From 5370d89bb9a50133c141a6a0228773d2b2f61fde Mon Sep 17 00:00:00 2001
From: Lucas Teles <lucas.teles@outlook.com>
Date: Fri, 15 Mar 2024 16:55:11 -0300
Subject: [PATCH] localnet fallback

---
 .run/SpaceWar.Lobby (9000).run.xml            |  2 +-
 .run/SpaceWar.Lobby (9001).run.xml            |  2 +-
 .run/SpaceWar.Lobby (9002).run.xml            |  2 +-
 .run/SpaceWar.Lobby (local 9100).run.xml      |  2 +-
 samples/LobbyServer/LobbyRepository.cs        |  1 +
 samples/LobbyServer/Models.cs                 |  9 +-
 samples/LobbyServer/Program.cs                |  2 -
 .../LobbyServer/appsettings.Development.json  |  1 -
 samples/SpaceWar.Lobby/AppSettings.cs         | 54 +++++++++--
 samples/SpaceWar.Lobby/Game1.cs               |  2 +-
 samples/SpaceWar.Lobby/Models/Peer.cs         |  1 +
 samples/SpaceWar.Lobby/Program.cs             | 42 +-------
 samples/SpaceWar.Lobby/README.md              | 95 ++++++++++++++++---
 .../Scenes/BattleSessionScene.cs              |  9 +-
 .../SpaceWar.Lobby/Scenes/ChooseNameScene.cs  |  2 +-
 samples/SpaceWar.Lobby/Scenes/LobbyScene.cs   | 19 ++--
 .../Services/LobbyHttpClient.cs               | 24 ++++-
 .../SpaceWar.Lobby/Services/LobbyUdpClient.cs | 17 +++-
 samples/SpaceWar.Lobby/SpaceWar.Lobby.csproj  |  3 +
 samples/SpaceWar.Lobby/appsettings.json       |  6 ++
 .../scripts/linux/build_server.sh             |  2 +-
 .../scripts/linux/start_2peers.sh             |  4 +-
 .../scripts/linux/start_3peers.sh             |  6 +-
 .../scripts/linux/start_4peers.sh             |  8 +-
 .../scripts/linux/start_5peers.sh             | 10 +-
 .../scripts/linux/start_6peers.sh             | 12 +--
 .../scripts/linux/start_6remote.sh            | 16 ++++
 .../scripts/windows/start_2peers.cmd          |  4 +-
 .../scripts/windows/start_3peers.cmd          |  6 +-
 .../scripts/windows/start_4peers.cmd          |  8 +-
 .../scripts/windows/start_5peers.cmd          | 10 +-
 .../scripts/windows/start_6_remote.cmd        | 13 +++
 .../scripts/windows/start_6peers.cmd          | 12 +--
 .../scripts/windows/start_server.cmd          |  6 +-
 34 files changed, 286 insertions(+), 126 deletions(-)
 create mode 100644 samples/SpaceWar.Lobby/appsettings.json
 create mode 100644 samples/SpaceWar.Lobby/scripts/linux/start_6remote.sh
 create mode 100644 samples/SpaceWar.Lobby/scripts/windows/start_6_remote.cmd

diff --git a/.run/SpaceWar.Lobby (9000).run.xml b/.run/SpaceWar.Lobby (9000).run.xml
index 9a578593..72d57d76 100644
--- a/.run/SpaceWar.Lobby (9000).run.xml	
+++ b/.run/SpaceWar.Lobby (9000).run.xml	
@@ -1,7 +1,7 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="SpaceWar.Lobby (9000)" type="DotNetProject" factoryName=".NET Project">
     <option name="EXE_PATH" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0/SpaceWar.exe" />
-    <option name="PROGRAM_PARAMETERS" value="9000" />
+    <option name="PROGRAM_PARAMETERS" value="-LocalPort 9000" />
     <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0" />
     <option name="PASS_PARENT_ENVS" value="1" />
     <option name="USE_EXTERNAL_CONSOLE" value="0" />
diff --git a/.run/SpaceWar.Lobby (9001).run.xml b/.run/SpaceWar.Lobby (9001).run.xml
index 2d9e26b8..3392f303 100644
--- a/.run/SpaceWar.Lobby (9001).run.xml	
+++ b/.run/SpaceWar.Lobby (9001).run.xml	
@@ -1,7 +1,7 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="SpaceWar.Lobby (9001)" type="DotNetProject" factoryName=".NET Project">
     <option name="EXE_PATH" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0/SpaceWar.exe" />
-    <option name="PROGRAM_PARAMETERS" value="9001" />
+    <option name="PROGRAM_PARAMETERS" value="-LocalPort  9001" />
     <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0" />
     <option name="PASS_PARENT_ENVS" value="1" />
     <option name="USE_EXTERNAL_CONSOLE" value="0" />
diff --git a/.run/SpaceWar.Lobby (9002).run.xml b/.run/SpaceWar.Lobby (9002).run.xml
index bad6baf3..89d64df2 100644
--- a/.run/SpaceWar.Lobby (9002).run.xml	
+++ b/.run/SpaceWar.Lobby (9002).run.xml	
@@ -1,7 +1,7 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="SpaceWar.Lobby (9002)" type="DotNetProject" factoryName=".NET Project">
     <option name="EXE_PATH" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0/SpaceWar.exe" />
-    <option name="PROGRAM_PARAMETERS" value="9002" />
+    <option name="PROGRAM_PARAMETERS" value="-LocalPort  9002" />
     <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0" />
     <option name="PASS_PARENT_ENVS" value="1" />
     <option name="USE_EXTERNAL_CONSOLE" value="0" />
diff --git a/.run/SpaceWar.Lobby (local 9100).run.xml b/.run/SpaceWar.Lobby (local 9100).run.xml
index 8fcc60d8..6eff1ff1 100644
--- a/.run/SpaceWar.Lobby (local 9100).run.xml	
+++ b/.run/SpaceWar.Lobby (local 9100).run.xml	
@@ -1,7 +1,7 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="SpaceWar.Lobby (local 9100)" type="DotNetProject" factoryName=".NET Project">
     <option name="EXE_PATH" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0/SpaceWar.exe" />
-    <option name="PROGRAM_PARAMETERS" value="9100 &quot;http://localhost:9999&quot;" />
+    <option name="PROGRAM_PARAMETERS" value="-LocalPort  9100  -ServerUrl &quot;http://localhost:9999&quot;" />
     <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/samples/SpaceWar.Lobby/bin/Debug/net8.0" />
     <option name="PASS_PARENT_ENVS" value="1" />
     <option name="USE_EXTERNAL_CONSOLE" value="0" />
diff --git a/samples/LobbyServer/LobbyRepository.cs b/samples/LobbyServer/LobbyRepository.cs
index 0383ddb3..02d1a883 100644
--- a/samples/LobbyServer/LobbyRepository.cs
+++ b/samples/LobbyServer/LobbyRepository.cs
@@ -47,6 +47,7 @@ IOptions<AppSettings> settings
             Peer peer = new(userName, remote)
             {
                 PeerId = peerId,
+                LocalEndpoint = req.LocalEndpoint,
             };
 
