arbeitszeitmessung/Backend/models/booking.go

package models

import (
	"database/sql"
	"fmt"
	"log"
	"net/url"
	"strconv"
	"time"
)

type SameBookingError struct{}

func (e SameBookingError) Error() string {
	return "the same booking already exists!"
}

type Booking struct {
	CardUID    string    `json:"card_uid"`
	GeraetID   int16     `json:"geraet_id"`
	CheckInOut int16     `json:"check_in_out"`
	Timestamp  time.Time `json:"timestamp"`
	CounterId  int       `json:"counter_id"`
}

var DB *sql.DB

func (b Booking) New(card_id string, geraet_id int16, check_in_out int16) Booking {
	return Booking{
		CardUID:    card_id,
		GeraetID:   geraet_id,
		CheckInOut: check_in_out,
	}
}

func (b *Booking) FromUrlParams(params url.Values) Booking {
	var booking Booking
	if _check_in_out, err := strconv.Atoi(params.Get("check_in_out")); err == nil {
		booking.CheckInOut = int16(_check_in_out)
	}
	if _geraet_id, err := strconv.Atoi(params.Get("geraet_id")); err == nil {
		booking.GeraetID = int16(_geraet_id)
	}
	booking.CardUID = params.Get("card_uid")
	return booking
}

func (b Booking) Verify() bool {
	if b.CardUID == "" || b.GeraetID == 0 || b.CheckInOut == 0 {
		return false
	}
	return true
}

func (b *Booking) Insert() error {
	if !checkLastBooking(*b) {
		return SameBookingError{}
	}
	stmt, err := DB.Prepare((`INSERT INTO anwesenheit (card_uid, geraet_id, check_in_out) VALUES ($1, $2, $3) RETURNING counter_id, timestamp`))
	if err != nil {
		return err
	}
	err = stmt.QueryRow(b.CardUID, b.GeraetID, b.CheckInOut).Scan(&b.CounterId, &b.Timestamp)
	if err != nil {
		return err
	}
	return nil
}

func (b *Booking) GetBookingById(booking_id int) (Booking, error) {
	var booking Booking
	qStr, err := DB.Prepare((`SELECT counter_id, timestamp, card_uid, geraet_id, check_in_out FROM anwesenheit WHERE counter_id = $1`))
	if err != nil {
		return booking, err
	}
	err = qStr.QueryRow(booking_id).Scan(&booking.CounterId, &booking.Timestamp, &booking.CardUID, &booking.GeraetID, &booking.CheckInOut)
	if err != nil {
		return booking, err
	}
	if !booking.Verify() {
		fmt.Printf("Booking verification failed")
		return booking, nil
	}
	return booking, nil
}

func (b *Booking) GetBookingsByCardID(card_id string) ([]Booking, error) {
	qStr, err := DB.Prepare((`SELECT counter_id, timestamp, card_uid, geraet_id, check_in_out FROM anwesenheit WHERE card_uid = $1`))
	if err != nil {
		return nil, err
	}
	var bookings []Booking
	rows, err := qStr.Query(card_id)
	if err == sql.ErrNoRows {
		return bookings, err
	}
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	for rows.Next() {
		var booking Booking
		if err := rows.Scan(&booking.CounterId, &booking.Timestamp, &booking.CardUID, &booking.GeraetID, &booking.CheckInOut); err != nil {
			return bookings, err
		}
		bookings = append(bookings, booking)
	}
	if err = rows.Err(); err != nil {
		return bookings, err
	}
	return bookings, nil
}

func (b Booking) Save() {
	qStr, err := DB.Prepare((`UPDATE "anwesenheit" SET "id" = $1, "card_uid" = $2, "reader_id" = $3, "booking_type" = $4 WHERE "id" = $1;`))
	if err != nil {
		log.Fatalf("Error preparing query: %v", err)
		return
	}
	_, err = qStr.Query(b.CounterId, b.CardUID, b.GeraetID, b.CheckInOut)
	if err != nil {
		log.Fatalf("Error executing query: %v", err)
		return
	}
}

func (b *Booking) Update(nb Booking) {
	if b.CheckInOut != nb.CheckInOut && nb.CheckInOut != 0 {
		b.CheckInOut = nb.CheckInOut
	}
	if b.CardUID != nb.CardUID && nb.CardUID != "" {
		b.CardUID = nb.CardUID
	}
	if b.GeraetID != nb.GeraetID && nb.GeraetID != 0 {
		b.GeraetID = nb.GeraetID
	}
}

func checkLastBooking(b Booking) bool {
	var check_in_out int
	stmt, err := DB.Prepare((`SELECT check_in_out FROM "anwesenheit" WHERE "card_uid" = $1 ORDER BY "timestamp" DESC LIMIT 1;`))
	if err != nil {
		log.Fatalf("Error preparing query: %v", err)
		return false
	}
	err = stmt.QueryRow(b.CardUID).Scan(&check_in_out)
	if err == sql.ErrNoRows {
		return true
	}
	if err != nil {
		log.Println("Error checking last booking: ", err)
		return false
	}
	if int16(check_in_out) == b.CheckInOut {
		return false
	}
	return true
}