class WorkItem < ApplicationRecord
  belongs_to :course
  has_many :tracked_time_entries, dependent: :destroy, as: :subject

  validate :due_date_after_start_date

  include Trackable

  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")
    end
  end

  def week_number
    ((start_time.beginning_of_week - course.semester_start_date.to_time) / 1.week).floor + 1
  end
end