From 05864a3a4bd8f47d294357379c89c0fcfea4ee48 Mon Sep 17 00:00:00 2001
From: Anna Velentsevich <annvelents@gmail.com>
Date: Tue, 14 Jan 2025 09:40:12 +0100
Subject: [PATCH] Feat(invoice_custom_sections): add
 create_invoice_applied_custom_sections service (#3008)

## Description

Add a service to create applied invoice custom sections for invoices
---
 app/controllers/api/v1/invoices_controller.rb |  2 +-
 .../invoice_custom_sections_resolver.rb       | 11 ++--
 app/models/customer.rb                        |  2 +-
 app/models/invoice_custom_section.rb          |  4 +-
 .../v1/invoice_custom_section_serializer.rb   |  6 +-
 app/serializers/v1/invoice_serializer.rb      |  9 +++
 ...plied_invoice_custom_section_serializer.rb | 18 ++++++
 .../manage_invoice_custom_sections_service.rb |  4 +-
 app/services/invoices/add_on_service.rb       |  1 +
 .../invoices/advance_charges_service.rb       |  1 +
 .../apply_invoice_custom_sections_service.rb  | 34 +++++++++++
 .../invoices/create_one_off_service.rb        |  1 +
 .../create_pay_in_advance_charge_service.rb   |  1 +
 app/services/invoices/paid_credit_service.rb  |  1 +
 .../invoices/progressive_billing_service.rb   |  1 +
 .../invoices/refresh_draft_service.rb         |  3 +
 app/services/invoices/subscription_service.rb |  1 +
 .../invoices/add_on_created_service.rb        |  2 +-
 .../webhooks/invoices/created_service.rb      |  2 +-
 .../invoices/one_off_created_service.rb       |  2 +-
 .../invoices/paid_credit_added_service.rb     |  2 +-
 app/views/templates/invoices/v3.slim          |  3 +
 .../invoices/v3/_custom_sections.slim         | 15 +++++
 app/views/templates/invoices/v3/charge.slim   |  3 +
 app/views/templates/invoices/v3/one_off.slim  |  3 +
 app/views/templates/invoices/v4.slim          | 18 ++++--
 .../invoices/v4/_custom_sections.slim         | 15 +++++
 app/views/templates/invoices/v4/charge.slim   |  3 +
 app/views/templates/invoices/v4/one_off.slim  |  3 +
 .../invoice_custom_sections_resolver_spec.rb  |  3 +-
 spec/models/customer_spec.rb                  |  4 +-
 .../api/v1/customers_controller_spec.rb       |  2 +-
 .../api/v1/invoices_controller_spec.rb        |  3 +-
 .../invoice_custom_section_serializer_spec.rb |  6 +-
 ..._invoice_custom_section_serializer_spec.rb | 32 +++++++++++
 spec/services/invoices/add_on_service_spec.rb |  4 ++
 ...ly_invoice_custom_sections_service_spec.rb | 57 +++++++++++++++++++
 .../invoices/create_one_off_service_spec.rb   |  4 ++
 ...eate_pay_in_advance_charge_service_spec.rb |  4 ++
 .../invoices/paid_credit_service_spec.rb      |  4 ++
 .../progressive_billing_service_spec.rb       |  4 ++
 ...refresh_draft_and_finalize_service_spec.rb |  4 ++
 .../invoices/refresh_draft_service_spec.rb    | 19 +++++++
 .../invoices/subscription_service_spec.rb     |  4 ++
 .../applied_invoice_custom_sections.rb        | 25 ++++++++
 45 files changed, 318 insertions(+), 32 deletions(-)
 create mode 100644 app/serializers/v1/invoices/applied_invoice_custom_section_serializer.rb
 create mode 100644 app/services/invoices/apply_invoice_custom_sections_service.rb
 create mode 100644 app/views/templates/invoices/v3/_custom_sections.slim
 create mode 100644 app/views/templates/invoices/v4/_custom_sections.slim
 create mode 100644 spec/serializers/v1/invoices/applied_invoice_custom_section_serializer_spec.rb
 create mode 100644 spec/services/invoices/apply_invoice_custom_sections_service_spec.rb

diff --git a/app/controllers/api/v1/invoices_controller.rb b/app/controllers/api/v1/invoices_controller.rb
index a203051cdd3..5be51b7b6c7 100644
--- a/app/controllers/api/v1/invoices_controller.rb
+++ b/app/controllers/api/v1/invoices_controller.rb
@@ -241,7 +241,7 @@ def render_invoice(invoice)
           json: ::V1::InvoiceSerializer.new(
             invoice,
             root_name: 'invoice',
-            includes: %i[customer subscriptions fees credits metadata applied_taxes error_details]
+            includes: %i[customer subscriptions fees credits metadata applied_taxes error_details applied_invoice_custom_sections]
           )
         )
       end
diff --git a/app/graphql/resolvers/invoice_custom_sections_resolver.rb b/app/graphql/resolvers/invoice_custom_sections_resolver.rb
index f34d3fc1c43..f759479ab7f 100644
--- a/app/graphql/resolvers/invoice_custom_sections_resolver.rb
+++ b/app/graphql/resolvers/invoice_custom_sections_resolver.rb
@@ -15,10 +15,13 @@ class InvoiceCustomSectionsResolver < Resolvers::BaseResolver
     type Types::InvoiceCustomSections::Object.collection_type, null: true
 
