using System.Diagnostics;
using LiteNetLib;
using LiteNetLib.Utils;
using Serilog;

namespace ClientTester.EchoDummyService;

public class DummyClients
{
    public NetManager Manager;
    public EventBasedNetListener Listener;
    public NetPeer? Peer;
    public int ClientId;

    // seq → 송신 타임스탬프 (Stopwatch tick)
    private readonly Dictionary<int, long> _pendingPings = new();
    private int _seqNumber;

    // 통계
    public int SentCount;
    public int ReceivedCount;
    public double LastRttMs;
    public double TotalRttMs;
    public int RttCount;

    public DummyClients(int clientId, string ip, int port, string key)
    {
        ClientId = clientId;
        Listener = new EventBasedNetListener();
        Manager  = new NetManager(Listener);

        Listener.PeerConnectedEvent += peer =>
        {
            Peer = peer;
            Log.Information("[Client {ClientId:00}] 연결됨", ClientId);
        };

        Listener.NetworkReceiveEvent += (peer, reader, channel, deliveryMethod) =>
        {
            var msg = reader.GetString();

            // "ack:seq:{seqNum}" 파싱
            var parts = msg.Split(':');
            if (parts.Length == 3 && parts[0] == "ack" && parts[1] == "seq"
                && int.TryParse(parts[2], out int seq)
                && _pendingPings.TryGetValue(seq, out long sentTick))
            {
                double rttMs = (Stopwatch.GetTimestamp() - sentTick)
                               * 1000.0 / Stopwatch.Frequency;
                LastRttMs  = rttMs;
                TotalRttMs += rttMs;
                RttCount++;
                _pendingPings.Remove(seq);
            }

            ReceivedCount++;
            reader.Recycle();
        };

        Listener.PeerDisconnectedEvent += (peer, info) =>
        {
            Log.Warning("[Client {ClientId:00}] 연결 끊김: {Reason}", ClientId, info.Reason);
            Peer = null;
        };

        Manager.Start();
        Manager.Connect(ip, port, key);
    }

    public void SendPing()
    {
        if (Peer is null) return;

        int seq = _seqNumber++;
        _pendingPings[seq] = Stopwatch.GetTimestamp();

        var writer = new NetDataWriter();
        writer.Put($"seq:{seq}");
        Peer.Send(writer, DeliveryMethod.ReliableOrdered);
        SentCount++;
    }

    public double AvgRttMs => RttCount > 0 ? TotalRttMs / RttCount : 0.0;

    public void PollEvents() => Manager.PollEvents();

    public void Stop() => Manager.Stop();
}