using System;
using System.Text;

namespace Curtain.Net.Sockets.PLC.Model
{
    /// <summary>
    /// 基本Socket服务模型
    /// </summary>
    public class SimpleSocketServerModel : ServerModel
    {
        /// <summary>
        /// 响应报文-头长度
        /// </summary>
        public override int HeadLength
        {
            get
            {
                return (FormatType == CommandFormatType.PLCCommand ? 4 : 1);
            }
        }

        /// <summary>
        /// 根据响应报文-头，计算响应报文-文本长度
        /// </summary>
        /// <param name="rs">报文</param>
        /// <returns>响应报文-文本长度</returns>
        public override int GetContentLength(ReceiveSession rs)
        {
            try
            {
                return Convert.ToInt32(Encoding.ASCII.GetString(rs.HeadBytes, 2, 2), 16);
            }
            catch
            {
                return -1;
            }
        }

        /// <summary>
        /// 验证响应报文-头
        /// </summary>
        /// <param name="rs">报文</param>
        /// <returns>是否通过</returns>
        public override bool CheckHead(ReceiveSession rs)
        {
            if (rs == null || rs.HeadBytes == null || rs.HeadBytes.Length != HeadLength)
            {
                return false;
            }

            if (FormatType == CommandFormatType.StartStopChar)
            {
                return CheckHeadChar(rs.HeadBytes);
            }

            rs.Command = ToCommandFromReceive(rs.HeadBytes);
            rs.Head = ToHeadFromReceive(rs.HeadBytes);

            return true;
        }

        /// <summary>
        /// 接收字节转换为命令
        /// </summary>
        /// <param name="receive">接收字节</param>
        /// <returns>响应报文</returns>
        public override string ToCommandFromReceive(byte[] receive)
        {
            if (receive == null || receive.Length == 0)
            {
                return null;
            }
            return Encoding.ASCII.GetString(receive, 0, 2);
        }

        /// <summary>
        /// 接收字节转换为报文头
        /// </summary>
        /// <param name="receive">接收字节</param>
        /// <returns>响应报文</returns>
        public override string ToHeadFromReceive(byte[] receive)
        {
            if (receive == null || receive.Length == 0)
            {
                return null;
            }
            //return Encoding.ASCII.GetString(receive, 0, HeadLength);
            return Encoding.ASCII.GetString(receive);
        }

        /// <summary>
        /// 接收字节转换为报文正文
        /// </summary>
        /// <param name="receive">接收字节</param>
        /// <returns>响应报文</returns>
        public override string ToContentFromReceive(byte[] receive)
        {
            if (receive == null || receive.Length == 0)
            {
                return null;
            }
            return Encoding.ASCII.GetString(receive);
        }

        /// <summary>
        /// 命令报文转换为发送字节
        /// </summary>
        /// <param name="command">命令报文</param>
        /// <returns>发送字节</returns>
        public override byte[] ToSendFromCommand(string command)
        {
            if (string.IsNullOrEmpty(command))
            {
                return null;
            }
            return Encoding.ASCII.GetBytes(command);
        }
    }
}