1 files changed, 84 insertions, 0 deletions
diff --git a/modules/validation/validatable.go b/modules/validation/validatable.go
new file mode 100644
index 0000000..94b5cc1
--- /dev/null
+++ b/modules/validation/validatable.go
@@ -0,0 +1,84 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"unicode/utf8"
+
+	"code.gitea.io/gitea/modules/timeutil"
+)
+
+// ErrNotValid represents an validation error
+type ErrNotValid struct {
+	Message string
+}
+
+func (err ErrNotValid) Error() string {
+	return fmt.Sprintf("Validation Error: %v", err.Message)
+}
+
+// IsErrNotValid checks if an error is a ErrNotValid.
+func IsErrNotValid(err error) bool {
+	_, ok := err.(ErrNotValid)
+	return ok
+}
+
+type Validateable interface {
+	Validate() []string
+}
+
+func IsValid(v Validateable) (bool, error) {
+	if err := v.Validate(); len(err) > 0 {
+		typeof := reflect.TypeOf(v)
+		errString := strings.Join(err, "\n")
+		return false, ErrNotValid{fmt.Sprint(typeof, ": ", errString)}
+	}
+
+	return true, nil
+}
+
+func ValidateNotEmpty(value any, name string) []string {
+	isValid := true
+	switch v := value.(type) {
+	case string:
+		if v == "" {
+			isValid = false
+		}
+	case timeutil.TimeStamp:
+		if v.IsZero() {
+			isValid = false
+		}
+	case int64:
+		if v == 0 {
+			isValid = false
+		}
+	default:
+		isValid = false
+	}
+
+	if isValid {
+		return []string{}
+	}
+	return []string{fmt.Sprintf("%v should not be empty", name)}
+}
+
+func ValidateMaxLen(value string, maxLen int, name string) []string {
+	if utf8.RuneCountInString(value) > maxLen {
+		return []string{fmt.Sprintf("Value %v was longer than %v", name, maxLen)}
+	}
+	return []string{}
+}
+
+func ValidateOneOf(value any, allowed []any, name string) []string {
+	for _, allowedElem := range allowed {
+		if value == allowedElem {
+			return []string{}
+		}
+	}
+	return []string{fmt.Sprintf("Value %v is not contained in allowed values %v", value, allowed)}
+}