educoder/app/models/course_attendance.rb

class CourseAttendance < ApplicationRecord
  # status: 0: 未开启，1：已开启，2：已截止
  # mode: 0 两种签到，1 二维码签到，2 数字签到，3 快捷签到
  enum mode: { ALL: 0, QRCODE: 1, NUMBER: 2, QUICK: 3 }

  belongs_to :course
  belongs_to :user

  has_many :course_attendance_groups, dependent: :destroy
  has_many :course_member_attendances, dependent: :destroy

  has_one :course_act, class_name: 'CourseActivity', as: :course_act, dependent: :destroy

  validates :name, presence: true, length: { maximum: 60, too_long: "不能超过60个字符" }
  validates :mode, presence: true
  validates :attendance_date, presence: true
  validates :start_time, presence: true
  validates :end_time, presence: true

  after_create :generate_attendance_code, :act_as_course_activity

  # 正常签到人数
  def normal_count
    course_member_attendances.select{|member_attendance| member_attendance.attendance_status == "NORMAL"}.size
  end

  # 请假人数
  def leave_count
    course_member_attendances.select{|member_attendance| member_attendance.attendance_status == "LEAVE"}.size
  end

  # 旷课人数
  def absence_count
    course_member_attendances.select{|member_attendance| member_attendance.attendance_status == "ABSENCE"}.size
  end

  # 总人数
  def all_count
    course_member_attendances.size
  end

  def current_attendance?
    a_start_time = "#{attendance_date} #{start_time}".to_time
    a_end_time = "#{attendance_date} #{end_time}".to_time
    a_start_time < Time.current && Time.current < a_end_time
  end

  #课程动态公共表记录
  def act_as_course_activity
    CourseActivity.create(user_id: user_id, course_id: course_id, course_act: self)
  end

  # 延迟生成邀请码
  def attendance_code
    return generate_attendance_code
  end

  # 生成邀请码
  CODES = %W(2 3 4 5 6 7 8 9 A B C D E F G H J K L N M O P Q R S T U V W X Y Z)
  def generate_attendance_code
    code = read_attribute(:attendance_code)
    if !code || code.size < 4
      code = CODES.sample(4).join
      return generate_attendance_code if CourseAttendance.where(attendance_code: code).present?
      update_attribute(:attendance_code, code)
    end
    code
  end
end