From 9abde36f944e15c1d1c175b54a3e80d6ab5aa529 Mon Sep 17 00:00:00 2001
From: kosiakkatrina <54268893+kosiakkatrina@users.noreply.github.com>
Date: Wed, 2 Aug 2023 12:36:33 +0100
Subject: [PATCH] CLDC-2570 Add merge organisations service and rake task
 (#1801)

* Create merge_organisations_service

* Refactor tests

* update schemes merge

* rename scope

* merge letings logs

* Merge sales logs

* refactor merge organisations service

* Rollback transaction if there's an error merging orgs

* Add logging

* add merge_organisations rake task

* mark organisations as merged

* update rake task

* Update rake task add tests for multiple merging orgs

* Add more tests for merging relationships

* Update merge logging

* set absorbing organisation relationship
---
 app/controllers/locations_controller.rb       |   4 +-
 app/controllers/schemes_controller.rb         |   4 +-
 app/models/lettings_log.rb                    |   2 +-
 app/models/sales_log.rb                       |   1 +
 .../merge/merge_organisations_service.rb      | 131 +++++++
 db/schema.rb                                  |   2 +-
 lib/tasks/merge_organisations.rake            |  12 +
 spec/lib/tasks/merge_organisations_spec.rb    |  41 +++
 .../merge/merge_organisations_service_spec.rb | 323 ++++++++++++++++++
 9 files changed, 514 insertions(+), 6 deletions(-)
 create mode 100644 app/services/merge/merge_organisations_service.rb
 create mode 100644 lib/tasks/merge_organisations.rake
 create mode 100644 spec/lib/tasks/merge_organisations_spec.rb
 create mode 100644 spec/services/merge/merge_organisations_service_spec.rb

diff --git a/app/controllers/locations_controller.rb b/app/controllers/locations_controller.rb
index f89325b41..83e90c373 100644
--- a/app/controllers/locations_controller.rb
+++ b/app/controllers/locations_controller.rb
@@ -173,7 +173,7 @@ class LocationsController < ApplicationController
   end
 
   def deactivate_confirm
-    @affected_logs = @location.lettings_logs.visible.filter_by_before_startdate(params[:deactivation_date])
+    @affected_logs = @location.lettings_logs.visible.after_date(params[:deactivation_date])
     if @affected_logs.count.zero?
       deactivate
     else
@@ -274,7 +274,7 @@ private
   end
 
   def reset_location_and_scheme_for_logs!
-    logs = @location.lettings_logs.visible.filter_by_before_startdate(params[:deactivation_date].to_time)
+    logs = @location.lettings_logs.visible.after_date(params[:deactivation_date].to_time)
     logs.update!(location: nil, scheme: nil, unresolved: true)
     logs
   end
diff --git a/app/controllers/schemes_controller.rb b/app/controllers/schemes_controller.rb
index a433832b5..e026a70b9 100644
--- a/app/controllers/schemes_controller.rb
+++ b/app/controllers/schemes_controller.rb
@@ -51,7 +51,7 @@ class SchemesController < ApplicationController
   end
 
   def deactivate_confirm
-    @affected_logs = @scheme.lettings_logs.visible.filter_by_before_startdate(params[:deactivation_date])
+    @affected_logs = @scheme.lettings_logs.visible.after_date(params[:deactivation_date])
     if @affected_logs.count.zero?
       deactivate
     else
@@ -335,7 +335,7 @@ private
   end
 
   def reset_location_and_scheme_for_logs!
-    logs = @scheme.lettings_logs.visible.filter_by_before_startdate(params[:deactivation_date].to_time)
+    logs = @scheme.lettings_logs.visible.after_date(params[:deactivation_date].to_time)
     logs.update!(location: nil, scheme: nil, unresolved: true)
     logs
   end
diff --git a/app/models/lettings_log.rb b/app/models/lettings_log.rb
index 0ac0e4bf5..bc4a44a5f 100644
--- a/app/models/lettings_log.rb
+++ b/app/models/lettings_log.rb
@@ -50,7 +50,7 @@ class LettingsLog < Log
         .or(filter_by_postcode(param))
         .or(filter_by_id(param))
   }
-  scope :filter_by_before_startdate, ->(date) { where("lettings_logs.startdate >= ?", date) }
+  scope :after_date, ->(date) { where("lettings_logs.startdate >= ?", date) }
   scope :unresolved, -> { where(unresolved: true) }
 