     def resolve(page: nil, limit: nil)
-      current_organization.invoice_custom_sections.left_outer_joins(:invoice_custom_section_selections).order(
-        Arel.sql('CASE WHEN invoice_custom_section_selections.id IS NOT NULL THEN 0 ELSE 1 END'),
-        :name
-      ).page(page).per(limit)
+      current_organization.invoice_custom_sections
+        .joins('LEFT JOIN invoice_custom_section_selections ON invoice_custom_sections.id = invoice_custom_section_selections.invoice_custom_section_id
+                AND invoice_custom_section_selections.customer_id is NULL')
+        .order(
+          Arel.sql('CASE WHEN invoice_custom_section_selections.id IS NOT NULL THEN 0 ELSE 1 END'),
+          :name
+        ).page(page).per(limit)
     end
   end
 end
diff --git a/app/models/customer.rb b/app/models/customer.rb
index 25aea92262a..91015b26df4 100644
--- a/app/models/customer.rb
+++ b/app/models/customer.rb
@@ -134,7 +134,7 @@ def applicable_net_payment_term
   def applicable_invoice_custom_sections
     return [] if skip_invoice_custom_sections?
 
-    selected_invoice_custom_sections.presence || organization.selected_invoice_custom_sections
+    selected_invoice_custom_sections.order(:name).presence || organization.selected_invoice_custom_sections.order(:name)
   end
 
   def editable?
diff --git a/app/models/invoice_custom_section.rb b/app/models/invoice_custom_section.rb
index 4842aaed333..bd049ead9cf 100644
--- a/app/models/invoice_custom_section.rb
+++ b/app/models/invoice_custom_section.rb
@@ -8,7 +8,9 @@ class InvoiceCustomSection < ApplicationRecord
   has_many :invoice_custom_section_selections, dependent: :destroy
 
   validates :name, presence: true
-  validates :code, presence: true, uniqueness: {scope: :organization_id}
+  validates :code,
+    presence: true,
+    uniqueness: {conditions: -> { where(deleted_at: nil) }, scope: :organization_id}
 
   default_scope -> { kept }
 
diff --git a/app/serializers/v1/invoice_custom_section_serializer.rb b/app/serializers/v1/invoice_custom_section_serializer.rb
index 87dd9b6e914..f430be28a5c 100644
--- a/app/serializers/v1/invoice_custom_section_serializer.rb
+++ b/app/serializers/v1/invoice_custom_section_serializer.rb
@@ -10,10 +10,8 @@ def serialize
         description: model.description,
         details: model.details,
         display_name: model.display_name,
-        selected_for_organization: model.selected_for_organization?,
-        organization: {
-          lago_id: model.organization_id
-        }
+        applied_to_organization: model.selected_for_organization?,
+        organization_id: model.organization_id
       }
     end
   end
diff --git a/app/serializers/v1/invoice_serializer.rb b/app/serializers/v1/invoice_serializer.rb
index 522f94ebd81..ef1169162e3 100644
--- a/app/serializers/v1/invoice_serializer.rb
+++ b/app/serializers/v1/invoice_serializer.rb
@@ -39,6 +39,7 @@ def serialize
       payload.merge!(applied_taxes) if include?(:applied_taxes)
       payload.merge!(error_details) if include?(:error_details)
       payload.merge!(applied_usage_thresholds) if model.progressive_billing?
+      payload.merge!(applied_invoice_custom_sections) if include?(:applied_invoice_custom_sections)
 
       payload
     end
@@ -112,5 +113,13 @@ def applied_usage_thresholds
         collection_name: 'applied_usage_thresholds'
       ).serialize
     end
+
+    def applied_invoice_custom_sections
+      ::CollectionSerializer.new(
+        model.applied_invoice_custom_sections,
+        ::V1::Invoices::AppliedInvoiceCustomSectionSerializer,
+        collection_name: 'applied_invoice_custom_sections'
+      ).serialize
+    end
   end
 end
diff --git a/app/serializers/v1/invoices/applied_invoice_custom_section_serializer.rb b/app/serializers/v1/invoices/applied_invoice_custom_section_serializer.rb
new file mode 100644
index 00000000000..7894892b62b
--- /dev/null
+++ b/app/serializers/v1/invoices/applied_invoice_custom_section_serializer.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module V1
+  module Invoices
+    class AppliedInvoiceCustomSectionSerializer < ModelSerializer
+      def serialize
+        {
+          lago_id: model.id,
+          lago_invoice_id: model.invoice_id,
+          code: model.code,
+          details: model.details,
+          display_name: model.display_name,
+          created_at: model.created_at.iso8601
+        }
+      end
+    end
+  end
+end
diff --git a/app/services/customers/manage_invoice_custom_sections_service.rb b/app/services/customers/manage_invoice_custom_sections_service.rb
index a7af90220ee..023e475bc6a 100644
--- a/app/services/customers/manage_invoice_custom_sections_service.rb
+++ b/app/services/customers/manage_invoice_custom_sections_service.rb
@@ -24,8 +24,8 @@ def call
 
         if !section_ids.nil? || !section_codes.nil?
           customer.skip_invoice_custom_sections = false
-          return result if customer.applicable_invoice_custom_sections.ids == section_ids ||
-            customer.applicable_invoice_custom_sections.map(&:code) == section_codes
+          return result if customer.selected_invoice_custom_sections.ids == section_ids ||
+            customer.selected_invoice_custom_sections.map(&:code) == section_codes
 
           assign_selected_sections
         end
diff --git a/app/services/invoices/add_on_service.rb b/app/services/invoices/add_on_service.rb
index 791665b2070..bc98bdd1110 100644
--- a/app/services/invoices/add_on_service.rb
+++ b/app/services/invoices/add_on_service.rb
@@ -26,6 +26,7 @@ def create
 
         create_add_on_fee(invoice)
         compute_amounts(invoice)
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
 
         invoice.save!
 
