combine "create" and "existing" GKE cluster views into one new page

# Conflicts:
#	app/controllers/projects/clusters/gcp_controller.rb
#	app/views/projects/clusters/gcp/_form.html.haml

app/assets/javascripts/pages/projects/clusters/gcp/login/index.js

-import gcpSignupOffer from '~/clusters/components/gcp_signup_offer';
-
-gcpSignupOffer();

app/assets/javascripts/pages/projects/clusters/new/index.js

-import gcpSignupOffer from '~/clusters/components/gcp_signup_offer';
-
-gcpSignupOffer();

app/assets/javascripts/pages/projects/index.js

+import gcpSignupOffer from '~/clusters/components/gcp_signup_offer';
+// TODO: Uncommment after https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17806 is merged.
+// import initGkeDropdowns from '~/projects/gke_cluster_dropdowns';
 import Project from './project';
 import ShortcutsNavigation from '../../shortcuts_navigation';
 
 document.addEventListener('DOMContentLoaded', () => {
+  const page = document.body.dataset.page;
+  const newClusterViews = ['projects:clusters:new', 'projects:clusters:create_cluster'];
+
+  if (newClusterViews.indexOf(page) > -1) {
+    gcpSignupOffer();
+    // initGkeDropdowns();
+  }
+
   new Project(); // eslint-disable-line no-new
   new ShortcutsNavigation(); // eslint-disable-line no-new
 });

app/controllers/projects/clusters/gcp_controller.rb

-class Projects::Clusters::GcpController < Projects::ApplicationController
-  before_action :authorize_read_cluster!
-  before_action :authorize_create_cluster!, only: [:new, :create]
-  before_action :authorize_google_api, except: :login
-
-  def login
-    begin
-      state = generate_session_key_redirect(gcp_new_namespace_project_clusters_path.to_s)
-
-      @authorize_url = GoogleApi::CloudPlatform::Client.new(
-        nil, callback_google_api_auth_url,
-        state: state).authorize_url
-    rescue GoogleApi::Auth::ConfigMissingError
-      # no-op
-    end
-  end
-
-  def new
-    @cluster = ::Clusters::Cluster.new.tap do |cluster|
-      cluster.build_provider_gcp
-    end
-  end
-
-  def create
-    @cluster = ::Clusters::CreateService
-      .new(project, current_user, create_params)
-      .execute(token_in_session)
-
-    if @cluster.persisted?
-      redirect_to project_cluster_path(project, @cluster)
-    else
-      render :new
-    end
-  end
-
-  private
-
-  def create_params
-    params.require(:cluster).permit(
-      :enabled,
-      :name,
-      :environment_scope,
-      provider_gcp_attributes: [
-        :gcp_project_id,
-        :zone,
-        :num_nodes,
-        :machine_type
-      ]).merge(
-        provider_type: :gcp,
-        platform_type: :kubernetes
-      )
-  end
-
-  def authorize_google_api
-    unless GoogleApi::CloudPlatform::Client.new(token_in_session, nil)
-                                           .validate_token(expires_at_in_session)
-      redirect_to action: 'login'
-    end
-  end
-
-  def token_in_session
-    @token_in_session ||=
-      session[GoogleApi::CloudPlatform::Client.session_key_for_token]
-  end
-
-  def expires_at_in_session
-    @expires_at_in_session ||=
-      session[GoogleApi::CloudPlatform::Client.session_key_for_expires_at]
-  end
-
-  def generate_session_key_redirect(uri)
-    GoogleApi::CloudPlatform::Client.new_session_key_for_redirect_uri do |key|
-      session[key] = uri
-    end
-  end
-end

app/controllers/projects/clusters/user_controller.rb

-class Projects::Clusters::UserController < Projects::ApplicationController
-  before_action :authorize_read_cluster!
-  before_action :authorize_create_cluster!, only: [:new, :create]
-
-  def new
-    @cluster = ::Clusters::Cluster.new.tap do |cluster|
-      cluster.build_platform_kubernetes
-    end
-  end
-
-  def create
-    @cluster = ::Clusters::CreateService
-      .new(project, current_user, create_params)
-      .execute
-
-    if @cluster.persisted?
-      redirect_to project_cluster_path(project, @cluster)
-    else
-      render :new
-    end
-  end
-
-  private
-
-  def create_params
-    params.require(:cluster).permit(
-      :enabled,
-      :name,
-      :environment_scope,
-      platform_kubernetes_attributes: [
-        :namespace,
-        :api_url,
-        :token,
-        :ca_cert
-      ]).merge(
-        provider_type: :user,
-        platform_type: :kubernetes
-      )
-  end
-end

app/controllers/projects/clusters_controller.rb

 class Projects::ClustersController < Projects::ApplicationController
-  before_action :cluster, except: [:index, :new]
+  before_action :cluster, except: [:index, :new, :create_cluster]
   before_action :authorize_read_cluster!
   before_action :authorize_create_cluster!, only: [:new]
   before_action :authorize_update_cluster!, only: [:update]
@@ -14,6 +14,9 @@ class Projects::ClustersController < Projects::ApplicationController
   end
 
   def new
+    generate_gcp_authorize_url
+    tap_new_cluster
+    tap_existing_cluster
   end
 
   def status
@@ -64,6 +67,52 @@ class Projects::ClustersController < Projects::ApplicationController
     end
   end
 
