using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web;

namespace Edu.Common.Plugin
{
    /// <summary>
    /// IP转化帮助类
    /// </summary>
    public class IPHelper
    {
        /// <summary>
        /// 判断是否是IP地址
        /// </summary>
        /// <param name="ipAddress"></param>
        /// <returns></returns>
        private static bool IsIPAddress(string ipAddress)
        {
            if (string.IsNullOrEmpty(ipAddress))
            {
                return false;
            }
            ipAddress = ipAddress.Trim();
            if (ipAddress.Length < 7 || ipAddress.Length > 15)
            {
                return false;
            }
            string pattern = @"^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$";
            Regex regex = new Regex(pattern, RegexOptions.IgnoreCase);
            return regex.IsMatch(ipAddress);
        }

        /// <summary>
        /// 判断是否是内网IP
        /// </summary>
        /// <param name="ipAddress"></param>
        /// <returns></returns>
        private static bool IsInnerIP(String ipAddress)
        {
            bool isInnerIp = false;
            long ipNum = GetIpNum(ipAddress);
            /***** ***** ***** ***** ***** *****
            私有IP：
            A类 10.0.0.0-10.255.255.255
            B类 172.16.0.0-172.31.255.255
            C类 192.168.0.0-192.168.255.255
            还有127.0.0.1这个环回地址
            ***** ***** ***** ***** ***** *****/
            long aBegin = GetIpNum("10.0.0.0");
            long aEnd = GetIpNum("10.255.255.255");
            long bBegin = GetIpNum("172.16.0.0");
            long bEnd = GetIpNum("172.31.255.255");
            long cBegin = GetIpNum("192.168.0.0");
            long cEnd = GetIpNum("192.168.255.255");
            isInnerIp = IsInner(ipNum, aBegin, aEnd) || IsInner(ipNum, bBegin, bEnd) || IsInner(ipNum, cBegin, cEnd) || ipAddress.Equals("127.0.0.1");
            return isInnerIp;
        }

        /// <summary>
        /// 获取IP地址
        /// </summary>
        /// <param name="ipAddress"></param>
        /// <returns></returns>
        private static long GetIpNum(String ipAddress)
        {
            String[] ip = ipAddress.Split('.');
            long a = int.Parse(ip[0]);
            long b = int.Parse(ip[1]);
            long c = int.Parse(ip[2]);
            long d = int.Parse(ip[3]);
            long ipNum = a * 256 * 256 * 256 + b * 256 * 256 + c * 256 + d;
            return ipNum;
        }

        /// <summary>
        /// 判断是否是整数
        /// </summary>
        /// <param name="userIp"></param>
        /// <param name="begin"></param>
        /// <param name="end"></param>
        /// <returns></returns>
        private static bool IsInner(long userIp, long begin, long end)
        {
            return (userIp >= begin) && (userIp <= end);
        }
    }
}