add middlewares, handlers and database models

internal/validation/email.go

@@ -0,0 +1,27 @@
+package validation
+
+import (
+	"errors"
+	"net/mail"
+)
+
+// ValidateEmail validates email format and length
+// Uses Go's built-in net/mail parser which follows RFC 5322
+func ValidateEmail(email string) error {
+	// Check length (RFC 5321: local part max 64, domain max 255, total max 254 with @)
+	if len(email) > 254 {
+		return errors.New("email address is too long (max 254 characters)")
+	}
+
+	if email == "" {
+		return errors.New("email address is required")
+	}
+
+	// Parse using Go's RFC 5322 compliant parser
+	_, err := mail.ParseAddress(email)
+	if err != nil {
+		return errors.New("invalid email address format")
+	}
+
+	return nil
+}