using System;
using System.IO;
using NewLife.Data;
using NewLife.Log;
using NewLife.Messaging;

namespace NewLife.Remoting
{
    /// <summary>编码器</summary>
    public interface IEncoder
    {
        /// <summary>编码 请求/响应</summary>
        /// <param name="action">服务动作</param>
        /// <param name="code">错误码</param>
        /// <param name="value">参数或结果</param>
        /// <returns></returns>
        Packet Encode(String action, Int32 code, Object value);

        ///// <summary>解码 请求/响应</summary>
        ///// <param name="msg">消息</param>
        ///// <param name="action">服务动作</param>
        ///// <param name="code">错误码</param>
        ///// <param name="value">参数或结果</param>
        ///// <returns></returns>
        //Boolean Decode(IMessage msg, out String action, out Int32 code, out Object value);

        /// <summary>解码</summary>
        /// <param name="action"></param>
        /// <param name="data"></param>
        /// <returns></returns>
        Object Decode(String action, Packet data);

        /// <summary>转换为对象</summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="obj"></param>
        /// <returns></returns>
        T Convert<T>(Object obj);

        /// <summary>转换为目标类型</summary>
        /// <param name="obj"></param>
        /// <param name="targetType"></param>
        /// <returns></returns>
        Object Convert(Object obj, Type targetType);

        /// <summary>日志提供者</summary>
        ILog Log { get; set; }
    }

    /// <summary>编码器基类</summary>
    public abstract class EncoderBase
    {
        #region 方法
        ///// <summary>编码 请求/响应</summary>
        ///// <param name="action"></param>
        ///// <param name="code"></param>
        ///// <param name="value"></param>
        ///// <returns></returns>
        //public Packet Encode(String action, Int32 code, Object value)
        //{
        //    var ms = new MemoryStream();
        //    ms.Seek(8, SeekOrigin.Begin);

        //    // 请求：action + args
        //    // 响应：code + action + result
        //    var writer = new BinaryWriter(ms);
        //    if (code != 0) writer.Write(code);
        //    writer.Write(action);

        //    // 参数或结果
        //    var len = 0;
        //    Packet pk2 = null;
        //    if (code != 0 || value != null)
        //    {
        //        // 二进制优先
        //        if (value is Packet pk3)
        //            pk2 = pk3;
        //        else
        //            pk2 = OnEncode(action, code, value);
        //        // 写入长度
        //        len = pk2.Total;
        //    }

        //    if (len == 0) WriteLog("{0}=>", action);

        //    // 不管有没有附加数据，都会写入长度
        //    ms.WriteEncodedInt(len);

        //    var pk = new Packet(ms.GetBuffer(), 8, (Int32)ms.Length - 8);
        //    if (pk2 != null) pk.Next = pk2;

        //    return pk;
        //}

        ///// <summary>编码</summary>
        ///// <param name="action">服务动作</param>
        ///// <param name="code">错误码</param>
        ///// <param name="value">参数或结果</param>
        ///// <returns></returns>
        //protected abstract Packet OnEncode(String action, Int32 code, Object value);

        ///// <summary>解码 请求/响应</summary>
        ///// <param name="msg">消息</param>
        ///// <param name="action">服务动作</param>
        ///// <param name="code">错误码</param>
        ///// <param name="value">参数或结果</param>
        ///// <returns></returns>
        //public Boolean Decode(IMessage msg, out String action, out Int32 code, out Object value)
        //{
        //    action = null;
        //    code = 0;
        //    value = null;

        //    // 请求：action + args
        //    // 响应：code + action + result
        //    var ms = msg.Payload.GetStream();
        //    var reader = new BinaryReader(ms);
        //    if (msg.Reply) code = reader.ReadInt32();
        //    action = reader.ReadString();
        //    if (action.IsNullOrEmpty()) return false;

        //    // 参数或结果
        //    if (ms.Length > ms.Position)
        //    {
        //        var len = ms.ReadEncodedInt();
        //        if (len > 0)
        //        {
        //            var pk = msg.Payload.Sub((Int32)ms.Position, len);
        //            //value = OnDecode(action, pk);
        //            // 这里不能识别二进制和Json
        //            value = pk;
        //        }
        //    }

        //    if (value == null) WriteLog("{0}<=", action);

        //    return true;
        //}

        ///// <summary>解码</summary>
        ///// <param name="action"></param>
        ///// <param name="data"></param>
        ///// <returns></returns>
        //protected virtual Object OnDecode(String action, Packet data) => data;
        #endregion

        #region 日志
        /// <summary>日志提供者</summary>
        public ILog Log { get; set; } = Logger.Null;

        /// <summary>写日志</summary>
        /// <param name="format"></param>
        /// <param name="args"></param>
        public virtual void WriteLog(String format, params Object[] args) => Log?.Info(format, args);
        #endregion
    }
}