Introduce pkg/mail.Addr

Signed-off-by: Émile Ré <nemile.re@gmail.com>

pkg/mail/addr.go

@@ -0,0 +1,74 @@
+package mail
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+	"net/mail"
+	"strings"
+)
+
+type Addr string
+
+var Nil Addr
+
+func (a Addr) String() string {
+	return string(a)
+}
+
+func (a *Addr) Domain() string {
+	return strings.Split(a.String(), "@")[1]
+}
+
+func ParseAddr(s string) (Addr, error) {
+	netMailAddr, err := mail.ParseAddress(s)
+	if err != nil {
+		return Nil, fmt.Errorf("cannot parse address %s: %w", s, err)
+	}
+
+	parts := strings.Split(netMailAddr.Address, "@")
+	if len(parts) != 2 {
+		return Nil, fmt.Errorf("invalid email address format")
+	}
+
+	return Addr(netMailAddr.Address), nil
+}
+
+func (a Addr) Value() (driver.Value, error) {
+	return a.String(), nil
+}
+
+func (a *Addr) Scan(value any) error {
+	switch v := value.(type) {
+	case string:
+		parsed, err := ParseAddr(v)
+		if err != nil {
+			return err
+		}
+
+		*a = parsed
+	default:
+		return fmt.Errorf("invalid type for mail.Addr: expected string, got %T", value)
+	}
+	return nil
+}
+
+func (a *Addr) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return fmt.Errorf("cannot unmarshal email string from JSON")
+	}
+
+	parsed, err := ParseAddr(s)
+	if err != nil {
+		return fmt.Errorf("cannot parse email address")
+	}
+
+	*a = parsed
+
+	return nil
+}
+
+func (a Addr) MarshalJSON() ([]byte, error) {
+	return json.Marshal(a.String())
+}