Add prompts when there are no games listed (CnCNet#849)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: SadPencil

DXMainClient/DXGUI/Multiplayer/CnCNet/CnCNetLobby.cs

@@ -441,7 +441,7 @@ private bool HostedGameMatches(GenericHostedGame hg)
 
             string textUpper = tbGameSearch?.Text?.ToUpperInvariant();
 
-            string translatedGameMode = string.IsNullOrEmpty(hg.GameMode) 
+            string translatedGameMode = string.IsNullOrEmpty(hg.GameMode)
                 ? "Unknown".L10N("Client:Main:Unknown")
                 : hg.GameMode.L10N($"INI:GameModes:{hg.GameMode}:UIName", notify: false);
 
@@ -784,7 +784,7 @@ private void SetLogOutButtonText()
         private void BtnJoinGame_LeftClick(object sender, EventArgs e) => JoinSelectedGame();
 
         private void LbGameList_DoubleLeftClick(object sender, EventArgs e) => JoinSelectedGame();
-        
+
         private void LbGameList_RightClick(object sender, EventArgs e)
         {
             lbGameList.SelectedIndex = lbGameList.HoveredIndex;
@@ -1364,7 +1364,7 @@ private void DdCurrentChannel_SelectedIndexChanged(object sender, EventArgs e)
             currentChatChannel = (Channel)ddCurrentChannel.SelectedItem?.Tag;
             if (currentChatChannel == null)
                 throw new Exception("Current selected chat channel is null. This should not happen.");
-            
+
             currentChatChannel.UserAdded += RefreshPlayerList;
             currentChatChannel.UserLeft += RefreshPlayerList;
             currentChatChannel.UserQuitIRC += RefreshPlayerList;
@@ -1507,6 +1507,20 @@ private void GameBroadcastChannel_CTCPReceived(object sender, ChannelCTCPEventAr
             if (splitMessage.Length != 13)
             {
                 Logger.Log("Ignoring CTCP game message because of an invalid amount of parameters.");
+
+                // Remind users that the network is good but the client is outdated or newer
+                if (lbGameList.Items.Count == 0)
+                {
+                    string message = "There are no games listed but you are indeed connected. The client did receive a game message but can't add it to the list because the message is invalid. " +
+                        "You can ignore this prompt if there are games listed later. " +
+                        "Otherwise, this usually means that your client is outdated, or, in a rare case, newer than others. Please check for updates.".L10N("Client:Main:InvalidGameMessage");
+
+                    if ((lbChatMessages.Items.LastOrDefault()?.Tag as ChatMessage)?.Message != message)
+                    {
+                        lbChatMessages.AddMessage(new ChatMessage(Color.Gray, message));
+                    }
+                }
+
                 return;
             }
 
@@ -1539,13 +1553,51 @@ private void GameBroadcastChannel_CTCPReceived(object sender, ChannelCTCPEventAr
 
                 CnCNetGame cncnetGame = gameCollection.GameList.Find(g => g.GameBroadcastChannel == channel.ChannelName);
 
+                if (cncnetGame == null)
+                    return;
+
+                // Find the tunnel server specified in the game message
+
+                if (tunnelHandler.Tunnels.Count == 0)
+                {
+                    Logger.Log("Ignoring CTCP game message because there are no tunnels at all. Available tunnel count: 0. Is the connection to CnCNet HTTP service broken?");
+
+                    // Remind users that the game is ignored because of no tunnel
+                    if (lbGameList.Items.Count == 0)
+                    {
+                        string message = "There are no games listed. The client did receive a valid game message but can't add it to the list because there are no available tunnels. " +
+                            "You can ignore this prompt if there are games listed later. Otherwise, it might indicate a network problem to CnCNet HTTP service.".L10N("Client:Main:NoTunnels");
+
+                        if ((lbChatMessages.Items.LastOrDefault()?.Tag as ChatMessage)?.Message != message)
+                        {
+                            lbChatMessages.AddMessage(new ChatMessage(Color.Gray, message));
+                        }
+                    }
+
+                    return;
+                }
+
                 CnCNetTunnel tunnel = tunnelHandler.Tunnels.Find(t => t.Address == tunnelAddress && t.Port == tunnelPort);
 
                 if (tunnel == null)
-                    return;
+                {
+                    Logger.Log(string.Format("Ignoring CTCP game message because the specified tunnel {0}:{1} is not available. Available tunnel count: {2}",
+                        tunnelAddress, tunnelPort, tunnelHandler.Tunnels.Count));
+
+                    // Remind users that the game is ignored because of no specified tunnel
+                    if (lbGameList.Items.Count == 0)
+                    {
+                        string message = string.Format("There are no games listed. The client did receive a valid game message but can't add it to the list because the specified tunnel is not available. " +
+                            "You can ignore this prompt if there are games listed later. Otherwise, please contact support at {0}.".L10N("Client:Main:NoTunnelForGames"), ClientConfiguration.Instance.LongSupportURL);
+
+                        if ((lbChatMessages.Items.LastOrDefault()?.Tag as ChatMessage)?.Message != message)
+                        {
+                            lbChatMessages.AddMessage(new ChatMessage(Color.Gray, message));
+                        }
+                    }
 
-                if (cncnetGame == null)
                     return;
+                }
 
                 HostedCnCNetGame game = new HostedCnCNetGame(gameRoomChannelName, revision, gameVersion, maxPlayers,
                     gameRoomDisplayName, isCustomPassword, true, players,