res_levis_backend/internal/pkg/service/beacon_service.go

package service

import (
	"context"
	"encoding/json"
	"fmt"
	"slices"
	"strings"

	"github.com/AFASystems/presence/internal/pkg/common/appcontext"
	"github.com/AFASystems/presence/internal/pkg/model"
	"github.com/segmentio/kafka-go"
	"gorm.io/gorm"
)

func LocationToBeaconService(msg model.HTTPLocation, db *gorm.DB, writer *kafka.Writer, ctx context.Context) {
	if msg.ID == "" {
		fmt.Println("empty ID")
		return
	}

	var zones []model.TrackerZones
	if err := db.Select("zoneList").Where("tracker = ?", msg.ID).Find(&zones).Error; err != nil {
		return
	}

	var allowedZones []string
	for _, z := range zones {
		allowedZones = append(allowedZones, z.ZoneList...)
	}

	var gw model.Gateway
	mac := formatMac(msg.Location)
	if err := db.Select("id").Where("mac = ?", mac).First(&gw).Error; err != nil {
		fmt.Printf("Gateway not found for MAC: %s\n", mac)
		return
	}

	if len(allowedZones) != 0 && !slices.Contains(allowedZones, gw.ID) {
		alert := model.Alert{
			ID:    msg.ID,
			Type:  "Restricted zone",
			Value: gw.ID,
		}

		eMsg, err := json.Marshal(alert)
		if err != nil {
			fmt.Println("Error in marshaling")
		} else {
			msg := kafka.Message{
				Value: eMsg,
			}
			writer.WriteMessages(ctx, msg)
		}
	}

	if err := db.Updates(&model.Tracker{ID: msg.ID, Location: gw.ID, Distance: msg.Distance}).Error; err != nil {
		fmt.Println("Error in saving distance for beacon: ", err)
		return
	}
}

func EventToBeaconService(msg model.BeaconEvent, appState *appcontext.AppState, ctx context.Context) error {
	id := msg.ID
	beacon, ok := appState.GetHTTPResult(id)
	if !ok {
		appState.UpdateHTTPResult(id, model.HTTPResult{ID: id, BeaconType: msg.Type, Battery: int64(msg.Battery), Event: msg.Event})
	} else {
		beacon.ID = id
		beacon.BeaconType = msg.Type
		beacon.Battery = int64(msg.Battery)
		beacon.Event = msg.Event
		appState.UpdateHTTPResult(id, beacon)
	}

	return nil
}

func formatMac(MAC string) string {
	var res strings.Builder
	for i := 0; i < len(MAC); i += 2 {
		if i > 0 {
			res.WriteByte(':')
		}

		end := min(i+2, len(MAC))

		res.WriteString(MAC[i:end])
	}

	return res.String()
}