Introduce top nav helper

- This provides a view model which will
  power both the responsive and wide view
  of the top nav.
- Introduces a PORO for TopNavMenuItem
- Adds some Builders to help improve
  readability and maintainability of this
- Migrates a fiew nav links from the views
  to here. These will be finished in a later
  commit.

app/helpers/nav/top_nav_helper.rb

+# frozen_string_literal: true
+
+module Nav
+  module TopNavHelper
+    PROJECTS_VIEW = :projects
+
+    def top_nav_view_model(project:)
+      builder = ::Gitlab::Nav::TopNavViewModelBuilder.new
+
+      if current_user
+        build_view_model(builder: builder, project: project)
+      else
+        build_anonymous_view_model(builder: builder)
+      end
+
+      builder.build
+    end
+
+    private
+
+    def build_anonymous_view_model(builder:)
+      # These come from `app/views/layouts/nav/_explore.html.ham`
+      # TODO: We will move the rest of them shortly
+      #   https://gitlab.com/gitlab-org/gitlab/-/merge_requests/56587
+      if explore_nav_link?(:projects)
+        builder.add_primary_menu_item(
+          **projects_menu_item_attrs.merge({
+            active: active_nav_link?(path: ['dashboard#show', 'root#show', 'projects#trending', 'projects#starred', 'projects#index']),
+            href: explore_root_path
+          })
+        )
+      end
+    end
+
+    def build_view_model(builder:, project:)
+      # These come from `app/views/layouts/nav/_dashboard.html.haml`
+      if dashboard_nav_link?(:projects)
+        current_item = project ? current_project(project: project) : {}
+
+        builder.add_primary_menu_item(
+          **projects_menu_item_attrs.merge({
+            active: active_nav_link?(path: ['root#index', 'projects#trending', 'projects#starred', 'dashboard/projects#index']),
+            css_class: 'qa-projects-dropdown',
+            data: { track_label: "projects_dropdown", track_event: "click_dropdown", track_experiment: "new_repo" },
+            view: PROJECTS_VIEW
+          })
+        )
+        builder.add_view(PROJECTS_VIEW, container_view_props(current_item: current_item, submenu: projects_submenu))
+      end
+
+      if dashboard_nav_link?(:milestones)
+        builder.add_primary_menu_item(
+          id: 'milestones',
+          title: 'Milestones',
+          active: active_nav_link?(controller: 'dashboard/milestones'),
+          icon: 'clock',
+          data: { qa_selector: 'milestones_link' },
+          href: dashboard_milestones_path
+        )
+      end
+
+      # Using admin? is generally discouraged because it does not check for
+      # "admin_mode". In this case we are migrating code and check both, so
+      # we should be good.
+      # rubocop: disable Cop/UserAdmin
+      if current_user&.admin?
+        builder.add_secondary_menu_item(
+          id: 'admin',
+          title: _('Admin'),
+          active: active_nav_link?(controller: 'admin/dashboard'),
+          icon: 'admin',
+          css_class: 'qa-admin-area-link',
+          href: admin_root_path
+        )
+      end
+
+      if Gitlab::CurrentSettings.admin_mode
+        if header_link?(:admin_mode)
+          builder.add_secondary_menu_item(
+            id: 'leave_admin_mode',
+            title: _('Leave Admin Mode'),
+            active: active_nav_link?(controller: 'admin/sessions'),
+            icon: 'lock-open',
+            href: destroy_admin_session_path,
+            method: :post
+          )
+        elsif current_user.admin?
+          builder.add_secondary_menu_item(
+            id: 'enter_admin_mode',
+            title: _('Enter Admin Mode'),
+            active: active_nav_link?(controller: 'admin/sessions'),
+            icon: 'lock',
+            href: new_admin_session_path
+          )
+        end
+      end
+      # rubocop: enable Cop/UserAdmin
+    end
+
+    def projects_menu_item_attrs
+      {
+        id: 'project',
+        title: _('Projects'),
+        icon: 'project'
+      }
+    end
+
+    def container_view_props(current_item:, submenu:)
+      {
+        namespace: 'projects',
+        currentUserName: current_user&.username,
+        currentItem: current_item,
+        linksPrimary: submenu[:primary],
+        linksSecondary: submenu[:secondary]
+      }
+    end
+
+    def current_project(project:)
+      return {} unless project.persisted?
+
+      {
+        id: project.id,
+        name: project.name,
+        namespace: project.full_name,
+        webUrl: project_path(project),
+        avatarUrl: project.avatar_url
+      }
+    end
+
+    def projects_submenu
+      # These project links come from `app/views/layouts/nav/projects_dropdown/_show.html.haml`
+      builder = ::Gitlab::Nav::TopNavMenuBuilder.new
+      builder.add_primary_menu_item(id: 'your', title: _('Your projects'), href: dashboard_projects_path)
+      builder.add_primary_menu_item(id: 'starred', title: _('Starred projects'), href: starred_dashboard_projects_path)
+      builder.add_primary_menu_item(id: 'explore', title: _('Explore projects'), href: explore_root_path)
+      builder.add_secondary_menu_item(id: 'create', title: _('Create new project'), href: new_project_path)
+      builder.build
+    end
+  end
+end
+
+Nav::TopNavHelper.prepend_ee_mod