             LobbyEntry entry = new(peer, req.Mode)
diff --git a/samples/LobbyServer/Models.cs b/samples/LobbyServer/Models.cs
index fa5da5b6..bf75e0ee 100644
--- a/samples/LobbyServer/Models.cs
+++ b/samples/LobbyServer/Models.cs
@@ -16,9 +16,11 @@ public sealed class Peer(string username, IPAddress requestAddress)
     public PeerId PeerId { get; init; } = Guid.NewGuid();
     public string Username { get; } = username;
     public IPAddress RequestAddress { get; } = requestAddress;
+    public IPEndPoint? LocalEndpoint { get; init; }
     public IPEndPoint? Endpoint { get; set; }
     public bool Ready { get; private set; }
     public bool Connected => Endpoint is not null;
+
     public void ToggleReady() => Ready = !Ready;
 }
 
@@ -153,7 +155,12 @@ public void Purge(DateTimeOffset now)
     }
 }
 
-public sealed record EnterLobbyRequest(string LobbyName, string Username, PeerMode Mode);
+public sealed record EnterLobbyRequest(
+    string LobbyName,
+    string Username,
+    PeerMode Mode,
+    IPEndPoint? LocalEndpoint = null
+);
 
 public sealed record EnterLobbyResponse(
     string Username,
diff --git a/samples/LobbyServer/Program.cs b/samples/LobbyServer/Program.cs
index 5d85335b..c07b6e82 100644
--- a/samples/LobbyServer/Program.cs
+++ b/samples/LobbyServer/Program.cs
@@ -20,7 +20,6 @@
     })
     .Configure<ForwardedHeadersOptions>(o => o.ForwardedHeaders = ForwardedHeaders.XForwardedFor)
     .AddMemoryCache()
-    .AddHttpLogging(_ => { })
     .AddSingleton(TimeProvider.System)
     .AddSingleton<LobbyRepository>();
 
@@ -28,7 +27,6 @@
 
 var app = builder.Build();
 Console.Title = app.Environment.ApplicationName;
-app.UseHttpLogging();
 app.UseForwardedHeaders();
 app.UseSwagger().UseSwaggerUI();
 
diff --git a/samples/LobbyServer/appsettings.Development.json b/samples/LobbyServer/appsettings.Development.json
index 17af1805..2947ac39 100644
--- a/samples/LobbyServer/appsettings.Development.json
+++ b/samples/LobbyServer/appsettings.Development.json
@@ -3,7 +3,6 @@
     "Logging": {
         "LogLevel": {
             "Default": "Information",
-            "Microsoft.AspNetCore.HttpLogging.HttpLoggingMiddleware": "Information",
             "Microsoft.AspNetCore": "Warning"
         }
     }
diff --git a/samples/SpaceWar.Lobby/AppSettings.cs b/samples/SpaceWar.Lobby/AppSettings.cs
index 4005b1c7..7077a61d 100644
--- a/samples/SpaceWar.Lobby/AppSettings.cs
+++ b/samples/SpaceWar.Lobby/AppSettings.cs
@@ -1,13 +1,55 @@
+using System.Reflection;
+using System.Text.Json;
+
 namespace SpaceWar;
 
