From 464e1d5d6d22905049342bdc87266a57b9b9c63e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Tue, 16 Aug 2022 13:52:50 +0200
Subject: [PATCH 1/8] feat(:free-units): Remove fixed amount target on
 Charge#properties

---
 .../charge_model_attributes_handler.rb        |  2 -
 .../types/charges/fixed_amount_target_enum.rb | 11 ----
 app/graphql/types/charges/input.rb            |  1 -
 app/graphql/types/charges/object.rb           |  7 ---
 app/models/charge.rb                          |  5 --
 .../charge_models/percentage_service.rb       |  8 +--
 .../charges/validators/percentage_service.rb  | 15 +----
 config/locales/en.yml                         |  1 -
 schema.graphql                                |  7 ---
 schema.json                                   | 49 ----------------
 spec/factories/charge_factory.rb              |  1 -
 spec/graphql/mutations/plans/create_spec.rb   |  1 -
 spec/graphql/mutations/plans/update_spec.rb   |  1 -
 spec/models/charge_spec.rb                    |  2 -
 .../charge_models/percentage_service_spec.rb  | 30 +---------
 .../validators/percentage_service_spec.rb     | 57 +------------------
 16 files changed, 5 insertions(+), 193 deletions(-)
 delete mode 100644 app/graphql/types/charges/fixed_amount_target_enum.rb

diff --git a/app/graphql/concerns/charge_model_attributes_handler.rb b/app/graphql/concerns/charge_model_attributes_handler.rb
index 1922471588e..f8fd8e68d9b 100644
--- a/app/graphql/concerns/charge_model_attributes_handler.rb
+++ b/app/graphql/concerns/charge_model_attributes_handler.rb
@@ -27,7 +27,6 @@ def prepare_arguments(arguments)
         output[:properties] = {
           rate: output[:rate],
           fixed_amount: output[:fixed_amount],
-          fixed_amount_target: output[:fixed_amount_target],
         }
       end
 
@@ -38,7 +37,6 @@ def prepare_arguments(arguments)
       output.delete(:package_size)
       output.delete(:rate)
       output.delete(:fixed_amount)
-      output.delete(:fixed_amount_target)
 
       output
     end
diff --git a/app/graphql/types/charges/fixed_amount_target_enum.rb b/app/graphql/types/charges/fixed_amount_target_enum.rb
deleted file mode 100644
index 3e68572171b..00000000000
--- a/app/graphql/types/charges/fixed_amount_target_enum.rb
+++ /dev/null
@@ -1,11 +0,0 @@
-# frozen_string_literal: true
-
-module Types
-  module Charges
-    class FixedAmountTargetEnum < Types::BaseEnum
-      Charge::FIXED_AMOUNT_TARGETS.each do |type|
-        value type
-      end
-    end
-  end
-end
diff --git a/app/graphql/types/charges/input.rb b/app/graphql/types/charges/input.rb
index e269b3df1f2..41407c7eb5b 100644
--- a/app/graphql/types/charges/input.rb
+++ b/app/graphql/types/charges/input.rb
@@ -23,7 +23,6 @@ class Input < Types::BaseInputObject
       # NOTE: Percentage charge model
       argument :rate, String, required: false
       argument :fixed_amount, String, required: false
-      argument :fixed_amount_target, Types::Charges::FixedAmountTargetEnum, required: false
     end
   end
 end
diff --git a/app/graphql/types/charges/object.rb b/app/graphql/types/charges/object.rb
index 332c0edb60d..192fc7ea2f2 100644
--- a/app/graphql/types/charges/object.rb
+++ b/app/graphql/types/charges/object.rb
@@ -26,7 +26,6 @@ class Object < Types::BaseObject
       # NOTE: Percentage charge model
       field :rate, String, null: true
       field :fixed_amount, String, null: true
-      field :fixed_amount_target, Types::Charges::FixedAmountTargetEnum, null: true
 
       def amount
         return unless object.standard? || object.package?
@@ -63,12 +62,6 @@ def fixed_amount
 
         object.properties['fixed_amount']
       end
-
-      def fixed_amount_target
-        return unless object.percentage?
-
-        object.properties['fixed_amount_target']
-      end
     end
   end
 end
diff --git a/app/models/charge.rb b/app/models/charge.rb
index 99d244cb9cf..42e73f835ba 100644
--- a/app/models/charge.rb
+++ b/app/models/charge.rb
@@ -15,11 +15,6 @@ class Charge < ApplicationRecord
     percentage
   ].freeze
 
-  FIXED_AMOUNT_TARGETS = %w[
-    all_units
-    each_unit
-  ].freeze
-
   enum charge_model: CHARGE_MODELS
 
   validates :amount_currency, inclusion: { in: currency_list }
diff --git a/app/services/charges/charge_models/percentage_service.rb b/app/services/charges/charge_models/percentage_service.rb
index 39e23858039..8f336df5b0b 100644
--- a/app/services/charges/charge_models/percentage_service.rb
+++ b/app/services/charges/charge_models/percentage_service.rb
@@ -15,9 +15,7 @@ def compute_percentage_amount(value)
 
       def compute_fixed_amount(value)
         return 0 if value.zero?
-        return 0 if (fixed_amount_target.nil? || fixed_amount.nil?)
-
-        return fixed_amount if fixed_amount_target == 'all_units'
+        return 0 if fixed_amount.nil?
 
         value * fixed_amount
       end
@@ -27,10 +25,6 @@ def rate
         BigDecimal(charge.properties['rate'])
       end
 
-      def fixed_amount_target
-        charge.properties['fixed_amount_target']
-      end
-
       def fixed_amount
         @fixed_amount ||= BigDecimal(charge.properties['fixed_amount'] || 0)
       end
diff --git a/app/services/charges/validators/percentage_service.rb b/app/services/charges/validators/percentage_service.rb
index dfd00ba1b89..51363f3c883 100644
--- a/app/services/charges/validators/percentage_service.rb
+++ b/app/services/charges/validators/percentage_service.rb
@@ -7,7 +7,6 @@ def validate
         errors = []
         errors << :invalid_rate unless valid_rate?
         errors << :invalid_fixed_amount unless valid_fixed_amount?
-        errors << :invalid_fixed_amount_target unless valid_fixed_amount_target?
 
         return result.fail!(code: :invalid_properties, message: errors) if errors.present?
 
@@ -29,22 +28,10 @@ def fixed_amount
       end
 
       def valid_fixed_amount?
-        return true if fixed_amount.nil? && fixed_amount_target.nil?
+        return true if fixed_amount.nil?
 
         ::Validators::DecimalAmountService.new(fixed_amount).valid_amount?
       end
-
-      def fixed_amount_target
-        properties['fixed_amount_target']
-      end
-
-      def valid_fixed_amount_target?
-        return true if fixed_amount.nil? && fixed_amount_target.nil?
-
-        fixed_amount_target.present? &&
-          fixed_amount_target.is_a?(String) &&
-          Charge::FIXED_AMOUNT_TARGETS.include?(fixed_amount_target)
-      end
     end
   end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index aa71df5aba8..d1994e9586b 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -19,7 +19,6 @@ en:
         invalid_package_size: invalid_package_size
         invalid_rate: invalid_rate
         invalid_fixed_amount: invalid_fixed_amount
-        invalid_fixed_amount_target: invalid_fixed_amount_target
         invalid_content_type: invalid_content_type
         invalid_size: invalid_size
         value_already_exists: value_already_exists
diff --git a/schema.graphql b/schema.graphql
index 32f2df4402c..f416bafe64d 100644
--- a/schema.graphql
+++ b/schema.graphql
@@ -135,7 +135,6 @@ type Charge {
   chargeModel: ChargeModelEnum!
   createdAt: ISO8601DateTime!
   fixedAmount: String
-  fixedAmountTarget: FixedAmountTargetEnum
   freeUnits: Int
   graduatedRanges: [GraduatedRange!]
   id: ID!
@@ -150,7 +149,6 @@ input ChargeInput {
   billableMetricId: ID!
   chargeModel: ChargeModelEnum!
   fixedAmount: String
-  fixedAmountTarget: FixedAmountTargetEnum
   freeUnits: Int
   graduatedRanges: [GraduatedRangeInput!]
   id: ID
@@ -2626,11 +2624,6 @@ type EventCollection {
   metadata: CollectionMetadata!
 }
 