ee/app/helpers/ee/nav/top_nav_helper.rb

+# frozen_string_literal: true
+
+module EE
+  module Nav
+    module TopNavHelper
+      extend ::Gitlab::Utils::Override
+
+      private
+
+      override :build_view_model
+      def build_view_model(builder:, project:)
+        super
+
+        # These come from `ee/app/views/dashboard/_nav_link_list.html.haml`
+        if dashboard_nav_link?(:environments)
+          builder.add_primary_menu_item(
+            id: 'environments',
+            title: 'Environments',
+            icon: 'environment',
+            data: { qa_selector: 'environment_link' },
+            href: operations_environments_path
+          )
+        end
+
+        if dashboard_nav_link?(:operations)
+          builder.add_primary_menu_item(
+            id: 'operations',
+            title: 'Operations',
+            icon: 'cloud-gear',
+            data: { qa_selector: 'operations_link' },
+            href: operations_path
+          )
+        end
+
+        if dashboard_nav_link?(:security)
+          builder.add_primary_menu_item(
+            id: 'security',
+            title: 'Security',
+            icon: 'shield',
+            data: { qa_selector: 'security_link' },
+            href: security_dashboard_path
+          )
+        end
+
+        # These come from `ee/app/views/layouts/nav/_geo_primary_node_url.html.haml`
+        if ::Gitlab::Geo.secondary? && ::Gitlab::Geo.primary_node_configured?
+          builder.add_secondary_menu_item(
+            id: 'geo',
+            title: _('Go to primary node'),
+            icon: 'location-dot',
+            href: ::Gitlab::Geo.primary_node.url
+          )
+        end
+      end
+    end
+  end
+end

