socialforge/app/controllers/exercise_controller.rb

class ExerciseController < ApplicationController
  layout "base_courses"

  before_filter :find_exercise_and_course, :only => [:create_exercise_question, :edit, :update, :show, :destroy, :commit_exercise, :commit_answer]
  before_filter :find_course, :only => [:index,:new,:create,:student_exercise_list]
  include ExerciseHelper

  include ExerciseHelper
  def index
    remove_invalid_exercise(@course)
    @is_teacher = User.current.allowed_to?(:as_teacher,@course)
    if @is_teacher
      exercises = @course.exercises
    else
      exercises = @course.exercises.where(:exercise_status => 2)
    end
    @exercises = paginateHelper exercises,20 #分页
    respond_to do |format|
      format.html
    end
  end

  def show
    @exercise = Exercise.find params[:id]
    @is_teacher = User.current.allowed_to?(:as_teacher,@course) || User.current.admin?
    if @exercise.exercise_status != 2 && (!User.current.allowed_to?(:as_teacher,@course) || User.current.admin?)
      render_403
      return
    end
    # 已提交问卷的用户不能再访问该界面
    if has_commit_exercise?(@exercise.id, User.current.id) && (!User.current.admin?)
      redirect_to exercise_index_url(:course_id=> @course.id)
    else
      @can_edit_excercise = (!has_commit_exercise?(@exercise.id,User.current.id)) || User.current.admin?
      # @percent = get_percent(@exercise,User.current)
      exercise_questions = @exercise.exercise_questions
      @exercise_questions = paginateHelper exercise_questions,5 #分页
      respond_to do |format|
        format.html {render :layout => 'base_courses'}
      end
    end
  end

  def new
    option = {
        :exercise_name => "",
        :course_id => @course.id,
        :exercise_status => 1,
        :user_id => User.current.id,
        :time => "",
        :end_time => "",
        :publish_time => "",
        :exercise_description => "",
        :show_result => ""
    }
    @exercise = Exercise.create option
    if @exercise
      redirect_to edit_exercise_url @exercise.id
    end
  end

  def create
    if params[:exercise]
      exercise = Exercise.find(params[:exercise_id]) if params[:exercise_id]
      exercise ||= Exercise.new
      exercise.exercise_name = params[:exercise][:exercise_name]
      exercise.exercise_description = params[:exercise][:exercise_description]
      exercise.end_time = params[:exercise][:end_time]
      exercise.publish_time = params[:exercise][:publish_time]
      exercise.user_id = User.current.id
      exercise.time = params[:exercise][:time]
      exercise.course_id = params[:course_id]
      exercise.exercise_status = 1
      if exercise.save
        @exercise = exercise
        respond_to do |format|
          format.js
        end
      end
    end
  end

  def edit
    respond_to do |format|
      format.html{render :layout => 'base_courses'}
  end
  end

  def update
    @exercise.exercise_name = params[:exercise][:exercise_name]
    @exercise.exercise_description = params[:exercise][:exercise_description]
    @exercise.time =  params[:exercise][:time]
    @exercise.end_time = params[:exercise][:end_time]
    @exercise.publish_time = params[:exercise][:publish_time]
    @exercise.show_result = params[:exercise][:show_result]
    if @exercise.save
      respond_to do |format|
        format.js
      end
    else
      render_404
      end
  end

  def destroy
    if @exercise && @exercise.destroy
      if @is_teacher
        exercises = Exercise.where("course_id =?", @course.id)
      else
        exercises = Exercise.where("course_id =? and exercise_status =?", @course.id, 2)
      end
      @exercises = paginateHelper exercises,20 #分页
      respond_to do |format|
        format.js
      end
    end
  end

  # 统计结果
  def statistics_result
    @exercise = Exercise.find(params[:id])
    exercise_questions = @exercise.exercise_questions
    @exercise_questions = paginateHelper exercise_questions, 5
    respond_to do |format|
      format.html{render :layout => 'base_courses'}
    end
  end