+[Serializable]
 public class AppSettings
 {
-    public string LobbyName = "spacewar";
-    public string Username = string.Empty;
-    public int Port = 9000;
+    public string Username { get; set; } = string.Empty;
+    public required string LobbyName { get; set; }
+    public required Uri ServerUrl { get; set; }
+    public int LocalPort { get; set; }
+    public int ServerUdpPort { get; set; }
+
+    public void ParseArgs(string[] args)
+    {
+        if (args is []) return;
+
+        var argsDict = args
+            .Chunk(2)
+            .Where(a => a[0].StartsWith('-'))
+            .Select(a => a is [{ } key, { } value]
+                ? (Key: key.TrimStart('-'), Value: value)
+                : throw new InvalidOperationException("Bad arguments")
+            ).ToDictionary(x => x.Key, x => x.Value, StringComparer.InvariantCultureIgnoreCase);
+
+        if (argsDict.TryGetValue(nameof(LocalPort), out var portArg) &&
+            int.TryParse(portArg, out var port) && port > 0)
+            LocalPort = port;
+
+        if (argsDict.TryGetValue(nameof(ServerUdpPort), out var lobbyPortArg) &&
+            int.TryParse(lobbyPortArg, out var lobbyPort) && lobbyPort > 0)
+            ServerUdpPort = lobbyPort;
+
+        if (argsDict.TryGetValue(nameof(ServerUrl), out var serverUrl) &&
+            Uri.TryCreate(serverUrl, UriKind.Absolute, out var serverUri))
+            ServerUrl = serverUri;
+
+        if (argsDict.TryGetValue(nameof(Username), out var usernameArg) &&
+            !string.IsNullOrWhiteSpace(usernameArg))
+            Username = usernameArg;
+    }
 
-    public int LobbyPort = 8888;
+    public static AppSettings LoadFromJson(string file)
+    {
+        var settingsFile = Path.Combine(
+            Path.GetDirectoryName(AppContext.BaseDirectory)
+            ?? Directory.GetCurrentDirectory(),
+            file
+        );
 
-    public Uri LobbyUrl = new("https://lobby-server.fly.dev");
-    // public readonly Uri LobbyUrl = new("http://localhost:9999");
+        return JsonSerializer.Deserialize<AppSettings>(File.ReadAllText(settingsFile))
+               ?? throw new InvalidOperationException($"unable to read {file}");
+    }
 }
diff --git a/samples/SpaceWar.Lobby/Game1.cs b/samples/SpaceWar.Lobby/Game1.cs
index 155825b1..34410276 100644
--- a/samples/SpaceWar.Lobby/Game1.cs
+++ b/samples/SpaceWar.Lobby/Game1.cs
@@ -23,7 +23,7 @@ public Game1(AppSettings appSettings)
 
     protected override void Initialize()
     {
-        Window.Title = $"SpaceWar {settings.Port}";
+        Window.Title = $"SpaceWar {settings.LocalPort}";
         graphics.PreferredBackBufferWidth = Config.InternalWidth;
         graphics.PreferredBackBufferHeight = Config.InternalHeight;
         graphics.ApplyChanges();
diff --git a/samples/SpaceWar.Lobby/Models/Peer.cs b/samples/SpaceWar.Lobby/Models/Peer.cs
index 20397598..0be0d3ad 100644
--- a/samples/SpaceWar.Lobby/Models/Peer.cs
+++ b/samples/SpaceWar.Lobby/Models/Peer.cs
@@ -7,6 +7,7 @@ public sealed class Peer
     public required Guid PeerId { get; init; }
     public required string Username { get; init; }
     public required IPEndPoint Endpoint { get; init; }
+    public IPEndPoint? LocalEndpoint { get; init; }
     public bool Connected { get; init; }
     public bool Ready { get; init; }
 }
diff --git a/samples/SpaceWar.Lobby/Program.cs b/samples/SpaceWar.Lobby/Program.cs
index f94d3431..28f07919 100644
--- a/samples/SpaceWar.Lobby/Program.cs
+++ b/samples/SpaceWar.Lobby/Program.cs
@@ -1,45 +1,7 @@
-using System.Diagnostics.CodeAnalysis;
 using SpaceWar;
 
-AppSettings settings = new();
-ReadProgramArgs();
+var settings = AppSettings.LoadFromJson("appsettings.json");
+settings.ParseArgs(args);
 
