Add deep links for selected value stream

Group value stream page has an option to select between
multiple value stream available. So we should be able to
get a link to a particular value stream directly.

ee/app/controllers/groups/analytics/cycle_analytics_controller.rb

@@ -10,6 +10,7 @@ class Groups::Analytics::CycleAnalyticsController < Groups::Analytics::Applicati
 
   before_action :load_group, only: :show
   before_action :load_project, only: :show
+  before_action :load_value_stream, only: :show
   before_action :request_params, only: :show
 
   before_action do
@@ -28,6 +29,12 @@ class Groups::Analytics::CycleAnalyticsController < Groups::Analytics::Applicati
 
   override :all_cycle_analytics_params
   def all_cycle_analytics_params
-    super.merge({ group: @group })
+    super.merge({ group: @group, value_stream: @value_stream })
+  end
+
+  def load_value_stream
+    return unless @group && params[:value_stream_id]
+
+    @value_stream = @group.value_streams.find(params[:value_stream_id])
   end
 end

ee/lib/gitlab/analytics/cycle_analytics/request_params.rb

@@ -34,6 +34,7 @@ module Gitlab
         attribute :created_before, :datetime
         attribute :group
         attribute :current_user
+        attribute :value_stream
 
         FINDER_PARAM_NAMES.each do |param_name|
           attribute param_name
@@ -68,6 +69,7 @@ module Gitlab
         def to_data_attributes
           {}.tap do |attrs|
             attrs[:group] = group_data_attributes if group
+            attrs[:value_stream] = value_stream_data_attributes if value_stream
             attrs[:created_after] = created_after.to_date.iso8601
             attrs[:created_before] = created_before.to_date.iso8601
             attrs[:projects] = group_projects(project_ids) if group && project_ids.present?
@@ -90,6 +92,12 @@ module Gitlab
           }
         end
 
+        def value_stream_data_attributes
+          {
+            id: value_stream.id
+          }
+        end
+
         def group_projects(project_ids)
           GroupProjectsFinder.new(
             group: group,

ee/spec/controllers/groups/analytics/cycle_analytics_controller_spec.rb

@@ -62,4 +62,16 @@ RSpec.describe Groups::Analytics::CycleAnalyticsController do
       expect(response).to have_gitlab_http_status(:not_found)
     end
   end
+
+  context 'with group and value stream params' do
+    let(:value_stream) { create(:cycle_analytics_group_value_stream, group: group) }
+
+    it 'builds request params with group and value stream' do
+      expect_next_instance_of(Gitlab::Analytics::CycleAnalytics::RequestParams) do |instance|
+        expect(instance).to have_attributes(group: group, value_stream: value_stream)
+      end
+
+      get(:show, params: { group_id: group, value_stream_id: value_stream })
+    end
+  end
 end

ee/spec/lib/gitlab/analytics/cycle_analytics/request_params_spec.rb

@@ -168,6 +168,26 @@ RSpec.describe Gitlab::Analytics::CycleAnalytics::RequestParams do
     end
   end
 
+  describe 'optional `value_stream`' do
+    context 'when `value_stream` is not empty' do
+      let(:value_stream) { instance_double('Analytics::CycleAnalytics::GroupValueStream') }
+
+      before do
+        params[:value_stream] = value_stream
+      end
+
+      it { expect(subject.value_stream).to eq(value_stream) }
+    end
+
+    context 'when `value_stream` is nil' do
+      before do
+        params[:value_stream] = nil
+      end
+
+      it { expect(subject.value_stream).to eq(nil) }
+    end
+  end
+
   describe 'issuable filter params' do
     before do
       params.merge!(