using System.Net.Sockets;
using MSCO.Server;

// Protokoll-Tests gegen den echten Server-Code: startet einen Server offline (ohne Master, ohne Lizenz) auf
// Port 17777 und spielt mehrere Clients durch - Beitreten, Ping, Weltzustand, Chat, Admin-Rechte, kaputte Daten.
// Ausführen im Server-Ordner:  dotnet run --project Tests
const int Port = 17777;
const string AdminId = "76561198910227878";
string dir = Path.Combine(Path.GetTempPath(), "msco-servertest-" + Guid.NewGuid().ToString("N")[..8]);
Directory.CreateDirectory(Path.Combine(dir, "save"));
// Platzhalter-Spielstand (der Inhalt ist für die Protokoll-Tests egal)
foreach (var name in new[] { "defaultES2File.txt", "items.txt", "meshsave.txt", "graveyard.txt", "notepad.txt" })
    File.WriteAllText(Path.Combine(dir, "save", name), "test " + name);
string configPath = Path.Combine(dir, "server.json");
var config = new ServerConfig { LicenseKey = "test", Name = "Test", Port = Port, MaxPlayers = 4, RequireSteam = false, Public = false, Admins = new() { AdminId } };
config.Save(configPath);

var server = new GameServer(config, dir, configPath, "Tester", offline: true);
if (!server.LoadSave()) { Console.WriteLine("FAIL: LoadSave"); return 1; }
var serverThread = new Thread(server.Run) { IsBackground = true };
serverThread.Start();
Thread.Sleep(500);

int failed = 0, passed = 0;
void Check(bool ok, string what) { if (ok) passed++; else failed++; Console.WriteLine((ok ? "  ok   " : "  FAIL ") + what); }

try
{
    Console.WriteLine("== Join");
    var alice = await TestClient.Join("Alice", 0, null);
    Check(alice.Welcome != null, "Alice gets Welcome");
    Check(alice.Id > 0, "Alice has id " + alice.Id);
    Check(alice.AdminStatus == false, "Alice is not admin");
    Check(alice.SaveFiles == 5, "Alice received save files (" + alice.SaveFiles + ")");
    Check(alice.GotStartGame, "Alice got StartGame");

    Console.WriteLine("== Ping");
    alice.Send(MsgType.Ping, BitConverter.GetBytes(12.5f));
    var pong = await alice.WaitFor(MsgType.Pong);
    Check(pong != null && BitConverter.ToSingle(pong, 0) == 12.5f, "Ping is echoed as Pong with the same timestamp");

    Console.WriteLine("== Ready / snapshot");
    alice.Send(MsgType.Ready, Array.Empty<byte>());
    var snap = await alice.WaitFor(MsgType.WorldSnapshot);
    Check(snap != null, "WorldSnapshot received");
    var s0 = Snapshot.Parse(snap);
    Check(s0.Ok, "Snapshot parses completely (" + s0.Info + ")");

    Console.WriteLine("== Second player, chat");
    var bob = await TestClient.Join("Bob", 0, null);
    Check(bob.Welcome != null, "Bob joins");
    var joined = await alice.WaitFor(MsgType.PlayerJoined);
    Check(joined != null, "Alice is told that Bob joined");
    alice.Send(MsgType.Chat, Wire.Build(w => w.Write("hello bob")));
    var chat = await bob.WaitFor(MsgType.Chat);
    Check(chat != null && new BinaryReader(new MemoryStream(chat)).ReadInt32() == alice.Id, "Bob receives Alice's chat with her id");
    Check(chat != null && ReadStringAfterSender(chat) == "hello bob", "Chat text arrives unchanged");

    Console.WriteLine("== Object states (valid / invalid)");
    alice.Send(MsgType.ObjStates, ObjStates((111, 10, 1, 20, 0, 0, 0, 1), (222, float.NaN, 0, 0, 0, 0, 0, 1), (333, 0, -5000, 0, 0, 0, 0, 1), (444, 1, 1, 1, 0, 0, 0, 0)));
    var relay = await bob.WaitFor(MsgType.ObjStates);
    Check(relay != null, "Object states are relayed to Bob");
    alice.Send(MsgType.VarSync, Wire.Build(w => { w.Write(2); w.Write(42); w.Write((byte)1); w.Write(3.5f); w.Write(43); w.Write((byte)3); w.Write(true); }));
    await bob.WaitFor(MsgType.VarSync);
    var carol = await TestClient.Join("Carol", 0, null);
    carol.Send(MsgType.Ready, Array.Empty<byte>());
    var snap2 = Snapshot.Parse(await carol.WaitFor(MsgType.WorldSnapshot));
    Check(snap2.ObjectIds.Contains(111), "Valid object pose is stored");
    Check(!snap2.ObjectIds.Contains(222), "NaN pose is rejected");
    Check(!snap2.ObjectIds.Contains(333), "Pose far below the map is rejected");
    Check(!snap2.ObjectIds.Contains(444), "Invalid quaternion is rejected");
    Check(snap2.Vars == 2, "Vehicle values are stored and sent to new players (" + snap2.Vars + ")");

