feat: moderate messages from XMPP

Includes a fix for the role of admin and
owner to "moderator", or else gajim wouldn't
display the option to actually moderate a
message.

Implements: https://todo.sr.ht/~nicoco/slidge-whatsapp/21

slidge_whatsapp/group.py

@@ -90,8 +90,10 @@ class MUC(LegacyMUC[str, str, Participant, str]):
                 participant.affiliation = "member"
                 if data.Affiliation == whatsapp.GroupAffiliationAdmin:
                     participant.affiliation = "admin"
+                    participant.role = "moderator"
                 elif data.Affiliation == whatsapp.GroupAffiliationOwner:
                     participant.affiliation = "owner"
+                    participant.role = "moderator"
 
     def replace_mentions(self, t: str):
         return replace_mentions(

slidge_whatsapp/session.go

@@ -220,7 +220,18 @@ func (s *Session) SendMessage(message Message) error {
 		payload = s.client.BuildEdit(s.device.JID().ToNonAD(), message.ID, s.getMessagePayload(message))
 	case MessageRevoke:
 		// Don't send message, but revoke existing message by ID.
-		payload = s.client.BuildRevoke(s.device.JID().ToNonAD(), types.EmptyJID, message.ID)
+		var originJID types.JID
+		if message.OriginJID == "" {
+			// A message retraction by the person who sent it
+			originJID = types.EmptyJID
+		} else {
+			// A message moderation
+			originJID, err = types.ParseJID(message.OriginJID)
+			if err != nil {
+				return fmt.Errorf("Could not parse sender JID for message: %s", err)
+			}
+		}
+		payload = s.client.BuildRevoke(jid, originJID, message.ID)
 	case MessageReaction:
 		// Send message as emoji reaction to a given message.
 		payload = &proto.Message{

slidge_whatsapp/session.py

@@ -387,6 +387,24 @@ class Session(BaseSession[str, Recipient]):
         )
         self.whatsapp.SendMessage(message)
 
+    async def on_moderate(
+        self,
+        muc: MUC,  # type:ignore
+        legacy_msg_id: str,
+        reason: Optional[str],
+    ):
+        message = whatsapp.Message(
+            Kind=whatsapp.MessageRevoke,
+            ID=legacy_msg_id,
+            JID=muc.legacy_id,
+            OriginJID=muc.get_message_sender(legacy_msg_id),
+        )
+        self.whatsapp.SendMessage(message)
+        # Apparently, no revoke event is received by whatsmeow after sending
+        # the revoke message, so we need to "echo" it here.
+        part = await muc.get_user_participant()
+        part.moderate(legacy_msg_id)
+
     async def on_correct(
         self,
         c: Recipient,