Handle next page and previous_template with `page`

app/controllers/merge_requests_controller.rb

@@ -1,7 +1,20 @@
 class MergeRequestsController < ApplicationController
-  before_action :find_resource, only: %i[update organisations update_organisations remove_merging_organisation absorbing_organisation confirm_telephone_number new_org_name]
+  before_action :find_resource, only: %i[
+    update
+    organisations
+    update_organisations
+    remove_merging_organisation
+    absorbing_organisation
+    confirm_telephone_number
+    new_org_name
+  ]
   before_action :authenticate_user!
   before_action :authenticate_scope!, except: [:create]
+  before_action :redirect_to_next_page
+
+  def absorbing_organisation; end
+  def confirm_telephone_number; end
+  def new_org_name; end
 
   def create
     ActiveRecord::Base.transaction do
@@ -13,18 +26,12 @@ class MergeRequestsController < ApplicationController
     render_not_found
   end
 
-  def absorbing_organisation; end
-  def confirm_telephone_number; end
-  def new_org_name; end
-
   def organisations
     @answer_options = organisations_answer_options
   end
 
   def update
-    if params.dig(:merge_request, :absorbing_organisation_id) == "other"
-      redirect_to next_page_path
-    elsif @merge_request.update(merge_request_params)
+    if @merge_request.update(merge_request_params)
       redirect_to next_page_path
     else
       render previous_template, status: :unprocessable_entity
@@ -49,6 +56,35 @@ class MergeRequestsController < ApplicationController
 
 private
 
+  def page
+    params.dig(:merge_request, :page)
+  end
+
+  def next_page_path
+    case page
+    when "absorbing_organisation"
+      if create_new_org?
+        new_org_name_merge_request_path(@merge_request)
+      else
+        confirm_telephone_number_merge_request_path(@merge_request)
+      end
+    when "organisations"
+      absorbing_organisation_merge_request_path(@merge_request)
+    end
+  end
+
+  def previous_template
+    page
+  end
+
+  def redirect_to_next_page
+    redirect_to next_page_path if create_new_org?
+  end
+
+  def create_new_org?
+    params.dig(:merge_request, :absorbing_organisation_id) == "other"
+  end
+
   def organisations_answer_options
     answer_options = { "" => "Select an option" }
 
@@ -84,25 +120,6 @@ private
     @merge_request = MergeRequest.find(params[:id])
   end
 
-  def next_page_path
-    if params.dig(:merge_request, :absorbing_organisation_id) == "other"
-      # TODO: flow to be implemented in follow up PR
-      new_org_name_merge_request_path(@merge_request)
-    elsif params.dig(:merge_request, :absorbing_organisation_id).present?
-      confirm_telephone_number_merge_request_path(@merge_request)
-    else
-      absorbing_organisation_merge_request_path(@merge_request)
-    end
-  end
-
-  def previous_template
-    if params.dig(:merge_request, :absorbing_organisation_id).present?
-      :absorbing_organisation
-    else
-      :organisations
-    end
-  end
-
   def authenticate_scope!
     if current_user.organisation != @merge_request.requesting_organisation && !current_user.support?
       render_not_found

app/views/merge_requests/absorbing_organisation.html.erb

@@ -30,6 +30,8 @@
         <%= f.govuk_radio_button :absorbing_organisation_id, "other", label: { text: "These organisations are merging into a new one" } %>
       <% end %>
 
+      <%= f.hidden_field :page, value: "absorbing_organisation" %>
+
       <%= f.govuk_submit %>
     <% end %>
   </div>

app/views/merge_requests/organisations.html.erb

@@ -44,6 +44,7 @@
       <%= f.govuk_text_area :other_merging_organisations, label: { text: "Other organisations" }, hint: { text: "List other organisations that are part of the merge but not registered on CORE." }, rows: 9 %>
     <% end %>
     <% if @merge_request.merging_organisations.count > 1 %>
+      <%= f.hidden_field :page, value: "organisations" %>
       <%= f.govuk_submit "Continue" %>
     <% end %>
   <% end %>

spec/requests/merge_requests_controller_spec.rb

@@ -238,7 +238,7 @@ RSpec.describe MergeRequestsController, type: :request do
 
       describe "#other_merging_organisations" do
         let(:other_merging_organisations) { "A list of other merging organisations" }
-        let(:params) { { merge_request: { other_merging_organisations: } } }
+        let(:params) { { merge_request: { other_merging_organisations:, page: "organisations" } } }
         let(:request) do
           patch "/merge-request/#{merge_request.id}", headers:, params:
         end
@@ -262,7 +262,7 @@ RSpec.describe MergeRequestsController, type: :request do
 
       context "when absorbing_organisation_id set to other" do
         let(:params) do
-          { merge_request: { absorbing_organisation_id: "other" } }
+          { merge_request: { absorbing_organisation_id: "other", page: "absorbing_organisation" } }
         end
 
         before do
@@ -276,7 +276,7 @@ RSpec.describe MergeRequestsController, type: :request do
 
       context "when absorbing_organisation_id set to id" do
         let(:params) do
-          { merge_request: { absorbing_organisation_id: other_organisation.id } }
+          { merge_request: { absorbing_organisation_id: other_organisation.id, page: "absorbing_organisation" } }
         end
 
         let(:request) do