Remove some hacks.

src/Aiursoft.ChessServer/Controllers/ChallengeController.cs

@@ -1,41 +0,0 @@
-using Microsoft.AspNetCore.Mvc;
-
-namespace Aiursoft.ChessServer.Controllers;
-
-[Route("challenges")]
-public class ChallengeController : ControllerBase
-{
-    [HttpPost]
-    [Route("create")]
-    public IActionResult Create(Guid userId)
-    {
-        // Create a new challenge. Add to database.
-        return Ok();
-    }
-
-    [HttpGet]
-    [Route("list")]
-    public IActionResult List()
-    {
-        // Show all public challenges.
-        return Ok();
-    }
-    
-    [HttpPost]
-    [Route("accept/{id:int}")]
-    public IActionResult Accept(int id, Guid userId)
-    {
-        // Accept a challenge. Remove the challenge from database.
-        // Create a new game. Redirect both players to the game.
-        return Ok();
-    }
-    
-    [HttpPost]
-    [Route("reject/{id:int}")]
-    public IActionResult Edit(int id, Guid userId)
-    {
-        // If challenge owner is the same as user id,
-        // Edit a challenge in database.
-        return Ok();
-    }
-}

src/Aiursoft.ChessServer/Controllers/HomeController.cs

@@ -21,7 +21,10 @@ public class HomeController : Controller
     [HttpGet]
     public IActionResult Index()
     {
-        var model = new IndexViewModel(_database.Challenges);
+        var model = new IndexViewModel
+        {
+            Challenges = _database.GetPublicChallenges()
+        };
         return View(model);
     }
 
@@ -29,17 +32,17 @@ public class HomeController : Controller
     public IActionResult Auto(Guid playerId)
     {
         // I created a challenge. Go to my challenge.
-        var iHaveAChallenge = _database.Challenges.FirstOrDefault(t => t.Value.Creator.Id == playerId);
-        if (iHaveAChallenge.Value != null)
+        var myChallengeKey = _database.GetMyChallengeKey(playerId);
+        if (myChallengeKey != null)
         {
-            return RedirectToAction(nameof(Challenge), new { id = iHaveAChallenge.Key, playerId });
+            return RedirectToAction(nameof(Challenge), new { id = (int)myChallengeKey, playerId });
         }
         
         // Exists a public challenge. Go to that challenge.
-        var otherChallenge = _database.Challenges.FirstOrDefault(t => t.Value.Permission == ChallengePermission.Public);
-        if (otherChallenge.Value != null)
+        var otherChallenge = _database.GetFirstPublicChallengeKey();
+        if (otherChallenge != null)
         {
-            return RedirectToAction(nameof(Challenge), new { id = otherChallenge.Key, playerId });
+            return RedirectToAction(nameof(Challenge), new { id = (int)otherChallenge, playerId });
         }
         
