CLDC-961: Model data versioning (#277)

* Replace Discard with Paper Trail

* Track who created or changed records via UI

* Track model updates by AdminUsers

Gemfile

@@ -23,8 +23,6 @@ gem "govuk_design_system_formbuilder"
 gem "notifications-ruby-client"
 # Turbo and Stimulus
 gem "hotwire-rails"
-# Soft delete ActiveRecords objects
-gem "discard"
 # Administration framework
 gem "activeadmin", git: "https://github.com/tagliala/activeadmin.git", branch: "feature/railties-7"
 # Admin charts
@@ -47,6 +45,10 @@ gem "postcodes_io"
 gem "view_component"
 # Use the AWS S3 SDK as storage mechanism
 gem "aws-sdk-s3"
+# Track changes to models for auditing or versioning.
+gem "paper_trail"
+# Store active record objects in version whodunnits
+gem "paper_trail-globalid"
 
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console

Gemfile.lock

@@ -156,8 +156,6 @@ GEM
     deep_merge (1.2.2)
     diff-lcs (1.5.0)
     digest (3.1.0)
-    discard (1.2.1)
-      activerecord (>= 4.2, < 8)
     docile (1.4.0)
     dotenv (2.7.6)
     dotenv-rails (2.7.6)
@@ -266,6 +264,12 @@ GEM
       childprocess (>= 0.6.3, < 5)
       iniparse (~> 1.4)
       rexml (~> 3.2)
+    paper_trail (12.2.0)
+      activerecord (>= 5.2)
+      request_store (~> 1.1)
+    paper_trail-globalid (0.2.0)
+      globalid
+      paper_trail (>= 3.0.0)
     parallel (1.21.0)
     parser (3.1.0.0)
       ast (~> 2.4.1)
@@ -326,6 +330,8 @@ GEM
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     regexp_parser (2.2.0)
+    request_store (1.5.1)
+      rack (>= 1.4)
     responders (3.0.1)
       actionpack (>= 5.0)
       railties (>= 5.0)
@@ -456,7 +462,6 @@ DEPENDENCIES
   capybara-lockstep
   chartkick
   devise!
-  discard
   dotenv-rails
   factory_bot_rails
   govuk-components
@@ -466,6 +471,8 @@ DEPENDENCIES
   listen (~> 3.3)
   notifications-ruby-client
   overcommit (>= 0.37.0)
+  paper_trail
+  paper_trail-globalid
   pg (~> 1.1)
   postcodes_io
   pry-byebug

app/concerns/admin/paper_trail.rb

@@ -0,0 +1,15 @@
+module Admin
+  module PaperTrail
+    extend ActiveSupport::Concern
+
+    included do
+      before_action :set_paper_trail_whodunnit
+    end
+
+  protected
+
+    def user_for_paper_trail
+      current_admin_user
+    end
+  end
+end

app/controllers/application_controller.rb

@@ -1,4 +1,6 @@
 class ApplicationController < ActionController::Base
+  before_action :set_paper_trail_whodunnit
+
   def render_not_found
     render "errors/not_found", status: :not_found
   end
@@ -6,4 +8,10 @@ class ApplicationController < ActionController::Base
   def render_not_found_json(class_name, id)
     render json: { error: "#{class_name} #{id} not found" }, status: :not_found
   end
+
+protected
+
+  def user_for_paper_trail
+    current_user
+  end
 end

app/controllers/case_logs_controller.rb

@@ -60,7 +60,7 @@ class CaseLogsController < ApplicationController
 
   def destroy
     if @case_log
-      if @case_log.discard
+      if @case_log.delete
         head :no_content
       else
         render json: { errors: @case_log.errors.messages }, status: :unprocessable_entity

app/models/admin_user.rb

@@ -6,6 +6,8 @@ class AdminUser < ApplicationRecord
 
   has_one_time_password(encrypted: true)
 
+  has_paper_trail
+
   validates :phone, presence: true, numericality: true
 
   MFA_SMS_TEMPLATE_ID = "bf309d93-804e-4f95-b1f4-bd513c48ecb0".freeze

app/models/case_log.rb

@@ -30,11 +30,11 @@ private
 end
 
 class CaseLog < ApplicationRecord
-  include Discard::Model
   include Validations::SoftValidations
   include Constants::CaseLog
   include Constants::IncomeRanges
-  default_scope -> { kept }
+
+  has_paper_trail
 
   validates_with CaseLogValidator
   before_validation :process_postcode_changes!, if: :property_postcode_changed?

