package random import ( "crypto/md5" // #nosec G501 // Unly used to convert a string into a numer, no need for cryptographic safety "fmt" "math" "math/rand" "github.com/pkg/errors" "github.com/Luzifer/twitch-bot/plugins" ) func Register(args plugins.RegistrationArguments) error { args.RegisterTemplateFunction("seededRandom", plugins.GenericTemplateFunctionGetter(stableRandomFromSeed)) return nil } func stableRandomFromSeed(seed string) (float64, error) { seedValue, err := stringToSeed(seed) if err != nil { return 0, errors.Wrap(err, "generating seed") } return rand.New(rand.NewSource(seedValue)).Float64(), nil // #nosec G404 // Only used for generating a random number from static string, no need for cryptographic safety } func stringToSeed(s string) (int64, error) { hash := md5.New() // #nosec G401 // Unly used to convert a string into a numer, no need for cryptographic safety if _, err := fmt.Fprint(hash, s); err != nil { return 0, errors.Wrap(err, "writing string to hasher") } var ( hashSum = hash.Sum(nil) sum int64 ) for i := 0; i < len(hashSum); i++ { sum += int64(float64(hashSum[len(hashSum)-1-i]%10) * math.Pow(10, float64(i))) //nolint:gomnd // No need to put the 10 of 10**i into a constant named "ten" } return sum, nil }