Keep direct rooms orthogonal (#183)

Signed-off-by: ajbura <ajbura@gmail.com>

src/app/organisms/invite-user/InviteUser.jsx

@@ -6,6 +6,7 @@ import initMatrix from '../../../client/initMatrix';
 import cons from '../../../client/state/cons';
 import * as roomActions from '../../../client/action/room';
 import { selectRoom } from '../../../client/action/navigation';
+import { hasDMWith } from '../../../util/matrixUtil';
 
 import Text from '../../atoms/text/Text';
 import Button from '../../atoms/button/Button';
@@ -104,6 +105,13 @@ function InviteUser({
 
   async function createDM(userId) {
     if (mx.getUserId() === userId) return;
+    const dmRoomId = hasDMWith(userId);
+    if (dmRoomId) {
+      selectRoom(dmRoomId);
+      onRequestClose();
+      return;
+    }
+
     try {
       addUserToProc(userId);
       procUserError.delete(userId);