function SpreeDeliveryOptions() {

  var that = this;

  this.initializeDatePicker = function() {
     $('#order_delivery_date').datepicker({dateFormat: "dd/mm/yy"});
  };

  this.initializeDeliveryTimeSelect = function() {
    this.update_delivery_time_options();

    $('#order_delivery_date').change(function(event){
      that.update_delivery_time_options();
    });
  };

  this.update_delivery_time_options = function() {
    delivery_time_options = $.parseJSON($('.delivery-time-options').attr("data"));

    if (delivery_time_options){
      weekdays = ['sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday'];
      var dateParts = $('#order_delivery_date').val().split('/')
      day_index = new Date(dateParts[2], dateParts[1]-1, dateParts[0]).getDay();
      weekday = weekdays[day_index];

      day_options = delivery_time_options[weekday];
      this.populate_delivery_time(day_options);
    }
  };

  this.populate_delivery_time = function(options) {
    if (options) {
      var arLen = options.length;
      var newList = "";
      for ( var i=0, len=arLen; i<len; ++i ){
        newList = newList + '<option>' + options[i]+'</option>';
      }
      $('#order_delivery_time').html(newList);
    } else {
      $('#order_delivery_time').html("<option>No deliveries available on this date</option>");
    }
  };

}

$(document).ready(function() {
  var deliveryOptions = new SpreeDeliveryOptions();
  deliveryOptions.initializeDatePicker();
  deliveryOptions.initializeDeliveryTimeSelect();
});