perf: update the logic to purchase credits (#12998)

## Description

- Replaces Stripe Checkout session flow with direct card charging for AI
credit top-ups
- Adds a two-step confirmation modal (select package → confirm purchase)
for better UX
- Creates Stripe invoice directly and charges the customer's default
payment method immediately

## Type of change

- [ ] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

- Using the specs
- UI manual test cases

<img width="945" height="580" alt="image"
src="https://github.com/user-attachments/assets/52bdad46-cd0e-4927-b13f-54c6b6353bcc"
/>

<img width="945" height="580" alt="image"
src="https://github.com/user-attachments/assets/231bc7e9-41ac-440d-a93d-cba45a4d3e3e"
/>


## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>

enterprise/app/controllers/enterprise/api/v1/accounts_controller.rb

@@ -59,10 +59,15 @@ class Enterprise::Api::V1::AccountsController < Api::BaseController
     return render json: { error: I18n.t('errors.topup.credits_required') }, status: :unprocessable_entity if params[:credits].blank?
 
     service = Enterprise::Billing::TopupCheckoutService.new(account: @account)
-    redirect_url = service.create_checkout_session(credits: params[:credits].to_i)
-    render json: { redirect_url: redirect_url }
-  rescue Enterprise::Billing::TopupCheckoutService::Error => e
-    Rails.logger.error("Topup checkout failed for account #{@account.id}: #{e.message}")
+    result = service.create_checkout_session(credits: params[:credits].to_i)
+
+    @account.reload
+    render json: result.merge(
+      id: @account.id,
+      limits: @account.limits,
+      custom_attributes: @account.custom_attributes
+    )
+  rescue Enterprise::Billing::TopupCheckoutService::Error, Stripe::StripeError => e
     render_could_not_create_error(e.message)
   end
 

enterprise/app/services/enterprise/billing/handle_stripe_event_service.rb

@@ -34,8 +34,6 @@ class Enterprise::Billing::HandleStripeEventService
       process_subscription_updated
     when 'customer.subscription.deleted'
       process_subscription_deleted
-    when 'checkout.session.completed'
-      process_checkout_session_completed
     else
       Rails.logger.debug { "Unhandled event type: #{event.type}" }
     end
@@ -92,31 +90,6 @@ class Enterprise::Billing::HandleStripeEventService
     Enterprise::Billing::CreateStripeCustomerService.new(account: account).perform
   end
 
-  def process_checkout_session_completed
-    session = @event.data.object
-    metadata = session.metadata
-
-    # Only process topup checkout sessions
-    return unless metadata.present? && metadata['topup'] == 'true'
-
-    topup_account = Account.find_by(id: metadata['account_id'])
-    return if topup_account.blank?
-
-    credits = metadata['credits'].to_i
-    amount_cents = metadata['amount_cents'].to_i
-    currency = metadata['currency'] || 'usd'
-
-    Rails.logger.info("Processing topup for account #{topup_account.id}: #{credits} credits, #{amount_cents} cents")
-    Enterprise::Billing::TopupFulfillmentService.new(account: topup_account).fulfill(
-      credits: credits,
-      amount_cents: amount_cents,
-      currency: currency
-    )
-  rescue StandardError => e
-    ChatwootExceptionTracker.new(e, account: topup_account).capture_exception
-    raise
-  end
-
   def update_plan_features
     if default_plan?
       disable_all_premium_features

enterprise/app/services/enterprise/billing/topup_checkout_service.rb

@@ -1,6 +1,5 @@
 class Enterprise::Billing::TopupCheckoutService
   include BillingHelper
-  include Rails.application.routes.url_helpers
 
   class Error < StandardError; end
 
@@ -15,8 +14,14 @@ class Enterprise::Billing::TopupCheckoutService
 
   def create_checkout_session(credits:)
     topup_option = validate_and_find_topup_option(credits)
-    session = create_stripe_session(topup_option, credits)
-    session.url
+    charge_customer(topup_option, credits)
+    fulfill_credits(credits, topup_option)
+
+    {
+      credits: credits,
+      amount: topup_option[:amount],
+      currency: topup_option[:currency]
+    }
   end
 
   private
@@ -24,69 +29,60 @@ class Enterprise::Billing::TopupCheckoutService
   def validate_and_find_topup_option(credits)
     raise Error, I18n.t('errors.topup.invalid_credits') unless credits.to_i.positive?
     raise Error, I18n.t('errors.topup.plan_not_eligible') if default_plan?(account)
+    raise Error, I18n.t('errors.topup.stripe_customer_not_configured') if stripe_customer_id.blank?
 
