if @exercises_count > 0
  json.exercises do
    json.array! @exercises do |exercise|
      json.extract! exercise, :id, :exercise_name,:is_public,:created_at
      if @is_teacher_or == 2
        second_left = get_exercise_left_time(exercise,@current_user_)
        json.time second_left.present? ? (second_left / 60) : nil
      end
      json.author exercise.user.real_name
      ex_index = exercise_index_show(exercise,@course,@is_teacher_or,@current_user_)
      json.exercise_status ex_index[:ex_status]
      json.lock_status ex_index[:lock_icon]
      json.publish_time ex_index[:publish_time]  # 试卷的发布时间
      json.end_time ex_index[:end_time]   # 试卷的截止时间
      json.exercise_answer ex_index[:exercise_answer]  # 已提交试卷的用户
      json.exercise_unanswer ex_index[:exercise_unanswer]  # 已查看试卷/开始答题，但是未提交试卷的用户
      json.exercise_left_time ex_index[:ex_left_time]
      json.current_status ex_index[:current_status]  #答题的状态
      json.unreview_count ex_index[:unreview_count]
      json.exercise_tips ex_index[:ex_tips]
    end
  end
else
  json.exercises []
end

json.course_types do
  json.course_status @course.is_end ? 1 : 0   #课堂的当前是否结束，如结束，则为1，否则为0
  json.course_end_time @course.end_date   #课堂的截止时间
  json.course_is_public @course.is_public  #判断课堂是否为公开，只有公开课才有设为公开的按钮
  json.user_permission @is_teacher_or # 当前用户存在且为课堂教师/管理员/超级管理员时为1 ，课堂成员为2，否则为0
end

json.exercises_counts do
  json.exercises_total_counts @exercises_count  #全部试卷数
  json.exercises_all_counts @exercises_select_count   #选择后的全部试卷数
  json.exercises_unpublish_counts @exercises_unpublish_counts  #未发布试卷数
  json.exercises_published_counts @exercises_published_counts  #已发布试卷数
  # json.exercises_ended_counts @exercises_ended_counts   #已截止试卷数
  json.left_banner_id @left_banner_id
  json.left_banner_name @left_banner_name
end