 using var game = new Game1(settings);
 game.Run();
-
-
-void ReadProgramArgs()
-{
-    if (TryGetConfig(0, "SPACEWAR_PORT", out var portArg) &&
-        int.TryParse(portArg, out var port))
-        settings.Port = port;
-
-    if (TryGetConfig(1, "SPACEWAR_LOBBY_URL", out var serverUrlArg)
-        && Uri.TryCreate(serverUrlArg, UriKind.Absolute, out var serverUrl))
-        settings.LobbyUrl = serverUrl;
-
-    if (TryGetConfig(2, "SPACEWAR_LOBBY_PORT", out var lobbyPortArg)
-        && int.TryParse(lobbyPortArg, out var lobbyPort))
-        settings.LobbyPort = lobbyPort;
-}
-
-bool TryGetConfig(int argsIndex, string envName,
-    [NotNullWhen(true)] out string? argValue)
-{
-    var tempValue = Environment.GetEnvironmentVariable(envName);
-    if (!string.IsNullOrWhiteSpace(tempValue))
-    {
-        argValue = tempValue;
-        return true;
-    }
-
-    tempValue = args.ElementAtOrDefault(argsIndex);
-    if (!string.IsNullOrWhiteSpace(tempValue))
-    {
-        argValue = tempValue;
-        return true;
-    }
-
-    argValue = null;
-    return false;
-}
diff --git a/samples/SpaceWar.Lobby/README.md b/samples/SpaceWar.Lobby/README.md
index 178eb84c..cca986a7 100644
--- a/samples/SpaceWar.Lobby/README.md
+++ b/samples/SpaceWar.Lobby/README.md
@@ -1,17 +1,86 @@
-# SpaceWar - NetCode Sample
-## Running
-Run one of the scripts in [/scripts](/samples/SpaceWar/scripts) to start multiple clients of the game. 
-> On Windows run the `.cmd` [/scripts/windows](/samples/SpaceWar/scripts/windows)
-> On Linux/Mac run the `.sh` files [/scripts/linux](/samples/SpaceWar/scripts/linux)
-Each script defines a configuration with up to 4 players, some of them with spectators, they are:
-- **start_2players**: start 2 game peer instances.
-- **start_2players_1spec:** Start 2 game peer instances with a single spectator on player 1.
-- **start_2players_2spec:** Start 2 game peer instances with two spectators. each observing one player.
-- **start_3players:** Start 3 game peer instances.
-- **start_4players:** Start 4 game peer instances.
-- **start_4players_2spec:** Start 4 game peer instances with two spectators. one observing player 1 and the other
-  observing player 2.
+# SpaceWar - NetCode Sample with online Lobby
+
+This shows a basic example of NAT traversal using [UDP hole punching](https://en.wikipedia.org/wiki/UDP_hole_punching)
+
+# How it works?
+
+This enable a P2P connection over the internet, this is possible using
+a [middle server](https://github.com/lucasteles/Backdash/tree/master/samples/LobbyServer)
+which all clients know.
+The server catches the IP address and port of a client and send it to the others.
+
+The current server runs almost as a simple http with json responses. It keeps the lobbies info with sliding expiration
+cache.
+
+When a client enters the lobby the server responds with a token of type `Guid`/`UUID`. It is used a very
+basic `Authentication` mechanism.
+
+The client use http pooling to get updated information of each lobby member/peer.
+
+When logged-in every client needs to send a `UDP` package with their token to the server. So the
+server updates their `IP` and open `Port` using the package headers metadata.
+
+> ⚠️ UDP Hole punching usually **does not** work witch clients behind the same NAT. To mitigate this the server
+> also tracks the clients local IPs and ports. So they can check if the peer is at the same network
+
 ## Controls
+
 - **Arrows**: Move
 - **Left Control**: Fire
 - **Enter**: Missile
+
+## Running
+
+### Server
+
+On the [server directory](https://github.com/lucasteles/Backdash/tree/master/samples/LobbyServer) run:
+
+```bash
+dotnet run .
+```
+
+- Default **HTTP**: `9999`
+- Default **UDP** : `8888`
+
+> 💡 Check the swagger `API` docs at http://localhost:9999/swagger
+
+### Clients
+
+On `SpaceWar.Lobby` project directory run
+
+```bash
+dotnet run .
+```
+
+The default client configuration is defined in this [JSON file](/appsettings.json):
+
+```json
+{
+    "LobbyName": "spacewar",
+    "LocalPort": 9000,
+    "ServerUrl": "http://localhost:9999",
+    "ServerUdpPort": 8888
+}
+```
+
+You can override the default port via command args:
+
+```sh
+dotnet run --project .\LobbyClient -LocalPort 9001
+```
+
+> 💡useful for starting clients in different ports
+
+
+You can also override the server URL and UDP Port configs:
+
+```bash
+dotnet run --project .\LobbyClient -ServerUrl "https://lobby-server.fly.dev" -ServerUdpPort 8888
+```
+
+Check the the [scripts directory](https://github.com/lucasteles/Backdash/tree/master/samples/SpaceWar.Lobby/scripts)
+to run local instances of the server and clients.
+
+> ⚠️ The default configured server is a remote server. To connect to localhost server
+> run: `dotnet run . -ServerUrl "http://localhost:9999"`
+
diff --git a/samples/SpaceWar.Lobby/Scenes/BattleSessionScene.cs b/samples/SpaceWar.Lobby/Scenes/BattleSessionScene.cs
index e5f15d3b..37f3c29b 100644
--- a/samples/SpaceWar.Lobby/Scenes/BattleSessionScene.cs
+++ b/samples/SpaceWar.Lobby/Scenes/BattleSessionScene.cs
@@ -1,3 +1,4 @@
+using System.Net;
 using Backdash;
 using Backdash.Core;
 using SpaceWar.Logic;
@@ -39,11 +40,15 @@ public BattleSessionScene(int port, IReadOnlyList<Player> players,
         rollbackSession.AddPlayers(players);
     }
 
-    public BattleSessionScene(int port, int playerCount, Peer host, IReadOnlyList<Peer> peersInfo)
+    public BattleSessionScene(
+        int port, int playerCount,
+        IPEndPoint host,
+        IReadOnlyList<Peer> peersInfo
+    )
     {
         this.peersInfo = peersInfo;
         rollbackSession = RollbackNetcode.CreateSpectatorSession<PlayerInputs, GameState>(
-            port, host.Endpoint, playerCount, options
+            port, host, playerCount, options
         );
     }
 
diff --git a/samples/SpaceWar.Lobby/Scenes/ChooseNameScene.cs b/samples/SpaceWar.Lobby/Scenes/ChooseNameScene.cs
index fccb4a9e..6b9edadf 100644
--- a/samples/SpaceWar.Lobby/Scenes/ChooseNameScene.cs
+++ b/samples/SpaceWar.Lobby/Scenes/ChooseNameScene.cs
@@ -38,7 +38,7 @@ public override void Initialize()
             ? Environment.UserName
             : Config.Username;
 
