Extract parent class, validate plans can be downgraded/upgraded

saas/app/controllers/account/subscriptions/downgrades_controller.rb

@@ -1,28 +1,12 @@
-class Account::Subscriptions::DowngradesController < ApplicationController
-  before_action :ensure_admin
-
-  def create
-    portal_session = Stripe::BillingPortal::Session.create(
-      customer: subscription.stripe_customer_id,
-      return_url: account_settings_url(anchor: "subscription"),
-      flow_data: {
-        type: "subscription_update_confirm",
-        subscription_update_confirm: {
-          subscription: subscription.stripe_subscription_id,
-          items: [ { id: stripe_subscription_item_id, price: Plan.paid.stripe_price_id } ]
-        }
-      }
-    )
-
-    redirect_to portal_session.url, allow_other_host: true
-  end
+class Account::Subscriptions::DowngradesController < Account::Subscriptions::UpdatePlanController
+  before_action :ensure_downgradeable
 
   private
-    def subscription
-      @subscription ||= Current.account.subscription
+    def target_plan
+      Plan.paid
     end
 
-    def stripe_subscription_item_id
-      Stripe::Subscription.retrieve(subscription.stripe_subscription_id).items.data.first.id
+    def ensure_downgradeable
+      head :bad_request unless subscription.plan == Plan.paid_with_extra_storage
     end
 end

saas/app/controllers/account/subscriptions/update_plan_controller.rb

@@ -0,0 +1,32 @@
+class Account::Subscriptions::UpdatePlanController < ApplicationController
+  before_action :ensure_admin
+
+  def create
+    portal_session = Stripe::BillingPortal::Session.create(
+      customer: subscription.stripe_customer_id,
+      return_url: account_settings_url(anchor: "subscription"),
+      flow_data: {
+        type: "subscription_update_confirm",
+        subscription_update_confirm: {
+          subscription: subscription.stripe_subscription_id,
+          items: [ { id: stripe_subscription_item_id, price: target_plan.stripe_price_id } ]
+        }
+      }
+    )
+
+    redirect_to portal_session.url, allow_other_host: true
+  end
+
+  private
+    def target_plan
+      raise NotImplementedError
+    end
+
+    def subscription
+      @subscription ||= Current.account.subscription
+    end
+
+    def stripe_subscription_item_id
+      Stripe::Subscription.retrieve(subscription.stripe_subscription_id).items.data.first.id
+    end
+end

saas/app/controllers/account/subscriptions/upgrades_controller.rb

@@ -1,28 +1,12 @@
-class Account::Subscriptions::UpgradesController < ApplicationController
-  before_action :ensure_admin
-
-  def create
-    portal_session = Stripe::BillingPortal::Session.create(
-      customer: subscription.stripe_customer_id,
-      return_url: account_settings_url(anchor: "subscription"),
-      flow_data: {
-        type: "subscription_update_confirm",
-        subscription_update_confirm: {
-          subscription: subscription.stripe_subscription_id,
-          items: [ { id: stripe_subscription_item_id, price: Plan.paid_with_extra_storage.stripe_price_id } ]
-        }
-      }
-    )
-
-    redirect_to portal_session.url, allow_other_host: true
-  end
+class Account::Subscriptions::UpgradesController < Account::Subscriptions::UpdatePlanController
+  before_action :ensure_upgradeable
 
   private
-    def subscription
-      @subscription ||= Current.account.subscription
+    def target_plan
+      Plan.paid_with_extra_storage
     end
 
-    def stripe_subscription_item_id
-      Stripe::Subscription.retrieve(subscription.stripe_subscription_id).items.data.first.id
+    def ensure_upgradeable
+      head :bad_request unless subscription.plan == Plan.paid
     end
 end

saas/test/controllers/accounts/subscriptions/downgrades_controller_test.rb

@@ -6,7 +6,7 @@ class Account::Subscriptions::DowngradesControllerTest < ActionDispatch::Integra
     sign_in_as :kevin
     accounts(:"37s").subscription.update!(
       stripe_subscription_id: "sub_123",
-      plan_key: Plan.paid_with_extra_storage.key
+      plan: Plan.paid_with_extra_storage
     )
   end
 
@@ -30,4 +30,11 @@ class Account::Subscriptions::DowngradesControllerTest < ActionDispatch::Integra
     post account_subscription_downgrade_path
     assert_response :forbidden
   end
+
+  test "downgrade requires downgradeable plan" do
+    accounts(:"37s").subscription.update!(plan: Plan.paid)
+
+    post account_subscription_downgrade_path
+    assert_response :bad_request
+  end
 end

saas/test/controllers/accounts/subscriptions/upgrades_controller_test.rb

@@ -6,7 +6,7 @@ class Account::Subscriptions::UpgradesControllerTest < ActionDispatch::Integrati
     sign_in_as :kevin
     accounts(:"37s").subscription.update!(
       stripe_subscription_id: "sub_123",
-      plan_key: Plan.paid.key
+      plan: Plan.paid
     )
   end
 
@@ -30,4 +30,11 @@ class Account::Subscriptions::UpgradesControllerTest < ActionDispatch::Integrati
     post account_subscription_upgrade_path
     assert_response :forbidden
   end
+
+  test "upgrade requires upgradeable plan" do
+    accounts(:"37s").subscription.update!(plan: Plan.paid_with_extra_storage)
+
+    post account_subscription_upgrade_path
+    assert_response :bad_request
+  end
 end