/*
 Sog 游戏基础库
 2016 by zouwei
 */


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

using Google.Protobuf.WellKnownTypes;
using Google.Protobuf;

namespace Sog
{
    
    public class ProtoBufPacker : IProtoPacker
    {
        // todo 效率不高，换成数组
        private Dictionary<int, MessageParser> m_typeMessageParser = new Dictionary<int, MessageParser>();

        public ProtoBufPacker()
        {

        }

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

        public int GetFullHeaderLength()
        {
            return 16;
        }

        //打包头
        public int PackHeader(MessageHeader header, byte[] headerBytes)
        {
            //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 | 0x8000;

                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;

            header.ServerID = BitConverter.ToUInt32(data, offset + 4);

            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 RequestPacket packet)
        {
            try
            {	
                MessageParser parser;
                m_typeMessageParser.TryGetValue(message.Header.Type,out parser);
                IMessage pbmessage = null;
	           
				packet = new RequestPacket(message.Header.Type, message.Header.ObjectID, message.Header.ServerID);

				//现在工具用的还是class不是struct,之后看看要不要移动
				//主要是message.Buffer.Data现在有缓存了,必须把message.Buffer.Length的正确长度传入
				if (parser != null)
                {
                    pbmessage = parser.ParseFrom(message.Buffer.Data, message.Buffer.Length);
                }
                else
                {
                    TraceLog.Error("protobuf decode package type {0} error, can not find MessageParser,please register it first!"
                        , message.Header.Type);

                    return false;
                }

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

        public virtual bool PackMessage(RequestPacket packet, ref MessageData message)
        {
            try
            {
                //这个基本不用了，这里不cache了
                message.Buffer.Data = MessageExtensions.ToByteArray((IMessage)packet.Message);
                message.Buffer.Length = message.Buffer.Data.Length;
                message.Header.Length = message.Buffer.Data.Length;
                message.Header.Type = packet.MsgID;


                //校验一下消息id，需要注册，不注册返回失败
                //校验类型是否匹配
                //影响效率
                if (TraceLog.GetLogLevel() <= Log.LogLevel.Trace)
                {
                    if (OSUtils.IsWindows())
                    {
                        MessageParser parser;
                        m_typeMessageParser.TryGetValue(packet.MsgID, out parser);
                        if (parser == null)
                        {
                            TraceLog.Error("protobuf encode package type {0} error, can not find MessageParser,please register it first!"
                                , packet.MsgID);
                            return false;
                        }

                        //windows下校验一下message是否会出问题

                        IMessage pbCheckMessage = parser.ParseFrom(message.Buffer.Data);
                        if (pbCheckMessage.GetType() != packet.Message.GetType())
                        {
                            TraceLog.Error("protobuf encode package type {0} error, Message type {1} != registed Message type {2}"
                                , packet.MsgID, packet.Message.GetType().Name, pbCheckMessage.GetType().Name);
                            return false;
                        }
                    }
                }

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

            return false;
        }


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

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

                return;
            }

            m_typeMessageParser.Add(iMsgID, parser);

        }
    }


}