Add token creation methods

Signed-off-by: Nikolai Rodionov <allanger@badhouseplants.net>

internal/helpers/token/token.go

@@ -0,0 +1,45 @@
+// Package token should be used to generate secure tokens
+package token
+
+import (
+	"fmt"
+
+	"github.com/db-operator/can-haz-password/password"
+)
+
+const (
+	TokenPrefix = "sft"
+)
+
+// GenerateToken generates secure password string
+func GenerateToken() (string, error) {
+	generator := password.NewGenerator(newTokenRule())
+	password, err := generator.Generate()
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%s_%s", TokenPrefix, password), nil
+}
+
+// Minimum length of 20 characters, maximum length of 30 characters.
+// Varied composition including special characters and uppercase and lowercase letters.
+// Excludes consecutive dashes (for hybris compatibility) and uses only url safe special characters.
+type tokenRule struct{}
+
+func newTokenRule() *tokenRule {
+	return &tokenRule{}
+}
+
+func (r *tokenRule) Config() *password.Configuration {
+	return &password.Configuration{
+		Length: 40,
+		CharacterClasses: []password.CharacterClassConfiguration{ // codespell:ignore
+			{Characters: password.LowercaseCharacters + password.UppercaseCharacters, Minimum: 10},
+			{Characters: password.DigitCharacters, Minimum: 8},
+		},
+	}
+}
+
+func (r *tokenRule) Valid(password []rune) bool {
+	return true
+}

internal/helpers/token/token_test.go

@@ -0,0 +1,16 @@
+package token_test
+
+import (
+	"strings"
+	"testing"
+
+	"gitea.badhouseplants.net/softplayer/softplayer-backend/internal/helpers/token"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUnitTokenGeneration(t *testing.T) {
+	token, err := token.GenerateToken()
+	assert.NoError(t, err)
+	assert.Len(t, token, 44)
+	assert.True(t, strings.HasPrefix(token, "sft_"))
+}