socialforge/app/models/students_for_course.rb

#encoding: utf-8
class StudentsForCourse < ActiveRecord::Base
  attr_accessible :course_id, :student_id
  
  belongs_to :course, :class_name => 'Course', :foreign_key => :course_id

  belongs_to :student, :class_name => 'User', :foreign_key => :student_id
  
  validates_presence_of :course_id, :student_id
  validates_uniqueness_of :student_id, :scope => :course_id

  after_destroy :delete_student_works, :delete_course_homework_statistic
  after_create :recovery_student_works, :create_student_works, :create_course_homework_statistic

  #退出班级或删除学生时隐藏学生的作品
  def delete_student_works
    course = self.course
    homework_ids = course.homework_commons.blank? ? "(-1)" : "(" + course.homework_commons.map{|hw| hw.id}.join(",") + ")"
    student_works = StudentWork.where("user_id = #{self.student_id} && homework_common_id in #{homework_ids}")
    student_works.update_all(:is_delete => 1)
  end

  #加入班级时还原作品
  def recovery_student_works
    course = self.course
    homework_ids = course.homework_commons.blank? ? "(-1)" : "(" + course.homework_commons.map{|hw| hw.id}.join(",") + ")"
    student_works = StudentWork.where("user_id = #{self.student_id} && homework_common_id in #{homework_ids}")
    student_works.update_all(:is_delete => 0)
  end

  #加入班级时创建已发布作业的作品
  def create_student_works
    course = self.course
    course.homework_commons.each do |hw|
      if hw.homework_type != 3 && hw.student_works.where("user_id = #{self.student_id}").count == 0
        hw.student_works << StudentWork.new(:user_id => self.student_id, :name => hw.name.to_s+"的作品提交", :work_status => 0)
      end
    end
  end

  #加入班级时创建一条记录
  def create_course_homework_statistic
    if CourseHomeworkStatistics.where(:user_id => self.student_id, :course_id => self.course_id).count == 0
      course = self.course
      user = self.student
      hw_count = course.homework_commons.includes(:homework_detail_manual).where("homework_detail_manuals.comment_status > 0").count
      homework_ids = course.homework_commons.empty? ? "(-1)" : "(" + course.homework_commons.map{|hw| hw.id}.join(",") + ")"
      student_works = StudentWork.where("homework_common_id in #{homework_ids} and work_status !=0")
      is_eva_homeworks = course.homework_commons.includes(:homework_detail_manual).where("homework_commons.anonymous_comment = 0 and homework_detail_manuals.comment_status = 2")
      is_eva_student_works = StudentWork.where(:homework_common_id => is_eva_homeworks.map{|hw| hw.id})
      has_eva_homeworks = course.homework_commons.includes(:homework_detail_manual).where("homework_commons.anonymous_comment = 0 and homework_detail_manuals.comment_status = 3")
      has_eva_student_works = StudentWork.where(:homework_common_id => has_eva_homeworks.map{|hw| hw.id})

      committed_work_num = user.student_works.where("homework_common_id in #{homework_ids} and work_status != 0").count
      un_commit_work_num = (hw_count - committed_work_num) < 0 ? 0 : (hw_count - committed_work_num)
      late_commit_work_num = user.student_works.where("homework_common_id in #{homework_ids} and work_status = 2").count
      absence_evaluation_work_num = user.student_works_evaluation_distributions.where(:student_work_id => has_eva_student_works.map(&:id)).count -
          user.student_works_scores.where(:reviewer_role => 3, :student_work_id => has_eva_student_works.map(&:id)).group_by(&:student_work_id).count
      absence_evaluation_work_num = absence_evaluation_work_num < 0 ? 0 : absence_evaluation_work_num
      un_evaluation_work_num = user.student_works_evaluation_distributions.where(:student_work_id => is_eva_student_works.map(&:id)).count -
          user.student_works_scores.where(:reviewer_role => 3, :student_work_id => is_eva_student_works.map(&:id)).group_by(&:student_work_id).count
      un_evaluation_work_num = un_evaluation_work_num < 0 ? 0 : un_evaluation_work_num
      appeal_num = user.student_works_scores.where(:student_work_id => student_works.map(&:id), :appeal_status => 3).count
      average_score = user.student_works.where(:id => student_works.map(&:id)).select("AVG(student_works.work_score) as score").first ? user.student_works.where(:id => student_works.map(&:id)).select("AVG(student_works.work_score) as score").first.score : 0
      total_score = user.student_works.where(:id => student_works.map(&:id)).select("SUM(student_works.work_score) as score").first ? user.student_works.where(:id => student_works.map(&:id)).select("SUM(student_works.work_score) as score").first.score : 0
      CourseHomeworkStatistics.create(:course_id => course.id, :user_id => user.id, :committed_work_num => committed_work_num, :un_commit_work_num => un_commit_work_num,
                                     :late_commit_work_num => late_commit_work_num, :absence_evaluation_work_num => absence_evaluation_work_num, :un_evaluation_work_num => un_evaluation_work_num,
                                     :appeal_num => appeal_num, :average_score => average_score, :total_score => total_score)
    end
  end

  def delete_course_homework_statistic
    CourseHomeworkStatistics.where(:user_id => self.student_id, :course_id => self.course_id).destroy_all
  end
end