app/models/organisation.rb

@@ -3,7 +3,10 @@ class Organisation < ApplicationRecord
   has_many :owned_case_logs, class_name: "CaseLog", foreign_key: "owning_organisation_id"
   has_many :managed_case_logs, class_name: "CaseLog", foreign_key: "managing_organisation_id"
 
+  has_paper_trail
+
   include Constants::Organisation
+
   enum provider_type: PROVIDER_TYPE
 
   def case_logs

app/models/user.rb

@@ -10,6 +10,8 @@ class User < ApplicationRecord
   has_many :owned_case_logs, through: :organisation
   has_many :managed_case_logs, through: :organisation
 
+  has_paper_trail
+
   enum role: ROLES
 
   def case_logs

config/initializers/active_admin.rb

@@ -340,3 +340,7 @@ end
 Rails.application.config.after_initialize do
   ActiveAdmin.application.stylesheets.delete("active_admin/print.css")
 end
+
+Rails.application.config.after_initialize do
+  ActiveAdmin::BaseController.include Admin::PaperTrail
+end

db/migrate/20220207151239_create_versions.rb

@@ -0,0 +1,22 @@
+# This migration creates the `versions` table, the only schema PT requires.
+# All other migrations PT provides are optional.
+class CreateVersions < ActiveRecord::Migration[7.0]
+  # The largest text column available in all supported RDBMS is
+  # 1024^3 - 1 bytes, roughly one gibibyte.  We specify a size
+  # so that MySQL will use `longtext` instead of `text`.  Otherwise,
+  # when serializing very large objects, `text` might not be big enough.
+  TEXT_BYTES = 1_073_741_823
+
+  def change
+    create_table :versions do |t|
+      t.string   :item_type, null: false, limit: 191
+      t.bigint   :item_id,   null: false
+      t.string   :event,     null: false
+      t.string   :whodunnit
+      t.text     :object, limit: TEXT_BYTES
+
+      t.datetime :created_at
+    end
+    add_index :versions, %i[item_type item_id]
+  end
+end

db/migrate/20220207151312_remove_discarded_at_from_case_logs.rb

@@ -0,0 +1,11 @@
+class RemoveDiscardedAtFromCaseLogs < ActiveRecord::Migration[7.0]
+  def up
+    remove_index :case_logs, :discarded_at
+    remove_column :case_logs, :discarded_at
+  end
+
+  def down
+    add_column :case_logs, :discarded_at, :datetime
+    add_index :case_logs, :discarded_at
+  end
+end

db/schema.rb

@@ -93,6 +93,7 @@ ActiveRecord::Schema.define(version: 202202071123100) do
     t.integer "beds"
     t.integer "offered"
     t.integer "wchair"
+    t.integer "earnings"
     t.integer "incfreq"
     t.integer "benefits"
     t.integer "period"
@@ -127,7 +128,6 @@ ActiveRecord::Schema.define(version: 202202071123100) do
     t.integer "rp_medwel"
     t.integer "rp_hardship"
     t.integer "rp_dontknow"
-    t.datetime "discarded_at"
     t.string "tenancyother"
     t.integer "override_net_income_validation"
     t.string "property_owner_organisation"
@@ -182,7 +182,6 @@ ActiveRecord::Schema.define(version: 202202071123100) do
     t.integer "is_carehome"
     t.integer "letting_in_sheltered_accomodation"
     t.integer "household_charge"
-    t.integer "earnings"
     t.integer "referral"
     t.decimal "brent", precision: 10, scale: 2
     t.decimal "scharge", precision: 10, scale: 2
@@ -192,7 +191,6 @@ ActiveRecord::Schema.define(version: 202202071123100) do
     t.decimal "tshortfall", precision: 10, scale: 2
     t.decimal "chcharge", precision: 10, scale: 2
     t.integer "declaration"
-    t.index ["discarded_at"], name: "index_case_logs_on_discarded_at"
     t.index ["managing_organisation_id"], name: "index_case_logs_on_managing_organisation_id"
     t.index ["owning_organisation_id"], name: "index_case_logs_on_owning_organisation_id"
   end
@@ -252,4 +250,14 @@ ActiveRecord::Schema.define(version: 202202071123100) do
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
+  create_table "versions", force: :cascade do |t|
+    t.string "item_type", limit: 191, null: false
+    t.bigint "item_id", null: false
+    t.string "event", null: false
+    t.string "whodunnit"
+    t.text "object"
+    t.datetime "created_at", precision: 6
+    t.index ["item_type", "item_id"], name: "index_versions_on_item_type_and_item_id"
+  end
+
 end