diff --git a/app/services/invoices/advance_charges_service.rb b/app/services/invoices/advance_charges_service.rb
index 159159ba036..a5ade782fde 100644
--- a/app/services/invoices/advance_charges_service.rb
+++ b/app/services/invoices/advance_charges_service.rb
@@ -69,6 +69,7 @@ def create_group_invoice
         end
 
         Invoices::ComputeAmountsFromFees.call(invoice:)
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
 
         invoice.payment_status = :succeeded
         Invoices::TransitionToFinalStatusService.call(invoice:)
diff --git a/app/services/invoices/apply_invoice_custom_sections_service.rb b/app/services/invoices/apply_invoice_custom_sections_service.rb
new file mode 100644
index 00000000000..f9349474a98
--- /dev/null
+++ b/app/services/invoices/apply_invoice_custom_sections_service.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module Invoices
+  class ApplyInvoiceCustomSectionsService < BaseService
+    def initialize(invoice:)
+      @invoice = invoice
+      @customer = invoice.customer
+
+      super()
+    end
+
+    def call
+      result.applied_sections = []
+      return result if customer.skip_invoice_custom_sections
+
+      customer.applicable_invoice_custom_sections.each do |custom_section|
+        invoice.applied_invoice_custom_sections.create!(
+          code: custom_section.code,
+          details: custom_section.details,
+          display_name: custom_section.display_name,
+          name: custom_section.name
+        )
+      end
+      result.applied_sections = invoice.applied_invoice_custom_sections
+      result
+    rescue ActiveRecord::RecordInvalid => e
+      result.record_validation_failure!(record: e.record)
+    end
+
+    private
+
+    attr_reader :invoice, :customer
+  end
+end
diff --git a/app/services/invoices/create_one_off_service.rb b/app/services/invoices/create_one_off_service.rb
index 44953c03332..b5719e92bdc 100644
--- a/app/services/invoices/create_one_off_service.rb
+++ b/app/services/invoices/create_one_off_service.rb
@@ -35,6 +35,7 @@ def call
         end
 
         Invoices::ComputeAmountsFromFees.call(invoice:, provider_taxes: result.fees_taxes)
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
         invoice.payment_status = invoice.total_amount_cents.positive? ? :pending : :succeeded
         Invoices::TransitionToFinalStatusService.call(invoice:)
         invoice.save!
diff --git a/app/services/invoices/create_pay_in_advance_charge_service.rb b/app/services/invoices/create_pay_in_advance_charge_service.rb
index d78a6bdc0be..f002e8d7b5a 100644
--- a/app/services/invoices/create_pay_in_advance_charge_service.rb
+++ b/app/services/invoices/create_pay_in_advance_charge_service.rb
@@ -41,6 +41,7 @@ def call
         Invoices::ComputeAmountsFromFees.call(invoice:, provider_taxes: result.fees_taxes)
         create_credit_note_credit
         create_applied_prepaid_credit if should_create_applied_prepaid_credit?
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
 
         invoice.payment_status = invoice.total_amount_cents.positive? ? :pending : :succeeded
         Invoices::TransitionToFinalStatusService.call(invoice:)
diff --git a/app/services/invoices/paid_credit_service.rb b/app/services/invoices/paid_credit_service.rb
index 401d04ef29d..3bf445b9735 100644
--- a/app/services/invoices/paid_credit_service.rb
+++ b/app/services/invoices/paid_credit_service.rb
@@ -22,6 +22,7 @@ def call
       ActiveRecord::Base.transaction do
         create_credit_fee(invoice)
         compute_amounts(invoice)
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
 
         if License.premium? && wallet_transaction.invoice_requires_successful_payment?
           invoice.open!
diff --git a/app/services/invoices/progressive_billing_service.rb b/app/services/invoices/progressive_billing_service.rb
index 514b11a8f6c..e07ac6a039f 100644
--- a/app/services/invoices/progressive_billing_service.rb
+++ b/app/services/invoices/progressive_billing_service.rb
@@ -21,6 +21,7 @@ def call
 
