feat: moved to C# thanks to deepseek

Services/LoginService.cs

@@ -0,0 +1,67 @@
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Phenix.Services;
+
+public class LoginService
+{
+    private readonly Dictionary<string, string> _users;
+    private readonly string _sessionKey;
+
+    private static readonly (string User, string Hash)[] OfficialUsers =
+    [
+        ("marqueur", "34373780cc542a1eddb6a08488ec149323b94d66025421acd98ffc20eb5055a0:6f2fa05777d45a2da9db79b7fd11e3bc69eb1807642ccb53d41a0b9eb71a3311"),
+        ("comite", "8649feff48a50f53448e59ce480db97b5549eef1d92c886c49b5a14ee22648e5:a0017b879c8834d2f34938e7a4fa3f4c7be8f70545b9bb22a28cf56ab2eb26d9"),
+    ];
+
+    public LoginService(string sessionKey)
+    {
+        _users = OfficialUsers.ToDictionary(x => x.User, x => x.Hash);
+        _sessionKey = sessionKey;
+    }
+
+    public bool ValidateCredentials(string username, string password)
+    {
+        if (!_users.TryGetValue(username, out var hashWithSalt))
+            return false;
+        return VerifyPassword(password, hashWithSalt);
+    }
+
+    public string SignSession(long expiresAt)
+    {
+        return ShittyHmac(expiresAt.ToString(), _sessionKey);
+    }
+
+    public bool VerifySession(string? expiresAt, string? signature)
+    {
+        if (expiresAt is null || signature is null)
+            return false;
+        if (!long.TryParse(expiresAt, out var ts))
+            return false;
+        if (signature != ShittyHmac(ts.ToString(), _sessionKey))
+            return false;
+        return DateTimeOffset.UtcNow.ToUnixTimeSeconds() < ts;
+    }
+
+    private static bool VerifyPassword(string password, string hashWithSalt)
+    {
+        var parts = hashWithSalt.Split(':');
+        if (parts.Length != 2) return false;
+        var salt = parts[0];
+        var expected = parts[1];
+        return ShittyHmac(password, salt) == expected;
+    }
+
+    private static string HashMessage(string message)
+    {
+        var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(message));
+        return Convert.ToHexStringLower(bytes);
+    }
+
+    private static string ShittyHmac(string message, string salt)
+    {
+        var h1 = HashMessage(message + salt);
+        var h2 = HashMessage(salt + message);
+        return HashMessage(h1 + h2);
+    }
+}