using System;
using System.Collections.Specialized;
using System.Net;
using System.Text;
using System.Web;

namespace CsharpHttpHelper.Helper
{
	/// <summary>
	/// 和Url相关的帮助方法  Copyright：http://www.httphelper.com/
	/// </summary>
	internal class HttpUrlHelper
	{
		/// <summary>
		/// 使用指定的编码对象将 URL 编码的字符串转换为已解码的字符串。
		/// </summary>
		/// <param name="text">指定的字符串</param>
		/// <param name="encoding">指定编码默认为Default</param>
		/// <returns></returns>
		internal static string URLDecode(string text, Encoding encoding = null)
		{
			if (encoding == null)
			{
				encoding = Encoding.Default;
			}
			return HttpUtility.UrlDecode(text, encoding);
		}

		/// <summary>
		/// 使用指定的编码对象对 URL 字符串进行编码。
		/// </summary>
		/// <param name="text">指定的字符串</param>
		/// <param name="encoding">指定编码默认为Default</param>
		/// <returns></returns>
		internal static string URLEncode(string text, Encoding encoding = null)
		{
			if (encoding == null)
			{
				encoding = Encoding.Default;
			}
			return HttpUtility.UrlEncode(text, encoding);
		}

		/// <summary>
		/// 将Url参数字符串转为一个Key和Value的集合
		/// </summary>
		/// <param name="str">要转为集合的字符串</param>
		/// <returns>NameValueCollection</returns>
		internal static NameValueCollection GetNameValueCollection(string str)
		{
			NameValueCollection result = null;
			try
			{
				result = HttpUtility.ParseQueryString(str);
			}
			catch
			{
			}
			return result;
		}

		/// <summary>
		/// 提取网站主机部分就是host
		/// </summary>
		/// <param name="url">url</param>
		/// <returns>host</returns>
		internal static string GetUrlHost(string url)
		{
			try
			{
				return new Uri(url).Host;
			}
			catch
			{
				return string.Empty;
			}
		}

		/// <summary>
		/// 提取网址对应的IP地址
		/// </summary>
		/// <param name="url">url</param>
		/// <returns>返回Url对应的IP地址</returns>
		internal static string GetUrlIp(string url)
		{
			try
			{
				IPHostEntry hostByName = Dns.GetHostEntry(GetUrlHost(url));
				//IPHostEntry hostByName = Dns.GetHostByName(GetUrlHost(url));
				return hostByName.AddressList[0].ToString();
			}
			catch
			{
				return string.Empty;
			}
		}

		/// <summary>
		/// 获取当前页面的URL（五个数字可选 1~5 ）
		/// </summary>
		/// <param name="selectNO">1完整url,2域名之后,3域名之后不含参数,4只有域名,5获取参数</param>
		/// <returns></returns>
		public string getNowURL(int selectNO)
		{
			//string text = "";
			switch (selectNO)
			{
			case 1:
				return HttpContext.Current.Request.Url.ToString();
			case 2:
				return HttpContext.Current.Request.RawUrl;
			case 3:
				return HttpContext.Current.Request.Url.AbsolutePath;
			case 4:
				return HttpContext.Current.Request.Url.Host;
			case 5:
				return HttpContext.Current.Request.Url.Query;
			default:
				return HttpContext.Current.Request.Url.ToString();
			}
		}
	}
}