   scope :filter_by_organisation, ->(org, _user = nil) { where(owning_organisation: org).or(where(managing_organisation: org)) }
diff --git a/app/models/sales_log.rb b/app/models/sales_log.rb
index fc57f3ba3..2a0a6d5c4 100644
--- a/app/models/sales_log.rb
+++ b/app/models/sales_log.rb
@@ -51,6 +51,7 @@ class SalesLog < Log
     .where.not(postcode_full: nil)
     .where("age1 IS NOT NULL OR age1_known = 1 OR age1_known = 2")
   }
+  scope :after_date, ->(date) { where("saledate >= ?", date) }
 
   OPTIONAL_FIELDS = %w[purchid othtype].freeze
   RETIREMENT_AGES = { "M" => 65, "F" => 60, "X" => 65 }.freeze
diff --git a/app/services/merge/merge_organisations_service.rb b/app/services/merge/merge_organisations_service.rb
new file mode 100644
index 000000000..5a417ef02
--- /dev/null
+++ b/app/services/merge/merge_organisations_service.rb
@@ -0,0 +1,131 @@
+class Merge::MergeOrganisationsService
+  def initialize(absorbing_organisation_id:, merging_organisation_ids:)
+    @absorbing_organisation = Organisation.find(absorbing_organisation_id)
+    @merging_organisations = Organisation.find(merging_organisation_ids)
+  end
+
+  def call
+    ActiveRecord::Base.transaction do
+      @merged_users = {}
+      @merged_schemes = {}
+      merge_organisation_details
+      @merging_organisations.each do |merging_organisation|
+        merge_rent_periods(merging_organisation)
+        merge_organisation_relationships(merging_organisation)
+        merge_users(merging_organisation)
+        merge_schemes_and_locations(merging_organisation)
+        merge_lettings_logs(merging_organisation)
+        merge_sales_logs(merging_organisation)
+        mark_organisation_as_merged(merging_organisation)
+      end
+      @absorbing_organisation.save!
+      log_success_message
+    rescue ActiveRecord::RecordInvalid => e
+      Rails.logger.error("Organisation merge failed with: #{e.message}")
+      raise ActiveRecord::Rollback
+    end
+  end
+
+private
+
+  def merge_organisation_details
+    @absorbing_organisation.holds_own_stock = merge_boolean_organisation_attribute("holds_own_stock")
+  end
+
+  def merge_rent_periods(merging_organisation)
+    merging_organisation.rent_periods.each do |rent_period|
+      @absorbing_organisation.organisation_rent_periods << OrganisationRentPeriod.new(rent_period:) unless @absorbing_organisation.rent_periods.include?(rent_period)
+    end
+  end
+
+  def merge_organisation_relationships(merging_organisation)
+    merging_organisation.parent_organisation_relationships.each do |parent_organisation_relationship|
+      if parent_relationship_exists_on_absorbing_organisation?(parent_organisation_relationship)
+        parent_organisation_relationship.destroy!
+      else
+        parent_organisation_relationship.update!(child_organisation: @absorbing_organisation)
+      end
+    end
+    merging_organisation.child_organisation_relationships.each do |child_organisation_relationship|
+      if child_relationship_exists_on_absorbing_organisation?(child_organisation_relationship)
+        child_organisation_relationship.destroy!
+      else
+        child_organisation_relationship.update!(parent_organisation: @absorbing_organisation)
+      end
+    end
+  end
+
+  def merge_users(merging_organisation)
+    @merged_users[merging_organisation.name] = merging_organisation.users.map { |user| { name: user.name, email: user.email } }
+    merging_organisation.users.update_all(organisation_id: @absorbing_organisation.id)
+  end
+
+  def merge_schemes_and_locations(merging_organisation)
+    @merged_schemes[merging_organisation.name] = []
+    merging_organisation.owned_schemes.each do |scheme|
+      next if scheme.deactivated?
+
+      new_scheme = Scheme.create!(scheme.attributes.except("id", "owning_organisation_id").merge(owning_organisation: @absorbing_organisation))
+      scheme.locations.each do |location|
+        new_scheme.locations << Location.new(location.attributes.except("id", "scheme_id")) unless location.deactivated?
+      end
+      @merged_schemes[merging_organisation.name] << { name: new_scheme.service_name, code: new_scheme.id }
+      SchemeDeactivationPeriod.create!(scheme:, deactivation_date: Time.zone.now)
+    end
+  end
+
