using System;
using System.Text.RegularExpressions;
using System.Web;
using System.Collections.Specialized;
namespace DotNet.Utilities
{
  /// <summary>
  /// URL的操作類
  /// </summary>
  public class UrlOper
  {
    static System.Text.Encoding encoding = System.Text.Encoding.UTF8;
    #region URL的64位編碼
    public static string Base64Encrypt(string sourthUrl)
    {
      string eurl = HttpUtility.UrlEncode(sourthUrl);
      eurl = Convert.ToBase64String(encoding.GetBytes(eurl));
      return eurl;
    }
    #endregion
    #region URL的64位解碼
    public static string Base64Decrypt(string eStr)
    {    
      if (!IsBase64(eStr))
      {
        return eStr;
      }
      byte[] buffer = Convert.FromBase64String(eStr);
      string sourthUrl = encoding.GetString(buffer);
      sourthUrl = HttpUtility.UrlDecode(sourthUrl);
      return sourthUrl;
    }
    /// <summary>
    /// 是否是Base64字符串
    /// </summary>
    /// <param name="eStr"></param>
    /// <returns></returns>
    public static bool IsBase64(string eStr)
    {
      if ((eStr.Length % 4) != 0)
      {
        return false;
      }
      if (!Regex.IsMatch(eStr, "^[A-Z0-9/+=]*$", RegexOptions.IgnoreCase))
      {
        return false;
      }
      return true;
    }
    #endregion
    /// <summary>
    /// 添加URL參數(shù)
    /// </summary>
    public static string AddParam(string url, string paramName, string value)
    {
      Uri uri = new Uri(url);
      if (string.IsNullOrEmpty(uri.Query))
      {
        string eval = HttpContext.Current.Server.UrlEncode(value);
        return String.Concat(url, "?" + paramName + "=" + eval);
      }
      else
      {
        string eval = HttpContext.Current.Server.UrlEncode(value);
        return String.Concat(url, "&" + paramName + "=" + eval);
      }
    }
    /// <summary>
    /// 更新URL參數(shù)
    /// </summary>
    public static string UpdateParam(string url, string paramName, string value)
    {
      string keyWord = paramName+"=";
      int index = url.IndexOf(keyWord)+keyWord.Length;
      int index1 = url.IndexOf("&", index);
      if (index1 == -1)
      {
        url = url.Remove(index, url.Length - index);
        url = string.Concat(url, value);
        return url;
      }
      url = url.Remove(index,index1 - index);
      url = url.Insert(index, value);
      return url;
    }
    #region 分析URL所屬的域
    public static void GetDomain(string fromUrl, out string domain, out string subDomain)
    {
      domain = "";
      subDomain = "";
      try
      {
        if (fromUrl.IndexOf("的名片") > -1)
        {
          subDomain = fromUrl;
          domain = "名片";
          return;
        }
        UriBuilder builder = new UriBuilder(fromUrl);
        fromUrl = builder.ToString();
        Uri u = new Uri(fromUrl);
        if (u.IsWellFormedOriginalString())
        {
          if (u.IsFile)
          {
            subDomain = domain = "客戶端本地文件路徑";
          }
          else
          {
            string Authority = u.Authority;
            string[] ss = u.Authority.Split('.');
            if (ss.Length == 2)
            {
              Authority = "www." + Authority;
            }
            int index = Authority.IndexOf('.', 0);
            domain = Authority.Substring(index + 1, Authority.Length - index - 1).Replace("comhttp","com");
            subDomain = Authority.Replace("comhttp", "com");
            if (ss.Length < 2)
            {
              domain = "不明路徑";
              subDomain = "不明路徑";
            }
          }
        }
        else
        {
          if (u.IsFile)
          {
            subDomain = domain = "客戶端本地文件路徑";
          }
          else
          {
            subDomain = domain = "不明路徑";
          }
        }
      }
      catch
      {
        subDomain = domain = "不明路徑";
      }
    }
    /// <summary>
    /// 分析 url 字符串中的參數(shù)信息。
    /// </summary>
    /// <param name="url">輸入的 URL</param>
    /// <param name="baseUrl">輸出 URL 的基礎部分</param>
    /// <param name="nvc">輸出分析后得到的 (參數(shù)名,參數(shù)值) 的集合</param>
    public static void ParseUrl(string url, out string baseUrl, out NameValueCollection nvc)
    {
      if (url == null)
        throw new ArgumentNullException("url");
      nvc = new NameValueCollection();
      baseUrl = "";
      if (url == "")
        return;
      int questionMarkIndex = url.IndexOf('?');
      if (questionMarkIndex == -1)
      {
        baseUrl = url;
        return;
      }
      baseUrl = url.Substring(0, questionMarkIndex);
      if (questionMarkIndex == url.Length - 1)
        return;
      string ps = url.Substring(questionMarkIndex + 1);
      // 開始分析參數(shù)對  
      Regex re = new Regex(@"(^|&)?(\w+)=([^&]+)(&|$)?", RegexOptions.Compiled);
      MatchCollection mc = re.Matches(ps);
      foreach (Match m in mc)
      {
        nvc.Add(m.Result("$2").ToLower(), m.Result("$3"));
      }
    }
    #endregion
  }
}