duplication_filter.rb

#by RoBeRt
#check the 'distance' between new posts/anwers and old ones for the same user
require 'text'

module DuplicationFilter

  def duplicate_content?
    @duplicate
  end

  def last_question_url
    @last_question_url
  end

  def duplication_check
    distance = YAML.load_file("config/duplicate_distance.yml")["default"]
    fau=User.find_by_username("fau")
    case self
    when Msg
      if self.user_id == fau.id && AnonymousItem.find_by_kind_and_kind_id(2,self.id)
        user_id=AnonymousItem.find_by_kind_and_kind_id(2,self.id).user_id
      else
        user_id=self.user_id
      end
      last_msg = Msg.find(:last, :conditions =>["user_id = ? and pending_delete = false and id != ?", user_id, self.id.to_i], :order=>"created_on")
      if last_msg
        if distance > distance_calculate(self.content, last_msg.content)
          @duplicate = true
          @last_question_url = last_msg.xtitle
          self.pending_delete = true
          send_duplication_delete_note
        end
      end

    when Reply
      if self.user_id == fau.id && AnonymousItem.find_by_kind_and_kind_id(4,self.id)
        user_id=AnonymousItem.find_by_kind_and_kind_id(4,self.id).user_id
      else
        user_id=self.user_id
      end

      last_reply = Reply.find(:last, :conditions =>["user_id = ? and pending_delete = false and id != ?", user_id, self.id.to_i], :order=>"created_on")
      if last_reply
        if distance > distance_calculate(self.content, last_reply.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
   #check the duplicate post in the same group by robert
    when GroupPost
      last_gp = GroupPost.find(:last, :conditions =>["user_id = ? and pending_delete = false and id != ? and group_id = ?", self.user_id, self.id.to_i, self.group_id], :order=>"created_on")
      if last_gp
        if distance > distance_calculate(self.content, last_gp.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
    #check the duplicate group comment in the same group post
  when GroupPostComment
      last_gpc = GroupPostComment.find(:last, :conditions=>["user_id = ? and pending_delete = false and id != ? and group_post_id = ?", self.user_id, self.id.to_i, self.group_post_id], :order=>"created_at")
      if last_gpc
        if distance > distance_calculate(self.content, last_gpc.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
     #check the duplicate profile comment in the same profile
   when Chat
      last_profile_comment = Chat.find(:last, :conditions=>["user_id = ? and pending_delete = false and id !=? and owner_id =?", self.user_id, self.id.to_i, self.owner_id], :order =>"created_on")
      if last_profile_comment
        if distance > distance_calculate(self.content, last_profile_comment.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
   #check the duplicate photo comment in the same photo
    when PhotoComment
      last_photo_comment = PhotoComment.find(:last, :conditions=>["user_id = ? and pending_delete = false and id !=? and photo_id = ?", self.user_id, self.id.to_i, self.photo_id], :order=>"created_on")
      if last_photo_comment
        if distance > distance_calculate(self.comment, last_photo_comment.comment)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
    end
    return true
  end
  def duplication_check_before_create
    distance = YAML.load_file("config/duplicate_distance.yml")["default"]
    fau=User.find_by_username("fau")
    case self
    when Msg
      if self.user_id == fau.id
        user_id=session[:user].id
        last_msg2 = Msg.find(:last, :conditions =>["user_id = ? and pending_delete = false and id != ?", fau_id, self.id.to_i], :order=>"created_on")
      else
        user_id=self.user_id
        last_msg2=nil
      end
      last_msg = Msg.find(:last, :conditions =>["user_id = ? and pending_delete = false and id != ?", user_id, self.id.to_i], :order=>"created_on")
      if last_msg
        if distance > distance_calculate(self.content, last_msg.content)
          @duplicate = true
          @last_question_url = last_msg.xtitle
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
      if last_msg2
        if distance > distance_calculate(self.content, last_msg2.content)
          @duplicate = true
          @last_question_url = last_msg2.xtitle
          self.pending_delete = true
          send_duplication_delete_note
        end
      end

    when Reply
      if self.user_id == fau.id && AnonymousItem.find_by_kind_and_kind_id(4,self.id)
        user_id=AnonymousItem.find_by_kind_and_kind_id(4,self.id).user_id
      else
        user_id=self.user_id
      end