+  def merge_lettings_logs(merging_organisation)
+    merging_organisation.owned_lettings_logs.after_date(Time.zone.today).each do |lettings_log|
+      if lettings_log.scheme.present?
+        scheme_to_set = @absorbing_organisation.owned_schemes.find_by(service_name: lettings_log.scheme.service_name)
+        location_to_set = scheme_to_set.locations.find_by(name: lettings_log.location&.name, postcode: lettings_log.location&.postcode)
+
+        lettings_log.scheme = scheme_to_set if scheme_to_set.present?
+        lettings_log.location = location_to_set if location_to_set.present?
+      end
+      lettings_log.owning_organisation = @absorbing_organisation
+      lettings_log.save!
+    end
+    merging_organisation.managed_lettings_logs.after_date(Time.zone.today).each do |lettings_log|
+      lettings_log.managing_organisation = @absorbing_organisation
+      lettings_log.save!
+    end
+  end
+
+  def merge_sales_logs(merging_organisation)
+    merging_organisation.sales_logs.after_date(Time.zone.today).each do |sales_log|
+      sales_log.update(owning_organisation: @absorbing_organisation)
+    end
+  end
+
+  def mark_organisation_as_merged(merging_organisation)
+    merging_organisation.update(merge_date: Time.zone.today, absorbing_organisation: @absorbing_organisation)
+  end
+
+  def log_success_message
+    @merged_users.each do |organisation_name, users|
+      Rails.logger.info("Merged users from #{organisation_name}:")
+      users.each do |user|
+        Rails.logger.info("\t#{user[:name]} (#{user[:email]})")
+      end
+    end
+    @merged_schemes.each do |organisation_name, schemes|
+      Rails.logger.info("New schemes from #{organisation_name}:")
+      schemes.each do |scheme|
+        Rails.logger.info("\t#{scheme[:name]} (S#{scheme[:code]})")
+      end
+    end
+  end
+
+  def merge_boolean_organisation_attribute(attribute)
+    @absorbing_organisation[attribute] ||= @merging_organisations.any? { |merging_organisation| merging_organisation[attribute] }
+  end
+
+  def parent_relationship_exists_on_absorbing_organisation?(parent_organisation_relationship)
+    parent_organisation_relationship.parent_organisation == @absorbing_organisation || @absorbing_organisation.parent_organisation_relationships.where(parent_organisation: parent_organisation_relationship.parent_organisation).exists?
+  end
+
+  def child_relationship_exists_on_absorbing_organisation?(child_organisation_relationship)
+    child_organisation_relationship.child_organisation == @absorbing_organisation || @absorbing_organisation.child_organisation_relationships.where(child_organisation: child_organisation_relationship.child_organisation).exists?
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index ee5c1c1ad..7b5167a24 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: 2023_07_25_081029) do
+ActiveRecord::Schema[7.0].define(version: 2023_07_19_150610) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
diff --git a/lib/tasks/merge_organisations.rake b/lib/tasks/merge_organisations.rake
new file mode 100644
index 000000000..820343883
--- /dev/null
+++ b/lib/tasks/merge_organisations.rake
@@ -0,0 +1,12 @@
+namespace :merge do
+  desc "Merge organisations into one"
+  task :merge_organisations, %i[absorbing_organisation_id merging_organisation_ids] => :environment do |_task, args|
+    absorbing_organisation_id = args[:absorbing_organisation_id]
+    merging_organisation_ids = args[:merging_organisation_ids]&.split(" ")&.map(&:to_i)
+
+    raise "Usage: rake merge:merge_organisations[absorbing_organisation_id, merging_organisation_ids]" if merging_organisation_ids.blank? || absorbing_organisation_id.blank?
+
+    service = Merge::MergeOrganisationsService.new(absorbing_organisation_id:, merging_organisation_ids:)
+    service.call
+  end
+end
diff --git a/spec/lib/tasks/merge_organisations_spec.rb b/spec/lib/tasks/merge_organisations_spec.rb
new file mode 100644
index 000000000..4155a4389
--- /dev/null
+++ b/spec/lib/tasks/merge_organisations_spec.rb
@@ -0,0 +1,41 @@
+require "rails_helper"
+require "rake"
+
+RSpec.describe "emails" do
+  describe ":merge_organisations", type: :task do
+    subject(:task) { Rake::Task["merge:merge_organisations"] }
+
+    let(:organisation) { create(:organisation) }
