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.

9 files changed, 275 insertions, 0 deletions

diff --git a/lib/solidus_subscriptions/checkout.rb b/lib/solidus_subscriptions/checkout.rb
new file mode 100644
index 0000000..83fc35c
--- /dev/null
+++ b/lib/solidus_subscriptions/checkout.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  class Checkout
+    attr_reader :installment
+
+    def initialize(installment)
+      @installment = installment
+    end
+
+    def process
+      order = create_order
+
+      begin
+        populate_order(order)
+        finalize_order(order)
+
+        SolidusSubscriptions.configuration.success_dispatcher_class.new(installment, order).dispatch
+      rescue StateMachines::InvalidTransition
+        if order.payments.any?(&:failed?)
+          SolidusSubscriptions.configuration.payment_failed_dispatcher_class.new(installment, order).dispatch
+        else
+          SolidusSubscriptions.configuration.failure_dispatcher_class.new(installment, order).dispatch
+        end
+      rescue ::Spree::Order::InsufficientStock
+        SolidusSubscriptions.configuration.out_of_stock_dispatcher_class.new(installment, order).dispatch
+      end
+
+      order
+    end
+
+    private
+
+    def create_order
+      ::Spree::Order.create(
+        user: installment.subscription.user,
+        email: installment.subscription.user.email,
+        store: installment.subscription.store || ::Spree::Store.default,
+        subscription_order: true,
+        subscription: installment.subscription
+      )
+    end
+
+    def populate_order(order)
+      installment.subscription.line_items.each do |line_item|
+        order.contents.add(line_item.subscribable, line_item.quantity)
+      end
+    end
+
+    def finalize_order(order)
+      ::Spree::PromotionHandler::Cart.new(order).activate
+      order.recalculate
+
+      order.checkout_steps[0...-1].each do
+        case order.state
+        when 'address'
+          order.ship_address = installment.subscription.shipping_address_to_use
+          order.bill_address = installment.subscription.billing_address_to_use
+        when 'payment'
+          order.payments.create(
+            payment_method: installment.subscription.payment_method_to_use,
+            source: installment.subscription.payment_source_to_use,
+            amount: order.total,
+          )
+        end
+
+        order.next!
+      end
+
+      order.complete!
+    end
+  end
+end
diff --git a/lib/solidus_subscriptions/dispatcher/base.rb b/lib/solidus_subscriptions/dispatcher/base.rb
new file mode 100644
index 0000000..30c5034
--- /dev/null
+++ b/lib/solidus_subscriptions/dispatcher/base.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  module Dispatcher
+    class Base
+      attr_reader :installment, :order
+
+      def initialize(installment, order)
+        @installment = installment
+        @order = order
+      end
+
+      def dispatch
+        raise NotImplementedError
+      end
+    end
+  end
+end
diff --git a/lib/solidus_subscriptions/dispatcher/failure_dispatcher.rb b/lib/solidus_subscriptions/dispatcher/failure_dispatcher.rb
new file mode 100644
index 0000000..54f8f2b
--- /dev/null
+++ b/lib/solidus_subscriptions/dispatcher/failure_dispatcher.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  module Dispatcher
+    class FailureDispatcher < Base
+      def dispatch
+        order.touch(:completed_at)
+        order.cancel
+        installment.failed!(order)
+      end
+    end
+  end
+end
diff --git a/lib/solidus_subscriptions/dispatcher/out_of_stock_dispatcher.rb b/lib/solidus_subscriptions/dispatcher/out_of_stock_dispatcher.rb
new file mode 100644
index 0000000..fe3e701
--- /dev/null
+++ b/lib/solidus_subscriptions/dispatcher/out_of_stock_dispatcher.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  module Dispatcher
+    class OutOfStockDispatcher < Base
+      def dispatch
+        installment.out_of_stock
+      end
+    end
+  end
+end
diff --git a/lib/solidus_subscriptions/dispatcher/payment_failed_dispatcher.rb b/lib/solidus_subscriptions/dispatcher/payment_failed_dispatcher.rb
new file mode 100644
index 0000000..a56332e
--- /dev/null
+++ b/lib/solidus_subscriptions/dispatcher/payment_failed_dispatcher.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  module Dispatcher
+    class PaymentFailedDispatcher < Base
+      def dispatch
+        order.touch(:completed_at)
+        order.cancel
+        installment.payment_failed!(order)
+
+        ::Spree::Event.fire(
+          'solidus_subscriptions.installment_failed_payment',
+          installment: installment,
+          order: order,
+        )
+      end
+    end
+  end
+end
diff --git a/lib/solidus_subscriptions/dispatcher/success_dispatcher.rb b/lib/solidus_subscriptions/dispatcher/success_dispatcher.rb
new file mode 100644
index 0000000..0ae71dc
--- /dev/null
+++ b/lib/solidus_subscriptions/dispatcher/success_dispatcher.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  module Dispatcher
+    class SuccessDispatcher < Base
+      def dispatch
+        installment.success!(order)
+
+        ::Spree::Event.fire(
+          'solidus_subscriptions.installment_succeeded',
+          installment: installment,
+          order: order,
+        )
+      end
+    end
+  end
+end
diff --git a/lib/solidus_subscriptions/line_item_builder.rb b/lib/solidus_subscriptions/line_item_builder.rb
new file mode 100644
index 0000000..c9aedb9
--- /dev/null
+++ b/lib/solidus_subscriptions/line_item_builder.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# This class is responsible for taking SubscriptionLineItems and building
+# them into Spree::LineItems which can be added to an order
+module SolidusSubscriptions
+  class LineItemBuilder
+    attr_reader :subscription_line_items
+
+    # Get a new instance of a LineItemBuilder
+    #
+    # @param subscription_line_items[Array<SolidusSubscriptions::LineItem>] The
+    #   subscription line item to be converted into a Spree::LineItem
+    #
+    # @return [SolidusSubscriptions::LineItemBuilder]
+    def initialize(subscription_line_items)
+      @subscription_line_items = subscription_line_items
+    end
+
+    # Get a new (unpersisted) Spree::LineItem which matches the details of
+    # :subscription_line_item
+    #
+    # @return [Array<Spree::LineItem>]
+    def spree_line_items
+      line_items = subscription_line_items.map do |subscription_line_item|
+        variant = subscription_line_item.subscribable
+
+        next unless variant.can_supply?(subscription_line_item.quantity)
+
+        ::Spree::LineItem.new(variant: variant, quantity: subscription_line_item.quantity)
+      end
+
+      # Either all line items for an installment are fulfilled or none are
+      line_items.all? ? line_items : []
+    end
+  end
+end
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
diff --git a/lib/solidus_subscriptions/subscription_line_item_builder.rb b/lib/solidus_subscriptions/subscription_line_item_builder.rb
new file mode 100644
index 0000000..7354102
--- /dev/null
+++ b/lib/solidus_subscriptions/subscription_line_item_builder.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  module SubscriptionLineItemBuilder
+    private
+
+    def create_subscription_line_item(line_item)
+      SolidusSubscriptions::LineItem.create!(
+        subscription_params.merge(spree_line_item: line_item)
+      )
+
+      # Rerun the promotion handler to pickup subscription promotions
+      ::Spree::PromotionHandler::Cart.new(line_item.order).activate
+      line_item.order.recalculate
+    end
+
+    def subscription_params
+      params.require(:subscription_line_item).permit(
+        SolidusSubscriptions.configuration.subscription_line_item_attributes
+      )
+    end
+  end
+end