using UnityEngine;
using System.Collections.Generic;
using System.Net;
using System.Threading;
using System;
using NeonTea.Quakeball.TeaNet.Packets;

namespace NeonTea.Quakeball.TeaNet.Peers {
    public class ConnectionManager {
        private ulong ConnectionCounter;
        private Dictionary<ulong, Connection> Connections = new Dictionary<ulong, Connection>();
        private Dictionary<IPEndPoint, ulong> IPtoID = new Dictionary<IPEndPoint, ulong>();
        private Dictionary<ulong, List<Packet>> PacketQueue = new Dictionary<ulong, List<Packet>>();
        private Peer Peer;

        private Thread UpdateThread;

        public long Timeout = 8000;
        public long Interval = 100;

        public ConnectionManager(Peer peer) {
            Peer = peer;
            UpdateThread = new Thread(new ThreadStart(UpdateThreadMethod));
            UpdateThread.Start();
        }

        public void StopThread() {
            UpdateThread.Abort();
        }

        public Connection Find(IPEndPoint endpoint) {
            if (IPtoID.ContainsKey(endpoint)) {
                return Connections[IPtoID[endpoint]];
            }
            Connection conn = new Connection(endpoint, ConnectionStatus.Awaiting);
            AddConnection(conn);
            return conn;
        }

        public bool StartConnection(IPEndPoint endpoint, byte protocolIdent) {
            if (IPtoID.ContainsKey(endpoint)) {
                return false;
            }
            Connection conn = new Connection(endpoint);
            conn.Internal.AssignedProtocol = protocolIdent;
            AddConnection(conn);
            return true;
        }

        public Connection GetConnection(ulong uid) {
            Connection conn;
            Connections.TryGetValue(uid, out conn);
            return conn;
        }

        public void AddPacketToQueue(ulong uid, Packet p) {
            if (!Connections.ContainsKey(uid)) {
                return;
            }
            p = p.ShallowCopy();
            p.Id = Connections[uid].Internal.ReliablePacketIDCounter++;
            PacketQueue[uid].Add(p);
        }

        public void SendPacketQueue(ulong uid) {
            if (!Connections.ContainsKey(uid)) {
                return;
            }
            Connection conn = Connections[uid];
            Protocol protocol = Peer.GetProtocol(conn.Internal.AssignedProtocol);
            if (protocol != null && conn.IsReady()) {
                ByteBuffer buffer = protocol.BuildMessage(conn);
                List<Packet> list = PacketQueue[uid];
                buffer.Write(list.Count);
                foreach (Packet p in list) {
                    buffer.WritePacket(protocol, p);
                }
                Send(conn, buffer);
            }
        }

        public void SendSingleUnreliable(ulong uid, Packet p) {
            if (!Connections.ContainsKey(uid)) {
                return;
            }
            Connection conn = Connections[uid];
            p.Id = conn.Internal.UnreliablePacketIDCounter++;
            p.Reliable = false;
            Protocol protocol = Peer.GetProtocol(conn.Internal.AssignedProtocol);
            if (protocol != null && conn.IsReady()) {
                ByteBuffer buffer = protocol.BuildMessage(conn);
                buffer.Write(1);
                buffer.WritePacket(protocol, p);
                Send(conn, buffer);
            }
        }

        private void AddConnection(Connection conn) {
            conn.uid = ConnectionCounter++;
            Connections.Add(conn.uid, conn);
            IPtoID.Add(conn.Endpoint, conn.uid);
            PacketQueue.Add(conn.uid, new List<Packet>());
        }

        private void RemoveConnection(Connection conn) {
            Connections.Remove(conn.uid);
            IPtoID.Remove(conn.Endpoint);
            PacketQueue.Remove(conn.uid);
        }

        private void SendPlain(Connection conn) {
            Protocol protocol = Peer.GetProtocol(conn.Internal.AssignedProtocol);
            if (protocol != null) {
                ByteBuffer buffer = protocol.BuildMessage(conn);
                Send(conn, buffer);
            }
        }

        private void Send(Connection conn, ByteBuffer buffer) {
            if (conn.Status == ConnectionStatus.Lost) {
                return;
            }
            byte[] bytes = buffer.Pack();
            Peer.ListenerThread.LastSentConnection = conn;
            Peer.UdpClient.Send(bytes, bytes.Length, conn.Endpoint);
        }

