danbooru/app/models/comment.rb

class Comment < ApplicationRecord
  validate :validate_creator_is_not_limited, :on => :create
  validates_presence_of :body, :message => "has no content"
  belongs_to :post
  belongs_to :creator, class_name: "User"
  belongs_to_updater
  has_many :moderation_reports, as: :model
  has_many :votes, :class_name => "CommentVote", :dependent => :destroy

  before_create :autoreport_spam
  after_create :update_last_commented_at_on_create
  after_update(:if => ->(rec) {(!rec.is_deleted? || !rec.saved_change_to_is_deleted?) && CurrentUser.id != rec.creator_id}) do |rec|
    ModAction.log("comment ##{rec.id} updated by #{CurrentUser.user.name}", :comment_update)
  end
  after_save :update_last_commented_at_on_destroy, :if => ->(rec) {rec.is_deleted? && rec.saved_change_to_is_deleted?}
  after_save(:if => ->(rec) {rec.is_deleted? && rec.saved_change_to_is_deleted? && CurrentUser.id != rec.creator_id}) do |rec|
    ModAction.log("comment ##{rec.id} deleted by #{CurrentUser.user.name}", :comment_delete)
  end

  deletable
  mentionable(
    :message_field => :body,
    :title => ->(user_name) {"#{creator.name} mentioned you in a comment on post ##{post_id}"},
    :body => ->(user_name) {"@#{creator.name} mentioned you in a \"comment\":#{Routes.post_path(post, anchor: "comment-#{id}")} on post ##{post_id}:\n\n[quote]\n#{DText.extract_mention(body, "@" + user_name)}\n[/quote]\n"}
  )

  module SearchMethods
    def search(params)
      q = search_attributes(params, :id, :created_at, :updated_at, :is_deleted, :is_sticky, :do_not_bump_post, :body, :score, :post, :creator, :updater)
      q = q.text_attribute_matches(:body, params[:body_matches], index_column: :body_index)

      case params[:order]
      when "post_id", "post_id_desc"
        q = q.order("comments.post_id DESC, comments.id DESC")
      when "score", "score_desc"
        q = q.order("comments.score DESC, comments.id DESC")
      when "updated_at", "updated_at_desc"
        q = q.order("comments.updated_at DESC")
      else
        q = q.apply_default_order(params)
      end

      q
    end
  end

  module VoteMethods
    def vote!(val, voter = CurrentUser.user)
      numerical_score = (val == "up") ? 1 : -1
      vote = votes.create!(user: voter, score: numerical_score)

      if vote.is_positive?
        update_column(:score, score + 1)
      elsif vote.is_negative?
        update_column(:score, score - 1)
      end

      return vote
    end

    def unvote!
      vote = votes.where("user_id = ?", CurrentUser.user.id).first

      if vote
        if vote.is_positive?
          update_column(:score, score - 1)
        else
          update_column(:score, score + 1)
        end

        vote.destroy
      else
        raise CommentVote::Error.new("You have not voted for this comment")
      end
    end
  end

  extend SearchMethods
  include VoteMethods

  def validate_creator_is_not_limited
    if creator.is_comment_limited? && !do_not_bump_post?
      errors.add(:base, "You can only post #{Danbooru.config.member_comment_limit} comments per hour")
    end
  end

  def autoreport_spam
    if SpamDetector.new(self).spam?
      moderation_reports << ModerationReport.new(creator: User.system, reason: "Spam.")
    end
  end

  def update_last_commented_at_on_create
    Post.where(:id => post_id).update_all(:last_commented_at => created_at)
    if Comment.where("post_id = ?", post_id).count <= Danbooru.config.comment_threshold && !do_not_bump_post?
      Post.where(:id => post_id).update_all(:last_comment_bumped_at => created_at)
    end
  end

  def update_last_commented_at_on_destroy
    other_comments = Comment.where("post_id = ? and id <> ?", post_id, id).order("id DESC")
    if other_comments.count == 0
      Post.where(:id => post_id).update_all(:last_commented_at => nil)
    else
      Post.where(:id => post_id).update_all(:last_commented_at => other_comments.first.created_at)
    end

    other_comments = other_comments.where("do_not_bump_post = FALSE")
    if other_comments.count == 0
      Post.where(:id => post_id).update_all(:last_comment_bumped_at => nil)
    else
      Post.where(:id => post_id).update_all(:last_comment_bumped_at => other_comments.first.created_at)
    end
  end

  def voted_by?(user)
    return false if user.is_anonymous?
    user.id.in?(votes.map(&:user_id))
  end

  def quoted_response
    DText.quote(body, creator.name)
  end

  def self.available_includes
    [:post, :creator, :updater]
  end
end