feat(customer-portal): plan switching + add-product + terminate

app/graphql/mutations/customer_portal/subscriptions/change_plan.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module Mutations
+  module CustomerPortal
+    module Subscriptions
+      # Switch an existing subscription to a different plan.
+      # Used by the "Change Plan" flow in the customer portal.
+      # Calls into Subscriptions::PlanUpgradeService which handles proration,
+      # invoice generation, and Stripe billing automatically.
+      class ChangePlan < BaseMutation
+        include AuthenticableCustomerPortalUser
+
+        graphql_name "ChangeCustomerPortalSubscriptionPlan"
+        description "Switch a customer-portal subscription to a different plan"
+
+        argument :subscription_id, ID, required: true,
+          description: "The Lago subscription to switch (must belong to the authenticated portal user)"
+        argument :plan_code, String, required: true,
+          description: "Target plan code within the same organization"
+
+        type Types::Subscriptions::Object
+
+        def resolve(subscription_id:, plan_code:)
+          customer = context[:customer_portal_user]
+          current_subscription = customer.subscriptions.find(subscription_id)
+          plan = customer.organization.plans.find_by!(code: plan_code, parent_id: nil)
+
+          result = ::Subscriptions::PlanUpgradeService.call(
+            current_subscription: current_subscription,
+            plan: plan,
+            params: {name: current_subscription.name}
+          )
+
+          result.success? ? result.subscription : result_error(result)
+        rescue ActiveRecord::RecordNotFound
+          execution_error(message: "subscription_not_found")
+        end
+      end
+    end
+  end
+end

app/graphql/mutations/customer_portal/subscriptions/create.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module Mutations
+  module CustomerPortal
+    module Subscriptions
+      # Add a NEW subscription (e.g. customer adds Growth OS to an account
+      # that previously only had AI Stack). External_id follows the parent
+      # app's bridge convention: `${customer.external_id}-${productKey}`
+      # where productKey is derived from the plan code's prefix.
+      class Create < BaseMutation
+        include AuthenticableCustomerPortalUser
+
+        graphql_name "CreateCustomerPortalSubscription"
+        description "Add a new product subscription for the customer-portal user"
+
+        argument :plan_code, String, required: true,
+          description: "Plan code to subscribe to (must be visible to this customer's organization)"
+
+        type Types::Subscriptions::Object
+
+        def resolve(plan_code:)
+          customer = context[:customer_portal_user]
+          plan = customer.organization.plans.find_by!(code: plan_code, parent_id: nil)
+          product_key = plan_code.split("-").first
+          external_id = "#{customer.external_id}-#{product_key}"
+
+          result = ::Subscriptions::CreateService.call(
+            customer: customer,
+            plan: plan,
+            params: {
+              name: nil,
+              external_id: external_id,
+              external_customer_id: customer.external_id,
+              billing_time: "calendar"
+            }
+          )
+
+          result.success? ? result.subscription : result_error(result)
+        rescue ActiveRecord::RecordNotFound
+          execution_error(message: "plan_not_found")
+        end
+      end
+    end
+  end
+end

app/graphql/mutations/customer_portal/subscriptions/terminate.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module Mutations
+  module CustomerPortal
+    module Subscriptions
+      # Cancel a single subscription within a multi-product account.
+      # The customer's other product subscriptions remain active.
+      class Terminate < BaseMutation
+        include AuthenticableCustomerPortalUser
+
+        graphql_name "TerminateCustomerPortalSubscription"
+        description "Cancel a single subscription belonging to the customer-portal user"
+
+        argument :subscription_id, ID, required: true
+
+        type Types::Subscriptions::Object
+
+        def resolve(subscription_id:)
+          customer = context[:customer_portal_user]
+          subscription = customer.subscriptions.find(subscription_id)
+
+          result = ::Subscriptions::TerminateService.call(subscription: subscription)
+          result.success? ? result.subscription : result_error(result)
+        rescue ActiveRecord::RecordNotFound
+          execution_error(message: "subscription_not_found")
+        end
+      end
+    end
+  end
+end

app/graphql/resolvers/customer_portal/available_plans_resolver.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module Resolvers
+  module CustomerPortal
+    # Lists plans visible to the current customer-portal user, optionally
+    # filtered to a single product via the `product_key` argument.
+    #
+    # Product key is extracted from the plan's `code` prefix: `aistack-*` →
+    # "aistack", `growth-*` → "growth", etc. This matches the prefix
+    # convention used by the parent app's bridge layer.
+    #
+    # When `exclude_current: true`, plans the customer is already subscribed
+    # to are removed from the result (used by the "Add a Product" cross-sell).
+    class AvailablePlansResolver < Resolvers::BaseResolver
+      include AuthenticableCustomerPortalUser
+
+      description "Lists plans available to the customer portal user, filtered by product"
+
+      argument :product_key, String, required: false,
+        description: "Filter to plans whose code starts with `${product_key}-`"
+      argument :exclude_current, Boolean, required: false, default_value: false,
+        description: "Omit plans the customer already has an active subscription to"
+
+      type [Types::Plans::Object], null: false
+
+      def resolve(product_key: nil, exclude_current: false)
+        customer = context[:customer_portal_user]
+        organization = customer.organization
+
+        plans = organization.plans.where(parent_id: nil).order(:amount_cents)
+        plans = plans.where("code LIKE ?", "#{product_key}-%") if product_key.present?
+
+        if exclude_current
+          active_plan_codes = customer.subscriptions.active.joins(:plan).pluck("plans.code")
+          plans = plans.where.not(code: active_plan_codes) if active_plan_codes.any?
+        end
+
+        plans
+      end
+    end
+  end
+end

app/graphql/types/mutation_type.rb

@@ -43,9 +43,12 @@ class MutationType < Types::BaseObject
     field :update_customer, mutation: Mutations::Customers::Update
     field :update_customer_invoice_grace_period, mutation: Mutations::Customers::UpdateInvoiceGracePeriod
 
+    field :change_customer_portal_subscription_plan, mutation: Mutations::CustomerPortal::Subscriptions::ChangePlan
+    field :create_customer_portal_subscription, mutation: Mutations::CustomerPortal::Subscriptions::Create
     field :create_customer_portal_wallet_transaction, mutation: Mutations::CustomerPortal::WalletTransactions::Create
     field :download_customer_portal_invoice, mutation: Mutations::CustomerPortal::DownloadInvoice
     field :generate_customer_portal_url, mutation: Mutations::CustomerPortal::GenerateUrl
+    field :terminate_customer_portal_subscription, mutation: Mutations::CustomerPortal::Subscriptions::Terminate
     field :update_customer_portal_customer, mutation: Mutations::CustomerPortal::UpdateCustomer
 
     field :create_credit_notes_data_export, mutation: Mutations::DataExports::CreditNotes::Create

app/graphql/types/query_type.rb

@@ -35,6 +35,7 @@ class QueryType < Types::BaseObject
     field :current_version, resolver: Resolvers::VersionResolver
     field :customer, resolver: Resolvers::CustomerResolver
     field :customer_invoices, resolver: Resolvers::Customers::InvoicesResolver
+    field :customer_portal_available_plans, resolver: Resolvers::CustomerPortal::AvailablePlansResolver
     field :customer_portal_customer_projected_usage, resolver: Resolvers::CustomerPortal::Customers::ProjectedUsageResolver
     field :customer_portal_customer_usage, resolver: Resolvers::CustomerPortal::Customers::UsageResolver
     field :customer_portal_invoice_collections, resolver: Resolvers::CustomerPortal::Analytics::InvoiceCollectionsResolver