+    let(:merging_organisation) { create(:organisation) }
+
+    let(:merge_organisations_service) { Merge::MergeOrganisationsService.new(absorbing_organisation_id: organisation.id, merging_organisation_ids: [merging_organisation.id]) }
+
+    before do
+      allow(Merge::MergeOrganisationsService).to receive(:new).and_return(merge_organisations_service)
+      allow(merge_organisations_service).to receive(:call).and_return(nil)
+      Rake.application.rake_require("tasks/merge_organisations")
+      Rake::Task.define_task(:environment)
+      task.reenable
+    end
+
+    context "when the rake task is run" do
+      it "raises an error when no parameters are given" do
+        expect { task.invoke(nil) }.to raise_error(RuntimeError, "Usage: rake merge:merge_organisations[absorbing_organisation_id, merging_organisation_ids]")
+      end
+
+      it "raises an error when only absorbing organisation is given" do
+        expect { task.invoke(1, nil) }.to raise_error(RuntimeError, "Usage: rake merge:merge_organisations[absorbing_organisation_id, merging_organisation_ids]")
+      end
+
+      it "raises an error when only merging organisations are given" do
+        expect { task.invoke(nil, "1 2") }.to raise_error(RuntimeError, "Usage: rake merge:merge_organisations[absorbing_organisation_id, merging_organisation_ids]")
+      end
+
+      it "raises runs the service with correct organisation IDs" do
+        expect(Merge::MergeOrganisationsService).to receive(:new).with(absorbing_organisation_id: 1, merging_organisation_ids: [2, 3]).once
+        expect(merge_organisations_service).to receive(:call).once
+        task.invoke(1, "2 3")
+      end
+    end
+  end
+end
diff --git a/spec/services/merge/merge_organisations_service_spec.rb b/spec/services/merge/merge_organisations_service_spec.rb
new file mode 100644
index 000000000..2c2af0f3e
--- /dev/null
+++ b/spec/services/merge/merge_organisations_service_spec.rb
@@ -0,0 +1,323 @@
+require "rails_helper"
+
+RSpec.describe Merge::MergeOrganisationsService do
+  subject(:merge_organisations_service) { described_class.new(absorbing_organisation_id: absorbing_organisation.id, merging_organisation_ids: [merging_organisation_ids]) }
+
+  let(:absorbing_organisation) {    create(:organisation, holds_own_stock: false) }
+  let(:absorbing_organisation_user) { create(:user, organisation: absorbing_organisation) }
+
+  describe "#call" do
+    context "when merging a single organisation into an existing organisation" do
+      let(:merging_organisation) { create(:organisation, holds_own_stock: true, name: "fake org") }
+
+      let(:merging_organisation_ids) { [merging_organisation.id] }
+      let!(:merging_organisation_user) { create(:user, organisation: merging_organisation, name: "fake name", email: "fake@email.com") }
+
+      it "moves the users from merging organisation to absorbing organisation" do
+        expect(Rails.logger).to receive(:info).with("Merged users from fake org:")
+        expect(Rails.logger).to receive(:info).with("\tDanny Rojas (#{merging_organisation.data_protection_officers.first.email})")
+        expect(Rails.logger).to receive(:info).with("\tfake name (fake@email.com)")
+        expect(Rails.logger).to receive(:info).with("New schemes from fake org:")
+        merge_organisations_service.call
+
+        merging_organisation_user.reload
+        expect(merging_organisation_user.organisation).to eq(absorbing_organisation)
+      end
+
+      it "sets merge date on merged organisation" do
+        merge_organisations_service.call
+
+        merging_organisation.reload
+        expect(merging_organisation.merge_date.to_date).to eq(Time.zone.today)
+        expect(merging_organisation.absorbing_organisation_id).to eq(absorbing_organisation.id)
+      end
+
+      it "combines organisation data" do
+        merge_organisations_service.call
+
+        absorbing_organisation.reload
+        expect(absorbing_organisation.holds_own_stock).to eq(true)
+      end
+
+      it "rolls back if there's an error" do
+        allow(Organisation).to receive(:find).with([merging_organisation_ids]).and_return(Organisation.find(merging_organisation_ids))