     topup_option = find_topup_option(credits)
     raise Error, I18n.t('errors.topup.invalid_option') unless topup_option
 
+    # Validate payment method exists
+    validate_payment_method!
+
     topup_option
   end
 
-  def create_stripe_session(topup_option, credits)
-    Stripe::Checkout::Session.create(
+  def validate_payment_method!
+    customer = Stripe::Customer.retrieve(stripe_customer_id)
+
+    return if customer.invoice_settings.default_payment_method.present? || customer.default_source.present?
+
+    # Auto-set first payment method as default if available
+    payment_methods = Stripe::PaymentMethod.list(customer: stripe_customer_id, limit: 1)
+    raise Error, I18n.t('errors.topup.no_payment_method') if payment_methods.data.empty?
+
+    Stripe::Customer.update(stripe_customer_id, invoice_settings: { default_payment_method: payment_methods.data.first.id })
+  end
+
+  def charge_customer(topup_option, credits)
+    amount_cents = (topup_option[:amount] * 100).to_i
+    currency = topup_option[:currency]
+    description = "AI Credits Topup: #{credits} credits"
+
+    invoice = Stripe::Invoice.create(
       customer: stripe_customer_id,
-      mode: 'payment',
-      line_items: [build_line_item(topup_option, credits)],
-      success_url: success_url,
-      cancel_url: cancel_url,
-      metadata: session_metadata(credits, topup_option),
-      payment_method_types: ['card'],
-      # Show saved payment methods and allow saving new ones
-      saved_payment_method_options: {
-        payment_method_save: 'enabled',
-        allow_redisplay_filters: %w[always limited]
-      },
-      # Create invoice for this payment so it appears in customer portal
-      invoice_creation: build_invoice_creation_data(credits, topup_option)
+      currency: currency,
+      collection_method: 'charge_automatically',
+      auto_advance: false,
+      description: description
     )
+
+    Stripe::InvoiceItem.create(
+      customer: stripe_customer_id,
+      amount: amount_cents,
+      currency: currency,
+      invoice: invoice.id,
+      description: description
+    )
+
+    Stripe::Invoice.finalize_invoice(invoice.id, { auto_advance: false })
+    Stripe::Invoice.pay(invoice.id)
   end
 
-  def build_invoice_creation_data(credits, topup_option)
-    {
-      enabled: true,
-      invoice_data: {
-        description: "AI Credits Topup: #{credits} credits",
-        metadata: session_metadata(credits, topup_option)
-      }
-    }
-  end
-
-  def build_line_item(topup_option, credits)
-    {
-      price_data: {
-        currency: topup_option[:currency],
-        unit_amount: (topup_option[:amount] * 100).to_i,
-        product_data: { name: "AI Credits Topup: #{credits} credits" }
-      },
-      quantity: 1
-    }
-  end
-
-  def session_metadata(credits, topup_option)
-    {
-      account_id: account.id.to_s,
-      credits: credits.to_s,
-      amount_cents: (topup_option[:amount] * 100).to_s,
-      currency: topup_option[:currency],
-      topup: 'true'
-    }
-  end
-
-  def success_url
-    app_account_billing_settings_url(account_id: account.id, topup: 'success')
-  end
-
-  def cancel_url
-    app_account_billing_settings_url(account_id: account.id)
+  def fulfill_credits(credits, topup_option)
+    Enterprise::Billing::TopupFulfillmentService.new(account: account).fulfill(
+      credits: credits,
+      amount_cents: (topup_option[:amount] * 100).to_i,
+      currency: topup_option[:currency]
+    )
   end
 
   def stripe_customer_id

enterprise/app/services/enterprise/billing/topup_fulfillment_service.rb

@@ -6,6 +6,8 @@ class Enterprise::Billing::TopupFulfillmentService
       create_stripe_credit_grant(credits, amount_cents, currency)
       update_account_credits(credits)
     end
+
+    Rails.logger.info("Topup fulfilled for account #{account.id}: #{credits} credits, #{amount_cents} cents")
   end
 
   private