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gootp/internal/otp.go

64 lines
1.4 KiB
Go

package internal
import (
"fmt"
"strings"
"time"
"github.com/pquerna/otp"
"github.com/pquerna/otp/totp"
)
func GenerateOTP(entry Entry, t time.Time) (string, error) {
algorithm, err := parseAlgorithm(entry.Algorithm)
if err != nil {
return "", fmt.Errorf("parseAlgorithm: %w", err)
}
digits, err := parseDigits(entry.Digits)
if err != nil {
return "", fmt.Errorf("parseDigits: %w", err)
}
switch strings.ToUpper(entry.Type) {
case "TOTP":
code, err := totp.GenerateCodeCustom(entry.Secret, t, totp.ValidateOpts{
Algorithm: algorithm,
Period: entry.Period,
Digits: digits,
})
if err != nil {
return "", fmt.Errorf("something went wrong while generating totp: %w", err)
}
return code, nil
default:
return "", fmt.Errorf("unsupported entry type: %s", entry.Type)
}
}
func parseAlgorithm(algorithm string) (otp.Algorithm, error) {
switch strings.ToUpper(algorithm) {
case "SHA1":
return otp.AlgorithmSHA1, nil
case "SHA256":
return otp.AlgorithmSHA256, nil
case "SHA512":
return otp.AlgorithmSHA512, nil
case "MD5":
return otp.AlgorithmMD5, nil
default:
return 0, fmt.Errorf("unsupported algorithm: %s", algorithm)
}
}
func parseDigits(digits uint) (otp.Digits, error) {
switch digits {
case 6:
return otp.DigitsSix, nil
case 8:
return otp.DigitsEight, nil
default:
return 0, fmt.Errorf("unsupported digits: %d", digits)
}
}