         Credits::ProgressiveBillingService.call(invoice:)
         Credits::AppliedCouponsService.call(invoice:)
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
 
         totals_result = Invoices::ComputeTaxesAndTotalsService.call(invoice:)
         return totals_result if !totals_result.success? && totals_result.error.is_a?(BaseService::UnknownTaxFailure)
diff --git a/app/services/invoices/refresh_draft_service.rb b/app/services/invoices/refresh_draft_service.rb
index 5a815a387f3..4f61285dea6 100644
--- a/app/services/invoices/refresh_draft_service.rb
+++ b/app/services/invoices/refresh_draft_service.rb
@@ -56,6 +56,7 @@ def call
           recurring:,
           context:
         )
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
 
         invoice.credit_notes.each do |credit_note|
           subscription_id = cn_subscription_ids.find { |h| h[:credit_note_id] == credit_note.id }[:subscription_id]
@@ -121,6 +122,7 @@ def reset_invoice_values
       invoice_subscriptions.destroy_all
       invoice.applied_taxes.destroy_all
       invoice.error_details.discard_all
+      invoice.applied_invoice_custom_sections.destroy_all
 
       invoice.taxes_amount_cents = 0
       invoice.total_amount_cents = 0
@@ -129,6 +131,7 @@ def reset_invoice_values
       invoice.sub_total_excluding_taxes_amount_cents = 0
       invoice.sub_total_including_taxes_amount_cents = 0
       invoice.progressive_billing_credit_amount_cents = 0
+
       invoice.save!
     end
   end
diff --git a/app/services/invoices/subscription_service.rb b/app/services/invoices/subscription_service.rb
index 2a5ce41ee3e..f4d20fd6abc 100644
--- a/app/services/invoices/subscription_service.rb
+++ b/app/services/invoices/subscription_service.rb
@@ -33,6 +33,7 @@ def call
           recurring:,
           context:
         )
+        Invoices::ApplyInvoiceCustomSectionsService.call(invoice:)
 
         set_invoice_generated_status unless invoice.pending?
         invoice.save!
diff --git a/app/services/webhooks/invoices/add_on_created_service.rb b/app/services/webhooks/invoices/add_on_created_service.rb
index 7ddffd3376c..92ddf958f13 100644
--- a/app/services/webhooks/invoices/add_on_created_service.rb
+++ b/app/services/webhooks/invoices/add_on_created_service.rb
@@ -13,7 +13,7 @@ def object_serializer
         ::V1::InvoiceSerializer.new(
           object,
           root_name: 'invoice',
-          includes: %i[customer subscriptions fees]
+          includes: %i[customer subscriptions fees applied_invoice_custom_sections]
         )
       end
 
diff --git a/app/services/webhooks/invoices/created_service.rb b/app/services/webhooks/invoices/created_service.rb
index 8358922784b..48e395326a6 100644
--- a/app/services/webhooks/invoices/created_service.rb
+++ b/app/services/webhooks/invoices/created_service.rb
@@ -13,7 +13,7 @@ def object_serializer
         ::V1::InvoiceSerializer.new(
           object,
           root_name: 'invoice',
-          includes: %i[customer subscriptions fees credits applied_taxes]
+          includes: %i[customer subscriptions fees credits applied_taxes applied_invoice_custom_sections]
         )
       end
 
diff --git a/app/services/webhooks/invoices/one_off_created_service.rb b/app/services/webhooks/invoices/one_off_created_service.rb
index 057fdddcd74..6090e5fb6c4 100644
--- a/app/services/webhooks/invoices/one_off_created_service.rb
+++ b/app/services/webhooks/invoices/one_off_created_service.rb
@@ -13,7 +13,7 @@ def object_serializer
         ::V1::InvoiceSerializer.new(
           object,
           root_name: 'invoice',
-          includes: %i[customer fees applied_taxes]
+          includes: %i[customer fees applied_taxes applied_invoice_custom_sections]
         )
       end
 
diff --git a/app/services/webhooks/invoices/paid_credit_added_service.rb b/app/services/webhooks/invoices/paid_credit_added_service.rb
index 91e1ef83058..6956fc4476b 100644
--- a/app/services/webhooks/invoices/paid_credit_added_service.rb
+++ b/app/services/webhooks/invoices/paid_credit_added_service.rb
@@ -13,7 +13,7 @@ def object_serializer
         ::V1::InvoiceSerializer.new(
           object,
           root_name: 'invoice',
-          includes: %i[customer fees applied_taxes]
+          includes: %i[customer fees applied_taxes applied_invoice_custom_sections]
         )
       end
 
diff --git a/app/views/templates/invoices/v3.slim b/app/views/templates/invoices/v3.slim
index 72a93e9eed1..44ef15c833c 100644
--- a/app/views/templates/invoices/v3.slim
+++ b/app/views/templates/invoices/v3.slim
@@ -425,6 +425,9 @@ html
         - else
           == SlimHelper.render('templates/invoices/v3/_subscriptions_summary', self)
 
+
+      - if applied_invoice_custom_sections.present?
+        == SlimHelper.render('templates/invoices/v3/_custom_sections', self)
       p.body-3.mb-24 = LineBreakHelper.break_lines(organization.invoice_footer)
 
       .powered-by
diff --git a/app/views/templates/invoices/v3/_custom_sections.slim b/app/views/templates/invoices/v3/_custom_sections.slim
new file mode 100644
index 00000000000..d6e60631f3c
--- /dev/null
+++ b/app/views/templates/invoices/v3/_custom_sections.slim
@@ -0,0 +1,15 @@
+css:
+  .invoice-custom-section {
+    margin-top: 24px;
+    border-bottom: 1px solid #D9DEE7;
+  }
+
+  .invoice-custom-section p.section-name {
+    margin-bottom: 8px;
+  }
+
+.invoice-custom-sections.body-3.mb-24
+  - applied_invoice_custom_sections.each do |section|
+    .invoice-custom-section
+      p.body-1.section-name = section.display_name
+      p.body-3.mb-24 = LineBreakHelper.break_lines(section.details)
diff --git a/app/views/templates/invoices/v3/charge.slim b/app/views/templates/invoices/v3/charge.slim
index a6f729c5f2e..d1d25b817bd 100644
--- a/app/views/templates/invoices/v3/charge.slim
+++ b/app/views/templates/invoices/v3/charge.slim
@@ -473,6 +473,9 @@ html
             td.body-1 = advance_charges? ? I18n.t('invoice.already_paid') : I18n.t('invoice.total_due')
             td.body-1 = MoneyHelper.format(total_amount)
 