+        allow(Organisation).to receive(:find).with(absorbing_organisation.id).and_return(absorbing_organisation)
+        allow(absorbing_organisation).to receive(:save!).and_raise(ActiveRecord::RecordInvalid)
+        expect(Rails.logger).to receive(:error).with("Organisation merge failed with: Record invalid")
+        merge_organisations_service.call
+
+        absorbing_organisation.reload
+        merging_organisation.reload
+        expect(absorbing_organisation.holds_own_stock).to eq(false)
+        expect(merging_organisation.merge_date).to eq(nil)
+        expect(merging_organisation.absorbing_organisation_id).to eq(nil)
+        expect(merging_organisation_user.organisation).to eq(merging_organisation)
+      end
+
+      context "and merging organisation rent periods" do
+        before do
+          OrganisationRentPeriod.create!(organisation: absorbing_organisation, rent_period: 1)
+          OrganisationRentPeriod.create!(organisation: absorbing_organisation, rent_period: 3)
+          OrganisationRentPeriod.create!(organisation: merging_organisation, rent_period: 1)
+          OrganisationRentPeriod.create!(organisation: merging_organisation, rent_period: 2)
+        end
+
+        it "combines organisation rent periods" do
+          expect(absorbing_organisation.rent_periods.count).to eq(2)
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          expect(absorbing_organisation.rent_periods.count).to eq(3)
+          expect(absorbing_organisation.rent_periods).to include(1)
+          expect(absorbing_organisation.rent_periods).to include(2)
+          expect(absorbing_organisation.rent_periods).to include(3)
+        end
+
+        it "rolls back if there's an error" do
+          allow(Organisation).to receive(:find).with([merging_organisation_ids]).and_return(Organisation.find(merging_organisation_ids))
+          allow(Organisation).to receive(:find).with(absorbing_organisation.id).and_return(absorbing_organisation)
+          allow(absorbing_organisation).to receive(:save!).and_raise(ActiveRecord::RecordInvalid)
+          expect(Rails.logger).to receive(:error).with("Organisation merge failed with: Record invalid")
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          merging_organisation.reload
+          expect(absorbing_organisation.rent_periods.count).to eq(2)
+          expect(merging_organisation.rent_periods.count).to eq(2)
+        end
+      end
+
+      context "and merging organisation relationships" do
+        let(:other_organisation) { create(:organisation) }
+        let!(:merging_organisation_relationship) { create(:organisation_relationship, parent_organisation: merging_organisation) }
+        let!(:absorbing_organisation_relationship) { create(:organisation_relationship, parent_organisation: absorbing_organisation) }
+
+        before do
+          create(:organisation_relationship, parent_organisation: absorbing_organisation, child_organisation: merging_organisation)
+          create(:organisation_relationship, parent_organisation: merging_organisation, child_organisation: other_organisation)
+          create(:organisation_relationship, parent_organisation: absorbing_organisation, child_organisation: other_organisation)
+        end
+
+        it "combines organisation relationships" do
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          expect(absorbing_organisation.child_organisations).to include(other_organisation)
+          expect(absorbing_organisation.child_organisations).to include(absorbing_organisation_relationship.child_organisation)
+          expect(absorbing_organisation.child_organisations).to include(merging_organisation_relationship.child_organisation)
+          expect(absorbing_organisation.child_organisations).not_to include(merging_organisation)
+          expect(absorbing_organisation.parent_organisations.count).to eq(0)
+          expect(absorbing_organisation.child_organisations.count).to eq(3)
+        end
+
+        it "rolls back if there's an error" do
+          allow(Organisation).to receive(:find).with([merging_organisation_ids]).and_return(Organisation.find(merging_organisation_ids))
+          allow(Organisation).to receive(:find).with(absorbing_organisation.id).and_return(absorbing_organisation)
