# Topic is a collection of posts
class Topic < ActiveRecord::Base
  has_many :posts, :exclusively_dependent => true
  belongs_to :forum
  has_many :topic_subscriptions, :exclusively_dependent => true
  has_many :topic_reads, :exclusively_dependent => true
  has_and_belongs_to_many :tags, :join_table => 'topics_tags'

  include ErrorRaising

  # CALLBACKS
  
  def before_create
    self.deleted = 0
  end

  # NORMAL METHODS

  # Add a reply to the root post in this topic.
  # TODO: transaction?
  def add_reply(post)
    root_post.add_reply(post)
  end

  def hidden?
    (self.deleted == 1)
  end

  # Hide topic with all posts
  def hide
    self.update_attribute('deleted', 1)
    self.root_post.hide(:recursive)
  end

  # Unhide topic and root post; if recursive, unhide all posts
  def unhide(recursive=false)
    self.update_attribute('deleted', 0)
    self.root_post.unhide(recursive)
  end

  # Get the data needed for the topic view.
  def posts_with_user_data(include_hidden = false)
    self.posts.find(
      :all, :include => [:user, :topic],
      :conditions => (include_hidden ? nil : "posts.deleted = 0"),
      :order => 'posts.created_at ASC, posts.id ASC'
    )
  end

  # Get the root post of the topic.
  def root_post
    res = posts.find_all("parent_id IS NULL")
    raise "Data integrity: topic #{} has #{res.size} root posts" if res.size > 1
    raise "Data integrity: topic #{} has no root posts" if res.empty?
    res[0]
  end

  def subscribed_by?(user)
    return false if user.guest?
    TopicSubscription.count("user_id = #{user.id} and topic_id = #{self.id}") > 0
  end

  def update_last_post_data(last_post=nil)
    last_post ||= posts.find_first 'deleted=0', 'created_at DESC,id DESC'
    if last_post
      self.last_post_created_at = last_post.created_at
      self.last_post_user_id = last_post.user_id
      self.last_post_author = last_post.get_display_name
    end
  end

  def update_post_counter
    self.post_counter = self.posts.count('deleted = 0')
  end
end