res_levis_backend/internal/pkg/controller/trackers_controller.go

package controller

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"

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

func SendKafkaMessage(writer *kafka.Writer, value *model.ApiUpdate, ctx context.Context) error {
	valueStr, err := json.Marshal(&value)
	if err != nil {
		fmt.Println("error in encoding: ", err)
		return err
	}
	msg := kafka.Message{
		Value: valueStr,
	}

	if err := writer.WriteMessages(ctx, msg); err != nil {
		fmt.Println("Error in sending kafka message: ", err)
		return err
	}

	return nil
}

func TrackerAdd(db *gorm.DB, writer *kafka.Writer, ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var tracker model.Tracker
		if err := json.NewDecoder(r.Body).Decode(&tracker); err != nil {
			http.Error(w, err.Error(), 400)
			return
		}
		db.Create(&tracker)

		apiUpdate := model.ApiUpdate{
			Method: "POST",
			ID:     tracker.ID,
			MAC:    tracker.MAC,
		}

		if err := SendKafkaMessage(writer, &apiUpdate, ctx); err != nil {
			fmt.Println("error in sending Kafka POST message")
			http.Error(w, "Error in sending kafka message", 500)
			return
		}

		w.Write([]byte("ok"))
	}
}

func TrackerList(db *gorm.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var list []model.Tracker
		db.Find(&list)
		json.NewEncoder(w).Encode(list)
	}
}

func TrackerUpdate(db *gorm.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var tracker model.Tracker

		if err := json.NewDecoder(r.Body).Decode(&tracker); err != nil {
			http.Error(w, "Invalid JSON", 400)
			return
		}

		id := tracker.ID

		if err := db.First(&model.Tracker{}, "id = ?", id).Error; err != nil {
			http.Error(w, err.Error(), 400)
			return
		}

		if err := db.Save(&tracker).Error; err != nil {
			http.Error(w, err.Error(), 500)
			return
		}

		w.Write([]byte("ok"))
	}
}

func TrackerDelete(db *gorm.DB, writer *kafka.Writer, ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		id := mux.Vars(r)["id"]
		var tracker model.Tracker
		db.Find(&tracker, "id = ?", id)

		if res := db.Delete(&model.Tracker{}, "id = ?", id); res.RowsAffected == 0 {
			http.Error(w, "no tracker with such ID found", 400)
			return
		}

		apiUpdate := model.ApiUpdate{
			Method: "Delete",
			ID:     tracker.ID,
		}

		fmt.Printf("Sending DELETE tracker id: %s message\n", id)

		if err := SendKafkaMessage(writer, &apiUpdate, ctx); err != nil {
			fmt.Println("error in sending Kafka DELETE message")
			http.Error(w, "Error in sending kafka message", 500)
			return
		}

		w.Write([]byte("ok"))
	}
}