Add functionality to accept a challenge in chess game

Introduced capability to accept a challenge, updated challenge viewer model to include challenge id, and updated the In-Memory database to handle adding new games. The corresponding endpoint was updated and the front-end scripts were added to handle challenge acceptance and game redirection. Changes were also made to ensure challenges are only seen when not accepted in the public view.

src/Aiursoft.ChessServer/Controllers/HomeController.cs

@@ -4,6 +4,7 @@ using Aiursoft.ChessServer.Data;
 using Aiursoft.ChessServer.Models;
 using Aiursoft.ChessServer.Models.ViewModels;
 using Aiursoft.CSTools.Services;
+using Aiursoft.WebTools.Attributes;
 using Microsoft.AspNetCore.Mvc;
 
 namespace Aiursoft.ChessServer.Controllers;
@@ -17,7 +18,7 @@ public class HomeController(
     {
         var model = new IndexViewModel
         {
-            Challenges = database.GetPublicChallenges()
+            Challenges = database.GetPublicUnAcceptedChallenges()
         };
         return View(model);
     }
@@ -119,7 +120,7 @@ public class HomeController(
         }
         var model = new ChallengeViewModel
         {
-            RoomId = id,
+            ChallengeId = id,
         };
         return View(model);
     }
@@ -139,6 +140,40 @@ public class HomeController(
         return RedirectToAction(nameof(Index));
     }
 
+    /// <summary>
+    /// This method accepts a challenge and updates the challenge's accepter.
+    /// </summary>
+    /// <param name="id">The ID of the challenge to accept.</param>
+    /// <param name="playerId">The ID of the player accepting the challenge.</param>
+    /// <returns>An IActionResult indicating the result of the operation.</returns>
+    [HttpPost]
+    public async Task<IActionResult> AcceptChallenge([FromRoute]int id, [FromQuery]Guid playerId)
+    {
+        var challenge = database.GetChallenge(id);
+        if (challenge == null)
+        {
+            return NotFound();
+        }
+        if (challenge.Accepter != null)
+        {
+            // Challenge already accepted.
+            return BadRequest("Challenge already accepted.");
+        }
+        if (challenge.Creator.Id == playerId)
+        {
+            // Cannot accept your own challenge.
+            return BadRequest("Cannot accept your own challenge!");
+        }
+        challenge.Accepter = database.GetOrAddPlayer(playerId);
+        var (newGameId, newGame) = database.AddNewGameAndGetId();
+        challenge.Game = newGame;
+        challenge.GameId = newGameId;
+        await challenge.ChallengeChangedChannel.BroadcastAsync("game-started-at-" + newGameId);
+        return Ok();
+    }
+
+    [Route("listen-challenge/{id:int}.ws")]
+    [EnforceWebSocket]
     public async Task ListenChallenge(int id)
     {
         var pusher = await HttpContext.AcceptWebSocketClient();

src/Aiursoft.ChessServer/Data/InMemoryDatabase.cs

@@ -25,6 +25,20 @@ public class InMemoryDatabase : ISingletonDependency
             return Games.GetOrAdd(id, _ => new Game());
         }
     }
+
+    public (int gameId, Game game) AddNewGameAndGetId()
+    {
+        lock (Games)
+        {
+            for (var id = 1;; id++)
+            {
+                if (Games.ContainsKey(id)) continue;
+                var newGame = new Game();
+                Games.TryAdd(id, newGame);
+                return (id, newGame);
+            }
+        }
+    }
     
     public Player GetOrAddPlayer(Guid id)
     {
@@ -37,12 +51,13 @@ public class InMemoryDatabase : ISingletonDependency
         }
     }
     
-    public IReadOnlyCollection<KeyValuePair<int, Challenge>> GetPublicChallenges()
+    public IReadOnlyCollection<KeyValuePair<int, Challenge>> GetPublicUnAcceptedChallenges()
     {
         lock (Challenges)
         {
             return Challenges
                 .Where(t => t.Value.Permission == ChallengePermission.Public)
+                .Where(t => t.Value.Accepter == null)
                 .ToArray();
         }
     }

src/Aiursoft.ChessServer/Models/Challenge.cs

@@ -9,6 +9,7 @@ public class Challenge(Player creator)
 
     public Player? Accepter { get; set; } = null;
     
+    public int? GameId { get; set; } = null;
     public Game? Game { get; set; } = null;
     
     public RoleRule RoleRule { get; set; } = RoleRule.Random;

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

@@ -2,5 +2,5 @@
 
 public class ChallengeViewModel
 {
-    public int RoomId { get; init; }
+    public int ChallengeId { get; init; }
 }

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

@@ -6,9 +6,9 @@
         <h1 class="display-4">Waiting for opponent 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/{nameof(HomeController.Challenge)}/{Model.RoomId}";
+            var link = $"{Context.Request.Scheme}://{Context.Request.Host}/Home/{nameof(HomeController.Challenge)}/{Model.ChallengeId}";
         }
-        <form asp-controller="Home" asp-action="DropChallenge" asp-route-id="@Model.RoomId" method="post" class="d-inline" asp-antiforgery="false">
+        <form asp-controller="Home" asp-action="DropChallenge" asp-route-id="@Model.ChallengeId" method="post" class="d-inline" asp-antiforgery="false">
             <div asp-validation-summary="All" class="text-danger"></div>
             <input type="hidden" name="playerId" value=""/>
             
@@ -42,4 +42,33 @@
                 placement: 'bottom'
         });
     </script>
+    <script type="module">
+        import { acceptChallenge, getUserId } from "/scripts/player.js";
+        
+        // Listen to the channel
+        const wsScheme = window.location.protocol === "https:" ? "wss://" : "ws://";
+        const socket = new WebSocket(
+            `${wsScheme}${window.location.host}/listen-challenge/${@Model.ChallengeId}.ws`
+        );
+        
+        socket.addEventListener('open', function (event) {
+            console.log('WebSocket is open now.');
+            
+            // Accept the challenge
+            acceptChallenge(@Model.ChallengeId, getUserId());
+        });
+
+        socket.onmessage = function (event) {
+            // alert(event.data);
+            // May get data like: game-started-at-{newGameId}
+            if (event.data.startsWith('game-started-at-')) {
+                const gameId = event.data.replace('game-started-at-', '');
+                const gameIdNumber = parseInt(gameId);
+                if (gameIdNumber) {
+                    window.location.href = `/games/${gameId}.html`;
+                }
+            }
+        };
+    
+    </script>
 }

src/Aiursoft.ChessServer/wwwroot/scripts/player.js

@@ -22,4 +22,9 @@ const changeName = async function (newName) {
     await fetch(`/players/${getUserId()}/new-name/${newName}`, { method: 'PUT' });
  }
 
-export { getUserId, getUserName, changeName };
+const acceptChallenge = async function (challengeId, playerId) {
+    // call /home/AcceptChallenge/{challengeId}?playerId={playerId} HTTP POST API:
+    await fetch(`/home/AcceptChallenge/${challengeId}?playerId=${playerId}`, { method: 'POST' });
+}
+
+export { getUserId, getUserName, changeName, acceptChallenge };