        public void Handle(IPEndPoint endpoint, ByteBuffer buffer) {
            Connection conn = Find(endpoint);
            conn.Internal.LastMessage = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
            ConnectionStatus oldStatus = conn.Status;
            byte protocolId = buffer.Read();
            Protocol protocol = Peer.GetProtocol(protocolId);
            PacketStage stage = buffer.ReadStage();
            switch (stage) {
                case PacketStage.Establishing:
                    if (conn.Status == ConnectionStatus.Awaiting) {
                        conn.Internal.AssignedProtocol = protocolId;
                        string version = buffer.ReadString();
                        if (protocol == null || !version.Equals(protocol.Version)) {
                            conn.Status = ConnectionStatus.Rejected;
                            conn.ClosingReason = ClosingReason.IncorrectVersion;
                        } else {
                            conn.Status = ConnectionStatus.Ready;
                        }
                        if (protocol != null) {
                            protocol.ConnectionStatusChanged(oldStatus, conn.Status, conn);
                        }
                    }
                    break;
                case PacketStage.Rejected:
                    conn.Status = ConnectionStatus.Closed;
                    conn.ClosingReason = buffer.ReadClosingReason();
                    if (protocol != null) {
                        protocol.ConnectionStatusChanged(oldStatus, conn.Status, conn);
                    }
                    break;
                case PacketStage.Closed:
                    if (conn.Status == ConnectionStatus.Stopped) {
                        break;
                    }
                    conn.Status = ConnectionStatus.Stopped;
                    if (protocol != null) {
                        protocol.ConnectionStatusChanged(oldStatus, conn.Status, conn);
                    }
                    break;
                case PacketStage.Ready:
                    if (conn.Internal.AssignedProtocol != protocolId || protocol == null) {
                        break;
                    }
                    if (oldStatus == ConnectionStatus.Establishing) { // Update connection status
                        conn.Status = ConnectionStatus.Ready;
                        protocol.ConnectionStatusChanged(oldStatus, conn.Status, conn);
                    }
                    conn.Internal.LatestOutwardReliable = buffer.ReadInt();

                    List<Packet> list = PacketQueue[conn.uid];
                    list.RemoveAll(p => p.Id <= conn.Internal.LatestOutwardReliable);
                    PacketQueue[conn.uid] = list;

                    int PacketAmount = buffer.ReadInt();
                    for (int i = 0; i < PacketAmount; i++) {
                        Packet p = buffer.ReadPacket(protocol);
                        if (p.Reliable) {
                            if (p.Id > conn.Internal.LatestInwardReliable) {
                                conn.Internal.LatestInwardReliable = p.Id;
                                protocol.Receive(conn, p);
                            }
                        } else if (p.Id > conn.Internal.LatestInwardUnreliable) {
                            conn.Internal.LatestInwardUnreliable = p.Id;
                            protocol.Receive(conn, p);
                        }
                    }
                    break;
            }
        }

        private void UpdateThreadMethod() {
            try {
                while (Thread.CurrentThread.IsAlive) {
                    long now = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
                    List<ulong> timedOut = new List<ulong>();
                    foreach (ulong uid in Connections.Keys) {
                        Connection conn = Connections[uid];
                        if ((now - conn.Internal.LastMessage) > Timeout || conn.Status == ConnectionStatus.Lost) {
                            timedOut.Add(uid);
                        }
                        if (conn.Status != ConnectionStatus.Awaiting || conn.Status != ConnectionStatus.Stopped) {
                            if (conn.Status == ConnectionStatus.Ready) {
                                SendPacketQueue(uid);
                            } else {
                                SendPlain(conn);
                            }
                        }
                    }
                    foreach (ulong uid in timedOut) {
                        Connection conn = Connections[uid];
                        RemoveConnection(conn);
                        if (conn.Status == ConnectionStatus.Ready
                            || conn.Status == ConnectionStatus.Establishing
                            || conn.Status == ConnectionStatus.Awaiting
                            || conn.Status == ConnectionStatus.Lost) {
                            Protocol protocol = Peer.GetProtocol(conn.Internal.AssignedProtocol);
                            if (protocol != null) {
                                protocol.Timeout(conn);
                            }
                        }
                    }
                    Thread.Sleep((int)Interval);
                }
            } catch (ThreadAbortException) {
                Peer.MessageListener.Message("Connection Thread Stopped");
            }
        }
    }
}