class AttendancesController < ApplicationController

  before_action :require_login
  before_action :find_course, only: [:index, :statistics]
  before_action :find_attendance, except: [:index, :statistics]
  before_action :user_course_identity

  def index
    current_date = Date.current
    current_end_time = Time.current.strftime("%H:%M:%S")

    member = @course.students.find_by(user_id: current_user.id)

    if params[:history]
      if @user_course_identity == Course::STUDENT
        history_attendance_ids = member.course_member_attendances.where(course_id: @course.id).pluck(:course_attendance_id)

        @attendances = @course.course_attendances.where(id: history_attendance_ids.uniq).
          where("attendance_date < '#{current_date}' or (attendance_date = '#{current_date}' and end_time < '#{current_end_time}')")
      else
        @attendances = @course.course_attendances.where("attendance_date < '#{current_date}' or
                            (attendance_date = '#{current_date}' and end_time < '#{current_end_time}')")
      end
    else
      @attendances = @course.course_attendances.where("attendance_date > '#{current_date}' or
                            (attendance_date = '#{current_date}' and end_time > '#{current_end_time}')")
    end

    if @user_course_identity == Course::STUDENT
      group_ids = [member&.course_group_id.to_i, 0]
      @attendances = @attendances.joins(:course_attendance_groups).where(course_attendance_groups: {course_group_id: group_ids})

      if params[:history]
        attendance_ids = @attendances.pluck(:id)
        @normal_count = @course.course_member_attendances.where(course_member_id: member&.id, course_attendance_id: attendance_ids, attendance_status: "NORMAL").size
        @leave_count = @course.course_member_attendances.where(course_member_id: member&.id, course_attendance_id: attendance_ids, attendance_status: "LEAVE").size
        @absence_count = @course.course_member_attendances.where(course_member_id: member&.id, course_attendance_id: attendance_ids, attendance_status: "ABSENCE").size
      else
        @attendances = @attendances.where("attendance_date = '#{current_date}' and start_time <= '#{current_end_time}' and end_time > '#{current_end_time}'")
      end

    end

    @attendances_count = @attendances.size

    @attendances = @attendances.order("attendance_date desc, start_time desc")
    @attendances = paginate @attendances.includes(:user, :course_member_attendances)
  end

  def statistics
    current_date = Date.current
    current_end_time = Time.current.strftime("%H:%M:%S")
    history_attendances = @course.course_attendances.where("attendance_date < '#{current_date}' or
                            (attendance_date = '#{current_date}' and end_time < '#{current_end_time}')")
    if params[:group_id].present?
      history_attendances = history_attendances.joins(:course_attendance_groups).where(course_attendance_groups: {course_group_id: [params[:group_id], 0]})
      all_member_attendances = CourseMemberAttendance.where(course_attendance_id: history_attendances)
                                 .joins(:course_member).where(course_members: {course_group_id: params[:group_id]})
    else
      all_member_attendances = CourseMemberAttendance.where(course_attendance_id: history_attendances)
    end

    history_attendances = history_attendances.order("attendance_date desc, start_time desc")
    data = AttendanceStatisticsService.call history_attendances, all_member_attendances
    @all_history_count = data[:all_history_count]
    @history_attendances = data[:history_attendances]
    @avg_normal_rate = data[:avg_normal_rate]
    @avg_absence_rate = data[:avg_absence_rate]
    @avg_leave_rate = data[:avg_leave_rate]
  end

  def edit
    @groups = @course.course_groups.where(id: @attendance.course_attendance_groups.pluck(:course_group_id))
  end

  def update
    tip_exception(403, "") unless @user_course_identity < Course::PROFESSOR || @attendance.user_id == current_user.id
    a_end_time = "#{@attendance.attendance_date} #{@attendance.end_time}".to_time
    new_end_time = "#{params[:attendance_date]} #{params[:end_time]}".to_time
    @attendance.update!(update_params)

    old_group_ids = @attendance.course_attendance_groups.pluck(:course_group_id)
    unless old_group_ids.include?(0)
      all_groups_ids = old_group_ids + params[:group_ids]
      # 如果新增的的分班加上之前的分班是课堂的全部分班，则只需创建一条记录
      if all_groups_ids.uniq.count == @course.course_groups_count
        @attendance.course_attendance_groups.destroy_all
        @attendance.course_attendance_groups.create!(course_group_id: 0, course_id: @attendance.course_id)
        new_group = true
      else
        new_group_ids = params[:group_ids] - old_group_ids
        new_group_ids.each do |group_id|
          @attendance.course_attendance_groups.create!(course_group_id: group_id, course_id: @attendance.course_id)
          new_group = true
        end
      end

    end

    # 如果新增了分班或者历史签到变为了正在签到，将未创建的学生签到数据补上
    if new_group || (a_end_time < Time.current && new_end_time > Time.current)
      create_absence_student_data
    end
    render_ok
  end

  private
  def find_attendance
    @attendance = CourseAttendance.find params[:id]
    @course = @attendance.course
  end

  def update_params
    params.permit(:name, :mode, :attendance_date, :start_time, :end_time)
  end

  def create_absence_student_data
    group_ids = @attendance.course_attendance_groups.pluck(:course_group_id)
    if group_ids.include?(0)
      students = @course.students
    else
      students = @course.students.where(course_group_id: group_ids)
    end

    none_users = students.where.not(user_id: @attendance.course_member_attendances.pluck(:user_id))

    attrs = %i[course_attendance_id user_id course_member_id course_id course_group_id created_at updated_at]

    same_attrs = {course_attendance_id: @attendance.id, course_id: @course.id}

    CourseMemberAttendance.bulk_insert(*attrs) do |worker|

      none_users.each do |student|
        next if @attendance.course_member_attendances.exists?(user_id: student.user_id)
        worker.add same_attrs.merge(user_id: student.user_id, course_member_id: student.id, course_group_id: student.course_group_id)
      end
    end
  end
end