using System.Diagnostics;
using GlobalClassLib;
using LiteNetLib;
using LiteNetLib.Utils;
using PacketLib;

namespace ONDServer.Net;

public static class Server {
    public static ServerPlayer P1;
    public static ServerPlayer P2;
    public static readonly Dictionary<int, ServerPlayer> Players = new();
    public static ServerPlayer OtherPlayer(ServerPlayer player) => player.State.Pid == P1.State.Pid ? P2 : P1;

    public static bool AutoStop{ get; set; } = true;
    
    private static EventBasedNetListener listener;
    private static NetManager server;
    
    private const int TARGET_TICK_RATE = 30;
    private const double TARGET_DELTA_TIME = 1.0 / TARGET_TICK_RATE;
    private const long TARGET_TICK_TIME_MS = 1000 / TARGET_TICK_RATE;
    
    private static NetDataWriter writer;
    private static NetPacketProcessor processor;
    
    private static bool isRunning;
    
    // AI generated
    public static void Start(int port) {
        writer = new NetDataWriter();
        processor = new NetPacketProcessor();
        
        NestedTypeManager.AutoRegister(processor);
        
        processor.SubscribeReusable<JoinPacket, NetPeer>(OnJoinReceived);
        processor.SubscribeReusable<PlayerCommandPacket, NetPeer>(OnCommandReceived);
        
        listener = new EventBasedNetListener(); // ← Initialize the listener!
        
        
        server = new NetManager(listener){
            AutoRecycle = true
        };

        Console.WriteLine($"Starting server on {port}");
        
        listener.ConnectionRequestEvent += request => {
            Console.WriteLine($"Connection Request from {request.RemoteEndPoint}");
            if (Players.Count >= 2){
                Console.WriteLine($"{request.RemoteEndPoint} denied, server full");
                return;
            }
            request.Accept();
        };

        listener.NetworkReceiveEvent += (peer, reader, channel, method) => {
            OnNetworkReceive(peer, reader, method);
        };

        listener.PeerDisconnectedEvent += OnPeerDisconnected;
        
        server.Start(port);
        
        Run();
    }
    
    public static void SendPacket<T>(T packet, NetPeer peer, DeliveryMethod deliveryMethod = DeliveryMethod.ReliableOrdered) where T : class, new() {
        if (peer != null) {
            writer.Reset();
            processor.Write(writer, packet);
            peer.Send(writer, deliveryMethod);
        }
    }
    public static void SendPacket<T>(T packet, int pid, DeliveryMethod deliveryMethod = DeliveryMethod.ReliableOrdered) where T : class, new() {
        SendPacket(packet, Players[pid].Peer, deliveryMethod);
    }
    public static void SendPacketToAll<T>(T packet, DeliveryMethod deliveryMethod = DeliveryMethod.ReliableOrdered) where T : class, new() {
        foreach (var player in Players.Values){
            SendPacket(packet, player.Peer, deliveryMethod);
        }
    }

    public static void SendUpdate(GameEvent[] gevents, int pid) {
        SendPacket(new UpdatePlayerPacket{Events = gevents}, pid);

    }

    public static void SendUpdateToAll(GameEvent[] gevents) {
        SendPacketToAll(new UpdatePlayerPacket{Events = gevents});

    }

    public static void OnJoinReceived(JoinPacket packet, NetPeer peer) {
        Console.WriteLine($"Received join from {packet.Username} (pid: {(uint)peer.Id})");

        ServerPlayer newPlayer = (Players[peer.Id] = new ServerPlayer {
            Peer = peer,
            State = new PlayerState(peer.Id, GameLogic.START_CAMERA, [false, false, false],
                Power.MAX_POWER_VALUE, false),
            Username = packet.Username
        });
        
        
        if (Players.Count == 1){
            newPlayer.State.OfficeTileId = 10;
            newPlayer.State.NeighbouringTiles = [5, 11, 15];
            SendPacket(new JoinAcceptPacket { State = newPlayer.State }, peer);
            P1 = newPlayer;
        }
        else{
            newPlayer.State.OfficeTileId = 14;
            newPlayer.State.NeighbouringTiles = [19, 13, 9];

            SendPacket(new JoinAcceptPacket { State = newPlayer.State }, peer);
            P2 = newPlayer;

            SendPacket(new OpponentInitPacket{State = newPlayer.State, Username = newPlayer.Username}, P1.Peer);
            SendPacket(new OpponentInitPacket{State = P1.State, Username = P1.Username}, P2.Peer);
            GameLogic.Init();
        }
        
    }
    
    public static void OnNetworkReceive(NetPeer peer, NetPacketReader reader, DeliveryMethod deliveryMethod) {
        processor.ReadAllPackets(reader, peer);
    }

    public static void OnPeerDisconnected(NetPeer peer, DisconnectInfo disconnectInfo) {
        if (Players.Count == 2){
            GameLogic.DeclareWinner(OtherPlayer(Players.Values.First(p => Equals(p.Peer, peer))));
        }
        
        Players.Remove(peer.Id);
        if (Players.Count == 0){
            Stop();
        }
    }

    public static void OnCommandReceived(PlayerCommandPacket packet, NetPeer peer) {
        CommandProcessor.Evaluate(packet.Commands, peer.Id);
    }
    
    public static void Update() {
        server.PollEvents();
        GameLogic.Update();
    }
    
    // AI generated
    public static void Run(CancellationToken cancellationToken = default)
    {
        isRunning = true;
        var stopwatch = Stopwatch.StartNew();
        long previousTicks = 0;
        
        while (isRunning && !cancellationToken.IsCancellationRequested)
        {
            long currentTicks = stopwatch.ElapsedMilliseconds;
            long elapsed = currentTicks - previousTicks;
            
            if (elapsed >= TARGET_TICK_TIME_MS)
            {
                Update();
                
                previousTicks = currentTicks;
                if (elapsed > TARGET_TICK_TIME_MS * 2)
                {
                    Console.WriteLine($"Warning: Tick took {elapsed}ms (target: {TARGET_TICK_TIME_MS}ms)");
                }
            }
            else
            {
                
                int sleepTime = (int)(TARGET_TICK_TIME_MS - elapsed - 2);
                if (sleepTime > 0)
                {
                    Thread.Sleep(sleepTime);
                }

                while (stopwatch.ElapsedMilliseconds - previousTicks < TARGET_TICK_TIME_MS){
                    Thread.SpinWait(1);
                }
            }
        }
    }
    
    public static void Stop()
    {
        isRunning = false;
        server.Stop();
    }
}