package main

import (
	"Backend/models"
	"database/sql"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"os"
	"strconv"

	_ "github.com/lib/pq"
)

var DB *sql.DB

func main() {
	var err error
	dbConnStr := getDBConn()
	DB, err = sql.Open("postgres", dbConnStr)
	if err!= nil {
        log.Fatal(err)
    }
	defer DB.Close()

	http.HandleFunc("/time", timeHandler)

	fmt.Println("Server is running at http://localhost:8080")
	log.Fatal(http.ListenAndServe(":8080", nil))
}

func timeHandler(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case "PUT":
		createBooking(w, r)
	default:
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
	}
}

func createBooking(w http.ResponseWriter, r *http.Request) {

	booking := getBooking(r.URL.Query())
	if models.VerifyBooking(booking) {
		err := models.InsertBooking(booking, DB)
		if err == fmt.Errorf("the same booking already exists") {
			http.Error(w, "Booking already exists", http.StatusConflict)
            return
		}
		if err != nil {
            log.Println("Error inserting booking: ", err)
            http.Error(w, "Internal Server Error", http.StatusInternalServerError)
            return
        }
		w.WriteHeader(http.StatusAccepted)
		json.NewEncoder(w).Encode(booking)
	}
	w.WriteHeader(http.StatusBadRequest)
}

func getBooking(query_params url.Values) models.Booking {
	bookingType, err := strconv.Atoi(query_params.Get("bookingType"))
	if err!= nil {
        log.Println("Error parsing bookingType: ", err)
        return models.Booking{}
    }
	return models.Booking{
		CradID:      query_params.Get("cardID"),
		ReaderID:    query_params.Get("readerID"),
		BookingType: bookingType,
	}
}

func getDBConn() string {
	dbHost := getEnv("POSTGRES_HOST", "localhost")
	dbName := getEnv("POSTGRES_DB", "arbeitszeitmessung")
	dbUser := getEnv("POSTGRES_USER", "arbeit_zeit")
	dbPassword := getEnv("POSTGRES_PASS", "password")

	return fmt.Sprintf("postgres://%s:%s@%s:5432/%s?sslmode=disable", dbUser, dbPassword, dbHost, dbName)
}

func getEnv(key, fallback string) string {
    if value, ok := os.LookupEnv(key); ok {
        return value
    }
    return fallback
}