feat: Add AI credit topup flow for Stripe (#12988)

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

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

@@ -1,5 +1,6 @@
 class Enterprise::Billing::HandleStripeEventService
   CLOUD_PLANS_CONFIG = 'CHATWOOT_CLOUD_PLANS'.freeze
+  CAPTAIN_CLOUD_PLAN_LIMITS = 'CAPTAIN_CLOUD_PLAN_LIMITS'.freeze
 
   # Plan hierarchy: Hacker (default) -> Startups -> Business -> Enterprise
   # Each higher tier includes all features from the lower tiers
@@ -33,6 +34,8 @@ 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
@@ -46,9 +49,25 @@ class Enterprise::Billing::HandleStripeEventService
     # skipping self hosted plan events
     return if plan.blank? || account.blank?
 
+    previous_usage = capture_previous_usage
     update_account_attributes(subscription, plan)
     update_plan_features
-    reset_captain_usage
+    handle_subscription_credits(plan, previous_usage)
+    account.reset_response_usage
+  end
+
+  def capture_previous_usage
+    {
+      responses: account.custom_attributes['captain_responses_usage'].to_i,
+      monthly: current_plan_credits[:responses]
+    }
+  end
+
+  def current_plan_credits
+    plan_name = account.custom_attributes['plan_name']
+    return { responses: 0, documents: 0 } if plan_name.blank?
+
+    get_plan_credits(plan_name)
   end
 
   def update_account_attributes(subscription, plan)
@@ -73,6 +92,31 @@ 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
@@ -101,8 +145,23 @@ class Enterprise::Billing::HandleStripeEventService
     enable_plan_specific_features
   end
 
-  def reset_captain_usage
-    account.reset_response_usage
+  def handle_subscription_credits(plan, previous_usage)
+    current_limits = account.limits || {}
+
+    current_credits = current_limits['captain_responses'].to_i
+    new_plan_credits = get_plan_credits(plan['name'])[:responses]
+
+    consumed_topup_credits = [previous_usage[:responses] - previous_usage[:monthly], 0].max
+    updated_credits = current_credits - consumed_topup_credits - previous_usage[:monthly] + new_plan_credits
+
+    Rails.logger.info("Updating subscription credits for account #{account.id}: #{current_credits} -> #{updated_credits}")
+    account.update!(limits: current_limits.merge('captain_responses' => updated_credits))
+  end
+
+  def get_plan_credits(plan_name)
+    config = InstallationConfig.find_by(name: CAPTAIN_CLOUD_PLAN_LIMITS).value
+    config = JSON.parse(config) if config.is_a?(String)
+    config[plan_name.downcase]&.symbolize_keys
   end
 
   def enable_plan_specific_features

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

@@ -0,0 +1,99 @@
+class Enterprise::Billing::TopupCheckoutService
+  include BillingHelper
+  include Rails.application.routes.url_helpers
+
+  class Error < StandardError; end
+
+  TOPUP_OPTIONS = [
+    { credits: 1000, amount: 20.0, currency: 'usd' },
+    { credits: 2500, amount: 50.0, currency: 'usd' },
+    { credits: 6000, amount: 100.0, currency: 'usd' },
+    { credits: 12_000, amount: 200.0, currency: 'usd' }
+  ].freeze
+
+  pattr_initialize [:account!]
+
+  def create_checkout_session(credits:)
+    topup_option = validate_and_find_topup_option(credits)
+    session = create_stripe_session(topup_option, credits)
+    session.url
+  end
+
+  private
+
+  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)
+
+    topup_option = find_topup_option(credits)
+    raise Error, I18n.t('errors.topup.invalid_option') unless topup_option
+
+    topup_option
+  end
+
+  def create_stripe_session(topup_option, credits)
+    Stripe::Checkout::Session.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)
+    )
+  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)
+  end
+
+  def stripe_customer_id
+    account.custom_attributes['stripe_customer_id']
+  end
+
+  def find_topup_option(credits)
+    TOPUP_OPTIONS.find { |opt| opt[:credits] == credits.to_i }
+  end
+end

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

@@ -0,0 +1,49 @@
+class Enterprise::Billing::TopupFulfillmentService
+  pattr_initialize [:account!]
+
+  def fulfill(credits:, amount_cents:, currency:)
+    account.with_lock do
+      create_stripe_credit_grant(credits, amount_cents, currency)
+      update_account_credits(credits)
+    end
+  end
+
+  private
+
+  def create_stripe_credit_grant(credits, amount_cents, currency)
+    Stripe::Billing::CreditGrant.create(
+      customer: stripe_customer_id,
+      name: "Topup: #{credits} credits",
+      amount: {
+        type: 'monetary',
+        monetary: { currency: currency, value: amount_cents }
+      },
+      applicability_config: {
+        scope: { price_type: 'metered' }
+      },
+      category: 'paid',
+      expires_at: 6.months.from_now.to_i,
+      metadata: {
+        account_id: account.id.to_s,
+        source: 'topup',
+        credits: credits.to_s
+      }
+    )
+  end
+
+  def update_account_credits(credits)
+    current_limits = account.limits || {}
+    current_total = current_limits['captain_responses'].to_i
+    new_total = current_total + credits
+
+    account.update!(
+      limits: current_limits.merge(
+        'captain_responses' => new_total
+      )
+    )
+  end
+
+  def stripe_customer_id
+    account.custom_attributes['stripe_customer_id']
+  end
+end