module JsOnDemandViewMixin
  def required_js_on_demand
    "if(!JsOnDemand) {
      var JsOnDemand = {};
      JsOnDemand.callbacks = {};
      JsOnDemand.num = 0;
      JsOnDemand.Get = function(url, callback) {
        this.callback = callback;
        var id = JsOnDemand.num++;
        JsOnDemand.callbacks[id] = this.callback;
        var script = document.createElement('script');
        script.type = 'text/javascript';
        var t = new Date();
        var cacheDefeater = '' + t.getYear() + t.getMonth() + t.getDay() + t.getHours() + t.getMinutes() + t.getSeconds() + id
        script.src = 'http://#{request.host_with_port}' + url + '&JsOnDemandNum=' + id + '&__no_cache=' + cacheDefeater;
        document.getElementsByTagName('head')[0].appendChild(script);
      }
    }"
  end
  
  def js_on_demand_get(options)
    query_string = ""
    if not options[:js_parameters].nil?
      query_string = options[:js_parameters].entries.collect { |key,value| "'" + key.to_s + "=' + " + value.to_s }.join(" + '&' + ")
      options.delete(:js_parameters)
    end
    callback = "callback"
    if not options[:callback].nil?
      callback = options[:callback].to_s
      options.delete(:callback)
    end
    url = url_for(options)
    if (url =~ /\?/).nil?
      query_string = "'?' + " + query_string
    else
      query_string = "'&' + " + query_string
    end
    "new JsOnDemand.Get('#{url}' + #{query_string}, #{callback});"
  end
  
end