spec/controllers/admin/admin_users_controller_spec.rb

@@ -6,8 +6,11 @@ describe Admin::AdminUsersController, type: :controller do
   let(:page) { Capybara::Node::Simple.new(response.body) }
   let(:resource_title) { "Admin Users" }
   let(:valid_session) { {} }
+  let(:signed_in_admin_user) { FactoryBot.create(:admin_user) }
 
-  login_admin_user
+  before do
+    sign_in signed_in_admin_user
+  end
 
   describe "Get admin users" do
     before do
@@ -27,22 +30,30 @@ describe Admin::AdminUsersController, type: :controller do
     it "creates a new admin user" do
       expect { post :create, session: valid_session, params: params }.to change(AdminUser, :count).by(1)
     end
+
+    it "tracks who created the record" do
+      post :create, session: valid_session, params: params
+      created_id = response.location.match(/[0-9]+/)[0]
+      whodunnit_actor = AdminUser.find_by(id: created_id).versions.last.actor
+      expect(whodunnit_actor).to be_a(AdminUser)
+      expect(whodunnit_actor.id).to eq(signed_in_admin_user.id)
+    end
   end
 
   describe "Update admin users" do
-    context "when editing the form" do
+    context "when viewing the form" do
       before do
         get :edit, session: valid_session, params: { id: AdminUser.first.id }
       end
 
-      it "shows an edit form" do
+      it "shows the correct fields" do
         expect(page).to have_field("admin_user_email")
         expect(page).to have_field("admin_user_password")
         expect(page).to have_field("admin_user_password_confirmation")
       end
     end
 
-    context "when updating the form" do
+    context "when updating an admin user" do
       let(:admin_user) { FactoryBot.create(:admin_user) }
       let(:email) { "new_email@example.com" }
       let(:params) { { id: admin_user.id, admin_user: { email: email } } }
@@ -55,6 +66,13 @@ describe Admin::AdminUsersController, type: :controller do
         admin_user.reload
         expect(admin_user.email).to eq(email)
       end
+
+      it "tracks who updated the record" do
+        admin_user.reload
+        whodunnit_actor = admin_user.versions.last.actor
+        expect(whodunnit_actor).to be_a(AdminUser)
+        expect(whodunnit_actor.id).to eq(signed_in_admin_user.id)
+      end
     end
   end
 end

spec/controllers/admin/case_logs_controller_spec.rb

@@ -5,14 +5,14 @@ require_relative "../../request_helper"
 describe Admin::CaseLogsController, type: :controller do
   before do
     RequestHelper.stub_http_requests
+    sign_in admin_user
   end
 
   render_views
   let(:page) { Capybara::Node::Simple.new(response.body) }
   let(:resource_title) { "Logs" }
   let(:valid_session) { {} }
-
+  let(:admin_user) { FactoryBot.create(:admin_user) }
-  login_admin_user
 
