From 0ad15cc71727e2bf8071a430bbb08f0cc226fdff Mon Sep 17 00:00:00 2001
From: Simon Vieille <simon@deblan.fr>
Date: Tue, 22 Jul 2025 21:10:33 +0200
Subject: [PATCH] feat: add constraints (isodd, iseven)

---
 validation/iseven.go | 34 ++++++++++++++++++++++++++++++++++
 validation/isodd.go  | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 validation/iseven.go
 create mode 100644 validation/isodd.go

diff --git a/validation/iseven.go b/validation/iseven.go
new file mode 100644
index 0000000..306cae2
--- /dev/null
+++ b/validation/iseven.go
@@ -0,0 +1,34 @@
+package validation
+
+import (
+	"strconv"
+)
+
+type IsEven struct {
+	Message          string
+	TypeErrorMessage string
+}
+
+func NewIsEven() IsEven {
+	return IsEven{
+		Message:          "This value is not an even number.",
+		TypeErrorMessage: "This value can not be processed.",
+	}
+}
+
+func (c IsEven) Validate(data any) []Error {
+	errors := []Error{}
+
+	// The constraint should not validate an empty data
+	if len(NewNotBlank().Validate(data)) == 0 {
+		i, err := strconv.Atoi(data.(string))
+
+		if err != nil {
+			errors = append(errors, Error(c.TypeErrorMessage))
+		} else if i%2 != 0 {
+			errors = append(errors, Error(c.Message))
+		}
+	}
+
+	return errors
+}
diff --git a/validation/isodd.go b/validation/isodd.go
new file mode 100644
index 0000000..d7e3b53
--- /dev/null
+++ b/validation/isodd.go
@@ -0,0 +1,34 @@
+package validation
+
+import (
+	"strconv"
+)
+
+type IsOdd struct {
+	Message          string
+	TypeErrorMessage string
+}
+
+func NewIsOdd() IsOdd {
+	return IsOdd{
+		Message:          "This value is not a odd number.",
+		TypeErrorMessage: "This value can not be processed.",
+	}
+}
+
+func (c IsOdd) Validate(data any) []Error {
+	errors := []Error{}
+
+	// The constraint should not validate an empty data
+	if len(NewNotBlank().Validate(data)) == 0 {
+		i, err := strconv.Atoi(data.(string))
+
+		if err != nil {
+			errors = append(errors, Error(c.TypeErrorMessage))
+		} else if i%2 != 1 {
+			errors = append(errors, Error(c.Message))
+		}
+	}
+
+	return errors
+}