-        username.Append(Regex.Replace(currentUser, "[^a-zA-Z0-9]", "_"));
+        username.Append(Regex.Replace(currentUser.ToLower(), "[^a-zA-Z0-9]", "_"));
         cursorSize = Assets.MainFont.MeasureString(" ");
         Window.TextInput += OnTextInput;
         keyboard.Update();
diff --git a/samples/SpaceWar.Lobby/Scenes/LobbyScene.cs b/samples/SpaceWar.Lobby/Scenes/LobbyScene.cs
index de731bb8..59dd7180 100644
--- a/samples/SpaceWar.Lobby/Scenes/LobbyScene.cs
+++ b/samples/SpaceWar.Lobby/Scenes/LobbyScene.cs
@@ -27,7 +27,7 @@ public override void Initialize()
     {
         client = Services.GetService<LobbyHttpClient>();
         networkCall = RequestLobby();
-        lobbyUdpClient = new(Config.Port, Config.LobbyUrl, Config.LobbyPort);
+        lobbyUdpClient = new(Config.LocalPort, Config.ServerUrl, Config.ServerUdpPort);
         keyboard.Update();
 
         StartPingTimer();
@@ -41,7 +41,7 @@ public override void Update(GameTime gameTime)
         keyboard.Update();
 
         if (user is not null && !Window.Title.Contains(user.Username))
-            Window.Title = $"Space War {Config.Port} - {user.Username}";
+            Window.Title = $"Space War {Config.LocalPort} - {user.Username}";
 
         if (PendingNetworkCall())
             return;
@@ -295,6 +295,9 @@ async Task RequestLobby()
         user = await client.EnterLobby(Config.LobbyName, Config.Username, mode);
         await RefreshLobby();
 
+        if (Array.Exists(lobbyInfo.Spectators, s => s.PeerId == user.PeerId))
+            mode = PlayerMode.Spectator;
+
         currentState = LobbyState.Waiting;
     }
 
@@ -360,7 +363,8 @@ void StartPlayerBattleScene()
 
             players.Add(player.PeerId == user.PeerId
                 ? new LocalPlayer(playerNumber)
-                : new RemotePlayer(playerNumber, player.Endpoint));
+                : new RemotePlayer(playerNumber,
+                    lobbyUdpClient.GetFallbackEndpoint(user, player)));
         }
 
         if (lobbyInfo.SpectatorMapping.SingleOrDefault(m => m.Host == user.PeerId)
@@ -371,7 +375,7 @@ void StartPlayerBattleScene()
                 players.Add(new Spectator(spectator.Endpoint));
         }
 
-        LoadScene(new BattleSessionScene(Config.Port, players, lobbyInfo.Players));
+        LoadScene(new BattleSessionScene(Config.LocalPort, players, lobbyInfo.Players));
     }
 
     void StartSpectatorBattleScene()
@@ -381,8 +385,11 @@ void StartSpectatorBattleScene()
             ?.Host;
         var host = lobbyInfo.Players.Single(x => x.PeerId == hostId);
         var playerCount = lobbyInfo.Players.Length;
-
-        LoadScene(new BattleSessionScene(Config.Port, playerCount, host, lobbyInfo.Players));
+        var hostEndpoint = lobbyUdpClient.GetFallbackEndpoint(user, host);
+        LoadScene(new BattleSessionScene(
+            Config.LocalPort, playerCount,
+            hostEndpoint, lobbyInfo.Players)
+        );
     }
 
     bool PendingNetworkCall()
diff --git a/samples/SpaceWar.Lobby/Services/LobbyHttpClient.cs b/samples/SpaceWar.Lobby/Services/LobbyHttpClient.cs
index 98808c95..6d6f1b37 100644
--- a/samples/SpaceWar.Lobby/Services/LobbyHttpClient.cs
+++ b/samples/SpaceWar.Lobby/Services/LobbyHttpClient.cs
@@ -1,5 +1,6 @@
 using System.Net;
 using System.Net.Http.Json;
+using System.Net.Sockets;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Backdash.JsonConverters;
@@ -21,16 +22,18 @@ public sealed class LobbyHttpClient(AppSettings appSettings)
 
     readonly HttpClient client = new()
     {
-        BaseAddress = appSettings.LobbyUrl,
+        BaseAddress = appSettings.ServerUrl,
     };
 
     public async Task<User> EnterLobby(string lobbyName, string username, PlayerMode mode)
     {
+        var localEndpoint = await GetLocalEndpoint();
         var response = await client.PostAsJsonAsync("/lobby", new
         {
             lobbyName,
             username,
             mode,
+            localEndpoint,
         }, JsonOptions);
 