ee/spec/helpers/nav/top_nav_helper_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Nav::TopNavHelper do
+  describe '#top_nav_view_model' do
+    let_it_be(:user) { build_stubbed(:user) }
+
+    let(:current_user) { user }
+    let(:with_environments) { false }
+    let(:with_operations) { false }
+    let(:with_security) { false }
+
+    let(:with_geo_secondary) { false }
+    let(:with_geo_primary_node_configured) { false }
+
+    let(:subject) { helper.top_nav_view_model(project: nil) }
+
+    before do
+      allow(helper).to receive(:current_user) { current_user }
+
+      allow(helper).to receive(:header_link?).with(anything) { false }
+
+      # Defaulting all `dashboard_nav_link?` calls to false ensures the CE-specific behavior
+      # is not tested in this EE spec
+      allow(helper).to receive(:dashboard_nav_link?).with(anything) { false }
+      allow(helper).to receive(:dashboard_nav_link?).with(:environments) { with_environments }
+      allow(helper).to receive(:dashboard_nav_link?).with(:operations) { with_operations }
+      allow(helper).to receive(:dashboard_nav_link?).with(:security) { with_security }
+
+      allow(::Gitlab::Geo).to receive(:secondary?) { with_geo_secondary }
+      allow(::Gitlab::Geo).to receive(:primary_node_configured?) { with_geo_primary_node_configured }
+    end
+
+    context 'with environments' do
+      let(:with_environments) { true }
+
+      it 'has expected :primary' do
+        expected_primary = ::Gitlab::Nav::TopNavMenuItem.build(
+          data: {
+            qa_selector: 'environment_link'
+          },
+          href: '/-/operations/environments',
+          icon: 'environment',
+          id: 'environments',
+          title: 'Environments'
+        )
+        expect(subject[:primary]).to eq([expected_primary])
+      end
+    end
+
+    context 'with operations' do
+      let(:with_operations) { true }
+
+      it 'has expected :primary' do
+        expected_primary = ::Gitlab::Nav::TopNavMenuItem.build(
+          data: {
+            qa_selector: 'operations_link'
+          },
+          href: '/-/operations',
+          icon: 'cloud-gear',
+          id: 'operations',
+          title: 'Operations'
+        )
+        expect(subject[:primary]).to eq([expected_primary])
+      end
+    end
+
+    context 'with security' do
+      let(:with_security) { true }
+
+      it 'has expected :primary' do
+        expected_primary = ::Gitlab::Nav::TopNavMenuItem.build(
+          data: {
+            qa_selector: 'security_link'
+          },
+          href: '/-/security/dashboard',
+          icon: 'shield',
+          id: 'security',
+          title: 'Security'
+        )
+        expect(subject[:primary]).to eq([expected_primary])
+      end
+    end
+
+    context 'with geo' do
+      let(:with_geo_secondary) { true }
+      let(:with_geo_primary_node_configured) { true }
+      let(:url) { 'fake_url' }
+
+      before do
+        allow(::Gitlab::Geo).to receive_message_chain(:primary_node, :url) { url }
+      end
+
+      it 'has expected :secondary' do
+        expected_secondary = ::Gitlab::Nav::TopNavMenuItem.build(
+          href: url,
+          icon: 'location-dot',
+          id: 'geo',
+          title: 'Go to primary node'
+        )
+        expect(subject[:secondary]).to eq([expected_secondary])
+      end
+    end
+  end
+end

lib/gitlab/nav/top_nav_menu_builder.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Nav
+    class TopNavMenuBuilder
+      def initialize
+        @primary = []
+        @secondary = []
+      end
+
+      def add_primary_menu_item(**args)
+        add_menu_item(dest: @primary, **args)
+      end
+
+      def add_secondary_menu_item(**args)
+        add_menu_item(dest: @secondary, **args)
+      end
+
+      def build
+        {
+          primary: @primary,
+          secondary: @secondary
+        }
+      end
+
+      private
+
+      def add_menu_item(dest:, **args)
+        item = ::Gitlab::Nav::TopNavMenuItem.build(**args)
+
+        dest.push(item)
+      end
+    end
+  end
+end

lib/gitlab/nav/top_nav_menu_item.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Nav
+    class TopNavMenuItem
+      # We want to have all keyword arguments for type safety.
+      # Ordinarily we could introduce a params object, but that's kind of what
+      # this is already :/. We could also take a hash and manually check every
+      # entry, but it's much more maintainable to do rely on native Ruby.
+      # rubocop: disable Metrics/ParameterLists
+      def self.build(id:, title:, active: false, icon: '', href: '', method: nil, view: '', css_class: '', data: {})
+        {
+          id: id,
+          title: title,
+          active: active,
+          icon: icon,
+          href: href,
+          method: method,
+          view: view.to_s,
+          css_class: css_class,
+          data: data
+        }
+      end
+      # rubocop: enable Metrics/ParameterLists
+    end
+  end
+end

lib/gitlab/nav/top_nav_view_model_builder.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Nav
+    class TopNavViewModelBuilder
+      def initialize
+        @menu_builder = ::Gitlab::Nav::TopNavMenuBuilder.new
+        @views = {}
+      end
+
+      delegate :add_primary_menu_item, :add_secondary_menu_item, to: :@menu_builder
+
+      def add_view(name, props)
+        @views[name] = props
+      end
+
+      def build
+        menu = @menu_builder.build
+
+        menu.merge({
+          views: @views,
+          activeTitle: _('Menu')
+        })
+      end
+    end
+  end
+end

locale/gitlab.pot

@@ -2165,6 +2165,9 @@ msgstr ""
 msgid "Adjust your filters/search criteria above. If you believe this may be an error, please refer to the %{linkStart}Geo Troubleshooting%{linkEnd} documentation for more information."
 msgstr ""
 
