Refactor GameRepository and GameManager architecture, introduce Player model, and update dependency registration in Program.cs.

API/Repository/GameRepo/GameRepository.cs

@@ -0,0 +1,52 @@
+using System.Security.Cryptography;
+using API.Models.DataClasses;
+using API.Models.Game;
+
+namespace API.Repository.GameRepo;
+
+public class GameRepository : IGameRepository
+{
+    private List<Game> _games = [];
+    public List<Game> GetAll()
+    {
+        return _games;
+    }
+
+    public Game? GetOne(string id)
+    {
+        return _games.FirstOrDefault(g => g.Id == id);
+    }
+    
+    public Game? GetOne(SixDigitInt gameCode)
+    {
+        return _games.FirstOrDefault(g => g.GameCode == gameCode);
+    }
+
+    public Game Create(Coordinates gameFieldSize, Player player)
+    {
+        Game newGame = new(gameFieldSize, GenerateGameCode());
+        
+        _games.Add(newGame);
+        
+        return newGame;
+    }
+
+    public void Destroy(string id)
+    {
+        _games.RemoveAll(g => g.Id == id);
+    }
+
+    private SixDigitInt GenerateGameCode()
+    {
+        while (true)
+        {
+            int value = RandomNumberGenerator.GetInt32(100000, 1000000);
+
+            bool exists = _games.Any(g => g.GameCode.Value == value);
+            if (!exists)
+            {
+                return new SixDigitInt(value);
+            }
+        }
+    }
+}