+          allow(absorbing_organisation).to receive(:save!).and_raise(ActiveRecord::RecordInvalid)
+          expect(Rails.logger).to receive(:error).with("Organisation merge failed with: Record invalid")
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          expect(absorbing_organisation.child_organisations.count).to eq(3)
+          expect(absorbing_organisation.child_organisations).to include(other_organisation)
+          expect(absorbing_organisation.child_organisations).to include(merging_organisation)
+          expect(absorbing_organisation.child_organisations).to include(absorbing_organisation_relationship.child_organisation)
+        end
+      end
+
+      context "and merging organisation schemes and locations" do
+        let!(:scheme) { create(:scheme, owning_organisation: merging_organisation) }
+        let!(:location) { create(:location, scheme:) }
+        let!(:deactivated_location) { create(:location, scheme:) }
+        let!(:deactivated_scheme) { create(:scheme, owning_organisation: merging_organisation) }
+        let!(:owned_lettings_log) { create(:lettings_log, :sh, scheme:, location:, startdate: Time.zone.tomorrow, owning_organisation: merging_organisation) }
+        let!(:owned_lettings_log_no_location) { create(:lettings_log, :sh, scheme:, startdate: Time.zone.tomorrow, owning_organisation: merging_organisation) }
+
+        before do
+          create(:location, scheme:, name: "fake location", postcode: "A1 1AA")
+          create(:location, scheme: deactivated_scheme)
+          create(:scheme_deactivation_period, scheme: deactivated_scheme, deactivation_date: Time.zone.today - 1.month)
+          create(:location_deactivation_period, location: deactivated_location, deactivation_date: Time.zone.today - 1.month)
+          create(:lettings_log, scheme:, location:, startdate: Time.zone.yesterday)
+          create(:lettings_log, startdate: Time.zone.tomorrow, managing_organisation: merging_organisation)
+        end
+
+        it "combines organisation schemes and locations" do
+          expect(Rails.logger).to receive(:info).with("Merged users from fake org:")
+          expect(Rails.logger).to receive(:info).with("\tDanny Rojas (#{merging_organisation.data_protection_officers.first.email})")
+          expect(Rails.logger).to receive(:info).with("\tfake name (fake@email.com)")
+          expect(Rails.logger).to receive(:info).with("New schemes from fake org:")
+          expect(Rails.logger).to receive(:info).with(/\t#{scheme.service_name} \(S/)
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          expect(absorbing_organisation.owned_schemes.count).to eq(1)
+          expect(absorbing_organisation.owned_schemes.first.service_name).to eq(scheme.service_name)
+          expect(absorbing_organisation.owned_schemes.first.locations.count).to eq(2)
+          expect(absorbing_organisation.owned_schemes.first.locations.first.postcode).to eq(location.postcode)
+          expect(scheme.scheme_deactivation_periods.count).to eq(1)
+          expect(scheme.scheme_deactivation_periods.first.deactivation_date.to_date).to eq(Time.zone.today)
+        end
+
+        it "moves relevant logs and assigns the new scheme" do
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          merging_organisation.reload
+          expect(absorbing_organisation.owned_lettings_logs.count).to eq(2)
+          expect(absorbing_organisation.managed_lettings_logs.count).to eq(1)
+          expect(absorbing_organisation.owned_lettings_logs.find(owned_lettings_log.id).scheme).to eq(absorbing_organisation.owned_schemes.first)
+          expect(absorbing_organisation.owned_lettings_logs.find(owned_lettings_log.id).location).to eq(absorbing_organisation.owned_schemes.first.locations.first)
+          expect(absorbing_organisation.owned_lettings_logs.find(owned_lettings_log_no_location.id).scheme).to eq(absorbing_organisation.owned_schemes.first)
+          expect(absorbing_organisation.owned_lettings_logs.find(owned_lettings_log_no_location.id).location).to eq(nil)
+        end
+
+        it "rolls back if there's an error" do
+          allow(Organisation).to receive(:find).with([merging_organisation_ids]).and_return(Organisation.find(merging_organisation_ids))
