Add reset! method to trending petition journal

app/models/signature.rb

@@ -114,6 +114,13 @@ def self.trending_ips(since: 1.hour.ago, limit: 20)
     count(:all)
   end
 
+  def self.validated_dates
+    validated.
+    where.not(validated_at: nil).
+    order("date").
+    pluck("DISTINCT date(validated_at) as date")
+  end
+
   scope :in_days, ->(number_of_days) { validated.where("updated_at > ?", number_of_days.day.ago) }
   scope :matching, ->(signature) { where(email: signature.email,
                                          name: signature.name,

app/models/trending_petition_journal.rb

@@ -34,6 +34,30 @@ def invalidate_signature_for(signature, now = Time.current)
       end
     end
 
+    def reset!
+      connection.execute "TRUNCATE TABLE trending_petition_journals"
+
+      Petition.find_each do |petition|
+        petition.signatures.validated_dates.each do |date|
+          journal = self.for(petition, date)
+
+          journal.with_lock do
+            updates = petition
+              .signatures
+              .validated
+              .select("count(petition_id), EXTRACT(hour from validated_at) as hour")
+              .where("date(validated_at) = ?", date)
+              .group("hour")
+              .each_with_object({}) do |interval, updates|
+                updates["hour_#{interval.hour.to_i}_signature_count"] = interval.count
+              end
+
+            journal.update_columns(updates.merge(updated_at: Time.current))
+          end
+        end
+      end
+    end
+
     private
 
     def unrecordable?(signature)

spec/models/signature_spec.rb

@@ -615,6 +615,25 @@
     end
   end
 
+  describe ".validated_dates" do
+    let(:now) { Time.parse("1 Jan 2017 08:30") }
+
+    around do |example|
+      travel_to(now) { example.run }
+    end
+
+    it "returns an ordered array of unique dates based on the validated at timestamp" do
+      FactoryGirl.create(:validated_signature, validated_at: now)
+      FactoryGirl.create(:validated_signature, validated_at: now)
+      FactoryGirl.create(:validated_signature, validated_at: now - 1.day)
+      FactoryGirl.create(:validated_signature, validated_at: now - 3.days)
+      FactoryGirl.create(:invalidated_signature, validated_at: now - 4.days)
+
+      expect(described_class.validated_dates)
+        .to eq [Date.parse("29 Dec 2016"), Date.parse("31 Dec 2016"), Date.parse("1 Jan 2017")]
+    end
+  end
+
   describe "#number" do
     let(:attributes) { FactoryGirl.attributes_for(:petition) }
     let(:creator) { FactoryGirl.create(:pending_signature) }

spec/models/trending_petition_journal_spec.rb

@@ -210,5 +210,69 @@ def journal
       end
     end
   end
+
+  describe ".reset!" do
+    let(:petition_1) { FactoryGirl.create(:petition) }
+    let(:petition_2) { FactoryGirl.create(:petition) }
+    let(:today) { Time.parse("1 Jan 2017 08:00") }
+    let(:two_hours_ago) { today - 2.hours }
+    let(:two_days_ago) { today - 2.days }
+
+    around do |example|
+      travel_to(today) { example.run }
+    end
+
+    before do
+      described_class.for(petition_1).update_attribute(:hour_8_signature_count, 20)
+      described_class.for(petition_2).update_attribute(:hour_8_signature_count, 100)
+    end
+
+    context "when there are no signatures" do
+      it "resets all the hourly counts to 0 except for 1 for the creator signature" do
+        described_class.reset!
+
+        expect(described_class.for(petition_1).hour_8_signature_count).to eq 1
+        expect(described_class.for(petition_2).hour_8_signature_count).to eq 1
+
+        [*0..7, *9..23].each do |hour|
+          expect(
+            described_class.for(petition_1)
+            .public_send("hour_#{hour}_signature_count")
+          ).to eq 0
+
+          expect(
+            described_class.for(petition_2)
+            .public_send("hour_#{hour}_signature_count")
+          ).to eq 0
+        end
+      end
+    end
+
+    context "when there are signatures" do
+      before do
+        2.times { FactoryGirl.create(:validated_signature, petition: petition_1, validated_at: today) }
+        2.times { FactoryGirl.create(:validated_signature, petition: petition_1, validated_at: two_hours_ago) }
+        3.times { FactoryGirl.create(:validated_signature, petition: petition_1, validated_at: two_days_ago) }
+        2.times { FactoryGirl.create(:pending_signature, petition: petition_1) }
+
+        1.times { FactoryGirl.create(:validated_signature, petition: petition_2, validated_at: today) }
+        1.times { FactoryGirl.create(:validated_signature, petition: petition_2, validated_at: two_hours_ago) }
+        2.times { FactoryGirl.create(:validated_signature, petition: petition_2, validated_at: two_days_ago) }
+        1.times { FactoryGirl.create(:pending_signature, petition: petition_2) }
+      end
+
+      it "resets the counts to that of the validated signatures for the petition, day and hour" do
+        described_class.reset!
+
+        expect(described_class.for(petition_1, today).hour_8_signature_count).to eq 3 # +1 for creator signature
+        expect(described_class.for(petition_1, today).hour_6_signature_count).to eq 2
+        expect(described_class.for(petition_1, two_days_ago).hour_8_signature_count).to eq 3
+
+        expect(described_class.for(petition_2, today).hour_8_signature_count).to eq 2 # +1 for creator signature
+        expect(described_class.for(petition_2, today).hour_6_signature_count).to eq 1
+        expect(described_class.for(petition_2, two_days_ago).hour_8_signature_count).to eq 2
+      end
+    end
+  end
 end