-enum FixedAmountTargetEnum {
-  all_units
-  each_unit
-}
-
 type GraduatedRange {
   flatAmount: String!
   fromValue: Int!
diff --git a/schema.json b/schema.json
index 0b0acc4982a..a53440234ec 100644
--- a/schema.json
+++ b/schema.json
@@ -1322,20 +1322,6 @@
 
               ]
             },
-            {
-              "name": "fixedAmountTarget",
-              "description": null,
-              "type": {
-                "kind": "ENUM",
-                "name": "FixedAmountTargetEnum",
-                "ofType": null
-              },
-              "isDeprecated": false,
-              "deprecationReason": null,
-              "args": [
-
-              ]
-            },
             {
               "name": "freeUnits",
               "description": null,
@@ -1587,18 +1573,6 @@
               "defaultValue": null,
               "isDeprecated": false,
               "deprecationReason": null
-            },
-            {
-              "name": "fixedAmountTarget",
-              "description": null,
-              "type": {
-                "kind": "ENUM",
-                "name": "FixedAmountTargetEnum",
-                "ofType": null
-              },
-              "defaultValue": null,
-              "isDeprecated": false,
-              "deprecationReason": null
             }
           ],
           "enumValues": null
@@ -7970,29 +7944,6 @@
           "inputFields": null,
           "enumValues": null
         },
-        {
-          "kind": "ENUM",
-          "name": "FixedAmountTargetEnum",
-          "description": null,
-          "interfaces": null,
-          "possibleTypes": null,
-          "fields": null,
-          "inputFields": null,
-          "enumValues": [
-            {
-              "name": "all_units",
-              "description": null,
-              "isDeprecated": false,
-              "deprecationReason": null
-            },
-            {
-              "name": "each_unit",
-              "description": null,
-              "isDeprecated": false,
-              "deprecationReason": null
-            }
-          ]
-        },
         {
           "kind": "SCALAR",
           "name": "Float",
diff --git a/spec/factories/charge_factory.rb b/spec/factories/charge_factory.rb
index cbf34de2d9d..b41bc07e0dd 100644
--- a/spec/factories/charge_factory.rb
+++ b/spec/factories/charge_factory.rb
@@ -36,7 +36,6 @@
         {
           rate: '0.0555',
           fixed_amount: '2',
-          fixed_amount_target: 'each_unit',
         }
       end
     end
diff --git a/spec/graphql/mutations/plans/create_spec.rb b/spec/graphql/mutations/plans/create_spec.rb
index 4017db16eca..89325c12586 100644
--- a/spec/graphql/mutations/plans/create_spec.rb
+++ b/spec/graphql/mutations/plans/create_spec.rb
@@ -64,7 +64,6 @@
               chargeModel: 'percentage',
               rate: '0.25',
               fixedAmount: '2',
-              fixedAmountTarget: 'all_units',
             },
             {
               billableMetricId: billable_metrics.last.id,
diff --git a/spec/graphql/mutations/plans/update_spec.rb b/spec/graphql/mutations/plans/update_spec.rb
index 95c1f80b1e9..a1b99eb3353 100644
--- a/spec/graphql/mutations/plans/update_spec.rb
+++ b/spec/graphql/mutations/plans/update_spec.rb
@@ -65,7 +65,6 @@
               chargeModel: 'percentage',
               rate: '0.25',
               fixedAmount: '2',
-              fixedAmountTarget: 'all_units',
             },
             {
               billableMetricId: billable_metrics.last.id,
diff --git a/spec/models/charge_spec.rb b/spec/models/charge_spec.rb
index 34702d60155..bd88226a9c4 100644
--- a/spec/models/charge_spec.rb
+++ b/spec/models/charge_spec.rb
@@ -172,7 +172,6 @@
         message: [
           :invalid_rate,
           :invalid_fixed_amount,
-          :invalid_fixed_amount_target,
         ],
       )
     end
@@ -188,7 +187,6 @@
         expect(charge.errors.messages.keys).to include(:properties)
         expect(charge.errors.messages[:properties]).to include('invalid_rate')
         expect(charge.errors.messages[:properties]).to include('invalid_fixed_amount')
-        expect(charge.errors.messages[:properties]).to include('invalid_fixed_amount_target')
 
         expect(Charges::Validators::PercentageService).to have_received(:new)
           .with(charge: charge)
diff --git a/spec/services/charges/charge_models/percentage_service_spec.rb b/spec/services/charges/charge_models/percentage_service_spec.rb
index a7b9828d3f2..f18e7e35f6e 100644
--- a/spec/services/charges/charge_models/percentage_service_spec.rb
+++ b/spec/services/charges/charge_models/percentage_service_spec.rb
@@ -11,7 +11,6 @@
       properties: {
         rate: '5.55',
         fixed_amount: '0',
-        fixed_amount_target: 'each_unit',
       },
     )
   end
@@ -29,7 +28,6 @@
         properties: {
           rate: '5.55',
           fixed_amount: nil,
-          fixed_amount_target: nil,
         },
       )
     end
@@ -39,43 +37,19 @@
     end
   end
 
-  context 'when fixed amount value is NOT zero and should be applied on each unit' do
+  context 'when fixed amount value is NOT zero' do
     let(:charge) do
       create(
         :percentage_charge,
         properties: {
           rate: '5.55',
           fixed_amount: '2',
-          fixed_amount_target: 'each_unit',
         },
       )
     end
 
-    it 'applies the percentage rate and the additional charge on each init' do
+    it 'applies the percentage rate and the additional charge on each unit' do
       expect(percentage_service.apply(value: 100).amount).to eq(205.55)
     end
   end
-
-  context 'when fixed amount value is NOT zero and should be applied on all units' do
-    let(:charge) do
-      create(
-        :percentage_charge,
-        properties: {
-          rate: '5.5555',
-          fixed_amount: '2',
-          fixed_amount_target: 'all_units',
-        },
-      )
-    end
-
-    it 'applies the percentage rate and the additional charge on all inits' do
-      expect(percentage_service.apply(value: 100).amount).to eq(7.5555)
-    end
-
-    context 'with value equal to zero' do
-      it 'applies the percentage rate and the additional charge on all inits' do
-        expect(percentage_service.apply(value: 0).amount).to eq(0)
-      end
-    end
-  end
 end
diff --git a/spec/services/charges/validators/percentage_service_spec.rb b/spec/services/charges/validators/percentage_service_spec.rb
index eca8299ece4..56fb685953e 100644
--- a/spec/services/charges/validators/percentage_service_spec.rb
+++ b/spec/services/charges/validators/percentage_service_spec.rb
@@ -11,7 +11,6 @@
     {
       rate: '0.25',
       fixed_amount: '2',
-      fixed_amount_target: 'all_units',
     }
   end
 
@@ -22,7 +21,6 @@
       let(:percentage_properties) do
         {
           fixed_amount: '2',
-          fixed_amount_target: 'all_units',
         }
       end
 
@@ -34,7 +32,6 @@
         {
           rate: 0.25,
           fixed_amount: '2',
-          fixed_amount_target: 'all_units',
         }
       end
 
@@ -46,7 +43,6 @@
         {
           rate: 'bla',
           fixed_amount: '2',
-          fixed_amount_target: 'all_units',
         }
       end
 
@@ -58,7 +54,6 @@
         {
           rate: '-0.50',
           fixed_amount: '2',
-          fixed_amount_target: 'all_units',
         }
       end
 
@@ -70,30 +65,17 @@
         {
           rate: '0.00',
           fixed_amount: '2',
-          fixed_amount_target: 'all_units',
         }
       end
 
       it { expect(percentage_service.validate.error).to include(:invalid_rate) }
     end
 
-    context 'without fixed amount' do
-      let(:percentage_properties) do
-        {
-          rate: '0.25',
-          fixed_amount_target: 'all_units',
-        }
-      end
-
-      it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount) }
-    end
-
     context 'when fixed amount cannot be converted to numeric format' do
       let(:percentage_properties) do
         {
           rate: '0.25',
           fixed_amount: 'bla',
-          fixed_amount_target: 'all_units',
         }
       end
 
@@ -105,7 +87,6 @@
         {
           rate: '0.25',
           fixed_amount: 2,
-          fixed_amount_target: 'all_units',
         }
       end
 
