using System;

namespace iWareCommon.Utils
{
  public  class StringHelper
  {
      private static string charStr = "0123456789";

       /// <summary>
       /// 格式化字符串，将物料中的单引号格式化为两个单引号
       /// </summary>
       /// <param name="str"></param>
       /// <returns></returns>
        
      public static string RelpaceQuot(string str)  
      {
          return string.IsNullOrEmpty(str)? "":str.Replace("'","''");
      }

      /// <summary>
      /// 将型如yyyyMMdd的日期类型转为yyyy-MM-dd的日期类型
      /// </summary>
      /// <param name="str"></param>
      /// <returns></returns>
        
      public static string ConvertDateTimeStr(string str)
      {
          if(string.IsNullOrEmpty(str) || str.Length != 8)
          {
              return str;
          }
          return str.Substring(0,4) + "-" + str.Substring(4,2) + "-" + str.Substring(6,2);
      }

      /// <summary>
      /// 获取下一个字符串
      /// </summary>
      /// <param name="str"></param>
      /// <returns></returns>
      public static string NextStr(string str)
      {
          var charArray = charStr.ToCharArray();
          var len = str.Length;
          if (str == "".PadLeft(len, charArray[charArray.Length-1])) { return "".PadLeft(len + 1, charArray[0]); }
          var strArray = str.ToCharArray();
          for (var i = 0; i < strArray.Length; i++)
          {
              var pos = charStr.IndexOf(strArray[i]);
          
              if (pos < charArray.Length - 1) 
              {
                  strArray[i] = charArray[pos + 1];
                  break;
              }

              strArray[i] = charArray[0];
          }    
          return new string(strArray);
      }

      /// <summary>
      /// 获取第一个字符串
      /// </summary>
      /// <returns></returns>
      public static string GetFirstStr()
      {
          var charArray = charStr.ToCharArray();
          return "".PadLeft(6, charArray[0]);
      }

      /// <summary>
      /// 压缩字符串的算法
      /// </summary>
      /// <param name="str"></param>
      /// <returns></returns>
      public static string Compress(string str)
      {
          var res = "";
          var lastChar = "\0";
          var frequency = 0;
          var currentChar = string.Empty;
          for (int i = 0; i < str.Length; i++)
          {
              if (str[i].ToString() != lastChar)
              {
                  if (!string.IsNullOrEmpty(currentChar)) { res += (frequency - 1 > 0 ? (frequency - 1).ToString() : string.Empty) + currentChar; }
                  currentChar = str[i].ToString();
                  lastChar = currentChar;
                  frequency = 1;
              }
              else { frequency += 1; }
          }
          if (!string.IsNullOrEmpty(currentChar)) { res += (frequency - 1 > 0 ? (frequency - 1).ToString() : string.Empty) + currentChar; }
          return res;
      }

      /// <summary>
      /// 解压字符串的算法
      /// </summary>
      /// <param name="str"></param>
      /// <returns></returns>
      public static string DeCompress(string str)
      {
          var nChars = "0123456789";
          var res = "";
          var nbStr = "0";
          for (int i = 0; i < str.Length; i++)
          {
              if (nChars.IndexOf(str[i]) > -1) { nbStr += str[i]; }
              else
              {
                  var nb = Convert.ToInt32(nbStr) + 1;
                  res += "".PadLeft(nb, str[i]);
                  nbStr = "0";
              }
          }
          return res;
      }
      /// <summary>
      /// 获取str字符串中key的值
      /// </summary>
      /// <param name="syntax"></param>
      /// <param name="key"></param>
      public static string GetValue(string syntax, string key)
      {
          var str = string.Format("\"{0}\":", key);
          var index = syntax.IndexOf(str);
          if (index < 0)
          {
              return "";
          }

          var beginIndex = syntax.IndexOf("\"", index + str.Length);
          var endIndex = syntax.IndexOf("\"", beginIndex + 1);
          return syntax.Substring(beginIndex + 1, endIndex - beginIndex - 1);
      }
  }
}