weechat-matrix: Fetch from the backlog if the buffer has < 10 lines at startup.

main.py

@@ -578,7 +578,9 @@ def buffer_switch_cb(_, _signal, buffer_ptr):
         # The buffer is empty and we are seeing it for the first time.
         # Let us fetch some messages from the room history so it doesn't feel so
         # empty.
-        if room_buffer.first_view and not last_event_id:
+        if room_buffer.first_view and room_buffer.weechat_buffer.num_lines < 10:
+            # TODO we may want to fetch 10 - num_lines messages here for
+            # consistency reasons.
             if server.room_get_messages(room_buffer.room.room_id):
                 room_buffer.first_view = True
 

matrix/buffer.py

@@ -446,6 +446,12 @@ class WeechatChannelBuffer(object):
         """Get the bar item input text of the buffer."""
         return W.buffer_get_string(self._ptr, "input")
 
+    @property
+    def num_lines(self):
+        own_lines = W.hdata_pointer(self._hdata, self._ptr, "own_lines")
+        return W.hdata_integer(W.hdata_get("lines"), own_lines, "lines_count")
+
+
     @property
     def lines(self):
         own_lines = W.hdata_pointer(self._hdata, self._ptr, "own_lines")