datawriter/cmd/websrv/main.go

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"

	"github.com/google/uuid"
	"gittea.marcokittel.de/elio/eliotools/datawriter/internal/api"
	"gittea.marcokittel.de/elio/eliotools/datawriter/internal/database"
)

var (
	connectionString = ""
	port             = ":8080"
)

type (
	//RegistrierungsID -> ProductID -> Product
	ProductStore map[string]map[string]database.Product
)

const (
	curlhelp = `
	Bewerbungsaufgabe von Marco Kittel 2025
	
	Produkte abrufen
	curl -X POST localhost:8080/api/products -d '{ "products": { "A6053": 2, "B3009": 1200 }, "context": { "country": "EU", "state": "" } }'

	Reservierung reservieren
	curl -X POST localhost:8080/api/products/reserve -d '{"id":"ab0d7184-a4ce-4802-897a-d8597335143a"}'

	Reservierung bestätigen
	curl -X POST localhost:8080/api/products/confirm -d '{"id":"ab0d7184-a4ce-4802-897a-d8597335143a"}'

	Reservierung abbrechen
	curl -X POST localhost:8080/api/products/abort -d '{"id":"ab0d7184-a4ce-4802-897a-d8597335143a"}'

	Reservierung freigeben
	curl -X POST localhost:8080/api/products/release -d '{"id":"ab0d7184-a4ce-4802-897a-d8597335143a"}'
	`
)

func main() {
	connectionString := os.Getenv("CONNECTIONSTRING")
	nps := database.NewProductService(connectionString)
	//Hier prüfe ich nach alten Registrierungen und gebe Sie frei.
	nps.Autorelease()
	if len(connectionString) == 0 {
		fmt.Println("Connectionstring fehlt!. Bsp.:  <user>:<passwort>@tcp(127.0.0.1:3306)/elio?parseTime=true")
		return
	}
	//Dependency Injection
	http.HandleFunc("/api/products", api.GetProductApiHandleFunc(nps))

	//Todo schöner machen
	http.HandleFunc("/api/products/reserve", func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			return
		}
		defer r.Body.Close()
		data, err := io.ReadAll(r.Body)
		if err != nil {
			log.Println(err)
			return
		}
		var payload database.Container
		err = json.Unmarshal(data, &payload)
		if err != nil {
			log.Printf("Could not parse Json: %s", err)
			return
		}
		groupId := uuid.New().String()
		result, err := nps.FetchReservationData(&payload, database.UUID(groupId))
		if err != nil {
			//Todo Fehlerhandling
			log.Println(err)
		}
		if len(result) == 0 {
			w.WriteHeader(http.StatusNoContent)
			fmt.Fprintln(w)
			return
		}
		_, err = nps.ReserviereBestellungen(result, database.UUID(groupId))
		if err != nil {
			log.Println(err)
		}
		jsonResult, err := json.Marshal(result[0])
		if err != nil {
			log.Println(err)
		}
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		fmt.Fprintln(w, string(jsonResult))
	})

	http.HandleFunc("/api/products/confirm", func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			return
		}
		defer r.Body.Close()
		data, err := io.ReadAll(r.Body)
		if err != nil {
			log.Println(err)
			return
		}
		payload := struct {
			Id string `json:"id"`
		}{}
		err = json.Unmarshal(data, &payload)
		if err != nil {
			//Todo Fehlerhandling
			log.Println(err)
		}
		err = nps.ConfirmBestellung(database.UUID(payload.Id))
		if err != nil {
			//Todo Fehlerhandling
			log.Println(err)
		}
		w.WriteHeader(http.StatusNoContent)
		fmt.Fprintln(w)
		return
	})

	http.HandleFunc("/api/products/release", func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			return
		}
		defer r.Body.Close()
		data, err := io.ReadAll(r.Body)
		if err != nil {
			log.Println(err)
			return
		}
		payload := struct {
			Id string `json:"id"`
		}{}
		err = json.Unmarshal(data, &payload)
		if err != nil {
			//Todo Fehlerhandling
			log.Println(err)
		}
		err = nps.ReleaseBestellung(database.UUID(payload.Id))
		if err != nil {
			//Todo Fehlerhandling
			log.Println(err)
		}
		w.WriteHeader(http.StatusNoContent)
		fmt.Fprintln(w)
		return
	})

	http.HandleFunc("/api/products/abort", func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			return
		}
		defer r.Body.Close()
		data, err := io.ReadAll(r.Body)
		if err != nil {
			log.Println(err)
			return
		}
		payload := struct {
			Id string `json:"id"`
		}{}
		err = json.Unmarshal(data, &payload)
		if err != nil {
			//Todo Fehlerhandling
			log.Println(err)
		}
		err = nps.AbortBestellung(database.UUID(payload.Id))
		if err != nil {
			//Todo Fehlerhandling
			log.Println(err)
		}
		w.WriteHeader(http.StatusNoContent)
		fmt.Fprintln(w)
		return
	})

	log.Printf("Easy Peasy: Die Party startet auf Port %s\n", port)
	log.Printf("Probiers mal damit: %s\n", curlhelp)
	log.Fatal(http.ListenAndServe(port, nil))
}