require 'rubygems'
require 'hpricot'

require 'date'

module Relax
  class Response
    attr_accessor :xml

    def initialize(xml)
      @xml = Hpricot.XML(xml.to_s)

      if parameter = self.class.instance_variable_get('@parameters')
        parameter.each do |parameter, options|
          element = options[:element] ? options[:element] : parameter

          if attribute = options[:attribute] and attribute == true
            node = attribute(root, element)
          elsif attribute
            node = attribute(element(element), attribute)
          elsif options[:collection]
            node = elements(element)
          else
            node = element(element)
          end

          if options[:collection]
            value = node.collect do |element|
              options[:collection].new(element)
            end
          else
            case options[:type]
              when :float
                value = float_value(node)

              when :integer
                value = integer_value(node)

              when :text
              else
                value = text_value(node)
            end
          end

          instance_variable_set("@#{parameter}", value)
        end
      end
    end

    def root
      @xml.root
    end

    def is?(name)
      root.name.gsub(/.*:(.*)/, '\1') == node_name(name)
    end

    def element(name)
      root.at(root_path(name))
    end

    def attribute(element, name)
      element[name]
    end

    def elements(name)
      root.search(root_path(name))
    end

    def value(value)
      value.is_a?(Hpricot::Elem) ? value.inner_text : value.to_s
    end

    def text_value(value)
      value(value)
    end

    def integer_value(value)
      value(value).to_i
    end

    def float_value(value)
      value(value).to_f
    end

    def date_value(value)
      Date.parse(value(value))
    end

    alias :has? :element

    class << self
      def parameter(name, options = {})
        attr_accessor name
        @parameters ||= {}
        @parameters[name] = options
      end
    end

    private

    def node_name(name)
      name.to_s.downcase
    end

    def root_path(name)
      "/#{node_name(name)}"
    end
  end
end