using System;
using System.Data;
using System.IO;
using System.Drawing;

namespace Payroll.BO
{
	#region Null Handler
	public class NullHandler
	{
		private IDataReader _reader;

		public  NullHandler()
		{
			
		}
		public static object GetNullValue(int Value)
		{
			if(Value<=0)
			{
				return null;
			}
			else
			{
				return Value; 
			}
		}
		
		public static object GetNullValue(DateTime Value)
		{
			if(DateTime.MinValue==Value)
			{
				return null;
			}
			else
			{
				return Value; 
			}
		}
		
		public static object GetNullValue(string Value)
		{
			if(Value.Length<=0)
			{
				return null;
			}
			else
			{
				return Value; 
			}
		}
		public NullHandler(IDataReader reader)
		{
			_reader = reader;
		}

		public IDataReader  Reader
		{
			get{return _reader;}
		}

		public bool IsNull(int index)
		{
			return _reader.IsDBNull(index);
		}

		#region Default Null Values
		public int GetInt32(int i)
		{
			return _reader.IsDBNull(i)? 0 : _reader.GetInt32(i);
		}

		public byte GetByte(int i)
		{
			return _reader.IsDBNull(i)? (byte)0 : _reader.GetByte(i);
		}

		public decimal GetDecimal(int i)
		{
			return _reader.IsDBNull(i)? 0 : _reader.GetDecimal(i);
		}
		public decimal GetDecimal(string sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? (decimal) 0 :Convert.ToDecimal(_reader[sFieldName]);
		}

		public long GetInt64(int i)
		{
			return _reader.IsDBNull(i)? (long) 0 : _reader.GetInt64(i);
		}

		public double GetDouble(int i)
		{
			return _reader.IsDBNull(i)? 0 : _reader.GetDouble(i);
		}

		public bool GetBoolean(int i)
		{
			return _reader.IsDBNull(i)? false : _reader.GetBoolean(i);
		}

		public Guid GetGuid(int i)
		{
			return _reader.IsDBNull(i)? Guid.Empty : _reader.GetGuid(i);
		}

		public DateTime GetDateTime(int i)
		{
			return _reader.IsDBNull(i)? DateTime.MinValue : _reader.GetDateTime(i);
		}

		public float GetFloat(int i)
		{
			return _reader.IsDBNull(i)? 0 : _reader.GetFloat(i);
		}

		public string GetString(int i)
		{
			return _reader.IsDBNull(i)? null : _reader.GetString(i);
		}

		public char GetChar(int i)
		{
			return _reader.IsDBNull(i)? '\0' : _reader.GetChar(i);
		}
		
		public short GetInt16(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? (Int16) 0 :Convert.ToInt16(_reader[sFieldName]);
		}
		
		public int GetInt32(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? (Int32) 0 :Convert.ToInt32(_reader[sFieldName]);
		}

		public byte GetByte(String sFieldName)
		{
			return _reader[sFieldName]==DBNull.Value? (byte)0 : Convert.ToByte(_reader[sFieldName]);
		}

		public long GetInt64(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? (Int64) 0 :Convert.ToInt64(_reader[sFieldName]);
		}
		
		public Double GetDouble(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? (Double) 0 :Convert.ToDouble(_reader[sFieldName]);
		}
		public bool GetBoolean(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)?  false :Convert.ToBoolean(_reader[sFieldName]);
		}
		public DateTime GetDateTime(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? DateTime.MinValue :Convert.ToDateTime(_reader[sFieldName]);
		}

		public char GetChar(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? '\0' : Convert.ToChar(_reader[sFieldName]);
		}

		public string GetString(String sFieldName)
		{
			return (_reader[sFieldName]==DBNull.Value)? (string) "" :Convert.ToString(_reader[sFieldName]);
		}

		public Image GetImage(String sFieldName)
		{
			try
			{
				byte[] imageData = null;
				long byteSize =0;
				byteSize = _reader.GetBytes(_reader.GetOrdinal(sFieldName), 0, null, 0, 0);

				imageData = new byte[byteSize];
				long bytesread = 0;
				int curpos = 0, chunkSize=500;
				while (bytesread < byteSize)
				{
					// chunkSize is an arbitrary application defined value 
					bytesread += _reader.GetBytes(_reader.GetOrdinal(sFieldName), curpos, imageData, curpos, chunkSize);
					curpos += chunkSize;
				}

				byte[] imgData =imageData;

				MemoryStream ms = new MemoryStream(imgData);
				Image oImage=Image.FromStream((Stream)ms);
				return oImage;
			}
			catch(Exception ex)
			{
				throw new Exception("Failed to get Image: " + ex.Message);
			}
		}

		#endregion

		#region Parameterized Null Value
		public int GetInt32(int i, int valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetInt32(i);
		}

		public byte GetByte(int i, byte valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetByte(i);
		}

		public decimal GetDecimal(int i, decimal valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetDecimal(i);
		}

		public long GetInt64(int i, long valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetInt64(i);
		}

		public double GetDouble(int i, double valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetDouble(i);
		}

		public bool GetBoolean(int i, bool valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetBoolean(i);
		}

		public Guid GetGuid(int i, Guid valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetGuid(i);
		}

		public DateTime GetDateTime(int i, DateTime valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetDateTime(i);
		}

		public float GetFloat(int i, float valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetFloat(i);
		}

		public string GetString(int i, string valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetString(i);
		}

		public char GetChar(int i, char valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetChar(i);
		}

		public short GetInt16(int i, short valueIfNull)
		{
			return _reader.IsDBNull(i)? valueIfNull : _reader.GetInt16(i);
		}
		#endregion
	}
	#endregion
}