poro.rb

class SchoolStatusManager

  def initialize(school)
    @school = school
  end

  def set_status!
    @school.update_attribute :status, school_status
  end

  private

  def school_status
    if @school.enrollment_begins_state?
      SchoolState::ENROLLMENT_BEGINS
    elsif @school.pre_enrollment_state?
      SchoolState::PRE_ENROLLMENT
    elsif @school.authorized_course_state?
      SchoolState::AUTHORIZED_COURSE
    end
  end
end

school.rb

 def authorized_course_state?(school = self)
    School.joins{ demands }.where{ demands.school_id.eq school.id }.any? && School.joins{ pre_enrollments }.where{ pre_enrollments.school_id.eq school.id }.empty?
  end

  def pre_enrollment_state?(school = self)
    School.joins{ pre_enrollments }.where{ pre_enrollments.school_id.eq school.id }.any? && School.joins{ pre_enrollments.enrollment }.where{ pre_enrollments.school_id.eq school.id }.empty?
  end

  def enrollment_begins_state?(school = self)
    School.joins{ pre_enrollments.enrollment }.where{ pre_enrollments.school_id.eq school.id }.any?
  end