+          allow(Organisation).to receive(:find).with(absorbing_organisation.id).and_return(absorbing_organisation)
+          allow(absorbing_organisation).to receive(:save!).and_raise(ActiveRecord::RecordInvalid)
+          expect(Rails.logger).to receive(:error).with("Organisation merge failed with: Record invalid")
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          merging_organisation.reload
+          expect(absorbing_organisation.owned_schemes.count).to eq(0)
+          expect(scheme.scheme_deactivation_periods.count).to eq(0)
+          expect(owned_lettings_log.owning_organisation).to eq(merging_organisation)
+          expect(owned_lettings_log_no_location.owning_organisation).to eq(merging_organisation)
+        end
+      end
+
+      context "and merging sales logs" do
+        let!(:sales_log) { create(:sales_log, saledate: Time.zone.tomorrow, owning_organisation: merging_organisation) }
+
+        before do
+          create(:sales_log, saledate: Time.zone.yesterday, owning_organisation: merging_organisation)
+        end
+
+        it "moves relevant logs" do
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          expect(SalesLog.filter_by_owning_organisation(absorbing_organisation).count).to eq(1)
+          expect(SalesLog.filter_by_owning_organisation(absorbing_organisation).first).to eq(sales_log)
+        end
+
+        it "rolls back if there's an error" do
+          allow(Organisation).to receive(:find).with([merging_organisation_ids]).and_return(Organisation.find(merging_organisation_ids))
+          allow(Organisation).to receive(:find).with(absorbing_organisation.id).and_return(absorbing_organisation)
+          allow(absorbing_organisation).to receive(:save!).and_raise(ActiveRecord::RecordInvalid)
+          expect(Rails.logger).to receive(:error).with("Organisation merge failed with: Record invalid")
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          expect(absorbing_organisation.sales_logs.count).to eq(0)
+          expect(sales_log.owning_organisation).to eq(merging_organisation)
+        end
+      end
+    end
+
+    context "when merging a multiple organisations into an existing organisation" do
+      let(:merging_organisation) { create(:organisation, holds_own_stock: true, name: "fake org") }
+      let(:merging_organisation_too) { create(:organisation, holds_own_stock: true, name: "second org") }
+
+      let(:merging_organisation_ids) { [merging_organisation.id, merging_organisation_too.id] }
+      let!(:merging_organisation_user) { create(:user, organisation: merging_organisation, name: "fake name", email: "fake@email.com") }
+
+      before do
+        create_list(:user, 5, organisation: merging_organisation_too)
+      end
+
+      it "moves the users from merging organisations to absorbing organisation" do
+        expect(Rails.logger).to receive(:info).with("Merged users from fake org:")
+        expect(Rails.logger).to receive(:info).with("\tDanny Rojas (#{merging_organisation.data_protection_officers.first.email})")
+        expect(Rails.logger).to receive(:info).with("\tfake name (fake@email.com)")
+        expect(Rails.logger).to receive(:info).with("Merged users from second org:")
+        expect(Rails.logger).to receive(:info).with(/\tDanny Rojas/).exactly(6).times
+        expect(Rails.logger).to receive(:info).with("New schemes from fake org:")
+        expect(Rails.logger).to receive(:info).with("New schemes from second org:")
+        merge_organisations_service.call
+
+        merging_organisation_user.reload
+        expect(merging_organisation_user.organisation).to eq(absorbing_organisation)
+      end
+
+      it "sets merge date and absorbing organisation on merged organisations" do
+        merge_organisations_service.call
+
+        merging_organisation.reload
+        merging_organisation_too.reload
+        expect(merging_organisation.merge_date.to_date).to eq(Time.zone.today)
+        expect(merging_organisation.absorbing_organisation_id).to eq(absorbing_organisation.id)
+        expect(merging_organisation_too.merge_date.to_date).to eq(Time.zone.today)
+        expect(merging_organisation_too.absorbing_organisation_id).to eq(absorbing_organisation.id)
+      end
+