+
+      - if applied_invoice_custom_sections.present?
+        == SlimHelper.render('templates/invoices/v3/_custom_sections', self)
       p.body-3.mb-24 = LineBreakHelper.break_lines(organization.invoice_footer)
 
       .powered-by
diff --git a/app/views/templates/invoices/v3/one_off.slim b/app/views/templates/invoices/v3/one_off.slim
index c6ee18861ee..ea687005b4f 100644
--- a/app/views/templates/invoices/v3/one_off.slim
+++ b/app/views/templates/invoices/v3/one_off.slim
@@ -457,6 +457,9 @@ html
             td.body-1 = MoneyHelper.format(total_amount)
 
 
+
+      - if applied_invoice_custom_sections.present?
+        == SlimHelper.render('templates/invoices/v3/_custom_sections', self)
       p.body-3.mb-24 = LineBreakHelper.break_lines(organization.invoice_footer)
 
       .powered-by
diff --git a/app/views/templates/invoices/v4.slim b/app/views/templates/invoices/v4.slim
index 4af9c015237..e71c74ae156 100644
--- a/app/views/templates/invoices/v4.slim
+++ b/app/views/templates/invoices/v4.slim
@@ -144,6 +144,9 @@ html
 
 
       /* ----------------------- variable ----------------------- */
+      :root {
+        --border-color: #D9DEE7;
+      }
 
       @font-face {
         font-family: 'Inter var';
@@ -245,7 +248,7 @@ html
         color: #66758F;
       }
       .invoice-resume-table tr {
-        border-bottom: 1px solid #D9DEE7;
+        border-bottom: 1px solid var(--border-color);
       }
       .invoice-resume-table tr td {
         padding-top: 8px;
@@ -284,12 +287,12 @@ html
         width: 50%;
       }
       .invoice-resume .total-table tr:not(:last-child) td:nth-child(2) {
-        border-bottom: 1px solid #D9DEE7;
+        border-bottom: 1px solid var(--border-color);
         text-align: left;
         width: 35%;
       }
       .invoice-resume .total-table tr:not(:last-child) td:nth-child(3) {
-        border-bottom: 1px solid #D9DEE7;
+        border-bottom: 1px solid var(--border-color);
         text-align: right;
         width: 15%;
       }
@@ -320,10 +323,10 @@ html
         text-align: right;
       }
       .breakdown-details-table tr td {
-        border-bottom: 1px solid #d9dee7;
+        border-bottom: 1px solid var(--border-color);
       }
       .breakdown-details-table tr:first-child td {
-        border-top: 1px solid #d9dee7;
+        border-top: 1px solid var(--border-color);
       }
 
       .powered-by {
@@ -365,7 +368,7 @@ html
       }
       .invoice-resume-table tr.details.subtotal td {
         padding-bottom: 8px;
-        border-bottom: 1px solid #d9dee7;
+        border-bottom: 1px solid var(--border-color);
         color: #19212e;
       }
 
@@ -463,6 +466,9 @@ html
           - applied_usage_threshold = applied_usage_thresholds.order(created_at: :asc).last
           = I18n.t('invoice.reached_usage_threshold', usage_amount: MoneyHelper.format(applied_usage_threshold.lifetime_usage_amount), threshold_amount: MoneyHelper.format(applied_usage_threshold.passed_threshold_amount))
 
+      - if applied_invoice_custom_sections.present?
+        == SlimHelper.render('templates/invoices/v4/_custom_sections', self)
+
       p.body-3.mb-24 = LineBreakHelper.break_lines(organization.invoice_footer)
 
       .powered-by
diff --git a/app/views/templates/invoices/v4/_custom_sections.slim b/app/views/templates/invoices/v4/_custom_sections.slim
new file mode 100644
index 00000000000..19381502b72
--- /dev/null
+++ b/app/views/templates/invoices/v4/_custom_sections.slim
@@ -0,0 +1,15 @@
+css:
+  .invoice-custom-section {
+    margin-top: 24px;
+    border-bottom: 1px solid #D9DEE7;
+  }
+
+  .invoice-custom-section p.section-name {
+      margin-bottom: 8px;
+  }
+
+.invoice-custom-sections.body-3.mb-24
+  - applied_invoice_custom_sections.each do |section|
+    .invoice-custom-section
+      p.body-1.section-name = section.display_name
+      p.body-3.mb-24 = LineBreakHelper.break_lines(section.details)
diff --git a/app/views/templates/invoices/v4/charge.slim b/app/views/templates/invoices/v4/charge.slim
index a3f5aeed39d..1ba78e6f734 100644
--- a/app/views/templates/invoices/v4/charge.slim
+++ b/app/views/templates/invoices/v4/charge.slim
@@ -560,6 +560,9 @@ html
 
