protected Cart validateOrRevertPromotion( HttpServletRequest request, Cart cart ) {
        log.trace( "validateOrRevertPromotion : enter" );

        Account account = null;
        if( SecurityContextHolder.getContext().getAuthentication().isAuthenticated() ) {

            Authentication auth = SecurityContextHolder.getContext().getAuthentication();
            if( null != auth ) {

                try {
                    account = userService.authenticated( (String) auth.getPrincipal() );
                } catch( MyAccountException e ) {
                    log.error( "validateOrRevertPromotion : error", e );

                    return cart;
                }

            } else {

                log.trace( "validateOrRevertPromotion : user is not authenticated" );
                return cart;
            }

        }

        if( account.getGuest() ) {

            if( null == cart.getPromotion() && StringUtils.isNotBlank( cart.getPromotionCode() ) ) {

                cart = Cart.fromCartDetails( promotionUtils.populatePromotion( cart.toCartDetails() ) );

                log.trace( "validateOrRevertPromotion : guest used promotion code '" + cart.getPromotionCode() + "'" );
            }

            log.trace( "validateOrRevertPromotion : cart is for guest" );
            return cart;
        }

        try {
            User user = userService.getUser( account.getGuid() );
            if( StringUtils.isNotBlank( user.getCampaign() ) && ( user.isCampaignVerified() && !user.isCampaignRevoked() ) ) {
                log.trace( "validateOrRevertPromotion : authenticated user is part of campaign" );

                ThirdPartyCampaign campaign = userService.getCampaign( user.getCampaign() );
                if( null != campaign ) {

                    cart.setPromotionCode( campaign.getPromoCode() );
                    cart = Cart.fromCartDetails( promotionUtils.populatePromotion( cart.toCartDetails() ) );

                    log.trace( "validateOrRevertPromotion : campaign added to cart" );
                }

                log.trace( "validateOrRevertPromotion : cart is for authenticated user with campaign" );
                return cart;
            } else {

                if( null == cart.getPromotion() && StringUtils.isNotBlank( cart.getPromotionCode() ) ) {

                    cart = Cart.fromCartDetails( promotionUtils.populatePromotion( cart.toCartDetails() ) );

                    log.trace( "validateOrRevertPromotion : authenticated user used promotion code '" + cart.getPromotionCode() + "'" );
                }

                log.trace( "validateOrRevertPromotion : cart is for authenticated user" );
                return cart;
            }

        } catch( MyAccountException e ) {
            log.error( "validateOrRevertPromotion : error", e );
        }


        log.trace( "validateOrRevertPromotion : exit, no promotion applied" );
        return cart;
    }