  # 添加题目
  # question_type 1：单选 2：多选 3：填空题
  def create_exercise_question
    question_title = params[:question_title].nil? || params[:question_title].empty? ? l(:label_enter_single_title) : params[:question_title]
    option = {
        :question_title => question_title,
        :question_type => params[:question_type] || 1,
        :question_number => @exercise.exercise_questions.count + 1,
        :question_score => params[:question_score]
    }
    @exercise_questions = @exercise.exercise_questions.new option
    # params[:question_answer] 题目选项
    if params[:question_answer]
      for i in 1..params[:question_answer].count
        answer = (params[:question_answer].values[i-1].nil? || params[:question_answer].values[i-1].empty?) ? l(:label_new_answer) : params[:question_answer].values[i-1]
        question_option = {
            :choice_position => i,
            :choice_text => answer
        }
        @exercise_questions.exercise_choices.new question_option
      end
    end
    # 如果是插入的话，那么从插入的这个id以后的question_num都将要+1
    if params[:quest_id]
      @is_insert = true
      @exercise.exercise_questions.where("question_number > #{params[:quest_num].to_i}").update_all(" question_number = question_number + 1")
      # @exercise_question_num = params[:quest_num].to_i
      @exercise_questions.question_number = params[:quest_num].to_i + 1
    end
    if @exercise_questions.save
      # params[:exercise_choice] 标准答案参数
      # 问答题标准答案有三个，单独处理
      if @exercise_questions.question_type == 3
        for i in 1..params[:exercise_choice].count
          standart_answer = ExerciseStandardAnswer.new
          standart_answer.exercise_question_id =  @exercise_questions.id
          standart_answer.answer_text = params[:exercise_choice].values[i-1]
          standart_answer.save
        end
      else
        standart_answer = ExerciseStandardAnswer.new
        standart_answer.exercise_question_id =  @exercise_questions.id
        if  @exercise_questions.question_type == 1
          standart_answer.exercise_choice_id = sigle_selection_standard_answer(params[:exercise_choice])
        else
          standart_answer.exercise_choice_id = multiselect_standard_answer(params[:exercise_choice])
        end
        standart_answer.save
      end
      respond_to do |format|
        format.js
      end
    end

  end

  # 修改题目
  # params[:exercise_question]  The id of exercise_question
  # params[:question_answer]  eg:A、B、C选项
  def update_exercise_question
    @exercise_question = ExerciseQuestion.find params[:exercise_question]
    @exercise_question.question_title = params[:question_title].nil? || params[:question_title].empty? ? l(:label_enter_single_title) : params[:question_title]
    @exercise_question.question_score = params[:question_score]
    # 处理选项:如果选了某个选项，那么则要删除之前的选项
    if params[:question_answer]
      @exercise_question.exercise_choices.each do |answer|
        answer.destroy unless params[:question_answer].keys.include? answer.id.to_s
      end
      for i in 1..params[:question_answer].count
        question = @exercise_question.exercise_choices.find_by_id params[:question_answer].keys[i-1]
        answer = (params[:question_answer].values[i-1].nil? || params[:question_answer].values[i-1].empty?) ? l(:label_new_answer) : params[:question_answer].values[i-1]
        if question
          question.choice_position = i
          question.choice_text = answer
          question.save
        else
          question_option = {
              :choice_position => i,
              :choice_text => answer
          }
          @exercise_question.exercise_choices.new question_option
        end
      end
    end
    # 更新标准答案
    if params[:exercise_choice]
      if @exercise_question.question_type == 3
        for i in 1..params[:exercise_choice].count
          # 找到对应的标准答案
          question_standart = @exercise_question.exercise_standard_answers.find_by_id params[:exercise_choice].keys[i-1]
          # 标准答案值
          answer_standart = (params[:exercise_choice].values[i-1].nil? || params[:exercise_choice].values[i-1].empty?) ? l(:label_new_answer) : params[:exercise_choice].values[i-1]
          if question_standart
            question_standart.answer_text = answer_standart
            question_standart.save
          else
            standart_answer_option = {
                :answer_text => question_standart
            }
            @exercise_question.exercise_standard_answers.new standart_answer_option
          end
        end
      else
        answer_standart = @exercise_question.exercise_standard_answers.first
        answer_standart.exercise_choice_id = @exercise_question.question_type == 1 ? sigle_selection_standard_answer(params[:exercise_choice]) : multiselect_standard_answer(params[:exercise_choice])
        answer_standart.save
      end
      @exercise_question.save
      respond_to do |format|
        format.js
      end
    end
  end

  # 删除题目
  def delete_exercise_question
    @exercise_question = ExerciseQuestion.find params[:exercise_question]
    @exercise = @exercise_question.exercise
    exercise_questions = @exercise.exercise_questions.where("question_number > #{@exercise_question.question_number}")
    exercise_questions.each do |question|
      question.question_number -= 1
      question.save
    end
    if @exercise_question && @exercise_question.destroy
      respond_to do |format|
        format.js
      end
    end
  end

