add like feature for comments

app/controllers/comment_controller.rb

@@ -178,4 +178,23 @@ def make_answer
     end
   end
 
+  def like_comment
+    @comment_id = params["comment_id"].to_i
+    @user_id = params["user_id"].to_i
+    comment = Comment.where(cid: @comment_id).first
+    like = comment.likes.where(user_id: @user_id)
+    @is_liked = like.count>0
+    if like.count>0
+      like.first.destroy
+    else
+      comment.likes.create(user_id: @user_id)
+    end
+
+    respond_with do |format|
+      format.js {
+       render template: 'comment/like_comment'
+      }
+    end
+  end
+
 end

app/models/comment.rb

@@ -9,6 +9,7 @@ class Comment < ActiveRecord::Base
                     # dependent: :destroy, counter_cache: true
   belongs_to :drupal_user, foreign_key: 'uid'
   belongs_to :answer, foreign_key: 'aid'
+  has_many :likes, :as => :likeable
 
   validates :comment, presence: true
 
@@ -194,4 +195,12 @@ def publish
     self
   end
 
+  def liked_by(user_id)
+    self.likes.where(user_id: user_id).count > 0
+  end
+
+  def likers
+    User.where(id: self.likes.pluck(:user_id))
+  end
+
 end

app/models/like.rb

@@ -0,0 +1,3 @@
+class Like < ActiveRecord::Base
+	belongs_to :likeable, polymorphic: true
+end

app/models/user.rb

@@ -33,6 +33,7 @@ class User < ActiveRecord::Base
   has_many :passive_relationships, class_name: 'Relationship', foreign_key: 'followed_id', dependent: :destroy
   has_many :following_users, through: :active_relationships, source: :followed
   has_many :followers, through: :passive_relationships, source: :follower
+  has_many :likes
 
   validates_with UniqueUsernameValidator, on: :create
   validates_format_of :username, with: /\A[A-Za-z\d_\-]+\z/

app/views/comment/like_comment.js.erb

@@ -0,0 +1,14 @@
+<% comment_star = "#comment-like-star-#{@comment_id}-#{@user_id}" %>
+<% comment_count = "#comment-like-count-#{@comment_id}-#{@user_id}" %>
+
+<% if @is_liked %>
+	$("<%= comment_star %>").removeClass("fa fa-star").addClass("fa fa-star-o");
+	oldValue = parseInt($("<%= comment_count %>").html());
+	newValue = oldValue-1;
+	$("<%= comment_count %>").html(newValue);
+<% else %>
+	$("<%= comment_star %>").removeClass("fa fa-star-o").addClass("fa fa-star");
+	oldValue = parseInt($("<%= comment_count %>").html());
+	newValue = oldValue+1;
+	$("<%= comment_count %>").html(newValue);	
+<% end %>

app/views/notes/_comment.html.erb

@@ -23,6 +23,26 @@
       <% end %>
     </div>
 
+      <div class="hidden-print btn-toolbar pull-right" style="margin-left:10px;">
+        <ul class="btn-group" style="margin-top: 16px; margin-right: 16px;">
+          <% if !current_user %>
+            <li rel="tooltip" title="Helpful? Like it and get updates!" class="btn btn-default btn-sm btn-like">
+            <%= link_to  new_user_session_path( return_to: request.path ), style: "text-decoration: none; color: black;" do %>
+              <span class="fa fa-star-o"></span>
+              <span><%= comment.likers.count %></span>
+            <% end %>
+          <% else %>
+            <% str = "/comment/like?comment_id=#{comment.cid}&user_id=#{current_user.uid}" %>
+            <li rel="tooltip" title="Helpful? Like it and get updates!" class="btn btn-default btn-sm btn-like">
+            <%= link_to str, data: { method: "post", remote: true }, style: "text-decoration: none; color: black;" do %>
+              <span id="comment-like-star-<%= comment.cid %>-<%= current_user.uid %>" class="fa fa-star<% if !comment.liked_by(current_user.uid) %>-o<% end %>"></span>
+              <span id="comment-like-count-<%= comment.cid %>-<%= current_user.uid %>"><%= comment.likers.count %></span>                
+            <% end %>
+          <% end %>
+          </li>
+        </ul>
+      </div>
+
     <div class="navbar-text navbar-right pull-right" style="padding-right:10px;">
       <% if comment.author && comment.author.user && comment.author.user.role %>
       <!-- Role icon for admins & moderators

config/routes.rb

@@ -269,6 +269,7 @@
 
   get 'comment/answer_create/:aid' => 'comment#answer_create'
   post 'comment/make_answer/:id' => 'comment#make_answer'
+  post '/comment/like' => 'comment#like_comment'
   # Sample resource route (maps HTTP verbs to controller actions automatically):
   #   resources :products
 

db/migrate/20180406080905_create_likes.rb

@@ -0,0 +1,11 @@
+class CreateLikes < ActiveRecord::Migration
+  def change
+    create_table :likes do |t|
+      t.integer :likeable_id
+      t.integer :user_id
+      t.string :likeable_type
+
+      t.timestamps
+    end
+  end
+end

test/fixtures/likes.yml

@@ -0,0 +1,9 @@
+# Read about fixtures at http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  likeable_id: 1
+  likeable_type: MyString
+
+two:
+  likeable_id: 1
+  likeable_type: MyString

test/models/like_test.rb

@@ -0,0 +1,7 @@
+require 'test_helper'
+
+class LikeTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end