Create alert for assignment_missing

Refs MBL-10482

Test Plan:
 - Create a super observer connected to a student
 - Student should be enrolled in a course
 - Create a threshold for `assignment_missing` for that student
   - POST /api/v1/users/observer_alert_thresholds
   - {
       student_id: :student_id,
       threshold: {
        alert_type: 'assignment_missing'
       }
     }
 - Create an assignment that is due in the course for a minute
   or two in the future
 - Wait at least 5 minutes
 - As the observer hit /api/v1/users/self/observer_alerts/:student_id
 - There should be an alert for that user

Change-Id: If2dea94052ff932c866a7382a2119a3287350c28
Reviewed-on: https://gerrit.instructure.com/152073
Reviewed-by: Cameron Sutter <csutter@instructure.com>
Product-Review: Cameron Sutter <csutter@instructure.com>
Tested-by: Jenkins
QA-Review: Taylor Wilson <twilson@instructure.com>

app/models/observer_alert.rb

@@ -19,7 +19,7 @@ class ObserverAlert < ActiveRecord::Base
   belongs_to :student, :class_name => 'User', inverse_of: :as_student_observer_alerts, :foreign_key => :user_id
   belongs_to :observer, :class_name => 'User', inverse_of: :as_observer_observer_alerts
   belongs_to :observer_alert_threshold, :inverse_of => :observer_alerts
-  belongs_to :context, polymorphic: [:discussion_topic, :assignment, :course, :account_notification]
+  belongs_to :context, polymorphic: [:discussion_topic, :assignment, :course, :account_notification, :submission]
 
   ALERT_TYPES = %w(
     assignment_missing
@@ -53,4 +53,45 @@ class ObserverAlert < ActiveRecord::Base
   def self.clean_up_old_alerts
     ObserverAlert.where('created_at < ?', 6.months.ago).delete_all
   end
+
+  def self.create_assignment_missing_alerts
+    submissions = Submission.active.
+      preload(user: :as_student_observer_alert_thresholds).
+      joins(:assignment).
+      joins("INNER JOIN #{ObserverAlertThreshold.quoted_table_name} observer_alert_thresholds ON observer_alert_thresholds.user_id = submissions.user_id AND observer_alert_thresholds.workflow_state <> 'deleted'").
+      joins("LEFT OUTER JOIN #{ObserverAlert.quoted_table_name} ON observer_alerts.context_id = submissions.id
+             AND observer_alerts.context_type = 'Submission'
+             AND observer_alerts.alert_type = 'assignment_missing'").
+      for_enrollments(Enrollment.all_active_or_pending).
+      missing.
+      merge(Assignment.submittable).
+      where('cached_due_date > ?', 1.day.ago).
+      where("observer_alerts.id IS NULL").
+      where("observer_alert_thresholds.alert_type = 'assignment_missing'")
+
+      alerts = []
+      submissions.find_each do |submission|
+        threshold = submission.user.as_student_observer_alert_thresholds.first
+        next unless threshold.users_are_still_linked?
+
+        now = Time.now.utc
+        alerts << { observer_id: threshold.observer.id,
+                    user_id: threshold.student.id,
+                    observer_alert_threshold_id: threshold.id,
+                    alert_type: "assignment_missing",
+                    context_type: 'Submission',
+                    context_id: submission.id,
+                    created_at: now,
+                    updated_at: now,
+                    action_date: now,
+                    title: I18n.t('Assignment missing: %{assignment_name} in %{course_name}', {
+                      assignment_name: submission.assignment.title,
+                      course_name: submission.assignment.course.name
+                    }) }
+      end
+
+      alerts.each_slice(1000) do |slice|
+        ObserverAlert.bulk_insert(slice)
+      end
+  end
 end

config/initializers/periodic_jobs.rb

@@ -216,6 +216,10 @@ Rails.configuration.after_initialize do
     with_each_shard_by_database(ObserverAlert, :clean_up_old_alerts)
   end
 
+  Delayed::Periodic.cron 'ObserverAlert.create_assignment_missing_alerts', '*/5 * * * *', priority: Delayed::LOW_PRIORITY do
+    with_each_shard_by_database(ObserverAlert, :create_missing_assignment_alerts)
+  end
+
   Delayed::Periodic.cron 'abandoned job cleanup', '*/10 * * * *' do
     Delayed::Worker::HealthCheck.reschedule_abandoned_jobs
   end

spec/models/observer_alert_spec.rb

@@ -155,6 +155,50 @@ describe ObserverAlert do
     end
   end
 
+  describe 'create_assignment_missing_alerts' do
+    before :once do
+      @course = course_factory()
+      @student1 = student_in_course(active_all: true, course: @course).user
+      @observer1 = course_with_observer(course: @course, associated_user_id: @student.id, active_all: true).user
+      observer_alert_threshold_model(student: @student, observer: @observer, alert_type: 'assignment_missing')
+
+      @student2 = student_in_course(active_all: true, course: @course).user
+      @observer2 = course_with_observer(course: @course, associated_user_id: @student2.id, active_all: true).user
+      @link2 = UserObservationLink.create!(student: @student2, observer: @observer2, root_account: @account)
+
+      assignment_model(context: @course, due_at: 5.minutes.ago, submission_types: 'online_text_entry')
+      @student3 = student_in_course(active_all: true, course: @course).user
+      @observer3 = course_with_observer(course: @course, associated_user_id: @student3.id, active_all: true).user
+      observer_alert_threshold_model(student: @student3, observer: @observer3, alert_type: 'assignment_missing')
+      @assignment.submit_homework(@student3, :submission_type => 'online_text_entry', :body => 'done')
+
+      ObserverAlert.create_assignment_missing_alerts
+    end
+
+    it 'creates an assignment_missing_alert' do
+      alert = ObserverAlert.active.where(student: @student1, alert_type: 'assignment_missing').first
+      expect(alert.alert_type).to eq 'assignment_missing'
+      expect(alert.context.user).to eq @student1
+    end
+
+    it 'doesnt create another alert if one already exists' do
+      alert = ObserverAlert.active.where(student: @student2, alert_type: 'assignment_missing').first
+      expect(alert).to be_nil
+    end
+
+    it 'doesnt create an alert if the submission is not missing' do
+      alert = ObserverAlert.where(student: @student3, alert_type: 'assignment_missing').first
+      expect(alert).to be_nil
+    end
+
+    it 'doesnt create an alert for if there is no threshold' do
+      ObserverAlert.create_assignment_missing_alerts
+      alert = ObserverAlert.where(student: @student2).first
+
+      expect(alert).to be_nil
+    end
+  end
+
   describe 'institution_announcement' do
     before :once do
       @no_link_account = account_model