Limit resource likes

app/assets/javascripts/resources.js

@@ -29,20 +29,92 @@ function scrollToTop(event) {
   $('html, body').animate({scrollTop: 0}, 'slow');
 }
 
-function incrementLike(event, target) {
+//getCookie function taken from http://www.w3schools.com/js/js_cookies.asp
+function getCookie(cname) {
+    var name = cname + "=";
+    var ca = document.cookie.split(';');
+    for(var i = 0; i <ca.length; i++) {
+        var c = ca[i];
+        while (c.charAt(0)==' ') {
+            c = c.substring(1);
+        }
+        if (c.indexOf(name) == 0) {
+            return c.substring(name.length,c.length);
+        }
+    }
+    return "";
+}
+
+//setCookie function taken from http://www.w3schools.com/js/js_cookies.asp
+function setCookie(cname, cvalue, exdays) {
+    var d = new Date();
+    d.setTime(d.getTime() + (exdays*24*60*60*1000));
+    var expires = "expires="+d.toUTCString();
+    document.cookie = cname + "=" + cvalue + "; " + expires;
+}
+
+function createNewCookie(target, resourceID){
+  document.cookie = "_shescoding_likes = {}";
+  newValue = JSON.stringify({[resourceID]: true});
+  setCookie("_shescoding_likes", newValue, 365);
+  incrementLikeinDb(target);
+}
+
+function processLike(event, target){
   event.preventDefault();
-  var form = $(target).parents('form');
+  resourceID = target.parentNode.parentNode.action.split('/').slice(-3)[0]
+  if (getCookie("_shescoding_likes") === ""){
+    createNewCookie(target, resourceID);
+  } 
+  else {
+    updateExistingCookie(target, resourceID);
+  };
+};
+
+function updateLikeInDb(target, direction) {
+  updateLikesHtmlNumber(target, direction);
+  let form = $(target).parents('form');
+  let incrementUrl = form.attr("action").substring(0, form.attr("action").length-1) + direction;
+  $.ajax(incrementUrl, {
+    type: "POST"
+  });
+}
 
+function updateExistingCookie(target, resourceID){
+  let direction;
+  var oldCookie = getCookie("_shescoding_likes");
+  var newCookie = JSON.parse(oldCookie);
+  //if resourceId does not exist in the cookie (not liked yet) add it to the cookie and increment the like
+  if (!(newCookie.hasOwnProperty(resourceID))){
+    newCookie[resourceID] = true;
+    direction = 1;
+  } else {
+    //if resource id does exist in the cookie (liked), remove that resource id from cookie
+    delete newCookie[resourceID];
+    direction = -1;
+  }
+  newValue = JSON.stringify(newCookie);
+  setCookie("_shescoding_likes", newValue, 365);
+  updateLikeInDb(target, direction); 
+}
+
+function updateLikesHtmlNumber(target, direction){
+  let form = $(target).parents('form');
   var counterEl = form.find('span')[0];
-  var newCount = 1 + parseInt(counterEl.innerText, 10);
-  counterEl.innerText = newCount;
+  var button = form.find('button');
+  var newCount = parseInt(counterEl.innerText, 10) + direction;
+
+  if (newCount >= 0){
+    counterEl.innerText = newCount;
+  }
+
+  if (newCount === 0) {
+    button.removeClass('filled-heart');
+    button.addClass('heart');
+  }
 
   if (newCount === 1) {
-    var button = form.find('button');
     button.addClass('filled-heart');
-  }
+  } 
+}
 
-  $.ajax(form.attr("action"), {
-    type: "POST"
-  });
-}

app/controllers/resources_controller.rb

@@ -58,7 +58,7 @@ def update
   end
 
   def like
-    @resource.likes += 1
+    @resource.likes += params[:count].to_i
     @resource.save
     redirect_to resources_path
   end

app/views/resources/index.html.erb

@@ -49,7 +49,7 @@
             <div class="panel-data">
               <div class="date"><%= format_date(resource.date) %></div>
               <div class="likes">
-                <%= button_to like_path(resource.id), method: :post, class: "heart #{empty_or_full_heart(resource)}" do %>
+                <%= button_to like_path(resource.id, 0), method: :post, class: "heart #{empty_or_full_heart(resource)}" do %>
                   <span><%= resource.likes %></span>
                 <% end %>
               </div>
@@ -97,7 +97,7 @@
 
     // Ajax Like
     $(".heart").click(function(e){
-      incrementLike(e, this);
+      processLike(e, this);
     });
   });
 </script>

config/routes.rb

@@ -5,7 +5,7 @@
 
   resources :resources,       only: [:index]
   get 'resources/tags/:tag',  to: 'resources#index',  as: :tag
-  post 'resources/:id/like',  to: 'resources#like',   as: :like
+  post 'resources/:id/like/:count', to: 'resources#like', as: :like
 
   # Static pages
   get 'about',            to: "static_pages#about"