@@ -117,25 +98,13 @@
         {
           rate: '0.25',
           fixed_amount: '-2',
-          fixed_amount_target: 'all_units',
         }
       end
 
       it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount) }
     end
 
-    context 'without fixed amount target' do
-      let(:percentage_properties) do
-        {
-          rate: '0.25',
-          fixed_amount: '2',
-        }
-      end
-
-      it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount_target) }
-    end
-
-    context 'without fixed amount and fixed amount target' do
+    context 'without fixed amount' do
       let(:percentage_properties) do
         {
           rate: '0.25'
@@ -144,29 +113,5 @@
 
       it { expect(percentage_service.validate.error).to be nil }
     end
-
-    context 'when fixed amount target is not string' do
-      let(:percentage_properties) do
-        {
-          rate: '0.25',
-          fixed_amount: '2',
-          fixed_amount_target: 5,
-        }
-      end
-
-      it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount_target) }
-    end
-
-    context 'when fixed amount target is not either all_units or each_unit' do
-      let(:percentage_properties) do
-        {
-          rate: '0.25',
-          fixed_amount: '2',
-          fixed_amount_target: 'bbb',
-        }
-      end
-
-      it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount_target) }
-    end
   end
 end

From a7108b07b5fd95ae8b911b30cff6799281dee229 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Tue, 16 Aug 2022 14:17:38 +0200
Subject: [PATCH 2/8] feat(free-units): Migrate existing charges

---
 ...7_update_properties_on_percentage_charges.rb |  6 ++++++
 db/schema.rb                                    |  2 +-
 lib/tasks/charges.rake                          | 17 +++++++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 db/migrate/20220816120137_update_properties_on_percentage_charges.rb
 create mode 100644 lib/tasks/charges.rake

diff --git a/db/migrate/20220816120137_update_properties_on_percentage_charges.rb b/db/migrate/20220816120137_update_properties_on_percentage_charges.rb
new file mode 100644
index 00000000000..b9f1a967079
--- /dev/null
+++ b/db/migrate/20220816120137_update_properties_on_percentage_charges.rb
@@ -0,0 +1,6 @@
+class UpdatePropertiesOnPercentageCharges < ActiveRecord::Migration[7.0]
+  def change
+    LagoApi::Application.load_tasks
+    Rake::Task['charges:update_properties_for_free_units'].invoke
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 9d68c597281..13c0602c526 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2022_08_11_155332) do
+ActiveRecord::Schema[7.0].define(version: 2022_08_16_120137) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
   enable_extension "plpgsql"
diff --git a/lib/tasks/charges.rake b/lib/tasks/charges.rake
new file mode 100644
index 00000000000..54e3bb08569
--- /dev/null
+++ b/lib/tasks/charges.rake
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+namespace :charges do
+  desc 'Update Properties for Fixed Fee and Free Units'
+  task update_properties_for_free_units: :environment do
+    # Notes: We consider that we don’t have any clients with a percentage charge
+    # created containing a fixed_amount. All existing charges have fixed_amount
+    # and fixed_amount_target with a null value.
+
+    Charge.percentage.where("properties -> 'fixed_amount_target' IS NOT NULL").find_each do |charge|
+      charge.properties.delete('fixed_amount_target')
+      charge.properties['free_units_per_events'] = nil
+      charge.properties['free_units_per_total_aggregation'] = nil
+      charge.save!
+    end
+  end
+end

From dc4eac4c9664b2b2cb05e1485a2c50aa74ed9b0d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Tue, 16 Aug 2022 14:42:42 +0200
Subject: [PATCH 3/8] feat(free-units): Add validations on free units

---
 .../charges/validators/percentage_service.rb  | 22 +++++++
 .../validators/percentage_service_spec.rb     | 63 +++++++++++++++++--
 2 files changed, 80 insertions(+), 5 deletions(-)

diff --git a/app/services/charges/validators/percentage_service.rb b/app/services/charges/validators/percentage_service.rb
index 51363f3c883..b43eded5041 100644
--- a/app/services/charges/validators/percentage_service.rb
+++ b/app/services/charges/validators/percentage_service.rb
@@ -7,6 +7,8 @@ def validate
         errors = []
         errors << :invalid_rate unless valid_rate?
         errors << :invalid_fixed_amount unless valid_fixed_amount?
+        errors << :invalid_free_units_per_events unless valid_free_units_per_events?
+        errors << :invalid_free_units_per_total_aggregation unless valid_free_units_per_total_aggregation?
 
         return result.fail!(code: :invalid_properties, message: errors) if errors.present?
 
@@ -32,6 +34,26 @@ def valid_fixed_amount?
 
         ::Validators::DecimalAmountService.new(fixed_amount).valid_amount?
       end
+
+      def free_units_per_events
+        properties['free_units_per_events']
+      end
+
+      def valid_free_units_per_events?
+        return true if free_units_per_events.nil?
+
+        free_units_per_events.is_a?(Integer) && free_units_per_events.positive?
+      end
+
+      def free_units_per_total_aggregation
+        properties['free_units_per_total_aggregation']
+      end
+
+      def valid_free_units_per_total_aggregation?
+        return true if free_units_per_total_aggregation.nil?
+
+        ::Validators::DecimalAmountService.new(free_units_per_total_aggregation).valid_amount?
+      end
     end
   end
 end
diff --git a/spec/services/charges/validators/percentage_service_spec.rb b/spec/services/charges/validators/percentage_service_spec.rb
index 56fb685953e..515acf0d289 100644
--- a/spec/services/charges/validators/percentage_service_spec.rb
+++ b/spec/services/charges/validators/percentage_service_spec.rb
@@ -71,15 +71,60 @@
       it { expect(percentage_service.validate.error).to include(:invalid_rate) }
     end
 
-    context 'when fixed amount cannot be converted to numeric format' do
+    context 'when free_units_per_events is not an integer' do
+      let(:percentage_properties) do
+        {
+          rate: '0.25',
+          free_units_per_events: 'foo',
+        }
+      end
+
+      it { expect(percentage_service.validate.error).to include(:invalid_free_units_per_events) }
+    end
+
+    context 'when free_units_per_events is negative amount' do
+      let(:percentage_properties) do
+        {
+          rate: '0.25',
+          free_units_per_events: -1,
+        }
+      end
+
+      it { expect(percentage_service.validate.error).to include(:invalid_free_units_per_events) }
+    end
+
+    context 'when fixed amount and free_units_per_total_aggregation cannot be converted to numeric' do
       let(:percentage_properties) do
         {
           rate: '0.25',
           fixed_amount: 'bla',
+          free_units_per_total_aggregation: 'bla',
         }
       end
 
-      it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount) }
+      it 'returns invalid amounts error' do
+        expect(percentage_service.validate.error).to include(
+          :invalid_fixed_amount,
+          :invalid_free_units_per_total_aggregation,
+        )
+      end
+    end
+
+    context 'when given fixed amount and free_units_per_total_aggregation are not string' do
+      let(:percentage_properties) do
+        {
+          rate: '0.25',
+          fixed_amount: 2,
+          free_units_per_total_aggregation: 1,
+        }
+      end
+
+      it 'returns invalid amounts error' do
+        expect(percentage_service.validate.error).to include(
+          :invalid_fixed_amount,
+          :invalid_free_units_per_total_aggregation,
+        )
+      end
     end
 
     context 'when given fixed amount is not string' do
@@ -93,18 +138,26 @@
       it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount) }
     end
 
-    context 'with negative fixed amount' do
+    context 'with negative fixed amount, free_units_per_events and free_units_per_total_aggregation' do
       let(:percentage_properties) do
         {
           rate: '0.25',
           fixed_amount: '-2',
+          free_units_per_events: '-1',
+          free_units_per_total_aggregation: '-1',
         }
       end
 
-      it { expect(percentage_service.validate.error).to include(:invalid_fixed_amount) }
+      it 'returns invalid amounts error' do
+        expect(percentage_service.validate.error).to include(
+          :invalid_fixed_amount,
+          :invalid_free_units_per_events,
+          :invalid_free_units_per_total_aggregation,
+        )
+      end
     end
 
-    context 'without fixed amount' do
+    context 'without fixed_amount, free_units_per_events and free_units_per_total_aggregation' do
       let(:percentage_properties) do
         {
           rate: '0.25'

From 1ac53704c2c360c3c97d6d38b01984612369b529 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Tue, 16 Aug 2022 15:06:42 +0200
Subject: [PATCH 4/8] feat(free-units): Add free units fields to GraphQL

---
 .../charge_model_attributes_handler.rb        |  5 ++
 app/graphql/types/charges/input.rb            |  2 +
 app/graphql/types/charges/object.rb           | 14 +++++
 config/locales/en.yml                         |  2 +
 schema.graphql                                |  4 ++
 schema.json                                   | 52 +++++++++++++++++++
 spec/factories/charge_factory.rb              |  2 +-
 spec/graphql/mutations/plans/create_spec.rb   |  2 +
 spec/graphql/mutations/plans/update_spec.rb   |  2 +
 spec/models/charge_spec.rb                    |  4 ++
 10 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/app/graphql/concerns/charge_model_attributes_handler.rb b/app/graphql/concerns/charge_model_attributes_handler.rb
index f8fd8e68d9b..827604f1c7e 100644
--- a/app/graphql/concerns/charge_model_attributes_handler.rb
+++ b/app/graphql/concerns/charge_model_attributes_handler.rb
@@ -6,6 +6,7 @@ module ChargeModelAttributesHandler
   #       - Standard model only has one property `amount_cents`
   #       - Graduated model relies on the the list of `GraduatedRange`
   #       - Package model has properties `amount_cents`, `package_size` and `free_units`
+  #       - Percentage model has properties `rate`, `fixed_amount`, `free_units_per_events`, `free_units_per_total_aggregation`
   def prepare_arguments(arguments)
     return arguments if arguments[:charges].blank?
 
