MSCO-Dedicated-Server/MasterClient.cs

using System.Net.Http.Json;

namespace MSCO.Server;

/// <summary>
/// Alle Server hängen am offiziellen Master (Keymaster + Serverliste). Die Adresse ist fest eingebaut,
/// damit niemand die Schlüsselprüfung über einen eigenen Master umgehen kann - nicht über server.json,
/// Umgebungsvariablen oder Startparameter änderbar.
/// </summary>
public static class MasterServer
{
    public const string OfficialUrl = "https://msco.mbm.wtf";
    public static string Url => OfficialUrl;
}

/// <summary>Spricht mit dem Master-Server: Lizenzschlüssel prüfen und Server in der Liste melden.</summary>
public sealed class MasterClient
{
    public sealed record KeyInfo(bool Valid, string Owner, string Label, string Error)
    {
        /// <summary>Master war nicht erreichbar (Netzwerk, Proxy-Fehler) - dann später erneut versuchen.</summary>
        public bool Unreachable { get; init; }
    }
    record HeartbeatBody(string Key, string Name, string Description, string Address, int Port, int Players, int MaxPlayers,
                         string Version, bool Public, bool RequireSteam, List<string> Tags, List<ModInfo> Mods);

    /// <summary>Mod des Servers für die Serverliste (die Dateien selbst bekommen Spieler direkt vom Server).</summary>
    public sealed record ModInfo(string Id, string Name, string Version);

    readonly HttpClient http = new() { Timeout = TimeSpan.FromSeconds(10) };
    readonly string baseUrl;

    public MasterClient(string masterUrl)
    {
        baseUrl = masterUrl.TrimEnd('/');
    }

    public async Task<KeyInfo> ValidateKeyAsync(string key)
    {
        try
        {
            var response = await http.PostAsJsonAsync(baseUrl + "/api/keys/validate", new { key });
            // 5xx (z.B. 502 vom Reverse Proxy, Master gerade nicht da) = nicht erreichbar, nicht "ungültig"
            if ((int)response.StatusCode >= 500)
                return new KeyInfo(false, null, null, "HTTP " + (int)response.StatusCode) { Unreachable = true };
            var info = await response.Content.ReadFromJsonAsync<KeyInfo>();
            return info ?? new KeyInfo(false, null, null, "Empty response") { Unreachable = true };
        }
        catch (Exception e)
        {
            return new KeyInfo(false, null, null, e.Message) { Unreachable = true };
        }
    }

    /// <summary>
    /// Antwort auf den Heartbeat. Status: HTTP-Code, 0 = Master nicht erreichbar, 401 = Schlüssel ungültig.
    /// Reachable: ob der Master den Server von außen erreicht (null = Prüfung läuft noch).
    /// </summary>
    public sealed record HeartbeatResult(int Status, bool? Reachable, bool Listed, string Address, int Port);
    record HeartbeatReply(bool? Reachable, bool Listed, string Address, int Port);

    /// <summary>Beim Beenden: sofort aus der Serverliste nehmen (sonst erst nach dem Heartbeat-Timeout).</summary>
    public async Task UnregisterAsync(string key)
    {
        try
        {
            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(3));
            await http.PostAsJsonAsync(baseUrl + "/api/servers/unregister", new { key }, cts.Token);
        }
        catch { }
    }

    public async Task<HeartbeatResult> HeartbeatAsync(ServerConfig config, int players, string version, List<ModInfo> mods = null)
    {
        try
        {
            var body = new HeartbeatBody(config.LicenseKey, config.Name, config.Description, config.PublicAddress, config.Port,
                                         players, config.MaxPlayers, version, config.Public, config.RequireSteam,
                                         ServerConfig.NormalizeTags(config.Tags, out _), mods ?? new List<ModInfo>());
            var response = await http.PostAsJsonAsync(baseUrl + "/api/servers/heartbeat", body);
            int status = (int)response.StatusCode;
            if (!response.IsSuccessStatusCode) return new HeartbeatResult(status, null, false, null, 0);

            HeartbeatReply reply = null;
            try { reply = await response.Content.ReadFromJsonAsync<HeartbeatReply>(); } catch { }
            return new HeartbeatResult(status, reply?.Reachable, reply?.Listed ?? false, reply?.Address, reply?.Port ?? 0);
        }
        catch
        {
            return new HeartbeatResult(0, null, false, null, 0);
        }
    }
}