+      it "combines organisation data" do
+        merge_organisations_service.call
+
+        absorbing_organisation.reload
+        expect(absorbing_organisation.holds_own_stock).to eq(true)
+      end
+
+      it "rolls back if there's an error" do
+        allow(Organisation).to receive(:find).with([merging_organisation_ids]).and_return(Organisation.find(merging_organisation_ids))
+        allow(Organisation).to receive(:find).with(absorbing_organisation.id).and_return(absorbing_organisation)
+        allow(absorbing_organisation).to receive(:save!).and_raise(ActiveRecord::RecordInvalid)
+        expect(Rails.logger).to receive(:error).with("Organisation merge failed with: Record invalid")
+        merge_organisations_service.call
+
+        absorbing_organisation.reload
+        merging_organisation.reload
+        expect(absorbing_organisation.holds_own_stock).to eq(false)
+        expect(merging_organisation.merge_date).to eq(nil)
+        expect(merging_organisation.absorbing_organisation_id).to eq(nil)
+        expect(merging_organisation_user.organisation).to eq(merging_organisation)
+      end
+
+      context "and merging organisation relationships" do
+        let(:other_organisation) { create(:organisation) }
+        let!(:merging_organisation_relationship) { create(:organisation_relationship, parent_organisation: merging_organisation) }
+        let!(:absorbing_organisation_relationship) { create(:organisation_relationship, parent_organisation: absorbing_organisation) }
+
+        before do
+          create(:organisation_relationship, parent_organisation: merging_organisation, child_organisation: absorbing_organisation)
+          create(:organisation_relationship, parent_organisation: merging_organisation, child_organisation: other_organisation)
+          create(:organisation_relationship, parent_organisation: absorbing_organisation, child_organisation: other_organisation)
+          create(:organisation_relationship, parent_organisation: merging_organisation, child_organisation: merging_organisation_too)
+        end
+
+        it "combines organisation relationships" do
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          expect(absorbing_organisation.child_organisations).to include(other_organisation)
+          expect(absorbing_organisation.child_organisations).to include(absorbing_organisation_relationship.child_organisation)
+          expect(absorbing_organisation.child_organisations).to include(merging_organisation_relationship.child_organisation)
+          expect(absorbing_organisation.child_organisations).not_to include(merging_organisation)
+          expect(absorbing_organisation.parent_organisations).not_to include(merging_organisation)
+          expect(absorbing_organisation.child_organisations).not_to include(merging_organisation_too)
+          expect(absorbing_organisation.parent_organisations).not_to include(merging_organisation_too)
+          expect(absorbing_organisation.parent_organisations.count).to eq(0)
+          expect(absorbing_organisation.child_organisations.count).to eq(3)
+        end
+
+        it "rolls back if there's an error" do
+          allow(Organisation).to receive(:find).with([merging_organisation_ids]).and_return(Organisation.find(merging_organisation_ids))
+          allow(Organisation).to receive(:find).with(absorbing_organisation.id).and_return(absorbing_organisation)
+          allow(absorbing_organisation).to receive(:save!).and_raise(ActiveRecord::RecordInvalid)
+          expect(Rails.logger).to receive(:error).with("Organisation merge failed with: Record invalid")
+          merge_organisations_service.call
+
+          absorbing_organisation.reload
+          merging_organisation.reload
+          expect(absorbing_organisation.child_organisations.count).to eq(2)
+          expect(absorbing_organisation.parent_organisations.count).to eq(1)
+          expect(absorbing_organisation.child_organisations).to include(other_organisation)
+          expect(absorbing_organisation.parent_organisations).to include(merging_organisation)
+          expect(absorbing_organisation.child_organisations).to include(absorbing_organisation_relationship.child_organisation)
+        end
+      end
+    end
+  end
+end