+  def tap_new_cluster
+    if GoogleApi::CloudPlatform::Client.new(token_in_session, nil)
+      .validate_token(expires_at_in_session)
+      @new_cluster = ::Clusters::Cluster.new.tap do |cluster|
+        cluster.build_provider_gcp
+      end
+    end
+  end
+
+  def tap_existing_cluster
+    @existing_cluster = ::Clusters::Cluster.new.tap do |cluster|
+      cluster.build_platform_kubernetes
+    end
+  end
+
+  def create_cluster
+    case params[:type]
+    when 'new'
+      cluster_params = create_new_cluster_params
+    when 'existing'
+      cluster_params = create_existing_cluster_params
+    end
+
+    @cluster = ::Clusters::CreateService
+      .new(project, current_user,  cluster_params)
+      .execute(token_in_session)
+
+    if @cluster.persisted?
+      redirect_to project_cluster_path(project, @cluster)
+    else
+      generate_gcp_authorize_url
+      active_tab = params[:type]
+
+      case params[:type]
+      when 'new'
+        @new_cluster = @cluster
+        tap_existing_cluster
+      when 'existing'
+        @existing_cluster = @cluster
+        tap_new_cluster
+      end
+
+      render :new, locals: { active_tab: active_tab }
+    end
+  end
+
   private
 
   def cluster
@@ -108,6 +157,64 @@ class Projects::ClustersController < Projects::ApplicationController
     end
   end
 
+  def create_new_cluster_params
+    params.require(:cluster).permit(
+      :enabled,
+      :name,
+      :environment_scope,
+      provider_gcp_attributes: [
+        :gcp_project_id,
+        :zone,
+        :num_nodes,
+        :machine_type
+      ]).merge(
+        provider_type: :gcp,
+        platform_type: :kubernetes
+      )
+  end
+
+  def create_existing_cluster_params
+    params.require(:cluster).permit(
+      :enabled,
+      :name,
+      :environment_scope,
+      platform_kubernetes_attributes: [
+        :namespace,
+        :api_url,
+        :token,
+        :ca_cert
+      ]).merge(
+        provider_type: :user,
+        platform_type: :kubernetes
+      )
+  end
+
+  def generate_gcp_authorize_url
+    state = generate_session_key_redirect(new_project_cluster_path(@project).to_s)
+
+    @authorize_url = GoogleApi::CloudPlatform::Client.new(
+      nil, callback_google_api_auth_url,
+      state: state).authorize_url
+  rescue GoogleApi::Auth::ConfigMissingError
+    # no-op
+  end
+
+  def token_in_session
+    @token_in_session ||=
+      session[GoogleApi::CloudPlatform::Client.session_key_for_token]
+  end
+
+  def expires_at_in_session
+    @expires_at_in_session ||=
+      session[GoogleApi::CloudPlatform::Client.session_key_for_expires_at]
+  end
+
+  def generate_session_key_redirect(uri)
+    GoogleApi::CloudPlatform::Client.new_session_key_for_redirect_uri do |key|
+      session[key] = uri
+    end
+  end
+
   def authorize_update_cluster!
     access_denied! unless can?(current_user, :update_cluster, cluster)
   end

app/views/projects/clusters/gcp/_form.html.haml

@@ -4,8 +4,10 @@
   - link_to_help_page = link_to(s_('ClusterIntegration|help page'), help_page_path('user/project/clusters/index'), target: '_blank', rel: 'noopener noreferrer')
   = s_('ClusterIntegration|Read our %{link_to_help_page} on Kubernetes cluster integration.').html_safe % { link_to_help_page: link_to_help_page}
 
