/*
AmountInWords
Copyright (C) 2003 Terry Voss
(http://aspalliance.com/164_Convert_Currency_to_dollar_words)
Originally in VB.NET
Translated to C# 2.0 by Rizal Almashoor on 5 December 2006

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

Example Usage:

AmountInWords aiw = new AmountInWords();
// Let's say we want 42 to be "Forty Two Dollars" and not "Forty Two Dollars And Zero Cents"
aiw.IncludeZeroMinorCurrencyUnit = false;
// Default is "Dollars" and "Cents"
String amountInWords = aiw.Convert(123456789.12);
// Other currencies:
aiw = new AmountInWords("Pound", "Pounds", "Penny", "Pence", true);
amountInWords = aiw.Convert(123456789.12);
aiw = new AmountInWords("Ringgit", "Ringgit", "Sen", "Sen", true);
amountInWords = aiw.Convert(123456789.12);
*/

using System.Text;
using System.Text.RegularExpressions;

public class AmountInWords
{
	private String _majorCurrencyUnitSingular;
	private String _majorCurrencyUnitPlural;
	private String _minorCurrencyUnitSingular;
	private String _minorCurrencyUnitPlural;
	private bool _includeZeroMinorCurrencyUnit;
	private String _oneWords;
	private String[] _ones;
	private String _tenWords;
	private String[] _tens;

	public String MajorCurrencyUnitSingular
	{
		get { return _majorCurrencyUnitSingular; }
		set { _majorCurrencyUnitSingular = (value == null ? "" : value); }
	}
	public String MajorCurrencyUnitPlural
	{
		get { return _majorCurrencyUnitPlural; }
		set { _majorCurrencyUnitPlural = (value == null ? "" : value); }
	}
	public String MinorCurrencyUnitSingular
	{
		get { return _minorCurrencyUnitSingular; }
		set { _minorCurrencyUnitSingular = (value == null ? "" : value); }
	}
	public String MinorCurrencyUnitPlural
	{
		get { return _minorCurrencyUnitPlural; }
		set { _minorCurrencyUnitPlural = (value == null ? "" : value); }
	}
	public bool IncludeZeroMinorCurrencyUnit
	{
		get { return _includeZeroMinorCurrencyUnit; }
		set { _includeZeroMinorCurrencyUnit = value; }
	}
	public AmountInWords()
	{
		_majorCurrencyUnitSingular = "Dollar";
		_majorCurrencyUnitPlural = "Dollars";
		_minorCurrencyUnitSingular = "Cent";
		_minorCurrencyUnitPlural = "Cents";
		_includeZeroMinorCurrencyUnit = true;
		_InitializeWords();
	}
	public AmountInWords(String majorCurrencyUnitSingular, String majorCurrencyUnitPlural, String minorCurrencyUnitSingular, String minorCurrencyUnitPlural, bool includeZeroMinorCurrencyUnit)
	{
		_majorCurrencyUnitSingular = (majorCurrencyUnitSingular == null ? "" : majorCurrencyUnitSingular);
		_majorCurrencyUnitPlural = (majorCurrencyUnitPlural == null ? "" : majorCurrencyUnitPlural);
		_minorCurrencyUnitSingular = (minorCurrencyUnitSingular == null ? "" : minorCurrencyUnitSingular);
		_minorCurrencyUnitPlural = (minorCurrencyUnitPlural == null ? "" : minorCurrencyUnitPlural);
		_includeZeroMinorCurrencyUnit = includeZeroMinorCurrencyUnit;
		_InitializeWords();
	}
	private void _InitializeWords()
	{
		_oneWords = ",One,Two,Three,Four,Five,Six,Seven,Eight,Nine,Ten,Eleven,Twelve,Thirteen,Fourteen,Fifteen,Sixteen,Seventeen,Eighteen,Nineteen";
		_ones = _oneWords.Split(",".ToCharArray());
		_tenWords = ",Ten,Twenty,Thirty,Forty,Fifty,Sixty,Seventy,Eighty,Ninety";
		_tens = _tenWords.Split(",".ToCharArray());
	}
	public String Convert(int number)
	{
		return Convert(System.Convert.ToDecimal(number));
	}
	public String Convert(double number)
	{
		return Convert(System.Convert.ToDecimal(number));
	}
	public String Convert(decimal number)
	{
		String input = number.ToString("0.00");
		if (input.Length > 12)
			return "Error in input value";
		StringBuilder output = new StringBuilder();
		String dollars = input.Substring(0, input.IndexOf(".")).PadLeft(9, '0');
		String cents = input.Substring(input.IndexOf(".") + 1).PadRight(2, '0');
		if (cents.Equals("00"))
			cents = "0";
		int mill = System.Convert.ToInt32(dollars.Substring(0, 3));
		String mills = _ConvertHundreds(mill);
		int thou = System.Convert.ToInt32(dollars.Substring(3, 3));
		String thous = _ConvertHundreds(thou);
		int hund = System.Convert.ToInt32(dollars.Substring(6, 3));
		String hunds = _ConvertHundreds(hund);
		int cent = System.Convert.ToInt32(cents);
		cents = _ConvertHundreds(cent);
		if (mills.Length > 0)
			output.Append(mills + " Million ");
		if (thous.Length > 0) 
			output.Append(thous + " Thousand ");
		if (hunds.Length > 0)
			output.Append(hunds + " ");
		if (output.Length == 0)
			output.Append("Zero ");
		output.Append(_majorCurrencyUnitPlural);
		if (cents.Length > 0)
			output.Append(" And " + cents + " " + _minorCurrencyUnitPlural);
		if (cents.Length == 0 && _includeZeroMinorCurrencyUnit)
			output.Append(" And Zero " + _minorCurrencyUnitPlural);
		output.Replace("One " + _majorCurrencyUnitPlural, "One " + _majorCurrencyUnitSingular);
		output.Replace("One " + _minorCurrencyUnitPlural, "One " + _minorCurrencyUnitSingular);
		Regex re = new Regex(@"\s\s+");
		return re.Replace(output.ToString(), " ").Trim();
	}
	private String _ConvertHundreds(int input)
	{
		StringBuilder output = new StringBuilder();
		if (input <= 99)
			output.Append(_ConvertTens(input));
		else
		{
			output.Append(_ones[(int)Math.Floor(input / 100.0)]);
			output.Append(" Hundred ");
			if (input - (int)Math.Floor(input / 100.0) * 100 == 0)
				output.Append("");
			else
				output.Append("" + _ConvertTens(input - (int)Math.Floor(input / 100.0) * 100));
		}
		return output.ToString();
	}
	private String _ConvertTens(int input)
	{
		StringBuilder output = new StringBuilder();
		if (input < 20)
		{
			output.Append(_ones[input]);
			input = 0;
		}
		else
		{
			output.Append(_tens[(int)Math.Floor(input / 10.0)]);
			input -= (int)Math.Floor(input / 10.0) * 10;
		}
		output.Append(_ones[input].Trim().Length == 0 ? "" : " " + _ones[input]);
		return output.ToString();
	}
}