perf: sync protocol and core hardening updates

internal/domain/login_code_delivery.go

@@ -0,0 +1,55 @@
+package domain
+
+import (
+	"fmt"
+	"math"
+	"strings"
+)
+
+const officialLoginCodeMessageTemplate = `Login code: %s. Do not give this code to anyone, even if they say they are from Telegram!
+
+This code can be used to log in to your Telegram account. We never ask it for anything else.
+
+If you didn't request this code by trying to log in on another device, simply ignore this message.`
+
+// LoginCodeDeliveryRequest describes one durable 777000 login-code delivery.
+// PhoneCodeHash is an opaque idempotency token and must never be persisted in
+// plaintext; store implementations persist only its SHA-256 digest.
+type LoginCodeDeliveryRequest struct {
+	UserID        int64
+	PhoneCodeHash string
+	Code          string
+	Date          int
+	// ExpiresAt is the unix second after which the compact idempotency receipt
+	// may be reclaimed. It must cover the corresponding code's usable lifetime.
+	ExpiresAt int64
+}
+
+// LoginCodeDeliveryResult returns the immutable first delivery. Created is
+// false when the same phone_code_hash was already committed and replayed.
+type LoginCodeDeliveryResult struct {
+	Message Message
+	Created bool
+}
+
+// OfficialLoginCodeMessage builds the account-visible incoming message from
+// Telegram's official notification account. Persistence assigns ID, UID and
+// Pts atomically.
+func OfficialLoginCodeMessage(userID int64, code string, date int) (Message, error) {
+	if userID <= 0 || IsSystemUserID(userID) || strings.TrimSpace(code) == "" || len(code) > 64 || date < 0 || date > math.MaxInt32 {
+		return Message{}, fmt.Errorf("%w: user=%d code_length=%d date=%d", ErrLoginCodeDeliveryInvalid, userID, len(code), date)
+	}
+	body := fmt.Sprintf(officialLoginCodeMessageTemplate, code)
+	codeOffset := len("Login code: ")
+	return Message{
+		OwnerUserID: userID,
+		Peer:        Peer{Type: PeerTypeUser, ID: OfficialSystemUserID},
+		From:        Peer{Type: PeerTypeUser, ID: OfficialSystemUserID},
+		Date:        date,
+		Body:        body,
+		Entities: []MessageEntity{
+			{Type: MessageEntityBold, Offset: 0, Length: len("Login code:")},
+			{Type: MessageEntityBold, Offset: codeOffset, Length: len(code)},
+		},
+	}, nil
+}