Resolve controller sharing concern

Use ClustersController as base while having Projects::ClustersController
to inform what `clusterable` is. Thanks @ayufan for the great suggestion
!

- View changes to work with new approach

- Fix javascript for new approach

- Fix feature specs for new approach

- Fix QA

4 files changed, 55 insertions, 40 deletions

diff --git a/app/controllers/clusters/base_controller.rb b/app/controllers/clusters/base_controller.rb
index 3a8575769c4..ef42f7c4074 100644
--- a/app/controllers/clusters/base_controller.rb
+++ b/app/controllers/clusters/base_controller.rb
@@ -2,31 +2,25 @@
 
 class Clusters::BaseController < ApplicationController
   include RoutableActions
-  include ProjectUnauthorized
 
   skip_before_action :authenticate_user!
-  before_action :require_project_id
-  before_action :project, if: :project_type?
-  before_action :repository, if: :project_type?
   before_action :authorize_read_cluster!
 
-  layout :determine_layout
-
   helper_method :clusterable
 
   private
 
-  # We can extend to `#group_type?` in the future
-  def require_project_id
-    not_found unless project_type?
+  def cluster
+    @cluster ||= clusterable.clusters.find(params[:id])
+                                 .present(current_user: current_user)
   end
 
-  def project
-    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]), not_found_or_authorized_proc: project_unauthorized_proc)
+  def authorize_update_cluster!
+    access_denied! unless can?(current_user, :update_cluster, cluster)
   end
 
-  def repository
-    @repository ||= project.repository
+  def authorize_admin_cluster!
+    access_denied! unless can?(current_user, :admin_cluster, cluster)
   end
 
   def authorize_read_cluster!
@@ -37,17 +31,7 @@ class Clusters::BaseController < ApplicationController
     access_denied! unless can?(current_user, :create_cluster, clusterable)
   end
 
-  def determine_layout
-    if project_type?
-      'project'
-    end
-  end
-
   def clusterable
-    @clusterable ||= ClusterablePresenter.fabricate(project, current_user: current_user)
-  end
-
-  def project_type?
-    params[:project_id].present?
+    raise NotImplementedError
   end
 end
diff --git a/app/controllers/clusters_controller.rb b/app/controllers/clusters/clusters_controller.rb
index 7aad70870ba..f6f2060ebb5 100644
--- a/app/controllers/clusters_controller.rb
+++ b/app/controllers/clusters/clusters_controller.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
-class ClustersController < Clusters::BaseController
+class Clusters::ClustersController < Clusters::BaseController
+  include RoutableActions
+
   before_action :cluster, except: [:index, :new, :create_gcp, :create_user]
   before_action :generate_gcp_authorize_url, only: [:new]
   before_action :validate_gcp_token, only: [:new]
@@ -9,7 +11,7 @@ class ClustersController < Clusters::BaseController
   before_action :authorize_create_cluster!, only: [:new]
   before_action :authorize_update_cluster!, only: [:update]
   before_action :authorize_admin_cluster!, only: [:destroy]
-  before_action :update_applications_status, only: [:status]
+  before_action :update_applications_status, only: [:cluster_status]
 
   helper_method :token_in_session
 
@@ -23,7 +25,8 @@ class ClustersController < Clusters::BaseController
   def new
   end
 
-  def status
+  # Overridding ActionController::Metal#status is NOT a good idea
+  def cluster_status
     respond_to do |format|
       format.json do
         Gitlab::PollingInterval.set_header(response, interval: STATUS_POLLING_INTERVAL)
@@ -107,11 +110,6 @@ class ClustersController < Clusters::BaseController
 
   private
 
-  def cluster
-    @cluster ||= clusterable.clusters.find(params[:id])
-                                 .present(current_user: current_user)
-  end
-
   def update_params
     if cluster.managed?
       params.require(:cluster).permit(
@@ -214,14 +212,6 @@ class ClustersController < Clusters::BaseController
     end
   end
 
-  def authorize_update_cluster!
-    access_denied! unless can?(current_user, :update_cluster, cluster)
-  end
-
-  def authorize_admin_cluster!
-    access_denied! unless can?(current_user, :admin_cluster, cluster)
-  end
-
   def update_applications_status
     @cluster.applications.each(&:schedule_status_update)
   end
diff --git a/app/controllers/projects/clusters/applications_controller.rb b/app/controllers/projects/clusters/applications_controller.rb
new file mode 100644
index 00000000000..c7b6218d007
--- /dev/null
+++ b/app/controllers/projects/clusters/applications_controller.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class Projects::Clusters::ApplicationsController < Clusters::ApplicationsController
+  include ProjectUnauthorized
+
+  prepend_before_action :project
+
+  private
+
+  def clusterable
+    @clusterable ||= ClusterablePresenter.fabricate(project, current_user: current_user)
+  end
+
+  def project
+    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]), not_found_or_authorized_proc: project_unauthorized_proc)
+  end
+end
diff --git a/app/controllers/projects/clusters_controller.rb b/app/controllers/projects/clusters_controller.rb
new file mode 100644
index 00000000000..feda6deeaa6
--- /dev/null
+++ b/app/controllers/projects/clusters_controller.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class Projects::ClustersController < Clusters::ClustersController
+  include ProjectUnauthorized
+
+  prepend_before_action :project
+  before_action :repository
+
+  layout 'project'
+
+  private
+
+  def clusterable
+    @clusterable ||= ClusterablePresenter.fabricate(project, current_user: current_user)
+  end
+
+  def project
+    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]), not_found_or_authorized_proc: project_unauthorized_proc)
+  end
+
+  def repository
+    @repository ||= project.repository
+  end
+end