@@ -27,6 +28,8 @@ def prepare_arguments(arguments)
         output[:properties] = {
           rate: output[:rate],
           fixed_amount: output[:fixed_amount],
+          free_units_per_events: output[:free_units_per_events],
+          free_units_per_total_aggregation: output[:free_units_per_total_aggregation],
         }
       end
 
@@ -37,6 +40,8 @@ def prepare_arguments(arguments)
       output.delete(:package_size)
       output.delete(:rate)
       output.delete(:fixed_amount)
+      output.delete(:free_units_per_events)
+      output.delete(:free_units_per_total_aggregation)
 
       output
     end
diff --git a/app/graphql/types/charges/input.rb b/app/graphql/types/charges/input.rb
index 41407c7eb5b..474e1da3d67 100644
--- a/app/graphql/types/charges/input.rb
+++ b/app/graphql/types/charges/input.rb
@@ -23,6 +23,8 @@ class Input < Types::BaseInputObject
       # NOTE: Percentage charge model
       argument :rate, String, required: false
       argument :fixed_amount, String, required: false
+      argument :free_units_per_events, Integer, required: false
+      argument :free_units_per_total_aggregation, String, required: false
     end
   end
 end
diff --git a/app/graphql/types/charges/object.rb b/app/graphql/types/charges/object.rb
index 192fc7ea2f2..001de65d1a8 100644
--- a/app/graphql/types/charges/object.rb
+++ b/app/graphql/types/charges/object.rb
@@ -26,6 +26,8 @@ class Object < Types::BaseObject
       # NOTE: Percentage charge model
       field :rate, String, null: true
       field :fixed_amount, String, null: true
+      field :free_units_per_events, Integer, null: true
+      field :free_units_per_total_aggregation, String, null: true
 
       def amount
         return unless object.standard? || object.package?
@@ -62,6 +64,18 @@ def fixed_amount
 
         object.properties['fixed_amount']
       end
+
+      def free_units_per_events
+        return unless object.percentage?
+
+        object.properties['free_units_per_events']
+      end
+
+      def free_units_per_total_aggregation
+        return unless object.percentage?
+
+        object.properties['free_units_per_total_aggregation']
+      end
     end
   end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index d1994e9586b..506ed99185c 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -19,6 +19,8 @@ en:
         invalid_package_size: invalid_package_size
         invalid_rate: invalid_rate
         invalid_fixed_amount: invalid_fixed_amount
+        invalid_free_units_per_events: invalid_free_units_per_events
+        invalid_free_units_per_total_aggregation: invalid_free_units_per_total_aggregation
         invalid_content_type: invalid_content_type
         invalid_size: invalid_size
         value_already_exists: value_already_exists
diff --git a/schema.graphql b/schema.graphql
index f416bafe64d..51742c7eb33 100644
--- a/schema.graphql
+++ b/schema.graphql
@@ -136,6 +136,8 @@ type Charge {
   createdAt: ISO8601DateTime!
   fixedAmount: String
   freeUnits: Int
+  freeUnitsPerEvents: Int
+  freeUnitsPerTotalAggregation: String
   graduatedRanges: [GraduatedRange!]
   id: ID!
   packageSize: Int
@@ -150,6 +152,8 @@ input ChargeInput {
   chargeModel: ChargeModelEnum!
   fixedAmount: String
   freeUnits: Int
+  freeUnitsPerEvents: Int
+  freeUnitsPerTotalAggregation: String
   graduatedRanges: [GraduatedRangeInput!]
   id: ID
   packageSize: Int
diff --git a/schema.json b/schema.json
index a53440234ec..aabf579877c 100644
--- a/schema.json
+++ b/schema.json
@@ -1336,6 +1336,34 @@
 
               ]
             },
+            {
+              "name": "freeUnitsPerEvents",
+              "description": null,
+              "type": {
+                "kind": "SCALAR",
+                "name": "Int",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null,
+              "args": [
+
+              ]
+            },
+            {
+              "name": "freeUnitsPerTotalAggregation",
+              "description": null,
+              "type": {
+                "kind": "SCALAR",
+                "name": "String",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null,
+              "args": [
+
+              ]
+            },
             {
               "name": "graduatedRanges",
               "description": null,
@@ -1573,6 +1601,30 @@
               "defaultValue": null,
               "isDeprecated": false,
               "deprecationReason": null
+            },
+            {
+              "name": "freeUnitsPerEvents",
+              "description": null,
+              "type": {
+                "kind": "SCALAR",
+                "name": "Int",
+                "ofType": null
+              },
+              "defaultValue": null,
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "freeUnitsPerTotalAggregation",
+              "description": null,
+              "type": {
+                "kind": "SCALAR",
+                "name": "String",
+                "ofType": null
+              },
+              "defaultValue": null,
+              "isDeprecated": false,
+              "deprecationReason": null
             }
           ],
           "enumValues": null
diff --git a/spec/factories/charge_factory.rb b/spec/factories/charge_factory.rb
index b41bc07e0dd..e2d214d21fb 100644
--- a/spec/factories/charge_factory.rb
+++ b/spec/factories/charge_factory.rb
@@ -35,7 +35,7 @@
       properties do
         {
           rate: '0.0555',
-          fixed_amount: '2',
+          fixed_amount: '2'
         }
       end
     end
diff --git a/spec/graphql/mutations/plans/create_spec.rb b/spec/graphql/mutations/plans/create_spec.rb
index 89325c12586..3beed374d68 100644
--- a/spec/graphql/mutations/plans/create_spec.rb
+++ b/spec/graphql/mutations/plans/create_spec.rb
@@ -64,6 +64,8 @@
               chargeModel: 'percentage',
               rate: '0.25',
               fixedAmount: '2',
+              freeUnitsPerEvents: 5,
+              freeUnitsPerTotalAggregation: '50',
             },
             {
               billableMetricId: billable_metrics.last.id,
diff --git a/spec/graphql/mutations/plans/update_spec.rb b/spec/graphql/mutations/plans/update_spec.rb
index a1b99eb3353..78050b60586 100644
--- a/spec/graphql/mutations/plans/update_spec.rb
+++ b/spec/graphql/mutations/plans/update_spec.rb
@@ -65,6 +65,8 @@
               chargeModel: 'percentage',
               rate: '0.25',
               fixedAmount: '2',
+              freeUnitsPerEvents: 5,
+              freeUnitsPerTotalAggregation: '50',
             },
             {
               billableMetricId: billable_metrics.last.id,
diff --git a/spec/models/charge_spec.rb b/spec/models/charge_spec.rb
index bd88226a9c4..bce49de5d2c 100644
--- a/spec/models/charge_spec.rb
+++ b/spec/models/charge_spec.rb
@@ -172,6 +172,8 @@
         message: [
           :invalid_rate,
           :invalid_fixed_amount,
+          :invalid_free_units_per_events,
+          :invalid_free_units_per_total_aggregation,
         ],
       )
     end
@@ -187,6 +189,8 @@
         expect(charge.errors.messages.keys).to include(:properties)
         expect(charge.errors.messages[:properties]).to include('invalid_rate')
         expect(charge.errors.messages[:properties]).to include('invalid_fixed_amount')
+        expect(charge.errors.messages[:properties]).to include('invalid_free_units_per_events')
+        expect(charge.errors.messages[:properties]).to include('invalid_free_units_per_total_aggregation')
 
         expect(Charges::Validators::PercentageService).to have_received(:new)
           .with(charge: charge)