  # 发布试卷
  def publish_excercise
    @exercise.exercise_status = 2
    @exercise.publish_time = Time.now
    if @exercise.save
      if params[:is_remote]
        redirect_to exercise_index_url(:course_id => @course.id)
      else
        respond_to do |format|
          format.js
        end
      end
    end
  end

  # 重新发布试卷
  def republish_excercise
    @exercise.exercise_questions.each do |exercise_question|
      exercise_question.exercise_ansers.destroy_all
    end
    # @poll.poll_users.destroy_all
    # @poll.polls_status = 1
    # @poll.save
    # respond_to do |format|
    #   format.js
    # end
  end

  def student_exercise_list
    @is_teacher = User.current.allowed_to?(:as_teacher,@course) || User.current.admin?
    @exercise = Exercise.find params[:id]
    @all_exercises = @course.exercises.order("created_at desc")
    @exercise_count = @exercise.exercise_users.where('score is not NULL').count
    if @is_teacher || (!@exercise.exercise_users.where(:user_id => User.current.id).empty? && Time.parse(@exercise.end_time.to_s).strftime("%Y-%m-%d-%H-%M-%S") <= Time.now.strftime("%Y-%m-%d-%H-%M-%S"))
      @exercise_users_list = @exercise.exercise_users.where('score is not NULL')
      @show_all = true;
    elsif !@exercise.exercise_users.where(:user_id => User.current.id).empty? && Time.parse(@exercise.end_time.to_s).strftime("%Y-%m-%d-%H-%M-%S") > Time.now.strftime("%Y-%m-%d-%H-%M-%S")
      @exercise_users_list = @exercise.exercise_users.where("user_id = ? and score is not NULL",User.current.id)
    else
      @exercise_users_list = []
    end
    respond_to do |format|
      format.html
    end
  end

  # 学生提交答卷，选中答案的过程中提交
  def commit_answer
    eq = ExerciseQuestion.find(params[:exercise_question_id])
    # 已提交过的则不允许答题
    if has_commit_exercise?(@exercise.id,User.current.id) && (!User.current.admin?)
      render :json => {:text => "failure"}
      return
    end
    if eq.question_type == 1
      # 单选题
      ea = ExerciseAnswer.find_by_exercise_question_id_and_user_id(params[:exercise_question_id],User.current.id)
      if ea.nil?
        # 尚未答该题，添加答案
        ea = ExerciseAnswer.new
        ea.user_id = User.current.id
        ea.exercise_question_id = params[:exercise_question_id]
      end
      #修改该题对应答案
      ea.exercise_choice_id = params[:exercise_choice_id]
      if ea.save
        # 保存成功返回成功信息及当前以答题百分比
        @percent = get_percent(@exercise,User.current)
        render :json => {:text => "ok" ,:percent => format("%.2f" ,@percent)}
      else
        #返回失败信息
        render :json => {:text => "failure"}
      end
    elsif eq.question_type == 2
      #多选题
      ea = ExerciseAnswer.find_by_exercise_question_id_and_user_id(params[:exercise_question_id],User.current.id)
      if ea.nil?
        #尚未答该题，添加答案
        ea = ExerciseAnswer.new
        ea.user_id = User.current.id
        ea.exercise_question_id = params[:exercise_question_id]
        ea.exercise_choice_id = params[:exercise_choice_id]
        if ea.save
          @percent = get_percent(@exercise,User.current)
          render :json => {:text => "true",:percent => format("%.2f" ,@percent)}
        else
          render :json => {:text => "failure"}
        end
      else
        #pv不为空，则当前选项之前已被选择，再次点击则是不再选择该项，故删除该答案
        if pv.delete
          @percent = get_percent(@exercise, User.current)
          render :json => {:text => "false" ,:percent => format("%.2f" , @percent)}
        else
          render :json => {:text => "failure"}
        end
      end
    elsif eq.question_type == 3
      #单行文本，多行文本题
      ea = ExerciseAnswer.find_by_exercise_question_id_and_user_id(params[:exercise_question_id], User.current.id)
      if ea.nil?
        # ea为空之前尚未答题，添加答案
        if params[:answer_text].nil? || params[:answer_text].blank?
          #用户提交空答案，视作不作答
          @percent = get_percent(@exercise,User.current)
          render :json => {:text => ea.answer_text,:percent => format("%.2f", @percent)}
        else
          #添加答案
          ea = ExerciseAnswer.new
          ea.user_id = User.current.id
          ea.exercise_question_id = params[:exercise_question_id]
          ea.answer_text = params[:answer_text]
          if ea.save
            @percent = get_percent(@exercise,User.current)
            render :json => {:text => pv.vote_text,:percent => format("%.2f",@percent)}
          else
            render :json => {:text => "failure"}
          end
        end
      else
        # ea不为空说明用户之前已作答
        if params[:answer_text].nil? || params[:answer_text].blank?
          # 用户提交空答案，视为删除答案
          if ea.delete
            @percent = get_percent(@exercise,User.current)
            render :json => {:text => ea.answer_text,:percent => format("%.2f", @percent)}
          else
            render :json => {:text => "failure"}
          end
        else
          #用户修改答案
          ea.answer_text = params[:answer_text]
          if ea.save
            @percent = get_percent(@exercise,User.current)
            render :json => {:text => pv.vote_text,:percent => format("%.2f", @percent)}
          else
            render :json => {:text => "failure"}
          end
        end
      end

