module Formol
  class Forum < ActiveRecord::Base
    #Modules
    include RankedModel
    include Tracking
    
    #Security
    attr_protected :posts_count, :topics_count
    
    #Associations
    belongs_to  :category
    belongs_to  :last_post, :class_name => 'Formol::Post'
    
    has_many    :topics,    :dependent  => :destroy
    has_many    :posts,     :through    => :topics
                          
    #Validations
    validates :category,    :presence   => true
    validates :label,       :presence   => true,
                            :length     => {  :in             => 3..32,
                                              :allow_blank    => true },
                            :uniqueness => {  :scope          => :category_id,
                                              :case_sensitive => false,
                                              :allow_blank    => true }
    validates :description, :length     => {  :maximum        => 128,
                                              :allow_blank    => true }
                        
    #Normalization
    normalize_attribute :label,       :with => [:squish, :blank]
    normalize_attribute :description
    
    #Sorting
    ranks :position, :with_same => :category_id
    
    #Scopes
    class << self
      # this scope eager loads conveniently topic for using it in breadcrumb
      def ready_for_breadcrumb
        includes(:category)
      end
      
      # return all unread forums for a given user
      def unread(user)
        unread_scope_base(user)
        .select('DISTINCT formol_forums.id')
        .joins(:topics => :last_post)
      end
    end
    
    #Business
    class << self
      # Sorts topics from an array of ids and sets the new category
      def reorganize(forum_ids, category_id = nil)
        category = Formol::Category.find(category_id) if category_id
        
        #TODO: should maybe optimize this?
        (forum_ids || []).each_with_index do |forum_id, index|
          attr = { :position => index }
          attr[:category] = category if category_id
          
          find(forum_id).update_attributes(attr)
        end
      end
    end
    
    # Register a post being the last one of the current forum
    def register_last_post(post)
      update_attribute(:last_post, post)
    end
    
    # Unregister a post by re-assigning last post.
    # Needed when a post is destroyed
    def unregister_last_post
      update_attributes!(:last_post => posts.order('formol_posts.id').last)
    end
    
    # Mark all unread topics as read for a given user
    def mark_as_read(user)
      topics.unread(user).each do |unread|
        unread.track_for_user!(user)
      end
    end
    
    def read?(user)
      topics.unread(user).blank?
    end
  end
end