From 5fdbffe7bac1a6c2b6232b8f525c19e96f0cf379 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Thu, 18 Aug 2022 11:22:25 +0200
Subject: [PATCH 5/8] feat(free-units): Calculate percentage based on fixed
 amount and free units

---
 .../charges/charge_models/base_service.rb     | 15 ++--
 .../charge_models/graduated_service.rb        | 12 ++--
 .../charges/charge_models/package_service.rb  |  4 +-
 .../charge_models/percentage_service.rb       | 42 ++++++++---
 .../charges/charge_models/standard_service.rb |  4 +-
 app/services/fees/charge_service.rb           | 10 +--
 .../charge_models/graduated_service_spec.rb   | 58 ++++++++++++----
 .../charge_models/package_service_spec.rb     | 17 +++--
 .../charge_models/percentage_service_spec.rb  | 69 +++++++++++--------
 .../charge_models/standard_service_spec.rb    | 15 +++-
 10 files changed, 170 insertions(+), 76 deletions(-)

diff --git a/app/services/charges/charge_models/base_service.rb b/app/services/charges/charge_models/base_service.rb
index 0f44f749581..6861ddc9694 100644
--- a/app/services/charges/charge_models/base_service.rb
+++ b/app/services/charges/charge_models/base_service.rb
@@ -3,20 +3,25 @@
 module Charges
   module ChargeModels
     class BaseService < ::BaseService
-      def initialize(charge:)
+      def self.apply(...)
+        new(...).apply
+      end
+
+      def initialize(charge:, aggregation_result:)
         super(nil)
         @charge = charge
+        @aggregation_result = aggregation_result
       end
 
-      def apply(value:)
-        result.units = value
-        result.amount = compute_amount(value)
+      def apply
+        result.units = aggregation_result.aggregation
+        result.amount = compute_amount
         result
       end
 
       protected
 
-      attr_accessor :charge
+      attr_accessor :charge, :aggregation_result
 
       def compute_amount(value)
         raise NotImplementedError
diff --git a/app/services/charges/charge_models/graduated_service.rb b/app/services/charges/charge_models/graduated_service.rb
index f06299af833..c8420166a12 100644
--- a/app/services/charges/charge_models/graduated_service.rb
+++ b/app/services/charges/charge_models/graduated_service.rb
@@ -9,7 +9,7 @@ def ranges
         charge.properties.map(&:with_indifferent_access)
       end
 
-      def compute_amount(value)
+      def compute_amount
         ranges.reduce(0) do |result_amount, range|
           flat_amount = BigDecimal(range[:flat_amount])
           per_unit_amount = BigDecimal(range[:per_unit_amount])
@@ -17,10 +17,10 @@ def compute_amount(value)
           # NOTE: Add flat amount to the total
           result_amount += flat_amount unless value.zero?
 
-          units = compute_range_units(range[:from_value], range[:to_value], value)
+          units = compute_range_units(range[:from_value], range[:to_value])
           result_amount += units * per_unit_amount
 
-          # NOTE: value is between the bounds of the current range,
+          # NOTE: aggregation_result.aggregation is between the bounds of the current range,
           #       we must stop the loop
           break result_amount if range[:to_value].nil? || range[:to_value] >= value
 
@@ -29,7 +29,7 @@ def compute_amount(value)
       end
 
       # NOTE: compute how many units to bill in the range
-      def compute_range_units(from_value, to_value, value)
+      def compute_range_units(from_value, to_value)
         # NOTE: value is higher than the to_value of the range
         if to_value && value >= to_value
           return to_value - (from_value.zero? ? 1 : from_value) + 1
@@ -41,6 +41,10 @@ def compute_range_units(from_value, to_value, value)
         # NOTE: value is in the range
         value - from_value + 1
       end
+
+      def value
+        aggregation_result.aggregation
+      end
     end
   end
 end
diff --git a/app/services/charges/charge_models/package_service.rb b/app/services/charges/charge_models/package_service.rb
index c1edc94b512..003f8ddf9bc 100644
--- a/app/services/charges/charge_models/package_service.rb
+++ b/app/services/charges/charge_models/package_service.rb
@@ -5,9 +5,9 @@ module ChargeModels
     class PackageService < Charges::ChargeModels::BaseService
       protected
 
-      def compute_amount(value)
+      def compute_amount
         # NOTE: exclude free units from the count
-        billed_units = value - free_units
+        billed_units = aggregation_result.aggregation - free_units
         return 0 if billed_units.negative?
 
         # NOTE: Check how many packages (groups of units) are consumed
diff --git a/app/services/charges/charge_models/percentage_service.rb b/app/services/charges/charge_models/percentage_service.rb
index 8f336df5b0b..2f7c617b2b2 100644
--- a/app/services/charges/charge_models/percentage_service.rb
+++ b/app/services/charges/charge_models/percentage_service.rb
@@ -5,22 +5,48 @@ module ChargeModels
     class PercentageService < Charges::ChargeModels::BaseService
       protected
 
-      def compute_amount(value)
-        compute_percentage_amount(value) + compute_fixed_amount(value)
+      def compute_amount
+        compute_percentage_amount + compute_fixed_amount
       end
 
-      def compute_percentage_amount(value)
-        value * (rate.fdiv(100))
+      def compute_percentage_amount
+        return 0 if free_units_value > aggregation_result.aggregation
+
+        (aggregation_result.aggregation - free_units_value) * rate.fdiv(100)
       end
 
-      def compute_fixed_amount(value)
-        return 0 if value.zero?
+      def compute_fixed_amount
+        return 0 if aggregation_result.aggregation.zero?
         return 0 if fixed_amount.nil?
 
-        value * fixed_amount
+        (aggregation_result.count - free_units_count) * fixed_amount
+      end
+
+      def free_units_value
+        return last_running_total unless last_running_total > free_units_per_total_aggregation
+
+        free_units_per_total_aggregation.to_i
+      end
+
+      def free_units_count
+        return free_units_per_events unless last_running_total > free_units_per_total_aggregation
+
+        aggregation_result.options[:running_total].count { |e| e < free_units_per_total_aggregation }
+      end
+
+      def last_running_total
+        @last_running_total ||= aggregation_result.options[:running_total].last
+      end
+
+      def free_units_per_total_aggregation
+        @free_units_per_total_aggregation ||= BigDecimal(charge.properties['free_units_per_total_aggregation'] || 0)
+      end
+
+      def free_units_per_events
+        @free_units_per_events ||= charge.properties['free_units_per_events'].to_i
       end
 
-      # NOTE: FE divides percentage rate with 100 and sends to BE
+      # NOTE: FE divides percentage rate with 100 and sends to BE.
       def rate
         BigDecimal(charge.properties['rate'])
       end
diff --git a/app/services/charges/charge_models/standard_service.rb b/app/services/charges/charge_models/standard_service.rb
index 35b25907264..de6340e1a79 100644
--- a/app/services/charges/charge_models/standard_service.rb
+++ b/app/services/charges/charge_models/standard_service.rb
@@ -5,8 +5,8 @@ module ChargeModels
     class StandardService < Charges::ChargeModels::BaseService
       protected
 
-      def compute_amount(value)
-        (value * BigDecimal(charge.properties['amount']))
+      def compute_amount
+        (aggregation_result.aggregation * BigDecimal(charge.properties['amount']))
       end
     end
   end
diff --git a/app/services/fees/charge_service.rb b/app/services/fees/charge_service.rb
index 562fa97efa1..8b8e5c29300 100644
--- a/app/services/fees/charge_service.rb
+++ b/app/services/fees/charge_service.rb
@@ -61,14 +61,14 @@ def init_fee
     end
 
     def compute_amount
-      aggregated_events = aggregator.aggregate(
+      aggregation_result = aggregator.aggregate(
         from_date: charges_from_date,
         to_date: boundaries.to_date,
         free_units_count: charge.properties.is_a?(Hash) ? charge.properties['free_units_per_events'].to_i : 0,
       )
-      return aggregated_events unless aggregated_events.success?
+      return aggregation_result unless aggregation_result.success?
 
