Implement languages graph page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/graphs_controller.rb

@@ -34,6 +34,26 @@ class Projects::GraphsController < Projects::ApplicationController
     @charts[:build_times] = Ci::Charts::BuildTime.new(ci_project)
   end
+  def languages
+    @languages = Linguist::Repository.new(@repository.rugged, @repository.rugged.head.target_id).languages
+    total = @languages.map(&:last).sum
+
+    @languages = @languages.map do |language|
+      name, share = language
+      color = Digest::SHA256.hexdigest(name)[0...6]
+      {
+        value: (share.to_f * 100 / total).round(2),
+        label: name,
+        color: "##{color}",
+        highlight: "##{color}"
+      }
+    end
+
+    @languages.sort! do |x, y|
+      y[:value] <=> x[:value]
+    end
+  end
+
   private
   def fetch_graph

app/views/projects/graphs/_head.html.haml

@@ -3,6 +3,8 @@
     = link_to 'Contributors', namespace_project_graph_path
   = nav_link(action: :commits) do
     = link_to 'Commits', commits_namespace_project_graph_path
+  = nav_link(action: :languages) do
+    = link_to 'Languages', languages_namespace_project_graph_path
   - if @project.builds_enabled?
     = nav_link(action: :ci) do
       = link_to ci_namespace_project_graph_path do

app/views/projects/graphs/languages.html.haml

+- page_title "Languages", "Graphs"
+= render "header_title"
+= render 'head'
+
+.gray-content-block.append-bottom-default
+  .oneline
+    Programming languages used in this repository
+
+.row
+  .col-md-8
+    %canvas#languages-chart{ height: 400 }
+  .col-md-4
+    %ul.bordered-list
+      - @languages.each do |language|
+        %li
+          %span{ style: "color: #{language[:color]}" }
+            = icon('circle')
+           
+          = language[:label]
+          .pull-right
+            = language[:value]
+            \%
+
+:javascript
+  var data = #{@languages.to_json};
+  var ctx = $("#languages-chart").get(0).getContext("2d");
+  var options = {
+    scaleOverlay: true,
+    responsive: true,
+    maintainAspectRatio: false
+  }
+  var myPieChart = new Chart(ctx).Pie(data, options);

config/routes.rb

@@ -500,6 +500,7 @@ Rails.application.routes.draw do
           member do
             get :commits
             get :ci
+            get :languages
           end
         end