are only supporting producer stock at the moment.
+      variant = item.variant
+      variant.semantic_links.present? &&
+        (variant.on_demand == false || variant.on_hand&.negative?)
+    end
+  end
+
+  def add_item_to_backorder(line_item, broker, backorder, orderer)
+    variant = line_item.variant
+    needed_quantity = needed_quantity(line_item)
     solution = broker.best_offer(variant.semantic_links[0].semantic_id)
 
     # The number of wholesale packs we need to order to fulfill the
@@ -88,6 +96,26 @@ def add_item_to_backorder(variant, broker, backorder, orderer)
     retail_quantity
   end
 
+  # We have two different types of stock management:
+  #
+  # 1. on demand
+  #    We don't restrict sales but account for the quantity sold in our local
+  #    stock level. If it goes negative, we need more stock and trigger a
+  #    backorder.
+  # 2. limited stock
+  #    The local stock level is a copy from another catalog. We limit sales
+  #    according to that stock level. Every order reduces the local stock level
+  #    and needs to trigger a backorder of the same quantity to stay in sync.
+  def needed_quantity(line_item)
+    variant = line_item.variant
+
+    if variant.on_demand
+      -1 * variant.on_hand # on_hand is negative and we need to replenish it.
+    else
+      line_item.quantity # We need to order exactly what's we sold.
+    end
+  end
+
   def load_broker(user, urls)
     FdcOfferBroker.new(user, urls)
   end

app/jobs/complete_backorder_job.rb

@@ -22,7 +22,7 @@ def perform(user, distributor, order_cycle, order_id)
     urls = FdcUrlBuilder.new(order.lines[0].offer.offeredItem.semanticId)
 
     variants = order_cycle.variants_distributed_by(distributor)
-    adjust_quantities(user, order, urls, variants)
+    adjust_quantities(order_cycle, user, order, urls, variants)
 
     FdcBackorderer.new(user, urls).complete_order(order)
   rescue StandardError
@@ -36,7 +36,7 @@ def perform(user, distributor, order_cycle, order_id)
   # Our local stock can increase when users cancel their orders.
   # But stock levels could also have been adjusted manually. So we review all
   # quantities before finalising the order.
-  def adjust_quantities(user, order, urls, variants)
+  def adjust_quantities(order_cycle, user, order, urls, variants)
     broker = FdcOfferBroker.new(user, urls)
 
     order.lines.each do |line|
@@ -45,18 +45,35 @@ def adjust_quantities(user, order, urls, variants)
       transformation = broker.wholesale_to_retail(wholesale_product_id)
       linked_variant = variants.linked_to(transformation.retail_product_id)
 
-      # Note that a division of integers dismisses the remainder, like `floor`:
-      wholesale_items_contained_in_stock = linked_variant.on_hand / transformation.factor
-
-      # But maybe we didn't actually order that much:
-      deductable_quantity = [line.quantity, wholesale_items_contained_in_stock].min
-      line.quantity -= deductable_quantity
-
-      retail_stock_changes = deductable_quantity * transformation.factor
-      linked_variant.on_hand -= retail_stock_changes
+      # Find all line items for this order cycle
+      # Update quantity accordingly
+      if linked_variant.on_demand
+        release_superfluous_stock(line, linked_variant, transformation)
+      else
+        aggregate_final_quantities(order_cycle, line, linked_variant, transformation)
+      end
     end
 
     # Clean up empty lines:
     order.lines.reject! { |line| line.quantity.zero? }
   end
+
+  def release_superfluous_stock(line, linked_variant, transformation)
+    # Note that a division of integers dismisses the remainder, like `floor`:
+    wholesale_items_contained_in_stock = linked_variant.on_hand / transformation.factor
+
+    # But maybe we didn't actually order that much:
+    deductable_quantity = [line.quantity, wholesale_items_contained_in_stock].min
+    line.quantity -= deductable_quantity
+
+    retail_stock_changes = deductable_quantity * transformation.factor
+    linked_variant.on_hand -= retail_stock_changes
+  end
+
+  def aggregate_final_quantities(order_cycle, line, variant, transformation)
+    orders = order_cycle.orders.invoiceable
+    quantity = Spree::LineItem.where(order: orders, variant:).sum(:quantity)
+    wholesale_quantity = (quantity.to_f / transformation.factor).ceil
+    line.quantity = wholesale_quantity
+  end
 end

app/jobs/stock_sync_job.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+class StockSyncJob < ApplicationJob
+  # No retry but stay as failed job:
+  sidekiq_options retry: 0
+
+  # We synchronise stock of stock-controlled variants linked to a remote
+  # product. These variants are rare though and we check first before we
+  # enqueue a new job. That should save some time loading the order with
+  # all the stock data to make this decision.
+  def self.sync_linked_catalogs(order)
+    stock_controlled_variants = order.variants.reject(&:on_demand)
+    links = SemanticLink.where(variant_id: stock_controlled_variants.map(&:id))
+    semantic_ids = links.pluck(:semantic_id)
+
+    return if semantic_ids.empty?
+
+    user = order.distributor.owner
+    reference_id = semantic_ids.first # Assuming one catalog for now.
+    perform_later(user, reference_id)
+  rescue StandardError => e
+    # Errors here shouldn't affect the shopping. So let's report them
+    # separately:
+    Bugsnag.notify(e) do |payload|
+      payload.add_metadata(:order, order)
+    end
+  end
+
+  def perform(user, semantic_id)
+    urls = FdcUrlBuilder.new(semantic_id)
+    json_catalog = DfcRequest.new(user).call(urls.catalog_url)
+    graph = DfcIo.import(json_catalog)
+
+    products = graph.select do |subject|
+      subject.is_a? DataFoodConsortium::Connector::SuppliedProduct
+    end
+    products_by_id = products.index_by(&:semanticId)
+    product_ids = products_by_id.keys
+    variants = Spree::Variant.where(supplier: user.enterprises)
+      .includes(:semantic_links).references(:semantic_links)
+      .where(semantic_links: { semantic_id: product_ids })
+
+    variants.each do |variant|
+      next if variant.on_demand
+
+      product = products_by_id[variant.semantic_links[0].semantic_id]
+      catalog_item = product&.catalogItems&.first
+      CatalogItemBuilder.apply_stock(catalog_item, variant)
+      variant.stock_items[0].save!
+    end
+  end
+end

app/mailers/backorder_mailer.rb

@@ -3,9 +3,9 @@
 class BackorderMailer < ApplicationMailer
   include I18nHelper
 
-  def backorder_failed(order, linked_variants)
+  def backorder_failed(order)
     @order = order
-    @linked_variants = linked_variants
+    @linked_variants = order.variants
 
     I18n.with_locale valid_locale(order.distributor.owner) do
       mail(to: order.distributor.owner.email)