-      charge_model.apply(value: aggregated_events.aggregation)
+      apply_charge_model_service(aggregation_result)
     end
 
     def already_billed?
@@ -98,7 +98,7 @@ def aggregator
       @aggregator = aggregator_service.new(billable_metric: billable_metric, subscription: subscription)
     end
 
-    def charge_model
+    def apply_charge_model_service(aggregation_result)
       return @charge_model if @charge_model
 
       model_service = case charge.charge_model.to_sym
@@ -114,7 +114,7 @@ def charge_model
                         raise NotImplementedError
       end
 
-      @charge_model = model_service.new(charge: charge)
+      @charge_model = model_service.apply(charge: charge, aggregation_result: aggregation_result)
     end
 
     def charges_from_date
diff --git a/spec/services/charges/charge_models/graduated_service_spec.rb b/spec/services/charges/charge_models/graduated_service_spec.rb
index 48d2a393801..61f74d27236 100644
--- a/spec/services/charges/charge_models/graduated_service_spec.rb
+++ b/spec/services/charges/charge_models/graduated_service_spec.rb
@@ -3,7 +3,15 @@
 require 'rails_helper'
 
 RSpec.describe Charges::ChargeModels::GraduatedService, type: :service do
-  subject(:graduated_service) { described_class.new(charge: charge) }
+  subject(:apply_graduated_service) do
+    described_class.apply(charge: charge, aggregation_result: aggregation_result)
+  end
+
+  before do
+    aggregation_result.aggregation = aggregation
+  end
+
+  let(:aggregation_result) { BaseService::Result.new }
 
   let(:charge) do
     create(
@@ -31,27 +39,51 @@
     )
   end
 
-  it 'does not apply the flat amount for 0' do
-    expect(graduated_service.apply(value: 0).amount).to eq(0)
+  context 'when aggregation is 0' do
+    let(:aggregation) { 0 }
+
+    it 'does not apply the flat amount' do
+      expect(apply_graduated_service.amount).to eq(0)
+    end
   end
 
-  it 'applies a unit amount for 1 and the flat rate for 1' do
-    expect(graduated_service.apply(value: 1).amount).to eq(12)
+  context 'when aggregation is 1' do
+    let(:aggregation) { 1 }
+
+    it 'applies a unit amount for 1 and the flat rate for 1' do
+      expect(apply_graduated_service.amount).to eq(12)
+    end
   end
 
-  it 'applies all unit amount for top bound' do
-    expect(graduated_service.apply(value: 10).amount).to eq(102)
+  context 'when aggregation is 10' do
+    let(:aggregation) { 10 }
+
+    it 'applies all unit amount for top bound' do
+      expect(apply_graduated_service.amount).to eq(102)
+    end
   end
 
-  it 'applies next range flat amount for the next step' do
-    expect(graduated_service.apply(value: 11).amount).to eq(110)
+  context 'when aggregation is 11' do
+    let(:aggregation) { 11 }
+
+    it 'applies next range flat amount for the next step' do
+      expect(apply_graduated_service.amount).to eq(110)
+    end
   end
 
-  it 'applies next unit amount for more unit in next step' do
-    expect(graduated_service.apply(value: 12).amount).to eq(115)
+  context 'when aggregation is 12' do
+    let(:aggregation) { 12 }
+
+    it 'applies next unit amount for more unit in next step' do
+      expect(apply_graduated_service.amount).to eq(115)
+    end
   end
 
-  it 'applies last unit amount for more unit in last step' do
-    expect(graduated_service.apply(value: 21).amount).to eq(163)
+  context 'when aggregation is 21' do
+    let(:aggregation) { 21 }
+
+    it 'applies last unit amount for more unit in last step' do
+      expect(apply_graduated_service.amount).to eq(163)
+    end
   end
 end
diff --git a/spec/services/charges/charge_models/package_service_spec.rb b/spec/services/charges/charge_models/package_service_spec.rb
index a1775abb57b..37a7d704c75 100644
--- a/spec/services/charges/charge_models/package_service_spec.rb
+++ b/spec/services/charges/charge_models/package_service_spec.rb
@@ -3,7 +3,16 @@
 require 'rails_helper'
 
 RSpec.describe Charges::ChargeModels::PackageService, type: :service do
-  subject(:package_service) { described_class.new(charge: charge) }
+  subject(:apply_package_service) do
+    described_class.apply(charge: charge, aggregation_result: aggregation_result)
+  end
+
+  before do
+    aggregation_result.aggregation = aggregation
+  end
+
+  let(:aggregation_result) { BaseService::Result.new }
+  let(:aggregation) { 121 }
 
   let(:charge) do
     create(
@@ -17,20 +26,20 @@
   end
 
   it 'applies the package size to the value' do
-    expect(package_service.apply(value: 121).amount).to eq(1300)
+    expect(apply_package_service.amount).to eq(1300)
   end
 
   context 'with free_units' do
     before { charge.properties['free_units'] = 10 }
 
     it 'substracts the free units from the value' do
-      expect(package_service.apply(value: 121).amount).to eq(1200)
+      expect(apply_package_service.amount).to eq(1200)
     end
 
     context 'when free units is higher than the value' do
       before { charge.properties['free_units'] = 200 }
 
-      it { expect(package_service.apply(value: 121).amount).to eq(0) }
+      it { expect(apply_package_service.amount).to eq(0) }
     end
   end
 end
diff --git a/spec/services/charges/charge_models/percentage_service_spec.rb b/spec/services/charges/charge_models/percentage_service_spec.rb
index f18e7e35f6e..c154a85e26d 100644
--- a/spec/services/charges/charge_models/percentage_service_spec.rb
+++ b/spec/services/charges/charge_models/percentage_service_spec.rb
@@ -3,53 +3,62 @@
 require 'rails_helper'
 
 RSpec.describe Charges::ChargeModels::PercentageService, type: :service do
-  subject(:percentage_service) { described_class.new(charge: charge) }
+  subject(:apply_percentage_service) do
+    described_class.apply(charge: charge, aggregation_result: aggregation_result)
+  end
+
+  before do
+    aggregation_result.aggregation = aggregation
+    aggregation_result.count = 4
+    aggregation_result.options = { running_total: [50, 150, 400] }
+  end
+
+  let(:aggregation_result) { BaseService::Result.new }
+  let(:fixed_amount) { '2.0' }
+  let(:aggregation) { 800 }
+  let(:free_units_per_events) { 3 }
+  let(:free_units_per_total_aggregation) { '250.0' }
+
+  let(:expected_percentage_amount) { (800 - 250) * (1.3 / 100) }
+  let(:expected_fixed_amount) { (4 - 2) * 2.0 }
 
   let(:charge) do
     create(
       :percentage_charge,
       properties: {
-        rate: '5.55',
-        fixed_amount: '0',
+        rate: '1.3',
+        fixed_amount: fixed_amount,
+        free_units_per_events: free_units_per_events,
+        free_units_per_total_aggregation: free_units_per_total_aggregation,
       },
     )
   end
 
-  context 'when fixed amount value is zero' do
-    it 'applies the percentage rate to the value' do
-      expect(percentage_service.apply(value: 100).amount).to eq(5.55)
+  context 'when aggregation value is 0' do
+    let(:aggregation) { 0 }
+
+    it 'returns 0' do
+      expect(apply_percentage_service.amount).to eq(0)
     end
   end
 
-  context 'when fixed amount value is nil and fixed amount target is nil' do
-    let(:charge) do
-      create(
-        :percentage_charge,
-        properties: {
-          rate: '5.55',
-          fixed_amount: nil,
-        },
+  context 'when fixed amount value is 0' do
+    it 'returns expected percentage amount' do
+      expect(apply_percentage_service.amount).to eq(
+        (expected_percentage_amount + expected_fixed_amount)
       )
     end
-
-    it 'applies the percentage rate to the value' do
-      expect(percentage_service.apply(value: 100).amount).to eq(5.55)
-    end
   end
 
-  context 'when fixed amount value is NOT zero' do
-    let(:charge) do
-      create(
-        :percentage_charge,
-        properties: {
-          rate: '5.55',
-          fixed_amount: '2',
-        },
-      )
-    end
+  context 'when free_units_per_total_aggregation > last running total' do
+    let(:free_units_per_total_aggregation) { '500.0' }
+    let(:expected_percentage_amount) { (800 - 400) * (1.3 / 100) }
+    let(:expected_fixed_amount) { (4 - 3) * 2.0 }
 
-    it 'applies the percentage rate and the additional charge on each unit' do
-      expect(percentage_service.apply(value: 100).amount).to eq(205.55)
+    it 'returns expected percentage amount based on last running total' do
+      expect(apply_percentage_service.amount).to eq(
+        (expected_percentage_amount + expected_fixed_amount)
+      )
     end
   end
 end
diff --git a/spec/services/charges/charge_models/standard_service_spec.rb b/spec/services/charges/charge_models/standard_service_spec.rb
index b681ed3a844..d7f9667010d 100644
--- a/spec/services/charges/charge_models/standard_service_spec.rb
+++ b/spec/services/charges/charge_models/standard_service_spec.rb
@@ -3,7 +3,16 @@
 require 'rails_helper'
 
