using System;
using XGame.Framework.Json;
using XGame.Framework.Network.Protobuf;

namespace XGame.Framework.Network
{
    /// <summary>
    /// Json实现，等服务器能用字节流了再更换实现
    /// 用json反序列化的消息不用存储，用完直接丢弃
    /// </summary>
    internal class JsonSerializer : ISerializer, IDisposable
    {
        private readonly CodedOutputStream _codedOutput = new CodedOutputStream();
        private readonly CodedInputStream _codedInput = new CodedInputStream();
        private IMsgGenerator _generator;
        public JsonSerializer(IMsgGenerator generator) 
        {
            _generator = generator;
        }

        void ISerializer.Write(IMessage msg, out byte[] bytes, out int offset, out int size)
        {
            bytes = SessionBufferPool.Acquire();
            offset = NetDefine.HEAD_LENGTH_REQUEST;
            _codedOutput.Buffer = bytes;
            _codedOutput.Reset(offset);
            try
            {
                var json = XJson.ToJson(msg);
                Log.Debug($"[Net] JsonSerializer write:{json}");
                _codedOutput.WriteString(json, false); //json消息，不写长度
                size = (int)_codedOutput.Position - offset;
            }
            catch (Exception ex)
            {
                Log.Exception($"[Net] message write exception.", ex);
                size = 0;
            }
        }
        void ISerializer.Read(byte[] bytes, int offset, int size, int protoId, out IMessage msg)
        {
            var json = string.Empty;
            try
            {
                var msgType = _generator.IdToType(protoId);
                _codedInput.Reset(bytes, offset, size);
                json = _codedInput.ReadString(size - offset); //json消息，使用外部传入的长度
                msg = XJson.ToObject(json, msgType) as IMessage;
            }
            catch (Exception ex)
            {
                Log.Exception($"[Net] message json exception: Proto:{protoId} Json:{json}.", ex);
                msg = null;
            }
        }

        void IDisposable.Dispose()
        {
            _generator = null;
        }
    }
}