module EnrollmentsController

  include Gaku::ClassNameDetector

  def enroll_students
    @selected_students = params[:selected_students].presence || []
    enroll_selected_students

    if params[:source] == class_name_underscored_plural
      set_resource
      set_count

      if class_name_underscored_plural == 'courses'
        render "gaku/#{class_name_underscored_plural}/enrollments/students/enroll_students"
      else
        render "gaku/#{class_name_underscored_plural}/students/enroll_students"
      end
    #else
    #  flash.now[:notice] = notice.html_safe
    #  render partial: 'gaku/shared/flash', locals: {flash: flash}
    end
  end

  private

  def set_resource
    @resource = class_name_minus_enrollment.constantize.find(params[enrollment_param])
  end

  def set_count
    @count = @resource.enrollments.count
  end

  def enroll_selected_students
    @err_enrollments = []
    @enrollments = []

    @selected_students.each do |student|
      student_id = student.split('-')[1].to_i
      enrollment = class_name.constantize.new(enrollment_param => params[enrollment_param], student_id: student_id)
      if enrollment.save
        @enrollments << enrollment
      else
        @err_enrollments << enrollment
      end
    end

    if @enrollments.empty?
      flash_failure @err_enrollments
    else
      flash_success @enrollments
    end
  end

  def flash_failure(enrollments)
    msg = ''
    enrollments.each do |enrollment|
      student = Gaku::Student.find(enrollment.student_id)
      msg += msg_for_failed_enrollment(student, enrollment.errors.full_messages.join(', '))
    end
    flash.now[:error] = msg.html_safe
  end


  def flash_success(enrollments)
    msg = ''
    enrollments.each do |enrollment|
      student = Gaku::Student.find(enrollment.student_id)
      msg += msg_for_enrollment(student)
    end
    flash.now[:success] = msg.html_safe
  end

  def msg_for_enrollment(student)
    "<p>#{student} : <span style='color:green;'> #{t(:'success.enrolled')}</span></p>"
  end


  def msg_for_failed_enrollment(student, errors)
    "<p>#{student} : <span style='color:orange;'> #{errors}</span></p>"
  end

end