         // Create a new challenge.
@@ -49,10 +52,10 @@ public class HomeController : Controller
     [HttpGet]
     public IActionResult Create(Guid playerId)
     {
-        var iHaveAChallenge = _database.Challenges.FirstOrDefault(t => t.Value.Creator.Id == playerId);
-        if (iHaveAChallenge.Value != null)
+        var myChallengeKey = _database.GetMyChallengeKey(playerId);
+        if (myChallengeKey != null)
         {
-            return RedirectToAction(nameof(Challenge), new { id = iHaveAChallenge.Key, playerId });
+            return RedirectToAction(nameof(Challenge), new { id = myChallengeKey, playerId });
         }
         var model = new CreateChallengeViewModel();
         return View(model);
@@ -75,20 +78,21 @@ public class HomeController : Controller
             TimeLimit = model.TimeLimit,
         };
         var roomId = _counter.GetUniqueNo();
-        _database.Challenges.TryAdd(roomId, challenge);
-        return RedirectToAction(nameof(Challenge), new { id = roomId, playerId = model.CreatorId });
+        _database.CreateChallenge(roomId, challenge);
+        return RedirectToAction(nameof(Challenge), new { id = roomId });
     }
-
+    
     [HttpGet]
-    public IActionResult Challenge(int id, Guid playerId)
+    public IActionResult Challenge(int id)
     {
-        var player = _database.GetOrAddPlayer(playerId);
-        var challenge = _database.GetOrAddChallenge(id, player);
-        var model = new ChallengeViewModel()
+        var challenge = _database.GetChallenge(id);
+        if (challenge == null)
+        {
+            return RedirectToAction(nameof(Index));
+        }
+        var model = new ChallengeViewModel
         {
             RoomId = id,
-            PlayerId = playerId,
-            IsCreator = challenge.Creator.Id == playerId,
         };
         return View(model);
     }
@@ -100,11 +104,10 @@ public class HomeController : Controller
         {
             return RedirectToAction(nameof(Challenge), new { id = model.Id, playerId = model.PlayerId });
         }
-        var player = _database.GetOrAddPlayer(model.PlayerId);
-        var challenge = _database.GetOrAddChallenge(model.Id, player);
-        if (challenge.Creator.Id == model.PlayerId)
+        var challenge = _database.GetChallenge(model.Id);
+        if (challenge != null && challenge.Creator.Id == model.PlayerId)
         {
-            _database.Challenges.TryRemove(model.Id, out _);
+            _database.DeleteChallenge(model.Id);
         }
         return RedirectToAction(nameof(Index));
     }

src/Aiursoft.ChessServer/Data/InMemoryDatabase.cs

@@ -10,7 +10,7 @@ public class InMemoryDatabase : ISingletonDependency
     
     private ConcurrentDictionary<Guid, Player> Players { get; } = new();
     
-    public ConcurrentDictionary<int, Challenge> Challenges { get; } = new();
+    private ConcurrentDictionary<int, Challenge> Challenges { get; } = new();
 
     public GameContext[] GetActiveGames()
     {
@@ -36,11 +36,66 @@ public class InMemoryDatabase : ISingletonDependency
         }
     }
     
-    public Challenge GetOrAddChallenge(int id, Player creator)
+    public IReadOnlyCollection<KeyValuePair<int, Challenge>> GetPublicChallenges()
     {
         lock (Challenges)
         {
-            return Challenges.GetOrAdd(id, _ => new Challenge(creator));
+            return Challenges
+                .Where(t => t.Value.Permission == ChallengePermission.Public)
+                .ToArray();
+        }
+    }
+    
+    public Challenge? GetChallenge(int id)
+    {
+        lock (Challenges)
+        {
+            return Challenges.GetValueOrDefault(id);
+        }
+    }
+    
+    public int? GetMyChallengeKey(Guid playerId)
+    {
+        lock (Challenges)
+        {
+            if (Challenges.All(t => t.Value.Creator.Id != playerId))
+            {
+                return null;
+            }
+            
+            return Challenges
+                .FirstOrDefault(t => t.Value.Creator.Id == playerId)
+                .Key;
+        }
+    }
+    
+    public int? GetFirstPublicChallengeKey()
+    {
+        lock (Challenges)
+        {
+            return Challenges
+                .FirstOrDefault(t => t.Value.Permission == ChallengePermission.Public)
+                .Key;
+        }
+    }
+    
+    public void DeleteChallenge(int id)
+    {
+        lock (Challenges)
+        {
+            Challenges.TryRemove(id, out _);
+        }
+    }
+    
+    public void CreateChallenge(int id, Challenge challenge)
+    {
+        lock (Challenges)
+        {
+            var result = Challenges.TryAdd(id, challenge);
+            if (!result)
+            {
+                throw new InvalidOperationException("Challenge already exists!");
+            }
         }
     }
 }

src/Aiursoft.ChessServer/Models/Game.cs

@@ -44,4 +44,13 @@ public class Challenge
     public TimeSpan TimeLimit { get; set; } = TimeSpan.FromMinutes(10);
     
     public ChallengePermission Permission { get; set; } = ChallengePermission.Public;
+    
+    // Possible messages:
+    // Player joined: p-joined-{player-nick-name}
+    // Player left: p-left-{player-nick-name}
+    // Room dropped: room-dropped
+    // Game started: game-started
+    // Creator transferred: creator-transferred-{new-owner-player-nick-name}
+    // Settings changed: settings-changed
+    public AsyncObservable<string> ChallengeChangedChannel { get; } = new();
 }