-= form_for @cluster, html: { class: 'js-gke-cluster-creation prepend-top-20', data: { token: @token_in_session } }, url: gcp_namespace_project_clusters_path(@project.namespace, @project), as: :cluster do |field|
-  = form_errors(@cluster)
+%p= link_to('Select a different Google account', @authorize_url)
+
+= form_for @new_cluster, html: { class: 'js-gke-cluster-creation prepend-top-20', data: { token: @token_in_session } }, url: new_namespace_project_clusters_path(@project.namespace, @project, { type: 'new' }), as: :cluster do |field|
+  = form_errors(@new_cluster)
   .form-group
     = field.label :name, s_('ClusterIntegration|Kubernetes cluster name')
     = field.text_field :name, class: 'form-control', placeholder: s_('ClusterIntegration|Kubernetes cluster name')
@@ -13,7 +15,7 @@
     = field.label :environment_scope, s_('ClusterIntegration|Environment scope')
     = field.text_field :environment_scope, class: 'form-control', readonly: !has_multiple_clusters?(@project), placeholder: s_('ClusterIntegration|Environment scope')
 
-  = field.fields_for :provider_gcp, @cluster.provider_gcp do |provider_gcp_field|
+  = field.fields_for :provider_gcp, @new_cluster.provider_gcp do |provider_gcp_field|
     .form-group
       = provider_gcp_field.label :gcp_project_id, s_('ClusterIntegration|Google Cloud Platform project ID')
       .js-gcp-project-id-dropdown-entry-point{ data: { docsUrl: 'https://console.cloud.google.com/home/dashboard' } }

app/views/projects/clusters/gcp/_header.html.haml

-%h4.prepend-top-20
+%h4
   = s_('ClusterIntegration|Enter the details for your Kubernetes cluster')
 %p
   = s_('ClusterIntegration|Please make sure that your Google account meets the following requirements:')

app/views/projects/clusters/gcp/login.html.haml

-- breadcrumb_title 'Kubernetes'
-- page_title _("Login")
-
-= render_gcp_signup_offer
-
-.row.prepend-top-default
-  .col-sm-4
-    = render 'projects/clusters/sidebar'
-  .col-sm-8
-    = render 'projects/clusters/dropdown', dropdown_text: s_('ClusterIntegration|Create Kubernetes cluster on Google Kubernetes Engine')
-    = render 'header'
-.row
-  .col-sm-8.offset-sm-4.signin-with-google
-    - if @authorize_url
-      = link_to @authorize_url do
-        = image_tag('auth_buttons/signin_with_google.png', width: '191px')
-      = _('or')
-      = link_to('create a new Google account', 'https://accounts.google.com/SignUpWithoutGmail?service=cloudconsole&continue=https%3A%2F%2Fconsole.cloud.google.com%2Ffreetrial%3Futm_campaign%3D2018_cpanel%26utm_source%3Dgitlab%26utm_medium%3Dreferral', target: '_blank', rel: 'noopener noreferrer')
-    - else
-      - link = link_to(s_('ClusterIntegration|properly configured'), help_page_path("integration/google"), target: '_blank', rel: 'noopener noreferrer')
-      = s_('Google authentication is not %{link_to_documentation}. Ask your GitLab administrator if you want to use this service.').html_safe % { link_to_documentation: link }

app/views/projects/clusters/gcp/new.html.haml

-- breadcrumb_title 'Kubernetes'
-- page_title _("New Kubernetes Cluster")
-
-.row.prepend-top-default
-  .col-sm-4
-    = render 'projects/clusters/sidebar'
-  .col-sm-8
-    = render 'projects/clusters/dropdown', dropdown_text: s_('ClusterIntegration|Create Kubernetes cluster on Google Kubernetes Engine')
-    = render 'header'
-    = render 'form'

app/views/projects/clusters/new.html.haml

+-# TODO: Combine gcp/new and user/new views
 - breadcrumb_title 'Kubernetes'
 - page_title _("Kubernetes Cluster")
+- active_tab = local_assigns.fetch(:active_tab, 'new')
+= javascript_include_tag 'https://apis.google.com/js/api.js'
+
 
 = render_gcp_signup_offer
 
 .row.prepend-top-default
-  .col-sm-4
+  .col-sm-3
     = render 'sidebar'
-  .col-sm-8
-    %h4.prepend-top-0= s_('ClusterIntegration|Choose how to set up Kubernetes cluster integration')
+  .col-lg-9.js-toggle-container
+    %ul.nav-links.gitlab-tabs{ role: 'tablist' }
+      %li{ class: active_when(active_tab == 'new'), role: 'presentation' }
+        %a{ href: '#create-new-cluster-pane', id: 'create-new-cluster-tab', data: { toggle: 'tab' }, role: 'tab' }
+          %span Create new Cluster on GKE
+      %li{ class: active_when(active_tab == 'existing'), role: 'presentation' }
+        %a{ href: '#add-existing-cluster-pane', id: 'add-existing-cluster-tab', data: { toggle: 'tab' }, role: 'tab' }
+          %span Add existing cluster
+
+    .tab-content.gitlab-tab-content
+      .tab-pane{ id: 'create-new-cluster-pane', class: active_when(active_tab == 'new'), role: 'tabpanel' }
+        = render 'projects/clusters/gcp/header'
+        - if @token_in_session
+          = render 'projects/clusters/gcp/form'
+        - elsif @authorize_url
+          = link_to @authorize_url do
+            = image_tag('auth_buttons/signin_with_google.png', width: '191px')
+          = _('or')
+          = link_to('create a new Google account', 'https://accounts.google.com/SignUpWithoutGmail?service=cloudconsole&continue=https%3A%2F%2Fconsole.cloud.google.com%2Ffreetrial%3Futm_campaign%3D2018_cpanel%26utm_source%3Dgitlab%26utm_medium%3Dreferral', target: '_blank', rel: 'noopener noreferrer')
+        - else
+          - link = link_to(s_('ClusterIntegration|properly configured'), help_page_path("integration/google"), target: '_blank', rel: 'noopener noreferrer')
+          = s_('Google authentication is not %{link_to_documentation}. Ask your GitLab administrator if you want to use this service.').html_safe % { link_to_documentation: link }
 
