using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;

namespace Sog
{
    public static class NetUtils
    {
        public static string GetHostIp()
        {
            string hostname = Dns.GetHostName(); //得到本机名
            IPHostEntry localhost = Dns.GetHostEntryAsync(hostname).Result;

            foreach (IPAddress localaddr in localhost.AddressList)
            {
                if (IPAddress.IsLoopback(localaddr))
                    continue;

                // 返回第一个IPv4地址
                if (localaddr.AddressFamily == AddressFamily.InterNetwork)
                {
                    return localaddr.ToString();
                }
            }

            return null;
        }

        /// <summary>
        /// 判断ip是否本机本地地址,ipv4
        /// </summary>
        /// <returns></returns>
        public static bool IsThisMachineAddress(string address)
        {
            try
            {
                if(address == "127.0.0.1" || address == "localhost")
                {
                    return true;
                }

                //System.Net.NetworkInformation.IPAddressCollection
                //Console.WriteLine("NetUtils.IsThisMachineLocalIp ipaddress {0}", ipaddress);

                string hostname = Dns.GetHostName();//得到本机名
                if(hostname == address)
                {
                    return true;
                }

                bool ismatching = false;
                

                IPHostEntry localhost = Dns.GetHostEntryAsync(hostname).Result;

                foreach (IPAddress localaddr in localhost.AddressList)
                {
                    if (localaddr.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
                        continue;
                    if (IPAddress.IsLoopback(localaddr))
                        continue;

                    string ip = localaddr.ToString();

                    //Console.WriteLine("NetUtils.IsThisMachineLocalIp Dns.GetHostEntryAsync ip {0} in list", ip);

                    if (ip == address)
                    {
                        ismatching = true;
                        return ismatching;
                    }

                }

                var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

                foreach (var network in networkInterfaces)
                {
                    if (network.OperationalStatus != OperationalStatus.Up)
                        continue;
                    var properties = network.GetIPProperties();
                    if (properties.GatewayAddresses.Count == 0)
                        continue;

                    foreach (var tmpaddress in properties.UnicastAddresses)
                    {
                        if (tmpaddress.Address.AddressFamily != AddressFamily.InterNetwork)
                            continue;
                        if (IPAddress.IsLoopback(tmpaddress.Address))
                            continue;

                        string ip = tmpaddress.Address.ToString();

                        //Console.WriteLine("NetUtils.IsThisMachineLocalIp NetworkInterface ip {0} in list", ip);

                        if (ip == address)
                        {
                            ismatching = true;
                            return ismatching;
                        }
                    }
                }

                return ismatching;
 
            }
            catch (Exception ex)
            {
                TraceLog.Exception(ex);
            }

            return false;
        }

        // 把ip地址转换成网络字节序(大端)的数字, 等于inet_aton
        public static uint IpAddrToNum(string addr)
        {
            uint ipNum = 0;
            var ipAddr = IPAddress.Parse(addr);
            if (ipAddr != null)
            {
                foreach (byte b in ipAddr.GetAddressBytes())
                {
                    ipNum = ipNum << 8;
                    ipNum |= b;
                }
            }
            return ipNum;
        }

        // 把网络字节序(大端)的数字转换成ip地址, 等于inet_ntoa
        public static string IpNumToAddr(uint ipNum)
        {
            byte[] ipArr = new byte[4];
            for (int i = 0; i < 4; i++)
            {
                ipArr[i] = (byte)(ipNum & 0xffff);
                ipNum = ipNum >> 8;
            }
            return string.Format("{0}.{1}.{2}.{3}", ipArr[3], ipArr[2], ipArr[1], ipArr[0]);
        }
    }
}