FEATURE: Warn a user when they have few likes remaining

app/assets/javascripts/discourse/mixins/ajax.js

@@ -66,6 +66,10 @@ Discourse.Ajax = Em.Mixin.create({
           });
         }
 
+        if (args.returnXHR) {
+          data = { result: data, xhr };
+        }
+
         Ember.run(null, resolve, data);
       };
 

app/assets/javascripts/discourse/models/action-summary.js.es6

@@ -18,10 +18,7 @@ export default RestModel.extend({
   },
 
   togglePromise(post) {
-    if (!this.get('acted')) {
-      return this.act(post).then(() => true);
-    }
-    return this.undo(post).then(() => false);
+    return this.get('acted') ? this.undo(post) : this.act(post);
   },
 
   toggle(post) {
@@ -64,11 +61,15 @@ export default RestModel.extend({
         message: opts.message,
         take_action: opts.takeAction,
         flag_topic: this.get('flagTopic') ? true : false
-      }
-    }).then(function(result) {
+      },
+      returnXHR: true,
+    }).then(function(data) {
       if (!self.get('flagTopic')) {
-        return post.updateActionsSummary(result);
+        post.updateActionsSummary(data.result);
       }
+      const remaining = parseInt(data.xhr.getResponseHeader('Discourse-Actions-Remaining') || 0);
+      const max = parseInt(data.xhr.getResponseHeader('Discourse-Actions-Max') || 0);
+      return { acted: true, remaining, max };
     }).catch(function(error) {
       popupAjaxError(error);
       self.removeAction(post);
@@ -83,7 +84,10 @@ export default RestModel.extend({
     return Discourse.ajax("/post_actions/" + post.get('id'), {
       type: 'DELETE',
       data: { post_action_type_id: this.get('id') }
-    }).then(result => post.updateActionsSummary(result));
+    }).then(result => {
+      post.updateActionsSummary(result);
+      return { acted: false };
+    });
   },
 
   deferFlags(post) {

app/assets/javascripts/discourse/widgets/post.js.es6

@@ -423,7 +423,27 @@ export default createWidget('post', {
     const likeAction = post.get('likeAction');
 
     if (likeAction && likeAction.get('canToggle')) {
-      return likeAction.togglePromise(post);
+      return likeAction.togglePromise(post).then(result => this._warnIfClose(result));
+    }
+  },
+
+  _warnIfClose(result) {
+    if (!result || !result.acted) { return; }
+
+    const kvs = this.keyValueStore;
+    const lastWarnedLikes = kvs.get('lastWarnedLikes');
+
+    // only warn once per day
+    const yesterday = new Date().getTime() - 1000 * 60 * 60 * 24;
+    if (lastWarnedLikes && parseInt(lastWarnedLikes) > yesterday) {
+      return;
+    }
+
+    const { remaining, max } = result;
+    const threshold = Math.ceil(max * 0.1);
+    if (remaining === threshold) {
+      bootbox.alert(I18n.t('post.few_likes_left'));
+      kvs.set({ key: 'lastWarnedLikes', value: new Date().getTime() });
     }
   },
 

app/assets/javascripts/discourse/widgets/widget.js.es6

@@ -119,6 +119,7 @@ export default class Widget {
     this.currentUser = container.lookup('current-user:main');
     this.store = container.lookup('store:main');
     this.appEvents = container.lookup('app-events:main');
+    this.keyValueStore = container.lookup('key-value-store:main');
 
     if (this.name) {
       const custom = _customSettings[this.name];

app/controllers/post_actions_controller.rb

@@ -21,6 +21,12 @@ class PostActionsController < ApplicationController
     else
       # We need to reload or otherwise we are showing the old values on the front end
       @post.reload
+
+      if @post_action_type_id == PostActionType.types[:like]
+        limiter = post_action.post_action_rate_limiter
+        response.headers['Discourse-Actions-Remaining'] = limiter.remaining.to_s
+        response.headers['Discourse-Actions-Max'] = limiter.max.to_s
+      end
       render_post_json(@post, _add_raw = false)
     end
   end

config/locales/client.en.yml

@@ -1511,6 +1511,8 @@ en:
       archetypes:
         save: 'Save Options'
 