   describe "Get case logs" do
     let!(:case_log) { FactoryBot.create(:case_log, :in_progress) }
@@ -44,5 +44,49 @@ describe Admin::CaseLogsController, type: :controller do
     it "creates a new case log" do
       expect { post :create, session: valid_session, params: params }.to change(CaseLog, :count).by(1)
     end
+
+    it "tracks who created the record" do
+      post :create, session: valid_session, params: params
+      created_id = response.location.match(/[0-9]+/)[0]
+      whodunnit_actor = CaseLog.find_by(id: created_id).versions.last.actor
+      expect(whodunnit_actor).to be_a(AdminUser)
+      expect(whodunnit_actor.id).to eq(admin_user.id)
+    end
+  end
+
+  describe "Update case log" do
+    let!(:case_log) { FactoryBot.create(:case_log, :in_progress) }
+
+    context "when viewing the edit form" do
+      before do
+        get :edit, session: valid_session, params: { id: case_log.id }
+      end
+
+      it "has the correct fields" do
+        expect(page).to have_field("case_log_age1")
+        expect(page).to have_field("case_log_tenant_code")
+      end
+    end
+
+    context "when updating the case_log" do
+      let(:tenant_code) { "New tenant code by Admin" }
+      let(:params) { { id: case_log.id, case_log: { tenant_code: tenant_code } } }
+
+      before do
+        patch :update, session: valid_session, params: params
+      end
+
+      it "updates the case log" do
+        case_log.reload
+        expect(case_log.tenant_code).to eq(tenant_code)
+      end
+
+      it "tracks who updated the record" do
+        case_log.reload
+        whodunnit_actor = case_log.versions.last.actor
+        expect(whodunnit_actor).to be_a(AdminUser)
+        expect(whodunnit_actor.id).to eq(admin_user.id)
+      end
+    end
   end
 end

spec/controllers/admin/dashboard_controller_spec.rb

@@ -5,14 +5,14 @@ require_relative "../../request_helper"
 describe Admin::DashboardController, type: :controller do
   before do
     RequestHelper.stub_http_requests
+    sign_in admin_user
   end
 
   render_views
   let(:page) { Capybara::Node::Simple.new(response.body) }
   let(:resource_title) { "Dashboard" }
   let(:valid_session) { {} }
-
+  let(:admin_user) { FactoryBot.create(:admin_user) }
-  login_admin_user
 
   describe "Get case logs" do
     before do

spec/controllers/admin/organisations_controller_spec.rb

@@ -7,8 +7,11 @@ describe Admin::OrganisationsController, type: :controller do
   let(:resource_title) { "Organisations" }
   let(:valid_session) { {} }
   let!(:organisation) { FactoryBot.create(:organisation) }
+  let!(:admin_user) { FactoryBot.create(:admin_user) }
 
-  login_admin_user
+  before do
+    sign_in admin_user
+  end
 
   describe "Organisations" do
     before do
@@ -22,23 +25,54 @@ describe Admin::OrganisationsController, type: :controller do
     end
   end
 
-  describe "Create admin users" do
+  describe "Create organisation" do
     let(:params) { { organisation: { name: "DLUHC" } } }
 
     it "creates a organisation" do
       expect { post :create, session: valid_session, params: params }.to change(Organisation, :count).by(1)
     end
+
+    it "tracks who created the record" do
+      post :create, session: valid_session, params: params
+      created_id = response.location.match(/[0-9]+/)[0]
+      whodunnit_actor = Organisation.find_by(id: created_id).versions.last.actor
+      expect(whodunnit_actor).to be_a(AdminUser)
+      expect(whodunnit_actor.id).to eq(admin_user.id)
+    end
   end
 
   describe "Update organisation" do
+    context "when viewing the edit form" do
       before do
         get :edit, session: valid_session, params: { id: organisation.id }
       end
 
-    it "creates a new admin users" do
+      it "has the correct fields" do
         expect(page).to have_field("organisation_name")
         expect(page).to have_field("organisation_provider_type")
         expect(page).to have_field("organisation_phone")
       end
     end
+
+    context "when updating the organisation" do
+      let(:name) { "New Org Name by Admin" }
+      let(:params) { { id: organisation.id, organisation: { name: name } } }
+
+      before do
+        patch :update, session: valid_session, params: params
+      end
+
+      it "updates the organisation" do
+        organisation.reload
+        expect(organisation.name).to eq(name)
+      end
+
+      it "tracks who updated the record" do
+        organisation.reload
+        whodunnit_actor = organisation.versions.last.actor
+        expect(whodunnit_actor).to be_a(AdminUser)
+        expect(whodunnit_actor.id).to eq(admin_user.id)
+      end
+    end
+  end
 end

spec/controllers/admin/users_controller_spec.rb

@@ -8,8 +8,11 @@ describe Admin::UsersController, type: :controller do
   let(:page) { Capybara::Node::Simple.new(response.body) }
   let(:resource_title) { "Users" }
   let(:valid_session) { {} }
+  let!(:admin_user) { FactoryBot.create(:admin_user) }
 