         if (response.StatusCode is HttpStatusCode.UnprocessableEntity)
@@ -61,4 +64,23 @@ public async Task ToggleReady(User user)
         var response = await client.PutAsync($"/lobby/{user.LobbyName}", null);
         response.EnsureSuccessStatusCode();
     }
+
+    async Task<IPEndPoint?> GetLocalEndpoint()
+    {
+        try
+        {
+            using Socket socket = new(AddressFamily.InterNetwork, SocketType.Dgram, 0);
+            await socket.ConnectAsync("8.8.8.8", 65530);
+            if (socket.LocalEndPoint is not IPEndPoint { Address: { } ipAddress })
+                return null;
+
+            return new(ipAddress, appSettings.LocalPort);
+        }
+        catch (Exception)
+        {
+            // skip
+        }
+
+        return null;
+    }
 }
diff --git a/samples/SpaceWar.Lobby/Services/LobbyUdpClient.cs b/samples/SpaceWar.Lobby/Services/LobbyUdpClient.cs
index 47743d61..25538eb9 100644
--- a/samples/SpaceWar.Lobby/Services/LobbyUdpClient.cs
+++ b/samples/SpaceWar.Lobby/Services/LobbyUdpClient.cs
@@ -7,7 +7,7 @@ namespace SpaceWar.Services;
 
 public sealed class LobbyUdpClient : IDisposable
 {
-    readonly IPEndPoint remoteEndPoint;
+    readonly IPEndPoint serverEndpoint;
     readonly UdpSocket socket;
     readonly CancellationTokenSource cts = new();
     readonly byte[] buffer = GC.AllocateArray<byte>(36, pinned: true);
@@ -18,7 +18,7 @@ public sealed class LobbyUdpClient : IDisposable
     public LobbyUdpClient(int localPort, Uri serverUrl, int serverPort)
     {
         var serverAddress = UdpSocket.GetDnsIpAddress(serverUrl.DnsSafeHost);
-        remoteEndPoint = new(serverAddress, serverPort);
+        serverEndpoint = new(serverAddress, serverPort);
         socket = new(localPort);
 
         Task.Run(() => Receive(cts.Token));
@@ -27,7 +27,7 @@ public LobbyUdpClient(int localPort, Uri serverUrl, int serverPort)
     public async Task HandShake(User user, CancellationToken ct = default)
     {
         if (!user.Token.TryFormat(buffer, out var bytesWritten) || bytesWritten is 0) return;
-        await socket.SendToAsync(buffer.AsMemory()[..bytesWritten], remoteEndPoint, ct)
+        await socket.SendToAsync(buffer.AsMemory()[..bytesWritten], serverEndpoint, ct)
             .ConfigureAwait(false);
     }
 
@@ -42,7 +42,7 @@ public async Task Ping(User user, Peer[] peers, CancellationToken ct = default)
         {
             var peer = peers[i];
             if (peer.Connected && peer.PeerId != user.PeerId)
-                await socket.SendToAsync(msgBytes, peer.Endpoint, ct);
+                await socket.SendToAsync(msgBytes, GetFallbackEndpoint(user, peer), ct);
         }
     }
 
@@ -77,6 +77,15 @@ async ValueTask Receive(CancellationToken stoppingToken)
         }
     }
 
+    // Use local IP when over same network
+    public IPEndPoint GetFallbackEndpoint(User user, Peer peer)
+    {
+        if (Equals(peer.Endpoint.Address, user.IP) && peer.LocalEndpoint is not null)
+            return peer.LocalEndpoint;
+
+        return peer.Endpoint;
+    }
+
     public bool IsKnown(Guid id) => knownClients.Contains(id);
 
     public void Stop()
diff --git a/samples/SpaceWar.Lobby/SpaceWar.Lobby.csproj b/samples/SpaceWar.Lobby/SpaceWar.Lobby.csproj
index c1d8d141..3d8b7636 100644
--- a/samples/SpaceWar.Lobby/SpaceWar.Lobby.csproj
+++ b/samples/SpaceWar.Lobby/SpaceWar.Lobby.csproj
@@ -17,6 +17,9 @@
     <ItemGroup>
         <None Remove="Icon.ico"/>
         <None Remove="Icon.bmp"/>
+        <None Update="appsettings.json">
+          <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+        </None>
     </ItemGroup>
     <ItemGroup>
         <EmbeddedResource Include="Icon.ico"/>
diff --git a/samples/SpaceWar.Lobby/appsettings.json b/samples/SpaceWar.Lobby/appsettings.json
new file mode 100644
index 00000000..6154dae2
--- /dev/null
+++ b/samples/SpaceWar.Lobby/appsettings.json
@@ -0,0 +1,6 @@
+{
+    "LobbyName": "spacewar",
+    "LocalPort": 9000,
+    "ServerUrl": "https://lobby-server.fly.dev",
+    "ServerUdpPort": 8888
+}
diff --git a/samples/SpaceWar.Lobby/scripts/linux/build_server.sh b/samples/SpaceWar.Lobby/scripts/linux/build_server.sh
index 41a8a66b..9c79e7a4 100644
--- a/samples/SpaceWar.Lobby/scripts/linux/build_server.sh
+++ b/samples/SpaceWar.Lobby/scripts/linux/build_server.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 dotnet build -c Release "$(dirname "$0")/../../../.."
-export SPACEWAR_LOBBY_URL=http://localhost:9999
+export LOBBY_SERVER_URL=http://localhost:9999
diff --git a/samples/SpaceWar.Lobby/scripts/linux/start_2peers.sh b/samples/SpaceWar.Lobby/scripts/linux/start_2peers.sh
index d987df8c..bcf29209 100644
--- a/samples/SpaceWar.Lobby/scripts/linux/start_2peers.sh
+++ b/samples/SpaceWar.Lobby/scripts/linux/start_2peers.sh
@@ -3,8 +3,8 @@ source "$(dirname "$0")/build_server.sh"
 pushd "$(dirname "$0")/../../bin/Release/net8.0" || exit
 rm ./*.log
 