+      few_likes_left: "Warning: You have few likes left to give today. Use them wisely!"
+
       controls:
         reply: "begin composing a reply to this post"
         like: "like this post"

lib/rate_limiter.rb

@@ -67,6 +67,15 @@ class RateLimiter
     $redis.lpop(@key)
   end
 
+  def remaining
+    return @max if @user && @user.staff?
+
+    arr = $redis.lrange(@key, 0, @max) || []
+    t0 = Time.now.to_i
+    arr.reject! {|a| (t0 - a.to_i) > @secs}
+    @max - arr.size
+  end
+
   private
 
   def seconds_to_wait

spec/components/rate_limiter_spec.rb

@@ -39,6 +39,16 @@ describe RateLimiter do
       end
     end
 
+    context "remaining" do
+      it "updates correctly" do
+        expect(rate_limiter.remaining).to eq(2)
+        rate_limiter.performed!
+        expect(rate_limiter.remaining).to eq(1)
+        rate_limiter.performed!
+        expect(rate_limiter.remaining).to eq(0)
+      end
+    end
+
     context "multiple calls" do
       before do
         rate_limiter.performed!
@@ -47,6 +57,7 @@ describe RateLimiter do
 
       it "returns false for can_perform when the limit has been hit" do
         expect(rate_limiter.can_perform?).to eq(false)
+        expect(rate_limiter.remaining).to eq(0)
       end
 
       it "raises an error the third time called" do
@@ -54,10 +65,10 @@ describe RateLimiter do
       end
 
       context "as an admin/moderator" do
-
         it "returns true for can_perform if the user is an admin" do
           user.admin = true
           expect(rate_limiter.can_perform?).to eq(true)
+          expect(rate_limiter.remaining).to eq(2)
         end
 
         it "doesn't raise an error when an admin performs the task" do
@@ -74,8 +85,6 @@ describe RateLimiter do
           user.moderator = true
           expect { rate_limiter.performed! }.not_to raise_error
         end
-
-
       end
 
       context "rollback!" do
@@ -90,7 +99,6 @@ describe RateLimiter do
         it "raises no error now that there is room" do
           expect { rate_limiter.performed! }.not_to raise_error
         end
-
       end
 
     end

spec/models/post_action_spec.rb

@@ -12,6 +12,10 @@ describe PostAction do
   let(:second_post) { Fabricate(:post, topic_id: post.topic_id) }
   let(:bookmark) { PostAction.new(user_id: post.user_id, post_action_type_id: PostActionType.types[:bookmark] , post_id: post.id) }
 
+  def value_for(user_id, dt)
+    GivenDailyLike.find_for(user_id, dt).pluck(:likes_given)[0] || 0
+  end
+
   describe "rate limits" do
 
     it "limits redo/undo" do
@@ -172,7 +176,7 @@ describe PostAction do
         # we need this to test it
         TopicUser.change(codinghorror, post.topic, posted: true)
 
-        expect(GivenDailyLike.value_for(moderator.id, Date.today)).to eq(0)
+        expect(value_for(moderator.id, Date.today)).to eq(0)
 
         PostAction.act(moderator, post, PostActionType.types[:like])
         PostAction.act(codinghorror, second_post, PostActionType.types[:like])
@@ -180,7 +184,7 @@ describe PostAction do
         post.topic.reload
         expect(post.topic.like_count).to eq(2)
 
-        expect(GivenDailyLike.value_for(moderator.id, Date.today)).to eq(1)
+        expect(value_for(moderator.id, Date.today)).to eq(1)
 
         tu = TopicUser.get(post.topic, codinghorror)
         expect(tu.liked).to be true
@@ -251,7 +255,7 @@ describe PostAction do
         expect(post.like_score).to eq(1)
         post.topic.reload
         expect(post.topic.like_count).to eq(1)
-        expect(GivenDailyLike.value_for(codinghorror.id, Date.today)).to eq(1)
+        expect(value_for(codinghorror.id, Date.today)).to eq(1)
 
         # When a staff member likes it
         PostAction.act(moderator, post, PostActionType.types[:like])
@@ -264,7 +268,7 @@ describe PostAction do
         post.reload
         expect(post.like_count).to eq(1)
         expect(post.like_score).to eq(3)
-        expect(GivenDailyLike.value_for(codinghorror.id, Date.today)).to eq(0)
+        expect(value_for(codinghorror.id, Date.today)).to eq(0)
 
         PostAction.remove_act(moderator, post, PostActionType.types[:like])
         post.reload