Added a text field that allows choosing custom homeserver in "Room directory" dialog. (#727)

* Added a text field that allows choosing custom homeserver in "Room directory" dialog.

* Moved "Choose custom homeserver" text field to the right and shrinked it to 30% of "Room directory" dialog's width.

* Adding "server_name=" when needed when joining room.

When joining room that is hosted on a different homeserver than
the account is registered on, the request fails. In such scenario
the server has to be explicitly mentioned in a server_name URL
parameter. More info here:
https://matrix.org/docs/spec/client_server/r0.6.1#post-matrix-client-r0-join-roomidoralias

* Minor fix: intentation (4 spaces -> 8 spaces)

Co-authored-by: Patryk Cisek <patryk@cisek.email>

resources/qml/RoomDirectory.qml

@@ -192,6 +192,17 @@ ApplicationWindow {
             onTextChanged: searchTimer.restart()
         }
 
+        MatrixTextField {
+            id: chooseServer
+            Layout.minimumWidth: 0.3 * header.width
+            Layout.maximumWidth: 0.3 * header.width
+
+            padding: Nheko.paddingMedium
+            color: Nheko.colors.text
+            placeholderText: qsTr("Choose custom homeserver")
+            onTextChanged: publicRooms.setMatrixServer(text)
+        }
+
         Timer {
             id: searchTimer
 

src/RoomDirectoryModel.cpp

@@ -98,6 +98,15 @@ RoomDirectoryModel::getViasForRoom(const std::vector<std::string> &aliases)
                        std::back_inserter(vias),
                        [](const auto &alias) { return alias.substr(alias.find(":") + 1); });
 
+        // When joining a room hosted on a homeserver other than the one the
+        // account has been registered on, the room's server has to be explicitly
+        // specified in the "server_name=..." URL parameter of the Matrix Join Room
+        // request. For more details consult the specs:
+        // https://matrix.org/docs/spec/client_server/r0.6.1#post-matrix-client-r0-join-roomidoralias
+        if (!server_.empty()) {
+                vias.push_back(server_);
+        }
+
         return vias;
 }