Adding upstream version 0.8.9.

Signed-off-by: Daniel Baumann <daniel@debian.org>

pkg/services/smtp/smtp_encmethod.go

@@ -0,0 +1,71 @@
+package smtp
+
+import (
+	"github.com/nicholas-fedor/shoutrrr/pkg/format"
+	"github.com/nicholas-fedor/shoutrrr/pkg/types"
+)
+
+const (
+	// EncNone represents no encryption.
+	EncNone encMethod = iota // 0
+	// EncExplicitTLS represents explicit TLS initiated with StartTLS.
+	EncExplicitTLS // 1
+	// EncImplicitTLS represents implicit TLS used throughout the session.
+	EncImplicitTLS // 2
+	// EncAuto represents automatic TLS selection based on port.
+	EncAuto // 3
+	// ImplicitTLSPort is the de facto standard SMTPS port for implicit TLS.
+	ImplicitTLSPort = 465
+)
+
+// EncMethods is the enum helper for populating the Encryption field.
+var EncMethods = &encMethodVals{
+	None:        EncNone,
+	ExplicitTLS: EncExplicitTLS,
+	ImplicitTLS: EncImplicitTLS,
+	Auto:        EncAuto,
+
+	Enum: format.CreateEnumFormatter(
+		[]string{
+			"None",
+			"ExplicitTLS",
+			"ImplicitTLS",
+			"Auto",
+		}),
+}
+
+type encMethod int
+
+type encMethodVals struct {
+	// None means no encryption
+	None encMethod
+	// ExplicitTLS means that TLS needs to be initiated by using StartTLS
+	ExplicitTLS encMethod
+	// ImplicitTLS means that TLS is used for the whole session
+	ImplicitTLS encMethod
+	// Auto means that TLS will be implicitly used for port 465, otherwise explicit TLS will be used if supported
+	Auto encMethod
+
+	// Enum is the EnumFormatter instance for EncMethods
+	Enum types.EnumFormatter
+}
+
+func (at encMethod) String() string {
+	return EncMethods.Enum.Print(int(at))
+}
+
+// useImplicitTLS determines if implicit TLS should be used based on encryption method and port.
+func useImplicitTLS(encryption encMethod, port uint16) bool {
+	switch encryption {
+	case EncNone:
+		return false
+	case EncExplicitTLS:
+		return false
+	case EncImplicitTLS:
+		return true
+	case EncAuto:
+		return port == ImplicitTLSPort
+	default:
+		return false // Unreachable due to enum constraints, but included for safety
+	}
+}