      last_reply = Reply.find(:last, :conditions =>["user_id = ? and pending_delete = false and id != ?", user_id, self.id.to_i], :order=>"created_on")
      if last_reply
        if distance > distance_calculate(self.content, last_reply.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
   #check the duplicate post in the same group by robert
    when GroupPost
      last_gp = GroupPost.find(:last, :conditions =>["user_id = ? and pending_delete = false and id != ? and group_id = ?", self.user_id, self.id.to_i, self.group_id], :order=>"created_on")
      if last_gp
        if distance > distance_calculate(self.content, last_gp.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
    #check the duplicate group comment in the same group post
  when GroupPostComment
      last_gpc = GroupPostComment.find(:last, :conditions=>["user_id = ? and pending_delete = false and id != ? and group_post_id = ?", self.user_id, self.id.to_i, self.group_post_id], :order=>"created_at")
      if last_gpc
        if distance > distance_calculate(self.content, last_gpc.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
     #check the duplicate profile comment in the same profile
   when Chat
      last_profile_comment = Chat.find(:last, :conditions=>["user_id = ? and pending_delete = false and id !=? and owner_id =?", self.user_id, self.id.to_i, self.owner_id], :order =>"created_on")
      if last_profile_comment
        if distance > distance_calculate(self.content, last_profile_comment.content)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
   #check the duplicate photo comment in the same photo
    when PhotoComment
      last_photo_comment = PhotoComment.find(:last, :conditions=>["user_id = ? and pending_delete = false and id !=? and photo_id = ?", self.user_id, self.id.to_i, self.photo_id], :order=>"created_on")
      if last_photo_comment
        if distance > distance_calculate(self.comment, last_photo_comment.comment)
          @duplicate = true
          self.pending_delete = true
          send_duplication_delete_note
        end
      end
    end
    return true
  end

  private
  def distance_calculate(new_post, last_post)
    Text::Levenshtein.distance(new_post, last_post)
  end

  #some hiddern problems for concurrency
  def send_duplication_delete_note
    case self
    when Msg
      link = "http://www.funadvice.com/q/" + Msg.find(:last, :conditions=>["user_id = ? and pending_delete = false", self.user_id], :order=>"created_on").xtitle.to_s
    when Reply
      reply = Reply.find(:last, :conditions=>["user_id = ? and pending_delete = false", self.user_id], :order =>"created_on")
      link = "http://www.funadvice.com/q/" + reply.msg.xtitle.to_s + "#" + reply.id.to_s
    when GroupPost
      group_post = GroupPost.find(:last, :conditions=>["user_id = ? and pending_delete = false", self.user_id], :order=>"created_on")
      link = "http://www.funadvice.com/group/" + group_post.group.user.username + "/" + group_post.id.to_s
    when GroupPostComment
      gpc = GroupPostComment.find(:last, :conditions=>["user_id = ? and pending_delete = false", self.user_id], :order => "created_at")
      link = "http://www.funadvic.com/group/" + gpc.group_post.group.user.username + "/" + gpc.group_post.id.to_s + "#comments"
    when Chat
      profile_comment = Chat.find(:last,:conditions=>["user_id = ? and pending_delete = false", self.user_id], :order=>"created_on")
      link = "http://www.funadvice.com/comments/view/" + profile_comment.owner.username+"#c" + profile_comment.id.to_s
    when PhotoComment
      photo_comment = PhotoComment.find(:last,:conditions=>["user_id = ? and pending_delete = false", self.user_id], :order=>"created_on")
      link = "http://www.funadvice.com/photos/view/" + photo_comment.photo_id.to_s + "#c" + photo_comment.id.to_s
    end

    fau=User.find_by_username("fau")
    if self.user_id == fau.id

      case self
      when Msg
        user_id=AnonymousItem.find_by_kind_and_kind_id(2,self.id).user_id
      when Reply
        user_id=AnonymousItem.find_by_kind_and_kind_id(4,self.id).user_id
      end

    else
      user_id=self.user_id
    end

    if User.find(user_id).deny_notifications != 1
      Notifier::deliver_duplicate_message(User.find(user_id),link,self.class.to_s)
    end
  end

end