Gut the Session interface

internal/smtp/mta.go

@@ -3,6 +3,7 @@ package smtp
 import (
 	"context"
 	"fmt"
+	"io"
 	"log"
 	"sync/atomic"
 
@@ -58,14 +59,21 @@ func (m *mta) Login(user, pass string) (smtp.User, error) {
 }
 
 func (m *mta) AnonymousLogin() (smtp.User, error) {
+	sid := atomic.AddUint64(&m.sid, uint64(1))
 	session := &Session{
-		ID:      atomic.AddUint64(&m.sid, uint64(1)),
-		Account: nil,
-		Handler: &Receiver{},
+		ID:      fmt.Sprintf("smtp:%d", sid),
+		Handler: m,
 	}
 
-	log.Printf("Beginning SMTP session %d", session.ID)
+	log.Printf("Beginning session %d", session.ID)
 	// FIXME: TODO: Track ongoing sessions for termination or notifications
 
 	return session, nil
 }
+
+// User implementation for go-smtp after this point
+// Since only anonymous login is permitted, there's no need to introduce an
+// intermediary to track the logged-in user.
+func (m *mta) ServeSMTP(from string, to []string, r io.Reader) error {
+	return fmt.Errorf("Not yet implemented")
+}