       == SlimHelper.render('templates/invoices/v4/_eu_tax_management', self)
 
+      - if applied_invoice_custom_sections.present?
+        == SlimHelper.render('templates/invoices/v4/_custom_sections', self)
+
       p.body-3.mb-24 = LineBreakHelper.break_lines(organization.invoice_footer)
 
       .powered-by
diff --git a/app/views/templates/invoices/v4/one_off.slim b/app/views/templates/invoices/v4/one_off.slim
index 287c66f89db..dd63a93aae8 100644
--- a/app/views/templates/invoices/v4/one_off.slim
+++ b/app/views/templates/invoices/v4/one_off.slim
@@ -465,6 +465,9 @@ html
 
       == SlimHelper.render('templates/invoices/v4/_eu_tax_management', self)
 
+      - if applied_invoice_custom_sections.present?
+        == SlimHelper.render('templates/invoices/v4/_custom_sections', self)
+
       p.body-3.mb-24 = LineBreakHelper.break_lines(organization.invoice_footer)
       .powered-by
         span.body-2
diff --git a/spec/graphql/resolvers/invoice_custom_sections_resolver_spec.rb b/spec/graphql/resolvers/invoice_custom_sections_resolver_spec.rb
index ee30a65aabd..4191f0a7525 100644
--- a/spec/graphql/resolvers/invoice_custom_sections_resolver_spec.rb
+++ b/spec/graphql/resolvers/invoice_custom_sections_resolver_spec.rb
@@ -31,13 +31,14 @@
 
   before do
     organization.selected_invoice_custom_sections.concat(invoice_custom_sections[2..4])
+    customer.selected_invoice_custom_sections.concat(invoice_custom_sections[0..1])
   end
 
   it_behaves_like 'requires current user'
   it_behaves_like 'requires current organization'
   it_behaves_like 'requires permission', 'invoice_custom_sections:view'
 
-  it 'returns a list of sorted invoice_custom_sections: alphabetical, selected first' do
+  it 'returns a list of sorted invoice_custom_sections: alphabetical, selected first without duplicates' do
     result = execute_graphql(
       current_user: membership.user,
       current_organization: organization,
diff --git a/spec/models/customer_spec.rb b/spec/models/customer_spec.rb
index b22169c920f..aea65daeb0d 100644
--- a/spec/models/customer_spec.rb
+++ b/spec/models/customer_spec.rb
@@ -433,8 +433,8 @@
     context 'when customer does not have any selected_invoice_custom_sections but organization has' do
       before { organization.selected_invoice_custom_sections << organization_section }
 
-      it 'returns the organization\'s invoice_custom_sections' do
-        expect(customer.applicable_invoice_custom_sections).to eq([organization_section])
+      it "returns the organization's invoice_custom_sections" do
+        expect(customer.applicable_invoice_custom_sections).to match_array([organization_section])
       end
     end
 
diff --git a/spec/requests/api/v1/customers_controller_spec.rb b/spec/requests/api/v1/customers_controller_spec.rb
index e186c2752ae..1536156af22 100644
--- a/spec/requests/api/v1/customers_controller_spec.rb
+++ b/spec/requests/api/v1/customers_controller_spec.rb
@@ -266,7 +266,7 @@
           sections = json[:customer][:applicable_invoice_custom_sections]
           expect(sections).to be_present
           expect(sections.length).to eq(2)
-          expect(sections.map { |sec| sec[:code] }).to eq(invoice_custom_sections.map(&:code))
+          expect(sections.map { |sec| sec[:code] }).to match_array(invoice_custom_section_codes)
         end
       end
 
diff --git a/spec/requests/api/v1/invoices_controller_spec.rb b/spec/requests/api/v1/invoices_controller_spec.rb
index e781277fc37..a67dbce749c 100644
--- a/spec/requests/api/v1/invoices_controller_spec.rb
+++ b/spec/requests/api/v1/invoices_controller_spec.rb
@@ -177,7 +177,8 @@
           customer: Hash,
           subscriptions: [],
           credits: [],
-          applied_taxes: []
+          applied_taxes: [],
+          applied_invoice_custom_sections: []
         )
         expect(json[:invoice][:fees].first).to include(lago_charge_filter_id: charge_filter.id)
       end
diff --git a/spec/serializers/v1/invoice_custom_section_serializer_spec.rb b/spec/serializers/v1/invoice_custom_section_serializer_spec.rb
index 8e7456110a4..14b7a298c03 100644
--- a/spec/serializers/v1/invoice_custom_section_serializer_spec.rb
+++ b/spec/serializers/v1/invoice_custom_section_serializer_spec.rb
@@ -18,10 +18,8 @@
         'description' => invoice_custom_section.description,
         'details' => invoice_custom_section.details,
         'display_name' => invoice_custom_section.display_name,
-        'selected_for_organization' => invoice_custom_section.selected_for_organization?,
-        'organization' => {
-          'lago_id' => invoice_custom_section.organization_id
-        }
+        'applied_to_organization' => invoice_custom_section.selected_for_organization?,
+        'organization_id' => invoice_custom_section.organization_id
       )
     end
   end
diff --git a/spec/serializers/v1/invoices/applied_invoice_custom_section_serializer_spec.rb b/spec/serializers/v1/invoices/applied_invoice_custom_section_serializer_spec.rb
new file mode 100644
index 00000000000..f09e914b9f1
--- /dev/null
+++ b/spec/serializers/v1/invoices/applied_invoice_custom_section_serializer_spec.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe V1::Invoices::AppliedInvoiceCustomSectionSerializer, type: :serializer do
+  subject(:serializer) { described_class.new(applied_invoice_custom_section) }
+
+  let(:invoice) { create(:invoice) }
+  let(:applied_invoice_custom_section) do
+    create(:applied_invoice_custom_section,
+      invoice:,
+      code: 'custom_code',
+      details: 'custom_details',
+      display_name: 'Custom Display Name',
+      created_at: Time.current)
+  end
+
+  describe '#serialize' do
+    it 'serializes the applied invoice custom section correctly' do
+      serialized_data = serializer.serialize
+
+      expect(serialized_data).to include(
+        lago_id: applied_invoice_custom_section.id,
+        lago_invoice_id: applied_invoice_custom_section.invoice_id,
+        code: 'custom_code',
+        details: 'custom_details',
+        display_name: 'Custom Display Name',
+        created_at: applied_invoice_custom_section.created_at.iso8601
+      )
+    end
+  end
+end
diff --git a/spec/services/invoices/add_on_service_spec.rb b/spec/services/invoices/add_on_service_spec.rb
index 7ca1edc1873..4430340863d 100644
--- a/spec/services/invoices/add_on_service_spec.rb
+++ b/spec/services/invoices/add_on_service_spec.rb
@@ -107,6 +107,10 @@
       let(:service_call) { invoice_service.create }
     end
 
