/*
 Sog 游戏基础库
 2016 by zouwei
 */


using System;
using System.Net;
using System.Text;
using System.Collections.Generic;

using ProtoCSStruct;

namespace Sog
{
    
    public class ProtoCSStructPacker
    {
        private Dictionary<int, IStructMessageParser> m_typeMessageParser = new Dictionary<int, IStructMessageParser>();

        public ProtoCSStructPacker()
        {

        }

        //最小8
        public int GetHeaderLength()
        {
            return 8;
        }

        public int GetFullHeaderLength()
        {
            return 16;
        }

        //打包头
        public int PackHeader(MessageHeader header, byte[] headerBytes)
        {
            // serverId最高位置1, 表示数据压缩
            if (header.isZip && header.ServerID <= 0x00FFFFFF)
            {
                header.ServerID |= 0x80000000;
            }

            //小字节序
            if(header.ObjectID == 0)
            {
                headerBytes[0] = (byte)(header.Length % 256);
                headerBytes[1] = (byte)(header.Length / 256);

                headerBytes[2] = (byte)(header.Type % 256);
                headerBytes[3] = (byte)(header.Type / 256);

                Span<byte> pbServerID = new Span<byte>(headerBytes, 4, 4);
                BitConverter.TryWriteBytes(pbServerID, header.ServerID);

                return 8;
            }
            else
            {
                headerBytes[0] = (byte)(header.Length % 256);
                headerBytes[1] = (byte)(header.Length / 256);

                //最高位置1
                int newType = header.Type | 0x00008000;

                headerBytes[2] = (byte)(newType % 256);
                headerBytes[3] = (byte)(newType / 256);

                Span<byte> pbServerID = new Span<byte>(headerBytes, 4, 4);
                BitConverter.TryWriteBytes(pbServerID, header.ServerID);

                Span<byte> pbObjectID = new Span<byte>(headerBytes,8,8);
                BitConverter.TryWriteBytes(pbObjectID, header.ObjectID);

                return 16;
            }


        }

        //解包头
        public int UnPackHeader(byte[] data, int offset, int length, ref MessageHeader header)
        {
            int byte0 = data[offset + 0];
            int byte1 = data[offset + 1];
            int byte2 = data[offset + 2];
            int byte3 = data[offset + 3];

            header.Length = byte1 * 256 + byte0;
            header.Type = byte3 * 256 + byte2;

            uint serverId = BitConverter.ToUInt32(data, offset + 4);
            if ((serverId & 0x80000000) > 0)
            {
                // 去掉首字节最高位
                serverId &= 0x7FFFFFFF;
                header.isZip = true;
            }

            header.ServerID = serverId;

            bool haveObjectID = (header.Type & 0x00008000) > 0;
            if (!haveObjectID)
            {
                return 8;
            }

            //头有16字节
            if (length < 16)
            {
                return 0;
            }

            //去掉最高位
            header.Type &= 0x00007fff;
            header.ObjectID = BitConverter.ToInt64(data, offset + 8);

            return 16;
        }

        public virtual bool UnpackMessage(MessageData message, out StructPacket packet)
        {
            try
            {
                IStructMessageParser parser;
                m_typeMessageParser.TryGetValue(message.Header.Type,out parser);

                packet = new StructPacket();
                packet.Header = message.Header;

                if (parser != null)
                {
                    parser.ParseFrom(message.Buffer.Data, message.Buffer.Length);
                }
                else
                {
                    TraceLog.Error("protocsstruct decode package type {0} error, can not find StructMessageParser,please register it first!"
                        , message.Header.Type);

                    return false;
                }

                packet.Parser = parser;
                //packet.MsgID = message.Header.Type;
                return true;
            }
            catch(Exception error)
            {
                TraceLog.Error("protocsstruct decode package type {0} error, {1}", message.Header.Type, error.Message);
                packet = null;
                throw;
            }
          
            return false;
        }

        public bool PackMessage<T>(ref T structMessage, ref MessageData message) where T : struct, IStructMessage<T>
        {
            try
            {
                int size = structMessage.CalculateSize();
                message.MallocData(size);
                CodedOutputStream ouput = new CodedOutputStream(message.Buffer.Data);

                structMessage.WriteTo(ouput);

                
                message.Header.Length = size;

                return true;
            }
            catch (Exception error)
            {
                TraceLog.Error("protocsstruct encode package type {0} error, {1}", message.Header.Type, error.Message);
                throw;
            }

            return false;
        }


        //需要注册，提高效率
        public void RegisterProtoType(int iMsgID, object obj)
        {
            IStructMessageParser parser = (IStructMessageParser)obj;
            if(m_typeMessageParser.ContainsKey(iMsgID))
            {
                IStructMessageParser oldparser = m_typeMessageParser[iMsgID];

                TraceLog.Error("protocsstruct RegisterProtoType msgId {0} duplicate,registed name {1} new name {2}"
                    , iMsgID, oldparser.GetMessageName(), parser.GetMessageName());
                

                return;
            }

            m_typeMessageParser.Add(iMsgID, parser);

            TraceLog.Trace("protocsstruct RegisterProtoType msgId {0} ,register name {1} StructSizeof {2}"
                , iMsgID, parser.GetMessageName(), parser.GetStructSizeof());

        }
    }


}