using System;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Text;

namespace TRI_TCP_Client
{
    /// <summary>
    /// Net : 提供静态方法，对常用的网络操作进行封装
    /// </summary>
    public sealed class Net
    {
        private Net() { }

        /// <summary>
        /// 向远程主机发送数据
        /// </summary>
        /// <param name="socket">要发送数据且已经连接到远程主机的 Socket</param>
        /// <param name="buffer">待发送的数据</param>
        /// <param name="outTime">发送数据的超时时间，以秒为单位，可以精确到微秒</param>
        /// <returns>0:发送数据成功；-1:超时；-2:发送数据出现错误；-3:发送数据时出现异常</returns>
        /// <remarks >
        /// 当 outTime 指定为-1时，将一直等待直到有数据需要发送
        /// </remarks>
        public static int SendData(Socket socket, byte[] buffer, int outTime)
        {
            if (socket == null || socket.Connected == false)
            {
                throw new ArgumentException("参数socket 为null，或者未连接到远程计算机");
            }
            if (buffer == null || buffer.Length == 0)
            {
                throw new ArgumentException("参数buffer 为null ,或者长度为 0");
            }

            int flag = 0;
            try
            {
                int left = buffer.Length;
                int sndLen = 0;

                while (true)
                {
                    if ((socket.Poll(outTime * 100, SelectMode.SelectWrite) == true))
                    {                                           // 收集了足够多的传出数据后开始发送
                        sndLen = socket.Send(buffer, sndLen, left, SocketFlags.None);
                        left -= sndLen;
                        if (left == 0)
                        {                                       // 数据已经全部发送
                            flag = 0;
                            break;
                        }
                        else
                        {
                            if (sndLen > 0)
                            {                                   // 数据部分已经被发送
                                continue;
                            }
                            else
                            {                                   // 发送数据发生错误
                                flag = -2;
                                break;
                            }
                        }
                    }
                    else
                    {                                           // 超时退出
                        flag = -1;
                        break;
                    }
                }
            }
            catch (SocketException)
            {

                flag = -3;
            }
            return flag;
        }


        /// <summary>
        /// 向远程主机发送文件
        /// </summary>
        /// <param name="socket" >要发送数据且已经连接到远程主机的 socket</param>
        /// <param name="filePath">待发送的文件</param>
        /// <param name="maxBufferLength">文件发送时的缓冲区大小</param>
        /// <param name="outTime">发送缓冲区中的数据的超时时间</param>
        /// <returns>0:发送文件成功；-1:超时；-2:发送文件出现错误；-3:发送文件出现异常；-4:读取待发送文件发生错误</returns>
        /// <remarks >
        /// 当 outTime 指定为-1时，将一直等待直到有数据需要发送
        /// </remarks>
        public static int SendFile(Socket socket, string filePath, int maxBufferLength, int outTime)
        {
            if (filePath == null || maxBufferLength <= 0)
            {
                throw new ArgumentException("待发送的文件名称为空或发送缓冲区的大小设置不正确.");
            }
            int flag = 0;
            try
            {
                FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
                long fileLen = fs.Length;                       // 文件长度
                long leftLen = fileLen;                         // 未读取部分
                int readLen = 0;                                // 已读取部分
                byte[] buffer = null;

                if (fileLen <= maxBufferLength)
                { //文件可以一次读取(+1指代结束标识符)
                    buffer = new byte[fileLen + 1];
                    readLen = fs.Read(buffer, 0, (int)(fileLen + 1));
                    buffer[fileLen] = (byte)'`';
                    flag = SendData(socket, buffer, outTime);
                }
                else
                {
                    //循环读取文件,并发送
                    while (leftLen != 0)
                    {
                        if (leftLen < maxBufferLength)
                        {
                            buffer = new byte[leftLen];
                            readLen = fs.Read(buffer, 0, Convert.ToInt32(leftLen));
                        }
                        else
                        {
                            buffer = new byte[maxBufferLength];
                            readLen = fs.Read(buffer, 0, maxBufferLength);
                        }
                        if ((flag = SendData(socket, buffer, outTime)) < 0)
                        {
                            break;
                        }
                        leftLen -= readLen;
                    }
                    //在结尾带上结束标识符: "`"
                    SendData(socket, System.Text.Encoding.Default.GetBytes("`"), outTime);
                }
                fs.Flush();
                fs.Close();
            }
            catch (IOException)
            {
                //读取待发送文件发生错误
                flag = -4;
            }
            return flag;
        }

        /// <summary>
        /// 使用TCP发送文件
        /// </summary>
        /// <param name="socket"></param>
        /// <param name="path"></param>
        /// <param name="bufsize"></param>
        /// <param name="outTime"></param>
        public static string TCPSend(Socket socket, string path, int maxBufferLength, int outTime)
        {
            string res = null;
            int _flag;
            //先发送一个标记："1000"标记为传文件
            //D:\KSATProjects\2021-10-ASM\settings\SPI\Lanto_HTTP.INI
            string eqpName = System.Text.RegularExpressions.Regex.IsMatch(path, "AOI") ? "AOI" : "SPI";
            string _filename = Path.GetFileName(path);
            _flag = Net.SendData(socket, Encoding.Default.GetBytes("1000&" + eqpName + "&" + _filename), outTime);
            Console.WriteLine(_flag + " 文件发送 " + DateTime.Now.ToString("yyyy:MM:dd HH:mm:ss:ff"));
            try
            {
                if (Net.SendFile(socket, path, maxBufferLength, outTime) != 0)
                {
                    if (Net.SendFile(socket, path, maxBufferLength, outTime) != 0)
                    {
                        res = "发送失败";
                    }
                    else
                    {
                        res = "重发成功";
                    }
                }
                else
                {
                    res = "发送成功";
                }
            }
            catch (Exception ex)
            {
                res ="[ERR]" + ex.Message.ToString();
            }
            return res;
        }
    }
}