src/Aiursoft.ChessServer/Models/ViewModels/ChallengeViewModel.cs

@@ -2,9 +2,5 @@
 
 public class ChallengeViewModel
 {
-    public int RoomId { get; set; }
-    
-    public Guid PlayerId { get; set; }
-    
-    public bool IsCreator { get; set; }
+    public int RoomId { get; init; }
 }

src/Aiursoft.ChessServer/Models/ViewModels/IndexViewModel.cs

@@ -4,10 +4,5 @@ namespace Aiursoft.ChessServer.Models;
 
 public class IndexViewModel
 {
-    public ConcurrentDictionary<int, Challenge> Challenges { get; }
-
-    public IndexViewModel(ConcurrentDictionary<int, Challenge> challenges)
-    {
-        Challenges = challenges;
-    }
+    public required IReadOnlyCollection<KeyValuePair<int, Challenge>> Challenges { get; init; }
 }

src/Aiursoft.ChessServer/Views/Home/Challenge.cshtml

@@ -1,15 +1,16 @@
-@model Aiursoft.ChessServer.Models.ChallengeViewModel
+@using Aiursoft.ChessServer.Controllers
+@model Aiursoft.ChessServer.Models.ChallengeViewModel
 
 <div class="jumbotron">
     <div class="container">
         <h1 class="display-4">Waiting for joining...</h1>
         <p class="lead">Please share the link of this room to your friend!</p>
         @{
-            var link = $"{Context.Request.Scheme}://{Context.Request.Host}/Home/Room/{Model.RoomId}";
+            var link = $"{Context.Request.Scheme}://{Context.Request.Host}/Home/{nameof(HomeController.Challenge)}/{Model.RoomId}";
         }
         <form asp-controller="Home" asp-action="DropChallenge" asp-route-id="@Model.RoomId" method="post" class="d-inline" asp-antiforgery="false">
             <div asp-validation-summary="All" class="text-danger"></div>
-            <input type="hidden" name="playerId" value="@Model.PlayerId"/>
+            <input type="hidden" name="playerId" value=""/>
             
             <input type="text" class="form-control" value="@link" readonly>
             <a class="btn btn-secondary btn-lg mt-4" data-clipboard-text="@link" role="button" data-toggle="tooltip" data-placement="top" title="Copied!">
@@ -24,6 +25,12 @@
 
 @section scripts
 {
+    <script type="module">
+        import { getUserId } from "/scripts/player.js";
+        const playerId = getUserId();
+        const playerIdControl = document.querySelector('input[name="playerId"]');
+        playerIdControl.value = playerId;
+    </script>
     <script src="/node_modules/clipboard/dist/clipboard.min.js"></script>
     <script>
         // Initialize clipboard.

src/Aiursoft.ChessServer/Views/Home/ChallengeNoId.cshtml

@@ -0,0 +1,10 @@
+@{
+    Layout = null;
+}
+<script type="module">
+    import { getUserId } from "/scripts/player.js";
+    const playerId = getUserId();
+    if (playerId) {
+        window.location.href = window.location.href.toLowerCase().replace("challengenoid", "Challenge") + `?playerId=${playerId}`;
+    }
+</script>

src/Aiursoft.ChessServer/Views/Home/Index.cshtml

@@ -1,4 +1,5 @@
-@model Aiursoft.ChessServer.Models.IndexViewModel
+@using Aiursoft.ChessServer.Models
+@model Aiursoft.ChessServer.Models.IndexViewModel
 
 <div class="jumbotron">
     <div class="container">
@@ -24,7 +25,7 @@
                                 <th>Creator</th>
                                 <th>Action</th>
                             </tr>
-                            @foreach (var item in Model.Challenges)
+                            @foreach (var item in Model.Challenges.Where(t => t.Value.Permission == ChallengePermission.Public))
                             {
                                 <tr>
                                     <td>@item.Value.Message</td>