Flesh out work items in the UI

app/models/concerns/Trackable.rb

@@ -0,0 +1,5 @@
+module Trackable
+  def total_overall_time
+    tracked_time_entries.sum(&:duration)
+  end
+end

app/models/concerns/course_item.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module CourseItem
+  def week_number
+    ((start_time.beginning_of_week - course.semester_start_date.to_time) / 1.week).floor + 1
+  end
+end

app/models/lecture.rb

@@ -9,7 +9,7 @@ class Lecture < ApplicationRecord
     :problems_class,
   ], default: :lecture
 
-  include Trackable
+  include Trackable, CourseItem
 
   def prepared?
     tracked_time_entries.where(kind: [:preparation]).any?
@@ -35,10 +35,6 @@ class Lecture < ApplicationRecord
     tracked_time_entries.review.sum(&:duration).seconds
   end
 
-  def week_number
-    ((start_time.beginning_of_week - course.semester_start_date.to_time) / 1.week).floor + 1
-  end
-
   def live_video_url
     nil
   end

app/models/work_item.rb

@@ -2,17 +2,38 @@ class WorkItem < ApplicationRecord
   belongs_to :course
   has_many :tracked_time_entries, dependent: :destroy, as: :subject
 
-  validate :due_date_after_start_date
+  validate :date_orderings
+  include Trackable, CourseItem
 
-  include Trackable
+  def start_time
+    available_from
+  end
 
-  def due_date_after_start_date
-    if due_date.present? && start_time.present? && due_date < start_time
-      errors.add(:due_date, "can't be before start date")
+  def completed?
+    completed_at.present?
+  end
+
+  def complete!
+    update(completed_at: Time.now)
+  end
+
+  def workable?
+    available_from.past? && !completed?
+  end
+
+  def started?
+    !tracked_time_entries.empty?
+  end
+
+  private
+
+  def date_orderings
+    if due_at.present? && available_from.present? && due_at < available_from
+      errors.add(:due_at, "can't be before date work item is available")
+    end
+
+    if completed_at.present? && available_from.present? && completed_at < available_from
+      errors.add(:completed_at, "can't be before date work item is available")
     end
   end
-
-  def week_number
-    ((start_time.beginning_of_week - course.semester_start_date.to_time) / 1.week).floor + 1
-  end
 end