/*
 Sog 游戏基础库
 2016 by zouwei
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Sog.Gate
{
    

    public enum GateMsgOpCode
    {
        None = 0,

        // trans msg to one session in connected stat
        Trans = 1,

        // trans msg to some session
        TransMulti = 2,

        // client connected
        ConnectedReq = 3,
        ConnectedRes = 4,

        DisconnectedReq = 5,
        DisconnectedRes = 6,

        //route packet to other logic server
        Route = 7,

        //notify gate client count to logic server
        ClientCount = 8,
        
    }

    public static class GateMsgDefine
    {
        public const int TransMultiSessionCountMax = 1000;
    }

    public struct GateMsgHeader
    {
        public byte OpCode;
        public long SessionID;
    }

    public struct GateMsgMultiSessionHeader
    {
        public int Count;
        unsafe public fixed long SessionIDs[GateMsgDefine.TransMultiSessionCountMax];

        public int GetLength()
        {
            return 8*Count + 4;
        }
    }



    public static class GateMsgHeaderPacker
    {
        public static int GetLength()
        {
            return 9;
        }

        public static byte[] Pack(ref GateMsgHeader header)
        {
            byte[] packetBytes = new byte[GetLength()];

            packetBytes[0] = header.OpCode;
            Span<byte> pbuffer = new Span<byte>(packetBytes,1,8);
            BitConverter.TryWriteBytes(pbuffer,header.SessionID);

            return packetBytes;
        }

        public static void Pack(ref GateMsgHeader header, byte[] packetBytes)
        {
            packetBytes[0] = header.OpCode;
            Span<byte> pbuffer = new Span<byte>(packetBytes, 1, 8);
            BitConverter.TryWriteBytes(pbuffer, header.SessionID);

            return;
        }

        public static byte[] Pack(ref GateMsgHeader header, ref GateMsgMultiSessionHeader multiSession)
        {
            byte[] packetBytes = new byte[GetLength() + multiSession.GetLength()];

            packetBytes[0] = header.OpCode;
            Span<byte> pbuffer = new Span<byte>(packetBytes, 1, 8);
            BitConverter.TryWriteBytes(pbuffer, header.SessionID);

            pbuffer = new Span<byte>(packetBytes, 9, 4);
            BitConverter.TryWriteBytes(pbuffer, multiSession.Count);
            int pos = 13;

            unsafe{
                fixed (long* psession = multiSession.SessionIDs) {
                    for (int i = 0; i < multiSession.Count; i++) {
                        pbuffer = new Span<byte>(packetBytes, pos, 8);
                        pos += 8;
                        BitConverter.TryWriteBytes(pbuffer, psession[i]);
                    }
                }
            }
            return packetBytes;
        }
        
        public static void UnPack(byte[] data, ref GateMsgHeader header)
        {
            header.OpCode = data[0];
            header.SessionID = BitConverter.ToInt64(data,1);

            return;
        }

        public static void RawSetGateMsgHeadOpCode(byte[] data, GateMsgOpCode opCode)
        {
            data[0] = (byte)opCode;
        }

        public static void UnPackMultiSessionHeader(byte[] data, ref GateMsgMultiSessionHeader header)
        {
            int pos = GetLength();
            header.Count = BitConverter.ToInt32(data,pos);
            pos += 4;
            unsafe
            {
                fixed (long* psession = header.SessionIDs)
                {
                    for (int i = 0; i < header.Count; i++)
                    {
                        psession[i] = BitConverter.ToInt64(data, pos);
                        pos += 8;
                    }
                }
            }

            return ;
        }
    }

    public class GateClientConnectedReq
    {
        public string IPAddress;

        public byte[] Pack()
        {
            byte[] ipBytes = System.Text.Encoding.UTF8.GetBytes(IPAddress);
            byte[] packetBytes = new byte[ipBytes.Length + 1];

            packetBytes[0] = (byte)ipBytes.Length;
            Buffer.BlockCopy(ipBytes, 0, packetBytes, 1, ipBytes.Length);

            return packetBytes;
        }

        public static GateClientConnectedReq ParseFrom(byte[] data, int offset)
        {
            byte iplength = data[offset];

            string ipstr = System.Text.Encoding.UTF8.GetString(data, offset + 1, iplength);

            GateClientConnectedReq req = new GateClientConnectedReq();
            req.IPAddress = ipstr;

            return req;
        }
    }
}