    Console.WriteLine("== Server full");
    var eve = await TestClient.Join("Eve", 0, null);
    var dave = await TestClient.Join("Dave", 0, null, expectReject: true);
    Check(dave.RejectReason != null && dave.RejectReason.Contains("full"), "Player over the limit is rejected: " + dave.RejectReason);
    eve.Close();

    Console.WriteLine("== Admin rights");
    alice.Send(MsgType.AdminListRequest, Array.Empty<byte>());
    var notAdmin = await alice.WaitFor(MsgType.AdminResult);
    Check(notAdmin != null && ReadString(notAdmin).Contains("not an admin"), "Non-admin cannot open the admin list");
    alice.Send(MsgType.AdminAction, Wire.Build(w => { w.Write((byte)1); w.Write(bob.Id); w.Write("x"); }));
    var kickTry = await alice.WaitFor(MsgType.AdminResult);
    Check(kickTry != null && ReadString(kickTry).Contains("not an admin"), "Non-admin cannot kick");
    carol.Close();
    await Task.Delay(300);

    // Jemand gibt sich mit der SteamID des Admins aus (ohne Steam Web API Key wird das Ticket nicht geprüft)
    var faker = await TestClient.Join("Faker", ulong.Parse(AdminId), new byte[] { 1, 2, 3, 4 });
    Check(faker.Welcome != null, "Player with a claimed SteamID joins (tickets not verified without key)");
    Check(faker.AdminStatus == false, "Claimed (unverified) SteamID must NOT get admin rights");
    var faker2 = await TestClient.Join("Faker2", ulong.Parse(AdminId), new byte[] { 9 }, expectReject: true);
    Check(faker2.RejectReason != null && faker2.RejectReason.Contains("already connected"),
          "Second player with the same unverified SteamID cannot push out the first: " + faker2.RejectReason);
    Check(!faker.IsClosedByServer(), "The first player stays connected");
    faker.Close();
    await Task.Delay(300);

    Console.WriteLine("== Robustness");
    var evil = await TestClient.Join("Evil", 0, null);
    evil.SendRaw(BitConverter.GetBytes(5 * 1024 * 1024)); // Paket, das 5 MB groß sein will
    await Task.Delay(500);
    Check(evil.IsClosedByServer(), "Oversized packet closes only that connection");
    var bob2 = await TestClient.Join("Bob2", 0, null);
    Check(bob2.Welcome != null, "Server still accepts players afterwards");
    bob2.Send(MsgType.VarSync, new byte[] { 1, 2 }); // kaputte Nachricht
    await Task.Delay(500);
    Check(bob2.IsClosedByServer(), "Malformed message closes only that connection");
    alice.Send(MsgType.Ping, BitConverter.GetBytes(1f));
    Check(await alice.WaitFor(MsgType.Pong) != null, "Other players are not affected");

    Console.WriteLine("== Chat limits");
    alice.Send(MsgType.Chat, Wire.Build(w => w.Write(new string('x', 5000))));
    var longChat = await bob.WaitFor(MsgType.Chat, 800);
    Check(longChat == null, "Huge chat messages are not relayed");
}
catch (Exception e)
{
    failed++;
    Console.WriteLine("  FAIL exception: " + e);
}

Console.WriteLine($"\n{passed} passed, {failed} failed");
server.EnqueueCommand("stop");
Thread.Sleep(300);
try { Directory.Delete(dir, true); } catch { }
return failed == 0 ? 0 : 1;

static string ReadString(byte[] p) => new BinaryReader(new MemoryStream(p)).ReadString();
static string ReadStringAfterSender(byte[] p) { var r = new BinaryReader(new MemoryStream(p)); r.ReadInt32(); return r.ReadString(); }

static byte[] ObjStates(params (int id, float x, float y, float z, float qx, float qy, float qz, float qw)[] items) => Wire.Build(w =>
{
    w.Write(items.Length);
    foreach (var i in items)
    {
        w.Write(i.id); w.Write(i.x); w.Write(i.y); w.Write(i.z);
        w.Write(i.qx); w.Write(i.qy); w.Write(i.qz); w.Write(i.qw);
        w.Write(0f); w.Write(0f); w.Write(0f);
    }
});

sealed class Snapshot
{
    public bool Ok;
    public string Info;
    public HashSet<int> ObjectIds = new();
    public int Vars = -1;

