require 'relax/query'

module Relax
  class Request
    def initialize(options = {})
      self.class.class_variables.each do |variable|
        instance_variable_set(variable.slice(1..-1), self.class.send(:class_variable_get, variable))
      end

      options.each do |key, value|
        instance_variable_set "@#{key}", value
      end
    end

    def to_query
      keys.inject(Query.new) do |parameters, key|
        parameters[convert_key(key)] = send(key)
        parameters
      end
    end

    def to_s
      keys.sort { |a, b| a.to_s <=> b.to_s }.collect do |key|
        "#{key.to_s}=#{ERB::Util.url_encode(send('[]', key).to_s)}"
      end.join('&')
    end

    class << self
      def parameter(name, options = {})
        attr_accessor name
        class_variable_set("@@#{name}", options.delete(:value)) if options[:value]
      end

      def []=(key, value)
        parameter(key, {:value => value})
      end
    end

    protected

    def keys
      instance_variables.collect { |v| v.sub('@', '') }
    end

    def convert_key(key)
      key
    end
  end
end