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { invoice_service.create }
+    end
+
     context 'with customer timezone' do
       before { applied_add_on.customer.update!(timezone: 'America/Los_Angeles') }
 
diff --git a/spec/services/invoices/apply_invoice_custom_sections_service_spec.rb b/spec/services/invoices/apply_invoice_custom_sections_service_spec.rb
new file mode 100644
index 00000000000..e74f6111e80
--- /dev/null
+++ b/spec/services/invoices/apply_invoice_custom_sections_service_spec.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Invoices::ApplyInvoiceCustomSectionsService, type: :service do
+  subject(:invoice_service) { described_class.new(invoice:) }
+
+  let(:organization) { create(:organization) }
+  let(:customer) { create(:customer, organization:) }
+  let(:invoice) { create(:invoice, customer:) }
+  let(:custom_sections) { create_list(:invoice_custom_section, 3, organization:) }
+
+  before do
+    organization.selected_invoice_custom_sections << custom_sections[1..2]
+  end
+
+  describe '#call' do
+    context 'when the customer has skip_invoice_custom_sections flag' do
+      let(:customer) { create(:customer, organization:, skip_invoice_custom_sections: true) }
+
+      it 'does not apply any custom sections' do
+        result = invoice_service.call
+        expect(result).to be_success
+        expect(result.applied_sections).to be_empty
+        expect(invoice.reload.applied_invoice_custom_sections).to be_empty
+      end
+    end
+
+    context 'when the customer has custom sections' do
+      before do
+        customer.selected_invoice_custom_sections << custom_sections[0..1]
+      end
+
+      it 'applies the custom sections to the invoice' do
+        result = invoice_service.call
+        expect(result).to be_success
+        sections = invoice.reload.applied_invoice_custom_sections
+        expect(sections.map(&:code)).to match_array(custom_sections[0..1].map(&:code))
+        expect(sections.map(&:details)).to match_array(custom_sections[0..1].map(&:details))
+        expect(sections.map(&:display_name)).to match_array(custom_sections[0..1].map(&:display_name))
+        expect(sections.map(&:name)).to match_array(custom_sections[0..1].map(&:name))
+      end
+    end
+
+    context 'when the customer inherits custom sections from the organization' do
+      it 'applies the organization\'s sections to the invoice' do
+        result = invoice_service.call
+        expect(result).to be_success
+        sections = invoice.reload.applied_invoice_custom_sections
+        expect(sections.map(&:code)).to match_array(custom_sections[1..2].map(&:code))
+        expect(sections.map(&:details)).to match_array(custom_sections[1..2].map(&:details))
+        expect(sections.map(&:display_name)).to match_array(custom_sections[1..2].map(&:display_name))
+        expect(sections.map(&:name)).to match_array(custom_sections[1..2].map(&:name))
+      end
+    end
+  end
+end
diff --git a/spec/services/invoices/create_one_off_service_spec.rb b/spec/services/invoices/create_one_off_service_spec.rb
index 501b0fdf269..af26b5f3f9c 100644
--- a/spec/services/invoices/create_one_off_service_spec.rb
+++ b/spec/services/invoices/create_one_off_service_spec.rb
@@ -67,6 +67,10 @@
       let(:service_call) { create_service.call }
     end
 
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { create_service.call }
+    end
+
     it 'calls SegmentTrackJob' do
       invoice = create_service.call.invoice
 
diff --git a/spec/services/invoices/create_pay_in_advance_charge_service_spec.rb b/spec/services/invoices/create_pay_in_advance_charge_service_spec.rb
index d7147173e9e..4667671be93 100644
--- a/spec/services/invoices/create_pay_in_advance_charge_service_spec.rb
+++ b/spec/services/invoices/create_pay_in_advance_charge_service_spec.rb
@@ -318,5 +318,9 @@
         expect(result.invoice).to be_finalized
       end
     end
+
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { invoice_service.call }
+    end
   end
 end
diff --git a/spec/services/invoices/paid_credit_service_spec.rb b/spec/services/invoices/paid_credit_service_spec.rb
index 388171cb682..10dd929980c 100644
--- a/spec/services/invoices/paid_credit_service_spec.rb
+++ b/spec/services/invoices/paid_credit_service_spec.rb
@@ -62,6 +62,10 @@
       let(:service_call) { invoice_service.call }
     end
 