-dotnet SpaceWar.dll 9000 &
-dotnet SpaceWar.dll 9001 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9000 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9001 &
 
 popd || exit
 source "$(dirname "$0")/start_server.sh"
diff --git a/samples/SpaceWar.Lobby/scripts/linux/start_3peers.sh b/samples/SpaceWar.Lobby/scripts/linux/start_3peers.sh
index cbc35048..caf216e8 100644
--- a/samples/SpaceWar.Lobby/scripts/linux/start_3peers.sh
+++ b/samples/SpaceWar.Lobby/scripts/linux/start_3peers.sh
@@ -3,9 +3,9 @@ source "$(dirname "$0")/build_server.sh"
 pushd "$(dirname "$0")/../../bin/Release/net8.0" || exit
 rm ./*.log
 
-dotnet SpaceWar.dll 9000 &
-dotnet SpaceWar.dll 9001 &
-dotnet SpaceWar.dll 9002 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9000 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9001 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9002 &
 
 popd || exit
 source "$(dirname "$0")/start_server.sh"
diff --git a/samples/SpaceWar.Lobby/scripts/linux/start_4peers.sh b/samples/SpaceWar.Lobby/scripts/linux/start_4peers.sh
index 6368591e..c408a6c5 100644
--- a/samples/SpaceWar.Lobby/scripts/linux/start_4peers.sh
+++ b/samples/SpaceWar.Lobby/scripts/linux/start_4peers.sh
@@ -3,10 +3,10 @@ source "$(dirname "$0")/build_server.sh"
 pushd "$(dirname "$0")/../../bin/Release/net8.0" || exit
 rm ./*.log
 
-dotnet SpaceWar.dll 9000 &
-dotnet SpaceWar.dll 9001 &
-dotnet SpaceWar.dll 9002 &
-dotnet SpaceWar.dll 9003 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9000 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9001 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9002 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9003 &
 
 popd || exit
 source "$(dirname "$0")/start_server.sh"
diff --git a/samples/SpaceWar.Lobby/scripts/linux/start_5peers.sh b/samples/SpaceWar.Lobby/scripts/linux/start_5peers.sh
index 7d5bbc90..7e236f8c 100644
--- a/samples/SpaceWar.Lobby/scripts/linux/start_5peers.sh
+++ b/samples/SpaceWar.Lobby/scripts/linux/start_5peers.sh
@@ -3,11 +3,11 @@ source "$(dirname "$0")/build_server.sh"
 pushd "$(dirname "$0")/../../bin/Release/net8.0" || exit
 rm ./*.log
 
-dotnet SpaceWar.dll 9000 &
-dotnet SpaceWar.dll 9001 &
-dotnet SpaceWar.dll 9002 &
-dotnet SpaceWar.dll 9003 &
-dotnet SpaceWar.dll 9004 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9000 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9001 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9002 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9003 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9004 &
 
 popd || exit
 source "$(dirname "$0")/start_server.sh"
diff --git a/samples/SpaceWar.Lobby/scripts/linux/start_6peers.sh b/samples/SpaceWar.Lobby/scripts/linux/start_6peers.sh
index 194c3a46..a496c9f1 100644
--- a/samples/SpaceWar.Lobby/scripts/linux/start_6peers.sh
+++ b/samples/SpaceWar.Lobby/scripts/linux/start_6peers.sh
@@ -3,12 +3,12 @@ source "$(dirname "$0")/build_server.sh"
 pushd "$(dirname "$0")/../../bin/Release/net8.0" || exit
 rm ./*.log
 
-dotnet SpaceWar.dll 9000 &
-dotnet SpaceWar.dll 9001 &
-dotnet SpaceWar.dll 9002 &
-dotnet SpaceWar.dll 9003 &
-dotnet SpaceWar.dll 9004 &
-dotnet SpaceWar.dll 9005 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9000 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9001 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9002 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9003 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9004 &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -Username player -LocalPort 9005 &
 
