offers/dining/go/offerFeedGenerator.go

package main

import (
	pb "feed/app/generated/ext/maps/booking/offers/proto"
	"fmt"
	"log"

	money "google.golang.org/genproto/googleapis/type/money"
	timestamppb "google.golang.org/protobuf/types/known/timestamppb"
	dayofweek "google.golang.org/genproto/googleapis/type/dayofweek"
	timeofday "google.golang.org/genproto/googleapis/type/timeofday"
	proto "google.golang.org/protobuf/proto"

	"google.golang.org/protobuf/encoding/protojson"
)

func main() {
	// 200 MB feed file size limit
	const MaxBytesDataFile = 200 * 1024 * 1024 

	// Create OfferFeed with offers
	feed := &pb.OfferFeed{}

	// Build the offers
	offer := &pb.Offer{
		OfferId:   "offer-1",
		EntityIds: []string{"dining-1"},
		OfferSource: pb.OfferSource_OFFER_SOURCE_AGGREGATOR,
		ActionType:  pb.ActionType_ACTION_TYPE_DINING,
		OfferModes: []pb.OfferMode{
			pb.OfferMode_OFFER_MODE_WALK_IN,
			pb.OfferMode_OFFER_MODE_FREE_RESERVATION,
		},
		OfferCategory: pb.OfferCategory_OFFER_CATEGORY_BASE_OFFER,
		OfferDetails: &pb.OfferDetails{
			OfferDisplayText: "₹100 off on your order",
			OfferSpecification: &pb.OfferDetails_DiscountValue{
        		DiscountValue: &money.Money{
            		CurrencyCode: "INR",
            		Units:        100,
				},
			},
		},
		OfferRestrictions: &pb.OfferRestrictions{
			CombinableWithOtherOffers: true,
			CombinableOfferCategories: []pb.OfferCategory{
				pb.OfferCategory_OFFER_CATEGORY_ADD_ON_PAYMENT_OFFER,
				pb.OfferCategory_OFFER_CATEGORY_ADD_ON_COUPON_OFFER,
			},
		},
		Terms: &pb.Terms{
			RestrictedToCertainUsers: false,
			TermsAndConditions:       "Valid on all menu items.",
		},
		ValidityPeriods: []*pb.ValidityPeriod{
			{
				ValidPeriod: &pb.ValidityRange{
					ValidFromTime:    &timestamppb.Timestamp{Seconds: 1687062000},
					ValidThroughTime: &timestamppb.Timestamp{Seconds: 1956556800},
				},
				TimeOfDay: []*pb.TimeOfDayWindow{
					// Monday - Thursday Window
					{
						TimeWindows: &pb.TimeOfDayRange{
							OpenTime:  &timeofday.TimeOfDay{Hours: 13},
							CloseTime: &timeofday.TimeOfDay{Hours: 23},
						},
						DayOfWeek: []dayofweek.DayOfWeek{
							dayofweek.DayOfWeek_MONDAY,
							dayofweek.DayOfWeek_TUESDAY,
							dayofweek.DayOfWeek_WEDNESDAY,
							dayofweek.DayOfWeek_THURSDAY,
						},
					},
					// Friday - Sunday Window
					{
						TimeWindows: &pb.TimeOfDayRange{
							OpenTime: &timeofday.TimeOfDay{Hours: 13},
							CloseTime: &timeofday.TimeOfDay{
								Hours:   23,
								Minutes: 59,
								Seconds: 59,
							},
						},
						DayOfWeek: []dayofweek.DayOfWeek{
							dayofweek.DayOfWeek_FRIDAY,
							dayofweek.DayOfWeek_SATURDAY,
							dayofweek.DayOfWeek_SUNDAY,
						},
					},
				},
			},
		},
		OfferUrl: "https://www.example-restaurant.com/offer/base_offer_1",
		ImageUrl: "https://www.example-restaurant.com/images/offer_base.jpg",
	}

	// Example testing for feed size
	// Protocol buffer message must be less than 2 GiB
	// https://protobuf.dev/programming-guides/proto-limits/
	// It is recommended to not exceed 200 MB, as there is an Actions
	// Center limit of 200 MB per file after compression.
	offerSize := proto.Size(offer)
	currentFeedSize := proto.Size(feed)

	if currentFeedSize + offerSize < MaxBytesDataFile {
		feed.Data = append(feed.Data, offer)
	} else {
		// 1. Serialize and save the current 'feed' to a file
		// 2. Reset 'feed' to a new empty OfferFeed
		// 3. Add the 'offer' to the new feed
	}

	// Serialize to JSON
	marshaler := protojson.MarshalOptions{
		UseProtoNames: true,
	}

	jsonOutput, err := marshaler.Marshal(feed)
	if err != nil {
		log.Fatalf("Failed to marshal feed: %v", err)
	}

	fmt.Println(string(jsonOutput))
}