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { invoice_service.call }
+    end
+
     it 'does not enqueue an SendEmailJob' do
       expect do
         invoice_service.call
diff --git a/spec/services/invoices/progressive_billing_service_spec.rb b/spec/services/invoices/progressive_billing_service_spec.rb
index 3977b46faf4..7d9b2e75468 100644
--- a/spec/services/invoices/progressive_billing_service_spec.rb
+++ b/spec/services/invoices/progressive_billing_service_spec.rb
@@ -232,5 +232,9 @@
     it_behaves_like 'syncs invoice' do
       let(:service_call) { create_service.call }
     end
+
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { create_service.call }
+    end
   end
 end
diff --git a/spec/services/invoices/refresh_draft_and_finalize_service_spec.rb b/spec/services/invoices/refresh_draft_and_finalize_service_spec.rb
index c16e9f10714..dfc977abbfd 100644
--- a/spec/services/invoices/refresh_draft_and_finalize_service_spec.rb
+++ b/spec/services/invoices/refresh_draft_and_finalize_service_spec.rb
@@ -79,6 +79,10 @@
       let(:service_call) { finalize_service.call }
     end
 
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { finalize_service.call }
+    end
+
     it 'enqueues a SendWebhookJob' do
       expect do
         finalize_service.call
diff --git a/spec/services/invoices/refresh_draft_service_spec.rb b/spec/services/invoices/refresh_draft_service_spec.rb
index 590e0d4860d..b41e2837f72 100644
--- a/spec/services/invoices/refresh_draft_service_spec.rb
+++ b/spec/services/invoices/refresh_draft_service_spec.rb
@@ -171,6 +171,10 @@
         .to change { invoice.reload.progressive_billing_credit_amount_cents }.from(1239000).to(0)
     end
 
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { refresh_service.call }
+    end
+
     context 'when there is a tax_integration set up' do
       let(:integration) { create(:anrok_integration, organization:) }
       let(:integration_customer) { create(:anrok_customer, integration:, customer:) }
@@ -203,6 +207,21 @@
       end
     end
 
+    context 'when invoice has other applied invoice_custom_sections' do
+      let(:invoice_custom_sections) { create_list(:invoice_custom_section, 4, organization: organization) }
+      let(:applied_invoice_custom_sections) { create_list(:applied_invoice_custom_section, 2, invoice: invoice) }
+
+      before do
+        applied_invoice_custom_sections
+        customer.selected_invoice_custom_sections = invoice_custom_sections.take(3)
+      end
+
+      it 'creates new applied_invoice_custom_sections' do
+        expect { refresh_service.call }.to change { invoice.reload.applied_invoice_custom_sections.count }.from(2).to(3)
+        expect(invoice.applied_invoice_custom_sections.map(&:code)).to match_array(customer.selected_invoice_custom_sections.map(&:code))
+      end
+    end
+
     it 'flags lifetime usage for refresh' do
       create(:usage_threshold, plan: subscription.plan)
 
diff --git a/spec/services/invoices/subscription_service_spec.rb b/spec/services/invoices/subscription_service_spec.rb
index 9a53d022525..3c03494b7d1 100644
--- a/spec/services/invoices/subscription_service_spec.rb
+++ b/spec/services/invoices/subscription_service_spec.rb
@@ -106,6 +106,10 @@
       let(:service_call) { invoice_service.call }
     end
 
+    it_behaves_like "applies invoice_custom_sections" do
+      let(:service_call) { invoice_service.call }
+    end
+
     it "enqueues a SendWebhookJob" do
       expect do
         invoice_service.call
diff --git a/spec/support/shared_examples/applied_invoice_custom_sections.rb b/spec/support/shared_examples/applied_invoice_custom_sections.rb
index e69de29bb2d..3b46340a9a4 100644
--- a/spec/support/shared_examples/applied_invoice_custom_sections.rb
+++ b/spec/support/shared_examples/applied_invoice_custom_sections.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+RSpec.shared_examples 'applies invoice_custom_sections' do
+  let(:invoice_custom_sections) { create_list(:invoice_custom_section, 4, organization:) }
+
+  before do
+    organization.selected_invoice_custom_sections = invoice_custom_sections[2..3]
+  end
+
+  context 'when the customer has :skip_invoice_custom_sections flag' do
+    before { customer.update(skip_invoice_custom_sections: true) }
+
+    it 'doesn\'t create applied_invoice_custom_section' do
+      expect { service_call }.not_to change(AppliedInvoiceCustomSection, :count)
+    end
+  end
+
+  context 'when customer follows organizations invoice_custom_sections' do
+    it 'creates applied_invoice_custom_sections' do
+      result = service_call
+      invoice = result.invoice
+      expect(invoice.applied_invoice_custom_sections.pluck(:code)).to match_array(organization.selected_invoice_custom_sections.pluck(:code))
+    end
+  end
+end