using UnityEngine;
using UnityEngine.Assertions;
using Unity.Collections;
using Unity.Networking.Transport;
using KairoEngine.Core;

namespace KairoEngine.Multiplayer
{
    public class ServerBehaviour : MonoBehaviour
    {
        public ushort port = 9000;
        public int players = 4;
        public bool autoStart = true;
        public string eventStreamName = "ServerEvents";
        public bool debug = false;
        public NetworkDriver m_Driver;
        public NativeList<NetworkConnection> m_Connections;
        private bool locked = false;

        void Start ()
        {
            if(autoStart) StartServer();
        }

        public void StartServer()
        {
            if(locked) return;
            m_Driver = NetworkDriver.Create();
            var endpoint = NetworkEndPoint.AnyIpv4;
            endpoint.Port = port;
            if (m_Driver.Bind(endpoint) != 0)
            {
                if(debug) Debug.Log($"Failed to bind to port {port}");
                GenericEvents.Trigger($"{eventStreamName}_PortError", $"Failed to bind to port {port}");
            }
            else
            {
                m_Driver.Listen();
                if(debug) Debug.Log($"Server listening on port {port}");
                GenericEvents.Trigger($"{eventStreamName}_Listening", $"Server listening on port {port}");
                locked = true;
            }
            m_Connections = new NativeList<NetworkConnection>(players, Allocator.Persistent);
        }

        public void StopServer()
        {
            NetDisconnectMsg netDisconnectMsg = new NetDisconnectMsg();
            SendNetMsgToAllClients((uint)NetOpCode.Disconnect, netDisconnectMsg);
            Timer.ExecuteRealTime(500, () => {
                if(debug) Debug.Log($"Server has stopped");
                GenericEvents.Trigger($"{eventStreamName}_Stopped", $"Server has stopped");
                m_Driver.Dispose();
                m_Connections.Dispose();
                locked = false;
            });
        }

        public void SendNetMsgToClient(int id, uint code, NetMsg netMsg)
        {
            DataStreamWriter writer = new DataStreamWriter();
            m_Driver.BeginSend(m_Connections[id], out writer);
            NetMsgController.Serialize(code, netMsg, ref writer, this, id);
            m_Driver.EndSend(writer);
        }

        public void SendNetMsgToAllClients(uint code, NetMsg netMsg)
        {
            for (int i = 0; i < m_Connections.Length; i++)
            {
                Assert.IsTrue(m_Connections[i].IsCreated);
                SendNetMsgToClient(i, code, netMsg);
            }
        }

        public void OnDestroy()
        {
            if(!m_Driver.IsCreated) return;
            m_Driver.Dispose();
            m_Connections.Dispose();
        }

        void Update ()
        {
            if(!m_Driver.IsCreated) return;
            m_Driver.ScheduleUpdate().Complete();

            // CleanUpConnections
            for (int i = 0; i < m_Connections.Length; i++)
            {
                if (!m_Connections[i].IsCreated)
                {
                    m_Connections.RemoveAtSwapBack(i);
                    --i;
                }
            }
            // AcceptNewConnections
            NetworkConnection c;
            while ((c = m_Driver.Accept()) != default(NetworkConnection))
            {
                m_Connections.Add(c);
                if(debug) Debug.Log($"Accepted a connection (ID {c.InternalId})");
                GenericEvents.Trigger($"{eventStreamName}_ClientConnected", $"Accepted a connection (ID {c.InternalId})", c.InternalId);
            }

            DataStreamReader stream;
            for (int i = 0; i < m_Connections.Length; i++)
            {
                Assert.IsTrue(m_Connections[i].IsCreated);

                NetworkEvent.Type cmd;
                while ((cmd = m_Driver.PopEventForConnection(m_Connections[i], out stream)) != NetworkEvent.Type.Empty)
                {
                    if (cmd == NetworkEvent.Type.Data)
                    {
                        //if(debug) Debug.Log("Server received data from client");
                        uint code = stream.ReadByte();
                        NetMsgController.Deserialize(code, ref stream, this, i);
                    }
                    else if (cmd == NetworkEvent.Type.Disconnect)
                    {
                        if(debug) Debug.Log($"Client disconnected from server (ID {m_Connections[i].InternalId})");
                        GenericEvents.Trigger($"{eventStreamName}_ClientDisconnected", $"Client disconnected from server (ID {m_Connections[i].InternalId})");
                        m_Connections[i] = default(NetworkConnection);
                    }
                }
            }
        }
    }
}