-    %p= s_('ClusterIntegration|Create a new Kubernetes cluster on Google Kubernetes Engine right from GitLab')
-    = link_to s_('ClusterIntegration|Create on Google Kubernetes Engine'), gcp_new_namespace_project_clusters_path(@project.namespace, @project), class: 'btn append-bottom-20'
-    %p= s_('ClusterIntegration|Enter the details for an existing Kubernetes cluster')
-    = link_to s_('ClusterIntegration|Add an existing Kubernetes cluster'), user_new_namespace_project_clusters_path(@project.namespace, @project), class: 'btn append-bottom-20'
+      .tab-pane{ id: 'add-existing-cluster-pane', class: active_when(active_tab == 'existing'), role: 'tabpanel' }
+        = render 'projects/clusters/user/header'
+        = render 'projects/clusters/user/form'

app/views/projects/clusters/user/_form.html.haml

-= form_for @cluster, url: user_namespace_project_clusters_path(@project.namespace, @project), as: :cluster do |field|
-  = form_errors(@cluster)
+= form_for @existing_cluster, url: new_namespace_project_clusters_path(@project.namespace, @project, { type: 'existing' }), as: :cluster do |field|
+  = form_errors(@existing_cluster)
   .form-group
     = field.label :name, s_('ClusterIntegration|Kubernetes cluster name')
     = field.text_field :name, class: 'form-control', placeholder: s_('ClusterIntegration|Kubernetes cluster name')
@@ -7,7 +7,7 @@
     = field.label :environment_scope, s_('ClusterIntegration|Environment scope')
     = field.text_field :environment_scope, class: 'form-control', readonly: !has_multiple_clusters?(@project), placeholder: s_('ClusterIntegration|Environment scope')
 
-  = field.fields_for :platform_kubernetes, @cluster.platform_kubernetes do |platform_kubernetes_field|
+  = field.fields_for :platform_kubernetes, @existing_cluster.platform_kubernetes do |platform_kubernetes_field|
     .form-group
       = platform_kubernetes_field.label :api_url, s_('ClusterIntegration|API URL')
       = platform_kubernetes_field.text_field :api_url, class: 'form-control', placeholder: s_('ClusterIntegration|API URL')

app/views/projects/clusters/user/_header.html.haml

-%h4.prepend-top-20
+%h4
   = s_('ClusterIntegration|Enter the details for your Kubernetes cluster')
 %p
   - link_to_help_page = link_to(s_('ClusterIntegration|documentation'), help_page_path('user/project/clusters/index', anchor: 'adding-an-existing-kubernetes-cluster'), target: '_blank', rel: 'noopener noreferrer')

app/views/projects/clusters/user/new.html.haml

-- breadcrumb_title 'Kubernetes'
-- page_title _("New Kubernetes cluster")
-
-.row.prepend-top-default
-  .col-sm-4
-    = render 'projects/clusters/sidebar'
-  .col-sm-8
-    = render 'projects/clusters/dropdown', dropdown_text: s_('ClusterIntegration|Add an existing Kubernetes cluster')
-    = render 'header'
-    .prepend-top-20
-      = render 'form'

config/routes/project.rb

@@ -206,14 +206,7 @@ constraints(::Constraints::ProjectUrlConstrainer.new) do
 
       resources :clusters, except: [:edit, :create] do
         collection do
-          scope :providers do
-            get '/user/new', to: 'clusters/user#new'
-            post '/user', to: 'clusters/user#create'
-
-            get '/gcp/new', to: 'clusters/gcp#new'
-            get '/gcp/login', to: 'clusters/gcp#login'
-            post '/gcp', to: 'clusters/gcp#create'
-          end
+          post '/new', to: 'clusters#create_cluster'
         end
 
         member do