using System;
using System.Diagnostics;
using System.Net;
using System.Net.Sockets;
using System.Text.RegularExpressions;

namespace LJLib.IP
{
    public static class IPUtils
    {
        [Obsolete("建议改用方法GetURLIPv4")]
        public static string GetURLIP(string URL)
        {
            string ip = string.Empty;
            try
            {
                IPHostEntry ipHost = Dns.GetHostEntry(URL);
                bool haveip = false;
                for (int i = 0; i < ipHost.AddressList.Length; i++)
                {
                    if (!haveip)
                    {
                        var tip = ipHost.AddressList[i].ToString();
                        if (tip != "::1")
                        {
                            ip = tip;
                            haveip = true;
                        }
                    }
                }
            }
            catch (System.Exception ex)
            {
                Debug.Write(string.Format("获取龙嘉网失败,URL:[{0}],{1}.", URL, ex.ToString()));
                ip = "获取龙嘉网失败:" + URL;
            }
            return ip;
        }

        /// <summary>
        /// 返回URL的IPv4的地址
        /// </summary>
        /// <param name="URL">URL地址</param>
        /// <returns>IPv4</returns>
        public static IPAddress GetURLIPv4(string URL)
        {
            IPAddress ip = null;
            if (IsIPv4Address(URL))
            {
                return IPAddress.Parse(URL);
            }
            try
            {
                var ipHost = Dns.GetHostEntry(URL);
                foreach (var ipAddress in ipHost.AddressList)
                {
                    if (ipAddress.AddressFamily == AddressFamily.InterNetwork)
                    {
                        if (!IPAddress.IsLoopback(ipAddress))
                        {
                            return ipAddress;
                        }

                        ip = ipAddress;
                    }
                }
            }
            catch (Exception ex)
            {
                Debug.Write(string.Format("获取龙嘉网失败,URL:[{0}],{1}.", URL, ex.ToString()));
            }
            return ip;
        }

        public static IPEndPoint GetIPEndPoint(string ipPortStr)
        {
            int index = ipPortStr.IndexOf(":");
            if (index < 0)
            {
                throw new Exception(string.Format("ip:port不合法,{0}", ipPortStr));
            }
            var ipStr = ipPortStr.Substring(0, index);
            var portStr = ipPortStr.Substring(index + 1);
            try
            {
                var address = IPAddress.Parse(ipStr);
                var port = int.Parse(portStr);
                return new IPEndPoint(address, port);
            }
            catch (Exception ex)
            {
                throw new Exception(string.Format("ip:port不合法,{0},异常:{1}", ipPortStr, ex));
            }
        }

        private static Regex r = null;

        public static bool IsIPv4Address(string ip)
        {
            if (r == null)
            {
                r = new Regex(@"^(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])$");
            }
            return r.IsMatch(ip);
        }

        /// <summary>
        /// 判断TcpClient是否在连接
        /// </summary>
        public static bool IsConnecting(TcpClient tcpclient)
        {
            try
            {
                if (!tcpclient.Connected)
                {
                    return false;
                }

                var ifSelectRead = tcpclient.Client.Poll(1000, SelectMode.SelectRead);
                if (!ifSelectRead) // 网络在连接无数据可读
                {
                    return true;
                }

                var ns = tcpclient.GetStream();
                return ns.CanRead && ns.DataAvailable;
            }
            catch (Exception ex)
            {
                if (!(ex is ObjectDisposedException) && !(ex is InvalidOperationException))
                {
                    Trace.Write(ex.ToString());
                }
                return false;
            }
        }
    }
}