 RSpec.describe Charges::ChargeModels::StandardService, type: :service do
-  subject(:standard_service) { described_class.new(charge: charge) }
+  subject(:apply_standard_service) do
+    described_class.apply(charge: charge, aggregation_result: aggregation_result)
+  end
+
+  before do
+    aggregation_result.aggregation = aggregation
+  end
+
+  let(:aggregation_result) { BaseService::Result.new }
+  let(:aggregation) { 10 }
 
   let(:charge) do
     create(
@@ -15,7 +24,7 @@
     )
   end
 
-  it 'apply the charge model to the value' do
-    expect(standard_service.apply(value: 10).amount).to eq(5000)
+  it 'applies the charge model to the value' do
+    expect(apply_standard_service.amount).to eq(5000)
   end
 end

From 38d6d7a53811f580b3f01080ee12fab32729abda Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Fri, 19 Aug 2022 11:02:02 +0200
Subject: [PATCH 6/8] feat(free-units): Use delegation for
 aggregation_result.aggregation

---
 .../charges/charge_models/base_service.rb     |  2 ++
 .../charge_models/graduated_service.rb        | 24 ++++++++-----------
 .../charges/charge_models/package_service.rb  |  2 +-
 .../charge_models/percentage_service.rb       |  6 ++---
 .../charges/charge_models/standard_service.rb |  2 +-
 5 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/app/services/charges/charge_models/base_service.rb b/app/services/charges/charge_models/base_service.rb
index 6861ddc9694..7fcfd91fb04 100644
--- a/app/services/charges/charge_models/base_service.rb
+++ b/app/services/charges/charge_models/base_service.rb
@@ -23,6 +23,8 @@ def apply
 
       attr_accessor :charge, :aggregation_result
 
+      delegate :units, to: :result
+
       def compute_amount(value)
         raise NotImplementedError
       end
diff --git a/app/services/charges/charge_models/graduated_service.rb b/app/services/charges/charge_models/graduated_service.rb
index c8420166a12..75ffe51cce0 100644
--- a/app/services/charges/charge_models/graduated_service.rb
+++ b/app/services/charges/charge_models/graduated_service.rb
@@ -15,14 +15,14 @@ def compute_amount
           per_unit_amount = BigDecimal(range[:per_unit_amount])
 
           # NOTE: Add flat amount to the total
-          result_amount += flat_amount unless value.zero?
+          result_amount += flat_amount unless units.zero?
 
-          units = compute_range_units(range[:from_value], range[:to_value])
-          result_amount += units * per_unit_amount
+          range_units = compute_range_units(range[:from_value], range[:to_value])
+          result_amount += range_units * per_unit_amount
 
           # NOTE: aggregation_result.aggregation is between the bounds of the current range,
           #       we must stop the loop
-          break result_amount if range[:to_value].nil? || range[:to_value] >= value
+          break result_amount if range[:to_value].nil? || range[:to_value] >= units
 
           result_amount
         end
@@ -30,20 +30,16 @@ def compute_amount
 
       # NOTE: compute how many units to bill in the range
       def compute_range_units(from_value, to_value)
-        # NOTE: value is higher than the to_value of the range
-        if to_value && value >= to_value
+        # NOTE: units is higher than the to_value of the range
+        if to_value && units >= to_value
           return to_value - (from_value.zero? ? 1 : from_value) + 1
         end
 
-        return to_value - from_value if to_value && value >= to_value
-        return value if from_value.zero?
+        return to_value - from_value if to_value && units >= to_value
+        return units if from_value.zero?
 
-        # NOTE: value is in the range
-        value - from_value + 1
-      end
-
-      def value
-        aggregation_result.aggregation
+        # NOTE: units is in the range
+        units - from_value + 1
       end
     end
   end
diff --git a/app/services/charges/charge_models/package_service.rb b/app/services/charges/charge_models/package_service.rb
index 003f8ddf9bc..1eb3209774c 100644
--- a/app/services/charges/charge_models/package_service.rb
+++ b/app/services/charges/charge_models/package_service.rb
@@ -7,7 +7,7 @@ class PackageService < Charges::ChargeModels::BaseService
 
       def compute_amount
         # NOTE: exclude free units from the count
-        billed_units = aggregation_result.aggregation - free_units
+        billed_units = units - free_units
         return 0 if billed_units.negative?
 
         # NOTE: Check how many packages (groups of units) are consumed
diff --git a/app/services/charges/charge_models/percentage_service.rb b/app/services/charges/charge_models/percentage_service.rb
index 2f7c617b2b2..6b0f8ebe104 100644
--- a/app/services/charges/charge_models/percentage_service.rb
+++ b/app/services/charges/charge_models/percentage_service.rb
@@ -10,13 +10,13 @@ def compute_amount
       end
 
       def compute_percentage_amount
-        return 0 if free_units_value > aggregation_result.aggregation
+        return 0 if free_units_value > units
 
-        (aggregation_result.aggregation - free_units_value) * rate.fdiv(100)
+        (units - free_units_value) * rate.fdiv(100)
       end
 
       def compute_fixed_amount
-        return 0 if aggregation_result.aggregation.zero?
+        return 0 if units.zero?
         return 0 if fixed_amount.nil?
 
         (aggregation_result.count - free_units_count) * fixed_amount
diff --git a/app/services/charges/charge_models/standard_service.rb b/app/services/charges/charge_models/standard_service.rb
index de6340e1a79..b88f91131e0 100644
--- a/app/services/charges/charge_models/standard_service.rb
+++ b/app/services/charges/charge_models/standard_service.rb
@@ -6,7 +6,7 @@ class StandardService < Charges::ChargeModels::BaseService
       protected
 
       def compute_amount
-        (aggregation_result.aggregation * BigDecimal(charge.properties['amount']))
+        (units * BigDecimal(charge.properties['amount']))
       end
     end
   end

From 47c53ed5f59ee5ef8012acd08fd91b998287950c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Thu, 18 Aug 2022 16:37:42 +0200
Subject: [PATCH 7/8] feat(free-units): Add events_count on Fee and update
 invoice

---
 app/models/fee.rb                                     | 1 +
 app/serializers/v1/fee_serializer.rb                  | 1 +
 app/services/charges/charge_models/base_service.rb    | 1 +
 app/services/fees/charge_service.rb                   | 3 ++-
 app/views/templates/invoice.slim                      | 5 ++++-
 db/migrate/20220818141616_add_events_count_to_fees.rb | 7 +++++++
 db/schema.rb                                          | 3 ++-
 spec/services/fees/add_on_service_spec.rb             | 1 +
 spec/services/fees/charge_service_spec.rb             | 1 +
 spec/services/fees/subscription_service_spec.rb       | 1 +
 10 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 db/migrate/20220818141616_add_events_count_to_fees.rb

diff --git a/app/models/fee.rb b/app/models/fee.rb
index c29440d4048..595416b7b3b 100644
--- a/app/models/fee.rb
+++ b/app/models/fee.rb
@@ -19,6 +19,7 @@ class Fee < ApplicationRecord
   validates :amount_currency, inclusion: { in: currency_list }
   validates :vat_amount_currency, inclusion: { in: currency_list }
   validates :units, numericality: { greated_than_or_equal_to: 0 }
+  validates :events_count, numericality: { greated_than_or_equal_to: 0 }, allow_nil: true
 
   scope :subscription_kind, -> { where(charge_id: nil, applied_add_on_id: nil) }
   scope :charge_kind, -> { where.not(charge_id: nil) }
diff --git a/app/serializers/v1/fee_serializer.rb b/app/serializers/v1/fee_serializer.rb
index 69278299b65..a358a09709f 100644
--- a/app/serializers/v1/fee_serializer.rb
+++ b/app/serializers/v1/fee_serializer.rb
@@ -14,6 +14,7 @@ def serialize
         vat_amount_cents: model.vat_amount_cents,
         vat_amount_currency: model.vat_amount_currency,
         units: model.units,
+        events_count: model.events_count,
       }
     end
   end
diff --git a/app/services/charges/charge_models/base_service.rb b/app/services/charges/charge_models/base_service.rb
index 7fcfd91fb04..0895cad6c22 100644
--- a/app/services/charges/charge_models/base_service.rb
+++ b/app/services/charges/charge_models/base_service.rb
@@ -15,6 +15,7 @@ def initialize(charge:, aggregation_result:)
 