    else
      render :json => {:text => "failure"}
    end
  end

  # 提交问卷
  def commit_exercise
    # 老师不需要提交
    if User.current.allowed_to?(:as_teacher,@course)
      redirect_to exercise_url(@exercise)
      # REDO: 提示提交成功
    else
      # 答题过程中需要统计完成量
      @uncomplete_question = get_uncomplete_question(@exercise, User.current)
      # 获取改学生的考试得分
      score = calculate_student_score(@exercise, User.current)
      if @uncomplete_question.count < 1
        # 查看是否有已提交记录
        eu = get_exercise_user(@exercise.id, User.current.id)
        eu.user_id = User.current.id
        eu.exercise_id = @exercise.id
        eu.score = score
        if eu.save
          #redirect_to poll_index_path(:polls_group_id => @course.id,:polls_type => 'Course')
          @status = 0 #提交成功
        else
          @status = 2 #未知错误
        end
      else
        @status = 1 #有未做得必答题
      end
      respond_to do |format|
        format.js
      end
    end
  end

  # 计算学生得分
  def calculate_student_score(exercise, user)
    score = 0
    exercise_qustions = exercise.exercise_questions
    exercise_qustions.each do |question|
      answer = get_user_answer(question, user)
      standard_answer = get_user_standard_answer(question, user)
      # 问答题有多个答案
      if question.question_type == 3
        if standard_answer.exercise_choice_id.include?(answer.exercise_choice_id)
          score = score + question.question_score
        end
      else
        if answer.exercise_choice_id == standard_answer.exercise_choice_id
          score = score + question.question_score
        end
      end
    end
    score
  end

  private
  # ExerciseUser记录用户是否已提交问卷有对应的记录则已提交，没有则新建一个
  def get_exercise_user exercise_id,user_id
    eu = ExerciseUser.find_by_exercise_id_and_user_id(exercise_id,user_id)
    if eu.nil?
      eu = ExerciseUser.new
    end
    eu
  end

  #获取未完成的题目
  def get_uncomplete_question exercise,user
    all_questions = exercise.exercise_questions
    uncomplete_question = []
    all_questions.each do |question|
      answers = get_user_answer(question, user)
      if answers.nil? || answers.count < 1
        uncomplete_question << question
      end
    end
    uncomplete_question
  end

  # 获取当前学生回答问题的答案
  def get_user_answer(question,user)
    user_answer = question.exercise_answers.where("#{ExerciseAnswer.table_name}.user_id = #{user.id}")
    user_answer
  end

  # 获取问题的标准答案
  def get_user_standard_answer(question,user)
    standard_answer = question.exercise_standard_answers
    standard_answer
  end

  # 是否完成了答题
  def get_complete_question(exercise,user)
    questions = exercise.exercise_questions
    complete_question = []
    questions.each do |question|
      answers = get_user_answer(question,user)
      if !(answers.nil? || answers.count < 1)
        complete_question << question
      end
    end
    complete_question
  end

  # 获取答题百分比
  def get_percent exercise,user
    complete_count = get_complete_question(exercise,user).count
    if exercise.exercise_questions.count == 0
      return 0
    else
      return (complete_count.to_f / exercise.exercise_questions.count.to_f)*100
    end
  end

  def remove_invalid_exercise(course)
    exercises = course.exercises.where("exercise_name=?","")
    unless exercises.empty?
      exercises.each do |exercise|
        exercise.destroy
      end
    end
  end

  def find_exercise_and_course
    @exercise = Exercise.find params[:id]
    @course = Course.find @exercise.course_id
  rescue Exception => e
    render_404
  end

  def find_course
    @course = Course.find params[:course_id]
  rescue Exception => e
    render_404
  end
end