improve syncing and storing

back/mails/utils/statusUtils.js

@@ -1,13 +1,23 @@
 function isDmOnEnvelope(envelope) {
-    const members =
-        envelope.bcc?.length +
-        envelope.cc?.length +
-        envelope.to?.length +
-        envelope.sender?.length +
-        envelope.from?.length;
-    return members === 2;
+    return nbMembers(envelope) === 2;
+}
+
+function nbMembers(envelope) {
+    let nbMembers =
+        (envelope.bcc?.length ?? 0) +
+        (envelope.cc?.length ?? 0) +
+        (envelope.to?.length ?? 0) +
+        (envelope.from?.length ?? 0);
+    if (
+        envelope.sender?.length > 0 &&
+        !(envelope.sender[0].mailbox == envelope.from[0].mailbox && envelope.sender[0].host == envelope.from[0].host)
+    ) {
+        nbMembers += envelope.sender?.length ?? 0;
+    }
+    return nbMembers;
 }
 
 module.exports = {
     isDmOnEnvelope,
+    nbMembers,
 };