cards/lib/validate.go
2025-01-31 19:28:11 +02:00

62 lines
853 B
Go

package validate
import (
"slices"
"strconv"
"strings"
)
type Card struct {
Pan string
Month string
Year string
}
type ValidationResult struct {
Code int
Error error
}
func Luhn(pan string) bool {
if pan == "" {
return false
}
lastIndex := len(pan) - 1
asDigits := []int{}
for _, char := range strings.Split(pan, "") {
digit, err := strconv.Atoi(char)
if err != nil {
return false
}
asDigits = append(asDigits, digit)
}
sum := 0
// do we really need reversed array?
for i, digit := range slices.Backward(asDigits[:lastIndex]) {
if i%2 == len(pan)%2 {
if digit > 4 {
sum += 2*digit - 9
} else {
sum += 2 * digit
}
} else {
sum += digit
}
}
return asDigits[lastIndex] == (10-(sum%10))%10
}
func Validate(card Card) (bool, ValidationResult) {
return true, ValidationResult{}
}