class Rtml::Dom::Property < Rtml::DocumentModelObject
  include Rtml::Links
  #set_table_name 'rtml_dom_properties'
  #serialize :options, HashWithIndifferentAccess
  #serialize :value
  #belongs_to :element, :class_name => 'Rtml::Dom::Element'
  #validates_presence_of :name
  #validates_uniqueness_of :name, :scope => :element_id
  attr_accessor :options, :name, :element
  attr_writer :value

  def document
    element ? element.document : nil
  end

  def initialize(options = {})
    options.reverse_merge!(:options => HashWithIndifferentAccess.new)
    self.options = options[:options].with_indifferent_access
    self.value = options[:value]
    self.name = options[:name]
    after_initialize if respond_to?(:after_initialize)
  end

  def value
    @value.kind_of?(Symbol) ? @value.to_s : @value
  end

  def to_s
    value.to_s
  end

  def blank?
    value.blank?
  end

  def nil?
    value.nil?
  end

  # Returns the TML counterpart of just the value of this property.
  # If this is a TML ID property, the return value is a call to Rtml::Dom::Element.find_or_create_tml_id(name).
  # If this is has the :id_ref option, the return value is a reference to the element with this ID.
  # In all other cases, the value of this property is returned.
  def tml_value
    val = value_or_id(tml_valid(@value))
    val.kind_of?(String) ? val : val.to_s
  end

  def value_or_id(value) #:nodoc:
    id_ref = options.key?(:id_ref) ? options[:id_ref] : self.name == 'uri'

    if self.name == 'id'
      Rtml::Dom::Element.find_or_create_tml_id(value)
    else
      if value.kind_of?(String)
        if value[0] == ?#
          id_ref = true
          value = value[1..-1]
        else
          return value unless id_ref
        end
      end

      if document && (screen = document.find_screen(value))
        id_for(screen.tml_id)
      else
        id_ref && local?(value) ? "##{value}" : value
      end
    end
  end

  # Produces the TML for this property.
  def to_tml
    val = tml_value
    return val if val.blank? and options[:drop_if_blank]
    return "" if val.nil? # always drop nils
    "#{self.name}=#{val.inspect.ljust(15)}" # the ljust is for pretty formatting during my tests and could be removed
  end
  
  # Handles various special-case values, like "true" and "false", which must be converted to 1, 0, and so on.
  def tml_valid(i)
    case i
      when true,  :true  then 1
      when false, :false then 0
      else i
    end
  end
end