+msgid "Admin"
+msgstr ""
+
 msgid "Admin Area"
 msgstr ""
 
@@ -9343,6 +9346,9 @@ msgstr ""
 msgid "Create new label"
 msgstr ""
 
+msgid "Create new project"
+msgstr ""
+
 msgid "Create new..."
 msgstr ""
 
@@ -15288,6 +15294,9 @@ msgstr ""
 msgid "Go to previous page"
 msgstr ""
 
+msgid "Go to primary node"
+msgstr ""
+
 msgid "Go to project"
 msgstr ""
 
@@ -20284,6 +20293,9 @@ msgstr ""
 msgid "Memory Usage"
 msgstr ""
 
+msgid "Menu"
+msgstr ""
+
 msgid "Merge"
 msgstr ""
 

spec/helpers/nav/top_nav_helper_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Nav::TopNavHelper do
+  include ActionView::Helpers::UrlHelper
+
+  describe '#top_nav_view_model' do
+    let_it_be(:user) { build_stubbed(:user) }
+    let_it_be(:admin) { build_stubbed(:user, :admin) }
+
+    let(:current_user) { nil }
+    let(:current_project) { nil }
+    let(:with_current_settings_admin_mode) { false }
+    let(:with_header_link_admin_mode) { false }
+    let(:with_projects) { false }
+    let(:with_milestones) { false }
+
+    let(:subject) { helper.top_nav_view_model(project: current_project) }
+
+    let(:active_title) { 'Menu' }
+
+    before do
+      allow(helper).to receive(:current_user) { current_user }
+      allow(Gitlab::CurrentSettings).to receive(:admin_mode) { with_current_settings_admin_mode }
+      allow(helper).to receive(:header_link?).with(:admin_mode) { with_header_link_admin_mode }
+
+      # Defaulting all `dashboard_nav_link?` calls to false ensures the EE-specific behavior
+      # is not enabled in this CE spec
+      allow(helper).to receive(:dashboard_nav_link?).with(anything) { false }
+
+      allow(helper).to receive(:dashboard_nav_link?).with(:projects) { with_projects }
+      allow(helper).to receive(:dashboard_nav_link?).with(:milestones) { with_milestones }
+    end
+
+    it 'has :activeTitle' do
+      expect(subject[:activeTitle]).to eq(active_title)
+    end
+
+    context 'when current_user is nil (anonymous)' do
+      it 'has expected :primary' do
+        expected_primary = ::Gitlab::Nav::TopNavMenuItem.build(
+          href: '/explore',
+          icon: 'project',
+          id: 'project',
+          title: 'Projects'
+        )
+        expect(subject[:primary]).to eq([expected_primary])
+      end
+    end
+
+    context 'when current_user is non-admin' do
+      let(:current_user) { user }
+
+      it 'has no menu items or views by default' do
+        expect(subject).to eq({ activeTitle: active_title,
+                                primary: [],
+                                secondary: [],
+                                views: {} })
+      end
+
+      context 'with projects' do
+        let(:with_projects) { true }
+        let(:projects_view) { subject[:views][:projects] }
+
+        it 'has expected :primary' do
+          expected_primary = ::Gitlab::Nav::TopNavMenuItem.build(
+            css_class: 'qa-projects-dropdown',
+            data: {
+              track_event: 'click_dropdown',
+              track_experiment: 'new_repo',
+              track_label: 'projects_dropdown'
+            },
+            icon: 'project',
+            id: 'project',
+            title: 'Projects',
+            view: 'projects'
+          )
+          expect(subject[:primary]).to eq([expected_primary])
+        end
+
+        context 'projects' do
+          it 'has expected :currentUserName' do
+            expect(projects_view[:currentUserName]).to eq(current_user.username)
+          end
+
+          it 'has expected :namespace' do
+            expect(projects_view[:namespace]).to eq('projects')
+          end
+
+          it 'has expected :linksPrimary' do
+            expected_links_primary = [
+              ::Gitlab::Nav::TopNavMenuItem.build(
+                href: '/dashboard/projects',
+                id: 'your',
+                title: 'Your projects'
+              ),
+              ::Gitlab::Nav::TopNavMenuItem.build(
+                href: '/dashboard/projects/starred',
+                id: 'starred',
+                title: 'Starred projects'
+              ),
