class BlogCategory
  include LuckySneaks::StringExtensions
  include Mongoid::Document
  include Mongoid::Timestamps
  include Mongoid::Tree

  # Mongoid ========================================================================================
  field :name
  field :description
  field :slug

  # Behavior =======================================================================================
  before_destroy :destroy_children
  before_save :set_slug
  has_and_belongs_to_many :posts
  validates_presence_of :name
  validates_uniqueness_of :name

  # Class methods: Overrides =======================================================================
  def self.children
    super.asc :name
  end

  def self.roots
    super.asc :name
  end

  # Class methods ==================================================================================
  def self.by_name value
    self.find :first, :conditions => {:name => value}
  end

  def self.by_slug value
    self.find :first, :conditions => {:slug => /^#{value}$/i}
  end

  def self.roots_with_posts
    self.roots.asc(:name).select{ |c| c.has_posts? }
  end

  # Instance methods: Overrides ====================================================================
  def children_with_posts
    self.children.asc(:name).select{ |c| c.has_posts? }
  end

  def parent_id= value
    self[:parent_id] = value == 'nil' ? nil : value
  end

  # Instance methods ===============================================================================
  def has_posts?
    ! self.all_posts.blank?
  end

  def parent_category=(name)
    unless name.blank?
      self.parent = BlogCategory.find_or_create_by :name => name
      self.save
    end
  end

  def all_posts
    (self.posts + self.children.map{ |c| c.posts }).uniq.flatten
  end

  def subcategory?
    ! self.root?
  end

  def url
    "#{Blog.first.path}topics/#{self.slug}"
  end

  private

  # Returns an array of this category's and its ancestors' names.
  def ancestors_and_self_names
    self.ancestors_and_self.map{ |l| l.name }
  end

  # Returns the permalink for this locale.
  def set_slug
    self.slug = (ancestors_and_self_names * '/').to_url.gsub('-slash-', '/')
  end
end