       def apply
         result.units = aggregation_result.aggregation
+        result.count = aggregation_result.count
         result.amount = compute_amount
         result
       end
diff --git a/app/services/fees/charge_service.rb b/app/services/fees/charge_service.rb
index 8b8e5c29300..8a71258a8ef 100644
--- a/app/services/fees/charge_service.rb
+++ b/app/services/fees/charge_service.rb
@@ -52,7 +52,8 @@ def init_fee
         amount_currency: charge.amount_currency,
         vat_rate: customer.applicable_vat_rate,
         units: amount_result.units,
-        properties: boundaries.to_h
+        properties: boundaries.to_h,
+        events_count: amount_result.count,
       )
 
       new_fee.compute_vat
diff --git a/app/views/templates/invoice.slim b/app/views/templates/invoice.slim
index 538de81f724..2427aac6745 100644
--- a/app/views/templates/invoice.slim
+++ b/app/views/templates/invoice.slim
@@ -315,7 +315,10 @@ html
                   td width="70%"
                     .body-1 = fee.billable_metric.name
                     .body-3
-                      | Total unit: #{fee.units}
+                      - if fee.charge.percentage?
+                        | Total unit: #{fee.events_count} events for #{fee.units}
+                      - else
+                        | Total unit: #{fee.units}
                   td.body-1 width="30%" = fee.amount.format
 
             table.total-table width="100%"
diff --git a/db/migrate/20220818141616_add_events_count_to_fees.rb b/db/migrate/20220818141616_add_events_count_to_fees.rb
new file mode 100644
index 00000000000..c504c8dfe03
--- /dev/null
+++ b/db/migrate/20220818141616_add_events_count_to_fees.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddEventsCountToFees < ActiveRecord::Migration[7.0]
+  def change
+    add_column :fees, :events_count, :integer
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 13c0602c526..4a69627148e 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2022_08_16_120137) do
+ActiveRecord::Schema[7.0].define(version: 2022_08_18_141616) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
   enable_extension "plpgsql"
@@ -194,6 +194,7 @@
     t.decimal "units", default: "0.0", null: false
     t.uuid "applied_add_on_id"
     t.jsonb "properties", default: {}, null: false
+    t.integer "events_count"
     t.index ["applied_add_on_id"], name: "index_fees_on_applied_add_on_id"
     t.index ["charge_id"], name: "index_fees_on_charge_id"
     t.index ["invoice_id"], name: "index_fees_on_invoice_id"
diff --git a/spec/services/fees/add_on_service_spec.rb b/spec/services/fees/add_on_service_spec.rb
index 1a1be6d898d..0552c1aa12b 100644
--- a/spec/services/fees/add_on_service_spec.rb
+++ b/spec/services/fees/add_on_service_spec.rb
@@ -28,6 +28,7 @@
         expect(created_fee.vat_amount_cents).to eq(40)
         expect(created_fee.vat_rate).to eq(20.0)
         expect(created_fee.units).to eq(1)
+        expect(created_fee.events_count).to be_nil
       end
     end
 
diff --git a/spec/services/fees/charge_service_spec.rb b/spec/services/fees/charge_service_spec.rb
index d0aedd70123..54816099a13 100644
--- a/spec/services/fees/charge_service_spec.rb
+++ b/spec/services/fees/charge_service_spec.rb
@@ -57,6 +57,7 @@
         expect(created_fee.vat_amount_cents).to eq(0)
         expect(created_fee.vat_rate).to eq(20.0)
         expect(created_fee.units).to eq(0)
+        expect(created_fee.events_count).to be_nil
       end
     end
 
diff --git a/spec/services/fees/subscription_service_spec.rb b/spec/services/fees/subscription_service_spec.rb
index 58ca0ba2b65..6404ab379b6 100644
--- a/spec/services/fees/subscription_service_spec.rb
+++ b/spec/services/fees/subscription_service_spec.rb
@@ -41,6 +41,7 @@
         expect(created_fee.vat_amount_cents).to eq(20)
         expect(created_fee.vat_rate).to eq(20.0)
         expect(created_fee.units).to eq(1)
+        expect(created_fee.events_count).to be_nil
       end
     end
 

From dfea40c3ff2d76f5a834a3e8f135bd0b532b1647 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Romain=20Semp=C3=A9?= <romain@getlago.com>
Date: Fri, 19 Aug 2022 15:08:36 +0200
Subject: [PATCH 8/8] feat(free-units): Calculate percentage without free units

---
 .../charge_models/percentage_service.rb       |  7 ++-
 .../charge_models/percentage_service_spec.rb  | 44 ++++++++++++++++++-
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/app/services/charges/charge_models/percentage_service.rb b/app/services/charges/charge_models/percentage_service.rb
index 6b0f8ebe104..fc2e1898788 100644
--- a/app/services/charges/charge_models/percentage_service.rb
+++ b/app/services/charges/charge_models/percentage_service.rb
@@ -23,19 +23,22 @@ def compute_fixed_amount
       end
 
       def free_units_value
+        return last_running_total if free_units_per_total_aggregation.zero?
+        return free_units_per_total_aggregation if last_running_total.zero?
         return last_running_total unless last_running_total > free_units_per_total_aggregation
 
-        free_units_per_total_aggregation.to_i
+        free_units_per_total_aggregation
       end
 
       def free_units_count
+        return free_units_per_events if free_units_per_total_aggregation.zero?
         return free_units_per_events unless last_running_total > free_units_per_total_aggregation
 
         aggregation_result.options[:running_total].count { |e| e < free_units_per_total_aggregation }
       end
 
       def last_running_total
-        @last_running_total ||= aggregation_result.options[:running_total].last
+        @last_running_total ||= aggregation_result.options[:running_total].last || 0
       end
 
       def free_units_per_total_aggregation
diff --git a/spec/services/charges/charge_models/percentage_service_spec.rb b/spec/services/charges/charge_models/percentage_service_spec.rb
index c154a85e26d..1215eb68034 100644
--- a/spec/services/charges/charge_models/percentage_service_spec.rb
+++ b/spec/services/charges/charge_models/percentage_service_spec.rb
@@ -10,9 +10,10 @@
   before do
     aggregation_result.aggregation = aggregation
     aggregation_result.count = 4
-    aggregation_result.options = { running_total: [50, 150, 400] }
+    aggregation_result.options = { running_total: running_total }
   end
 
+  let(:running_total) { [50, 150, 400] }
   let(:aggregation_result) { BaseService::Result.new }
   let(:fixed_amount) { '2.0' }
   let(:aggregation) { 800 }
@@ -50,6 +51,47 @@
     end
   end
 
+  context 'when free_units_per_events is nil' do
+    let(:free_units_per_events) { nil }
+    let(:running_total) { [] }
+
+    let(:expected_percentage_amount) { (800 - 250) * (1.3 / 100) }
+    let(:expected_fixed_amount) { (4 - 0) * 2.0 }
+
+    it 'returns expected percentage amount' do
+      expect(apply_percentage_service.amount).to eq(
+        (expected_percentage_amount + expected_fixed_amount)
+      )
+    end
+  end
+
+  context 'when free_units_per_total_aggregation is nil' do
+    let(:free_units_per_total_aggregation) { nil }
+    let(:expected_percentage_amount) { (800 - 400) * (1.3 / 100) }
+    let(:expected_fixed_amount) { (4 - 3) * 2.0 }
+
+    it 'returns expected percentage amount' do
+      expect(apply_percentage_service.amount).to eq(
+        (expected_percentage_amount + expected_fixed_amount)
+      )
+    end
+  end
+
+  context 'when free units are not set' do
+    let(:free_units_per_total_aggregation) { nil }
+    let(:free_units_per_events) { nil }
+    let(:running_total) { [] }
+
+    let(:expected_percentage_amount) { 800 * (1.3 / 100) }
+    let(:expected_fixed_amount) { 4 * 2.0 }
+
+    it 'returns expected percentage amount' do
+      expect(apply_percentage_service.amount).to eq(
+        (expected_percentage_amount + expected_fixed_amount)
+      )
+    end
+  end
+
   context 'when free_units_per_total_aggregation > last running total' do
     let(:free_units_per_total_aggregation) { '500.0' }
     let(:expected_percentage_amount) { (800 - 400) * (1.3 / 100) }