controller.js

function tripOverviewController ($scope, pricingService) {
  this.includeMeetAndGreet = function () {
    if(this.checkoutData){
        return this.checkoutData.trip.includeMeetAndGreet === 1;
    }
    return false;
  };

  this.showCouponField = function () {
    if(this.checkoutData){
        return this.checkoutData.trip.voyages[0].provider.acceptCoupon;
    }
    return false;
  };


  this.showGratuity = function() {
    if (this.checkoutData) {
      var type = this.checkoutData.trip.voyages[0].vehicle.type.toLowerCase().replace(/\s/g, '');
      if (type === 'bus' || type === 'expresstrain') {
        return false;
      }
      var gratuityIncluded = this.checkoutData.trip.voyages[0].bookingDetails.gratuityIncluded !== 0;
      var acceptsGratuity = this.checkoutData.trip.voyages[0].bookingDetails.acceptsGratuity !== 0;
      return true && !gratuityIncluded && acceptsGratuity;
    }
    return false;
  };


  this.updateGratuity = function (gratuityPercent) {
    var price = this.checkoutData.trip.price;
    var params = {
      amount: price.raw,
      gratuity: gratuityPercent,
      meet_and_greet_amount: (this.checkoutData.includeMeetAndGreet === 0)? 0 : this.checkoutData.meetAndGreetPrice
    };
    if('coupon_code' in this.checkoutData){
      params.coupon_code = this.checkoutData.coupon_code;
    }

    pricingService.getPrice(params).then(function(data) {
      this.checkoutData.trip.price.total = data.final_price;
      this.checkoutData.gratuity = this.gratuity;
      this.checkoutData.gratuityPrice = data.gratuity;
    }.bind(this));
  }


}