 popd || exit
 source "$(dirname "$0")/start_server.sh"
diff --git a/samples/SpaceWar.Lobby/scripts/linux/start_6remote.sh b/samples/SpaceWar.Lobby/scripts/linux/start_6remote.sh
new file mode 100644
index 00000000..2b90095a
--- /dev/null
+++ b/samples/SpaceWar.Lobby/scripts/linux/start_6remote.sh
@@ -0,0 +1,16 @@
+#!/bin/bash
+dotnet build -c Release "$(dirname "$0")/../../../.."
+pushd "$(dirname "$0")/../../bin/Release/net8.0" || exit
+rm ./*.log
+
+export LOBBY_SERVER_URL=https://lobby-server.fly.dev
+
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -LocalPort 9000 -Username ryu  &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -LocalPort 9001 -Username liu_kang &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -LocalPort 9002 -Username kyo &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -LocalPort 9003 -Username jin &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -LocalPort 9004 -Username sol_badguy &
+dotnet SpaceWar.dll -ServerURl "$LOBBY_SERVER_URL" -LocalPort 9005 -Username jago &
+
+popd || exit
+source "$(dirname "$0")/start_server.sh"
diff --git a/samples/SpaceWar.Lobby/scripts/windows/start_2peers.cmd b/samples/SpaceWar.Lobby/scripts/windows/start_2peers.cmd
index 0aae5b30..6777d706 100644
--- a/samples/SpaceWar.Lobby/scripts/windows/start_2peers.cmd
+++ b/samples/SpaceWar.Lobby/scripts/windows/start_2peers.cmd
@@ -1,6 +1,6 @@
 call %~dp0\start_server.cmd
 @pushd %~dp0\..\..\bin\Release\net8.0
 del *.log
-start SpaceWar 9000
-start SpaceWar 9001
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9000
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9001
 @popd
diff --git a/samples/SpaceWar.Lobby/scripts/windows/start_3peers.cmd b/samples/SpaceWar.Lobby/scripts/windows/start_3peers.cmd
index d2c9fa28..b65175ad 100644
--- a/samples/SpaceWar.Lobby/scripts/windows/start_3peers.cmd
+++ b/samples/SpaceWar.Lobby/scripts/windows/start_3peers.cmd
@@ -1,7 +1,7 @@
 call %~dp0\start_server.cmd
 pushd %~dp0\..\..\bin\Release\net8.0
 del *.log
-start SpaceWar 9000
-start SpaceWar 9001
-start SpaceWar 9002
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -Username player  -LocalPort 9000
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9001
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9002
 popd
diff --git a/samples/SpaceWar.Lobby/scripts/windows/start_4peers.cmd b/samples/SpaceWar.Lobby/scripts/windows/start_4peers.cmd
index dbbfc6f9..4596e974 100644
--- a/samples/SpaceWar.Lobby/scripts/windows/start_4peers.cmd
+++ b/samples/SpaceWar.Lobby/scripts/windows/start_4peers.cmd
@@ -1,8 +1,8 @@
 call %~dp0\start_server.cmd
 pushd %~dp0\..\..\bin\Release\net8.0
 del *.log
-start SpaceWar 9000
-start SpaceWar 9001
-start SpaceWar 9002
-start SpaceWar 9003
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort  9000
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort  9001
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort  9002
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort  9003
 popd
diff --git a/samples/SpaceWar.Lobby/scripts/windows/start_5peers.cmd b/samples/SpaceWar.Lobby/scripts/windows/start_5peers.cmd
index 10c0490b..bbb68481 100644
--- a/samples/SpaceWar.Lobby/scripts/windows/start_5peers.cmd
+++ b/samples/SpaceWar.Lobby/scripts/windows/start_5peers.cmd
@@ -1,9 +1,9 @@
 call %~dp0\start_server.cmd
 pushd %~dp0\..\..\bin\Release\net8.0
 del *.log
-start SpaceWar 9000
-start SpaceWar 9001
-start SpaceWar 9002
-start SpaceWar 9003
-start SpaceWar 9004
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9000
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9001
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9002
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9003
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9004
 popd
diff --git a/samples/SpaceWar.Lobby/scripts/windows/start_6_remote.cmd b/samples/SpaceWar.Lobby/scripts/windows/start_6_remote.cmd
new file mode 100644
index 00000000..a389aefc
--- /dev/null
+++ b/samples/SpaceWar.Lobby/scripts/windows/start_6_remote.cmd
@@ -0,0 +1,13 @@
+dotnet build -c Release %~dp0\..\..\..\..
+pushd %~dp0\..\..\bin\Release\net8.0
+del *.log
+@set LOBBY_SERVER_URL=https://lobby-server.fly.dev
+
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -LocalPort 9000 -Username ryu
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -LocalPort 9001 -Username liu_kang
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -LocalPort 9002 -Username kyo
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -LocalPort 9003 -Username jin
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -LocalPort 9004 -Username sol_badguy
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -LocalPort 9005 -Username jago
+
+popd
diff --git a/samples/SpaceWar.Lobby/scripts/windows/start_6peers.cmd b/samples/SpaceWar.Lobby/scripts/windows/start_6peers.cmd
index 2bd7b49f..4c89583d 100644
--- a/samples/SpaceWar.Lobby/scripts/windows/start_6peers.cmd
+++ b/samples/SpaceWar.Lobby/scripts/windows/start_6peers.cmd
@@ -1,10 +1,10 @@
 call %~dp0\start_server.cmd
 pushd %~dp0\..\..\bin\Release\net8.0
 del *.log
-start SpaceWar 9000
-start SpaceWar 9001
-start SpaceWar 9002
-start SpaceWar 9003
-start SpaceWar 9004
-start SpaceWar 9005
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9000
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9001
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9002
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9003
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9004
+start SpaceWar -ServerURl %LOBBY_SERVER_URL% -Username player -LocalPort 9005
 popd
diff --git a/samples/SpaceWar.Lobby/scripts/windows/start_server.cmd b/samples/SpaceWar.Lobby/scripts/windows/start_server.cmd
index 0ba0ab73..3cfb8f7f 100644
--- a/samples/SpaceWar.Lobby/scripts/windows/start_server.cmd
+++ b/samples/SpaceWar.Lobby/scripts/windows/start_server.cmd
@@ -1,6 +1,6 @@
 dotnet build -c Release %~dp0\..\..\..\..
-pushd %~dp0\..\..\..\LobbyServer
+@pushd %~dp0\..\..\..\LobbyServer
 
-@set SPACEWAR_LOBBY_URL=http://localhost:9999
+@set LOBBY_SERVER_URL=http://localhost:9999
 start dotnet run --no-build -c Release
-popd
+@popd