    public static Snapshot Parse(byte[] data)
    {
        var s = new Snapshot();
        if (data == null) { s.Info = "no data"; return s; }
        try
        {
            var r = new BinaryReader(new MemoryStream(data));
            if (r.ReadBoolean()) { r.ReadSingle(); r.ReadSingle(); r.ReadSingle(); }
            int objects = r.ReadInt32();
            for (int i = 0; i < objects; i++) { s.ObjectIds.Add(r.ReadInt32()); for (int k = 0; k < 7; k++) r.ReadSingle(); }
            int events = r.ReadInt32();
            for (int i = 0; i < events; i++) r.ReadBytes(r.ReadInt32());
            float money = r.ReadSingle();
            int doors = r.ReadInt32();
            for (int i = 0; i < doors; i++) { r.ReadString(); r.ReadString(); }
            s.Vars = r.ReadInt32();
            for (int i = 0; i < s.Vars; i++) { r.ReadInt32(); byte t = r.ReadByte(); r.ReadBytes(t == 3 ? 1 : 4); }
            s.Ok = r.BaseStream.Position == r.BaseStream.Length;
            s.Info = $"{objects} objects, {events} events, money {money}, {doors} doors, {s.Vars} vars";
        }
        catch (Exception e) { s.Info = "parse error " + e.Message; }
        return s;
    }
}

sealed class TestClient
{
    const int Port = 17777;
    TcpClient tcp;
    NetworkStream stream;
    readonly List<(MsgType type, byte[] payload)> inbox = new();
    readonly object gate = new();
    bool closed;

    public byte[] Welcome;
    public int Id;
    public bool? AdminStatus;
    public int SaveFiles;
    public bool GotStartGame;
    public string RejectReason;

    public static async Task<TestClient> Join(string name, ulong steamId, byte[] ticket, bool expectReject = false)
    {
        var c = new TestClient { tcp = new TcpClient() };
        await c.tcp.ConnectAsync("127.0.0.1", Port);
        c.stream = c.tcp.GetStream();
        _ = Task.Run(c.ReadLoop);
        c.Send(MsgType.Hello, Wire.Build(w =>
        {
            w.Write("2.6");
            w.Write(name);
            w.Write(steamId);
            w.Write(ticket?.Length ?? 0);
            if (ticket != null) w.Write(ticket);
        }));
        if (expectReject)
        {
            var rej = await c.WaitFor(MsgType.Reject);
            if (rej != null) c.RejectReason = new BinaryReader(new MemoryStream(rej)).ReadString();
            return c;
        }
        c.Welcome = await c.WaitFor(MsgType.Welcome);
        if (c.Welcome != null) c.Id = BitConverter.ToInt32(c.Welcome, 0);
        var admin = await c.WaitFor(MsgType.AdminStatus);
        if (admin != null) c.AdminStatus = admin[0] != 0;
        await c.WaitFor(MsgType.SaveBegin);
        while (await c.WaitFor(MsgType.SaveFile, 1500) != null) c.SaveFiles++;
        c.GotStartGame = await c.WaitFor(MsgType.StartGame, 1500) != null || c.SaveFiles > 0;
        return c;
    }

    async Task ReadLoop()
    {
        var header = new byte[4];
        try
        {
            while (true)
            {
                await ReadExact(header, 4);
                int len = BitConverter.ToInt32(header, 0);
                var body = new byte[len];
                await ReadExact(body, len);
                lock (gate) inbox.Add(((MsgType)body[0], body[1..]));
            }
        }
        catch { closed = true; }
    }

    async Task ReadExact(byte[] buf, int count)
    {
        int off = 0;
        while (off < count)
        {
            int n = await stream.ReadAsync(buf.AsMemory(off, count - off));
            if (n <= 0) throw new IOException("closed");
            off += n;
        }
    }

    public void Send(MsgType type, byte[] payload)
    {
        byte[] frame = Wire.Frame(type, payload);
        try { stream.Write(frame, 0, frame.Length); } catch { closed = true; }
    }

    public void SendRaw(byte[] data) { try { stream.Write(data, 0, data.Length); stream.Write(new byte[16], 0, 16); } catch { closed = true; } }

    public async Task<byte[]> WaitFor(MsgType type, int timeoutMs = 3000)
    {
        var end = DateTime.UtcNow.AddMilliseconds(timeoutMs);
        while (DateTime.UtcNow < end)
        {
            lock (gate)
            {
                int i = inbox.FindIndex(m => m.type == type);
                if (i >= 0) { var p = inbox[i].payload; inbox.RemoveAt(i); return p; }
            }
            await Task.Delay(20);
        }
        return null;
    }

    public bool IsClosedByServer() => closed;
    public void Close() { try { tcp.Close(); } catch { } }
}