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/v3/plugins" ) func Register(args plugins.RegistrationArguments) error { args.RegisterTemplateFunction("randomString", plugins.GenericTemplateFunctionGetter(randomString), plugins.TemplateFuncDocumentation{ Description: "Randomly picks a string from a list of strings", Syntax: "randomString [...string]", Example: &plugins.TemplateFuncDocumentationExample{ Template: `{{ randomString "a" "b" "c" "d" }}`, FakedOutput: "a", }, }) args.RegisterTemplateFunction("seededRandom", plugins.GenericTemplateFunctionGetter(stableRandomFromSeed), plugins.TemplateFuncDocumentation{ Description: "Returns a float value stable for the given seed", Syntax: "seededRandom ", Example: &plugins.TemplateFuncDocumentationExample{ Template: `Your int this hour: {{ printf "%.0f" (mulf (seededRandom (list "int" .username (now | date "2006-01-02 15") | join ":")) 100) }}%`, }, }) return nil } func randomString(lst ...string) (string, error) { if len(lst) == 0 { return "", errors.New("empty list given") } return lst[rand.Intn(len(lst))], nil // #nosec:G404 // This is used to select a random string from a list, no crypto-use } 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 }