using NewLife.Data;
using NewLife.Messaging;
using NewLife.Model;

namespace NewLife.Net.Handlers;

/// <summary>标准网络封包。头部4字节定长</summary>
public class StandardCodec : MessageCodec<IMessage>
{
    private Int32 _gid;

    /// <summary>写入数据</summary>
    /// <param name="context"></param>
    /// <param name="message"></param>
    /// <returns></returns>
    public override Object Write(IHandlerContext context, Object message)
    {
        if (UserPacket && message is Packet pk)
            message = new DefaultMessage { Payload = pk, Sequence = (Byte)Interlocked.Increment(ref _gid) };
        else if (message is DefaultMessage msg && !msg.Reply && msg.Sequence == 0)
            msg.Sequence = (Byte)Interlocked.Increment(ref _gid);

        return base.Write(context, message);
    }

    /// <summary>加入队列</summary>
    /// <param name="context"></param>
    /// <param name="msg"></param>
    /// <returns></returns>
    protected override void AddToQueue(IHandlerContext context, IMessage msg)
    {
        if (!msg.Reply) base.AddToQueue(context, msg);
    }

    /// <summary>解码</summary>
    /// <param name="context"></param>
    /// <param name="pk"></param>
    /// <returns></returns>
    protected override IList<IMessage> Decode(IHandlerContext context, Packet pk)
    {
        var ss = context.Owner as IExtend;
        if (ss["Codec"] is not PacketCodec pc)
        {
            ss["Codec"] = pc = new PacketCodec
            {
                GetLength = DefaultMessage.GetLength,
                Tracer = (context.Owner as ISocket)?.Tracer
            };
        }

        var pks = pc.Parse(pk);
        var list = pks.Select(e =>
        {
            var msg = new DefaultMessage();
            if (!msg.Read(e)) return null;

            return msg as IMessage;
        }).ToList();

        return list;
    }

    /// <summary>是否匹配响应</summary>
    /// <param name="request"></param>
    /// <param name="response"></param>
    /// <returns></returns>
    protected override Boolean IsMatch(Object request, Object response)
    {
        return request is DefaultMessage req &&
            response is DefaultMessage res &&
            req.Sequence == res.Sequence;
    }

    /// <summary>连接关闭时，清空粘包编码器</summary>
    /// <param name="context"></param>
    /// <param name="reason"></param>
    /// <returns></returns>
    public override Boolean Close(IHandlerContext context, String reason)
    {
        if (context.Owner is IExtend ss) ss["Codec"] = null;

        return base.Close(context, reason);
    }
}