-  login_admin_user
+  before do
+    sign_in admin_user
+  end
 
   describe "Get users" do
     before do
@@ -39,15 +42,23 @@ describe Admin::UsersController, type: :controller do
     it "creates a new user" do
       expect { post :create, session: valid_session, params: params }.to change(User, :count).by(1)
     end
+
+    it "tracks who created the record" do
+      post :create, session: valid_session, params: params
+      created_id = response.location.match(/[0-9]+/)[0]
+      whodunnit_actor = User.find_by(id: created_id).versions.last.actor
+      expect(whodunnit_actor).to be_a(AdminUser)
+      expect(whodunnit_actor.id).to eq(admin_user.id)
+    end
   end
 
   describe "Update users" do
-    context "when updating the form" do
+    context "when viewing the edit form" do
       before do
         get :edit, session: valid_session, params: { id: user.id }
       end
 
-      it "shows an edit form" do
+      it "has the correct fields" do
         expect(page).to have_field("user_email")
         expect(page).to have_field("user_name")
         expect(page).to have_field("user_organisation_id")
@@ -69,6 +80,13 @@ describe Admin::UsersController, type: :controller do
         user.reload
         expect(user.name).to eq(name)
       end
+
+      it "tracks who updated the record" do
+        user.reload
+        whodunnit_actor = user.versions.last.actor
+        expect(whodunnit_actor).to be_a(AdminUser)
+        expect(whodunnit_actor.id).to eq(admin_user.id)
+      end
     end
   end
 end

spec/factories/case_log.rb

@@ -108,7 +108,6 @@ FactoryBot.define do
       rp_medwel { "No" }
       rp_hardship { "No" }
       rp_dontknow { "No" }
-      discarded_at { nil }
       tenancyother { nil }
       override_net_income_validation { nil }
       net_income_known { "Yes" }

spec/models/admin_user_spec.rb

@@ -20,7 +20,6 @@ RSpec.describe AdminUser, type: :model do
         )
       }.to raise_error(ActiveRecord::RecordInvalid)
     end
-  end
 
     it "requires an email" do
       expect {
@@ -50,3 +49,17 @@ RSpec.describe AdminUser, type: :model do
       }.to change(described_class, :count).by(1)
     end
   end
+
+  describe "paper trail" do
+    let(:admin_user) { FactoryBot.create(:admin_user) }
+
+    it "creates a record of changes to a log" do
+      expect { admin_user.update!(phone: "09673867853") }.to change(admin_user.versions, :count).by(1)
+    end
+
+    it "allows case logs to be restored to a previous version" do
+      admin_user.update!(phone: "09673867853")
+      expect(admin_user.paper_trail.previous_version.phone).to eq("07563867654")
+    end
+  end
+end

spec/models/case_log_spec.rb

@@ -1172,4 +1172,17 @@ RSpec.describe CaseLog do
       end
     end
   end
+
+  describe "paper trail" do
+    let(:case_log) { FactoryBot.create(:case_log, :in_progress) }
+
+    it "creates a record of changes to a log" do
+      expect { case_log.update!(age1: 64) }.to change(case_log.versions, :count).by(1)
+    end
+
+    it "allows case logs to be restored to a previous version" do
+      case_log.update!(age1: 63)
+      expect(case_log.paper_trail.previous_version.age1).to eq(17)
+    end
+  end
 end

spec/models/organisation_spec.rb

@@ -54,4 +54,17 @@ RSpec.describe Organisation, type: :model do
       end
     end
   end
+
+  describe "paper trail" do
+    let(:organisation) { FactoryBot.create(:organisation) }
+
+    it "creates a record of changes to a log" do
+      expect { organisation.update!(name: "new test name") }.to change(organisation.versions, :count).by(1)
+    end
+
+    it "allows case logs to be restored to a previous version" do
+      organisation.update!(name: "new test name")
+      expect(organisation.paper_trail.previous_version.name).to eq("DLUHC")
+    end
+  end
 end

spec/models/user_spec.rb

@@ -52,4 +52,17 @@ RSpec.describe User, type: :model do
       expect(user.data_coordinator?).to be false
     end
   end
+
+  describe "paper trail" do
+    let(:user) { FactoryBot.create(:user) }
+
+    it "creates a record of changes to a log" do
+      expect { user.update!(name: "new test name") }.to change(user.versions, :count).by(1)
+    end
+
+    it "allows case logs to be restored to a previous version" do
+      user.update!(name: "new test name")
+      expect(user.paper_trail.previous_version.name).to eq("Danny Rojas")
+    end
+  end
 end

spec/requests/case_logs_controller_spec.rb

@@ -34,6 +34,7 @@ RSpec.describe CaseLogsController, type: :request do
     let(:in_progress) { "in_progress" }
     let(:completed) { "completed" }
 
