FEATURE: simpler and friendlier unsubscribe workflow

- All unsubscribes go to the exact same page
- You may unsubscribe from watching a category on that page
- You no longer need to be logged in to unsubscribe from a topic
- Simplified footer on emails

app/controllers/email_controller.rb

@@ -1,45 +1,123 @@
 class EmailController < ApplicationController
-  skip_before_filter :check_xhr, :preload_json
+  skip_before_filter :check_xhr, :preload_json, :redirect_to_login_if_required
   layout 'no_ember'
 
   before_filter :ensure_logged_in, only: :preferences_redirect
-  skip_before_filter :redirect_to_login_if_required
 
   def preferences_redirect
     redirect_to(email_preferences_path(current_user.username_lower))
   end
 
   def unsubscribe
-    @user = DigestUnsubscribeKey.user_for_key(params[:key])
-    RateLimiter.new(@user, "unsubscribe_via_email", 3, 1.day).performed! unless @user && @user.staff?
+    key = UnsubscribeKey.find_by(key: params[:key])
 
-    # Don't allow the use of a key while logged in as a different user
-    if current_user.present? && (@user != current_user)
-      @different_user = true
-      return
+    if key
+      @user = key.user
+      post = key.post
+      @topic = (post && post.topic) || key.topic
+      @type = key.unsubscribe_key_type
+
+      if current_user.present? && (@user != current_user)
+        @different_user = @user.name
+        @return_url = request.original_url
+      end
+
+      @watching_topic = @topic && TopicUser.exists?(user_id: @user.id,
+                                                    notification_level: TopicUser.notification_levels[:watching],
+                                                    topic_id: @topic.id)
+
+      @watched_count = nil
+      if @topic && @topic.category_id
+        if CategoryUser.exists?(user_id: @user.id,
+                             notification_level: CategoryUser.notification_levels[:watching],
+                             category_id: @topic.category_id)
+          @watched_count = TopicUser.joins(:topic)
+                                    .where(:user => @user,
+                                           :notification_level => TopicUser.notification_levels[:watching],
+                                           "topics.category_id" => @topic.category_id
+                                          ).count
+        end
+      end
     end
 
     if @user.blank?
       @not_found = true
-      return
     end
-
-    if params[:from_all]
-      @user.user_option.update_columns(email_always: false,
-                                       email_digests: false,
-                                       email_direct: false,
-                                       email_private_messages: false)
-    else
-      @user.user_option.update_column(:email_digests, false)
-    end
-
-    @success = true
   end
 
-  def resubscribe
-    @user = DigestUnsubscribeKey.user_for_key(params[:key])
-    raise Discourse::NotFound unless @user.present?
-    @user.user_option.update_column(:email_digests, true)
+  def perform_unsubscribe
+
+    key = UnsubscribeKey.find_by(key: params[:key])
+    unless key && key.user
+      raise Discourse::NotFound
+    end
+
+    topic = (key.post && key.post.topic) || key.topic
+    user = key.user
+
+    updated = false
+
+    if topic
+      if params["unwatch_topic"]
+        TopicUser.where(topic_id: topic.id, user_id: user.id)
+                 .update_all(notification_level: TopicUser.notification_levels[:tracking])
+        updated = true
+      end
+
+      if params["unwatch_category"] && topic.category_id
+        TopicUser.joins(:topic)
+                 .where(:user => user,
+                       :notification_level => TopicUser.notification_levels[:watching],
+                       "topics.category_id" => topic.category_id)
+                 .update_all(notification_level: TopicUser.notification_levels[:tracking])
+
+        CategoryUser.where(user_id: user.id,
+                          category_id: topic.category_id,
+                          notification_level: CategoryUser.notification_levels[:watching]
+                         )
+                 .destroy_all
+        updated = true
+      end
+
+      if params["mute_topic"]
+        TopicUser.where(topic_id: topic.id, user_id: user.id)
+                 .update_all(notification_level: TopicUser.notification_levels[:muted])
+        updated = true
+      end
+    end
+
+    if params["disable_mailing_list"]
+      user.user_option.update_columns(email_always: false)
+      updated = true
+    end
+
+    if params["disable_digest_emails"]
+      user.user_option.update_columns(email_digests: false)
+      updated = true
+    end
+
+    if params["unsubscribe_all"]
+      user.user_option.update_columns(email_always: false,
+                                     email_digests: false,
+                                     email_direct: false,
+                                     email_private_messages: false)
+      updated = true
+    end
+
+    unless updated
+      redirect_to :back
+    else
+      if topic
+        redirect_to path("/email/unsubscribed?topic_id=#{topic.id}")
+      else
+        redirect_to path("/email/unsubscribed")
+      end
+    end
+
+  end
+
+  def unsubscribed
+    @topic = Topic.find_by(id: params[:topic_id].to_i) if params[:topic_id]
   end
 
 end