Move all business logic to `lib`

It wasn't clear why certain business logic should live in `app/services`
while other should live in `lib`. By unifying everything in one directory,
we make it easier for developers to inspect the code and reduce the
cognitive load when implementing new classes.

1 files changed, 65 insertions, 0 deletions

diff --git a/lib/solidus_subscriptions/subscription_generator.rb b/lib/solidus_subscriptions/subscription_generator.rb
new file mode 100644
index 0000000..8153912
--- /dev/null
+++ b/lib/solidus_subscriptions/subscription_generator.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+# This module is responsible for taking SolidusSubscriptions::LineItem
+# objects and creating SolidusSubscriptions::Subscription Objects
+module SolidusSubscriptions
+  module SubscriptionGenerator
+    extend self
+
+    SubscriptionConfiguration = Struct.new(:interval_length, :interval_units, :end_date)
+
+    # Create and persist a subscription for a collection of subscription
+    #   line items
+    #
+    # @param subscription_line_items [Array<SolidusSubscriptions::LineItem>] The
+    #   subscription_line_items to be activated
+    #
+    # @return [SolidusSubscriptions::Subscription]
+    def activate(subscription_line_items)
+      return if subscription_line_items.empty?
+
+      order = subscription_line_items.first.order
+      configuration = subscription_configuration(subscription_line_items.first)
+
+      subscription_attributes = {
+        user: order.user,
+        line_items: subscription_line_items,
+        store: order.store,
+        shipping_address: order.ship_address,
+        billing_address: order.bill_address,
+        payment_source: order.payments.valid.last&.payment_source,
+        payment_method: order.payments.valid.last&.payment_method,
+        **configuration.to_h
+      }
+
+      Subscription.create!(subscription_attributes) do |sub|
+        sub.actionable_date = sub.next_actionable_date
+      end
+    end
+
+    # Group a collection of line items by common subscription configuration
+    # options. Grouped subscription_line_items can belong to a single
+    # subscription.
+    #
+    # @param subscription_line_items [Array<SolidusSubscriptions::LineItem>] The
+    #   subscription_line_items to be grouped.
+    #
+    # @return [Array<Array<SolidusSubscriptions::LineItem>>]
+    def group(subscription_line_items)
+      subscription_line_items.group_by do |li|
+        subscription_configuration(li)
+      end.
+        values
+    end
+
+    private
+
+    def subscription_configuration(subscription_line_item)
+      SubscriptionConfiguration.new(
+        subscription_line_item.interval_length,
+        subscription_line_item.interval_units,
+        subscription_line_item.end_date
+      )
+    end
+  end
+end