# The base class for all API objects that can be converted to XML.
# The class provides basic functionality to convert objects to and from xml based
# on the default Caren API format.
class Caren::Base
  
  attr_accessor :attributes
  
  # Basic initializer, handles quick setting of passed attributes.
  def initialize args={}
    self.attributes = {}
    self.class.keys.each do |key|
      self.attributes[key] = args[key] || args[key.to_s] || nil
    end
  end
  
  # List of available attributes for this object
  def self.keys
    []
  end
  
  # Root name of the XML array of objects
  def self.array_root
    :objects
  end
  
  # Name of each XML if converted to XML
  def self.node_root
    :object
  end
  
  # The relative location of this resource.
  def self.resource_location
    raise "No resource location found"
  end
  
  # Convert an array of these objects to XML
  def self.to_xml array
    array.to_xml( :root => self.array_root )
  end
  
  # Convert a XML string to a single object or an array of objects
  def self.from_xml xml
    hash = xml.is_a?(Hash) ? xml : Hash.from_xml(xml)
    if hash.has_key?(self.array_root.to_s)
      return hash[self.array_root.to_s].map{ |h| self.from_xml(h) }
    elsif hash.has_key?(self.node_root)
      return self.new( hash[self.node_root.to_s] )
    else
      return self.new( hash )
    end
  end
  
  # Convert this object to XML
  def to_xml options={}
    self.as_xml.to_xml(options.merge( :root => self.class.node_root ))
  end
  
  # Overridable hash of attributes that is used for converting to XML.
  def as_xml
    attributes
  end
  
  # The absolute (constructed url) to the resource.
  def self.resource_url id=nil
    "#{Caren::Api.url}#{self.resource_location}#{id}"
  end
  
  def self.search_url key, value
    "#{self.resource_url}?key=#{key.to_s.dasherize}&value=#{value}"
  end
  
  # The absolute (constructed url) to the resource.
  def resource_url id=nil
    self.class.resource_url(id)
  end
  
  private
  
  # Method missing calls to enable getters/setters
  def method_missing args, value=nil
    return self.attributes[args] if self.class.keys.include?(args)
    return self.attributes[args] = value if self.class.keys.include?(args.to_s.gsub('=','').to_sym)
    super
  end
  
end