+              ::Gitlab::Nav::TopNavMenuItem.build(
+                href: '/explore',
+                id: 'explore',
+                title: 'Explore projects'
+              )
+            ]
+            expect(projects_view[:linksPrimary]).to eq(expected_links_primary)
+          end
+
+          it 'has expected :linksSecondary' do
+            expected_links_secondary = [
+              ::Gitlab::Nav::TopNavMenuItem.build(
+                href: '/projects/new',
+                id: 'create',
+                title: 'Create new project'
+              )
+            ]
+            expect(projects_view[:linksSecondary]).to eq(expected_links_secondary)
+          end
+
+          context 'with persisted project' do
+            let_it_be(:project) { build_stubbed(:project) }
+
+            let(:current_project) { project }
+            let(:avatar_url) { 'avatar_url' }
+
+            before do
+              allow(project).to receive(:persisted?) { true }
+              allow(project).to receive(:avatar_url) { avatar_url }
+            end
+
+            it 'has project as :container' do
+              expected_container = {
+                avatarUrl: avatar_url,
+                id: project.id,
+                name: project.name,
+                namespace: project.full_name,
+                webUrl: project_path(project)
+              }
+
+              expect(projects_view[:currentItem]).to eq(expected_container)
+            end
+          end
+        end
+      end
+
+      context 'with milestones' do
+        let(:with_milestones) { true }
+
+        it 'has expected :primary' do
+          expected_primary = ::Gitlab::Nav::TopNavMenuItem.build(
+            data: {
+              qa_selector: 'milestones_link'
+            },
+            href: '/dashboard/milestones',
+            icon: 'clock',
+            id: 'milestones',
+            title: 'Milestones'
+          )
+          expect(subject[:primary]).to eq([expected_primary])
+        end
+      end
+    end
+
+    context 'when current_user is admin' do
+      let_it_be(:current_user) { admin }
+
+      let(:with_current_settings_admin_mode) { true }
+
+      it 'has admin as first :secondary item' do
+        expected_admin_item = ::Gitlab::Nav::TopNavMenuItem.build(
+          id: 'admin',
+          title: 'Admin',
+          icon: 'admin',
+          href: '/admin',
+          css_class: 'qa-admin-area-link'
+        )
+
+        expect(subject[:secondary].first).to eq(expected_admin_item)
+      end
+
+      context 'with header link admin_mode true' do
+        let(:with_header_link_admin_mode) { true }
+
+        it 'has leave_admin_mode as last :secondary item' do
+          expected_leave_admin_mode_item = ::Gitlab::Nav::TopNavMenuItem.build(
+            id: 'leave_admin_mode',
+            title: 'Leave Admin Mode',
+            icon: 'lock-open',
+            href: '/admin/session/destroy',
+            method: :post
+          )
+          expect(subject[:secondary].last).to eq(expected_leave_admin_mode_item)
+        end
+      end
+
+      context 'with header link admin_mode false' do
+        let(:with_header_link_admin_mode) { false }
+
+        it 'has enter_admin_mode as last :secondary item' do
+          expected_enter_admin_mode_item = ::Gitlab::Nav::TopNavMenuItem.build(
+            id: 'enter_admin_mode',
+            title: 'Enter Admin Mode',
+            icon: 'lock',
+            href: '/admin/session/new'
+          )
+          expect(subject[:secondary].last).to eq(expected_enter_admin_mode_item)
+        end
+      end
+    end
+  end
+end

spec/lib/gitlab/nav/top_nav_menu_item_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe ::Gitlab::Nav::TopNavMenuItem do
+  describe '.build' do
+    it 'builds a hash from the given args' do
+      item = {
+        id: 'id',
+        title: 'Title',
+        active: true,
+        icon: 'icon',
+        href: 'href',
+        method: 'method',
+        view: 'view',
+        css_class: 'css_class',
+        data: {}
+      }
+
+      expect(described_class.build(**item)).to eq(item)
+    end
+  end
+end