using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlTypes;
using System.Security.Cryptography;
using Microsoft.VisualBasic;

namespace SqlCustomFunctions
{
  public static class ClsConversions
  {
    [Microsoft.SqlServer.Server.SqlFunction()]
    static public SqlGuid StringToGUID(SqlString theInputString)
    {
      SqlGuid gx = Guid.Empty;
      string myString = theInputString.Value.ToString();

      using (MD5 hasher = MD5.Create())
      {
        var dbytes = hasher.ComputeHash(Encoding.UTF8.GetBytes(myString));
        var sBuilder = new StringBuilder();

        for (int n = 0; n < dbytes.Length; n++)
          sBuilder.Append(dbytes[n].ToString("X2"));

        gx = Guid.Parse(sBuilder.ToString());
      }

      return gx;
    }

    [Microsoft.SqlServer.Server.SqlFunction()]
    static public SqlString FormatPhone(SqlInt64 Num)
    {
      SqlString rv = string.Empty;

      if (Num.Value.ToString().Trim().Length != 10)
        rv = Num.Value.ToString();
      else
        rv = string.Format("{0:(000) 000-0000}", Num.Value);

      return rv;
    }

    [Microsoft.SqlServer.Server.SqlFunction()]
    static public SqlDateTime dtFirstDayOfMonth(SqlDateTime InDate)
    {
      SqlDateTime rv = DateSerial(InDate.Value.Year, Convert.ToInt16(InDate.Value.Month), 1);
      return rv;
    }
    [Microsoft.SqlServer.Server.SqlFunction()]
    static public SqlDateTime dtLastDayOfMonth(SqlDateTime InDate)
    {
      SqlDateTime rv = DateSerial(InDate.Value.Year, Convert.ToInt16(InDate.Value.Month + 1), 0);
      return rv;
    }

    public static SqlDateTime dtSerial(int year, short month, short day)
    {
      if (year < 0)
      {
        year = DateTime.Now.Year + year;
      }
      else if (year < 100)
      {
        year = 1930 + year;
      }
      DateTime dt = new DateTime(year, 1, 1);
      dt = dt.AddMonths(month - 1);
      dt = dt.AddDays(day - 1);

      return dt;
    }

    private static DateTime DateSerial(int year, short month, short day)
    {
      if (year < 0)
      {
        year = DateTime.Now.Year + year;
      }
      else if (year < 100)
      {
        year = 1930 + year;
      }
      DateTime dt = new DateTime(year, 1, 1);
      dt = dt.AddMonths(month - 1);
      dt = dt.AddDays(day - 1);

      return dt;
    }



  }
}