+    context "when API" do
       let(:params) do
         {
           "owning_organisation_id": owning_organisation.id,
@@ -116,6 +117,25 @@ RSpec.describe CaseLogsController, type: :request do
       end
     end
 
+    context "when UI" do
+      let(:user) { FactoryBot.create(:user) }
+      let(:headers) { { "Accept" => "text/html" } }
+
+      before do
+        RequestHelper.stub_http_requests
+        sign_in user
+        post "/logs", headers: headers
+      end
+
+      it "tracks who created the record" do
+        created_id = response.location.match(/[0-9]+/)[0]
+        whodunnit_actor = CaseLog.find_by(id: created_id).versions.last.actor
+        expect(whodunnit_actor).to be_a(User)
+        expect(whodunnit_actor.id).to eq(user.id)
+      end
+    end
+  end
+
   describe "GET" do
     let(:user) { FactoryBot.create(:user) }
     let(:organisation) { user.organisation }
@@ -401,9 +421,8 @@ RSpec.describe CaseLogsController, type: :request do
         expect(response).to have_http_status(:success)
       end
 
-      it "soft deletes the case log" do
+      it "deletes the case log" do
         expect { CaseLog.find(id) }.to raise_error(ActiveRecord::RecordNotFound)
-        expect(CaseLog.with_discarded.find(id)).to be_a(CaseLog)
       end
 
       context "with an invalid case log id" do
@@ -428,7 +447,7 @@ RSpec.describe CaseLogsController, type: :request do
     context "when a case log deletion fails" do
       before do
         allow(CaseLog).to receive(:find_by).and_return(case_log)
-        allow(case_log).to receive(:discard).and_return(false)
+        allow(case_log).to receive(:delete).and_return(false)
         delete "/logs/#{id}", headers: headers
       end
 

spec/requests/form_controller_spec.rb

@@ -155,6 +155,13 @@ RSpec.describe FormController, type: :request do
             expect(case_log.age1).to eq(answer)
             expect(case_log.age2).to be nil
           end
+
+          it "tracks who updated the record" do
+            case_log.reload
+            whodunnit_actor = case_log.versions.last.actor
+            expect(whodunnit_actor).to be_a(User)
+            expect(whodunnit_actor.id).to eq(user.id)
+          end
         end
       end
 

spec/requests/organisations_controller_spec.rb

@@ -185,6 +185,13 @@ RSpec.describe OrganisationsController, type: :request do
             follow_redirect!
             expect(page).to have_css(".govuk-notification-banner.govuk-notification-banner--success")
           end
+
+          it "tracks who updated the record" do
+            organisation.reload
+            whodunnit_actor = organisation.versions.last.actor
+            expect(whodunnit_actor).to be_a(User)
+            expect(whodunnit_actor.id).to eq(user.id)
+          end
         end
 
         context "with an organisation that the user does not belong to" do

spec/requests/users_controller_spec.rb

@@ -196,6 +196,13 @@ RSpec.describe UsersController, type: :request do
         user.reload
         expect(user.name).to eq(new_value)
       end
+
+      it "tracks who updated the record" do
+        user.reload
+        whodunnit_actor = user.versions.last.actor
+        expect(whodunnit_actor).to be_a(User)
+        expect(whodunnit_actor.id).to eq(user.id)
+      end
     end
 
     context "when the update fails to persist" do

spec/support/controller_macros.rb

@@ -6,12 +6,4 @@ module ControllerMacros
       sign_in user
     end
   end
-
-  def login_admin_user
-    before do
-      @request.env["devise.mapping"] = Devise.mappings[:admin_user]
-      admin_user = FactoryBot.create(:admin_user)
-      sign_in admin_user
-    end
-  end
 end