/// <summary>
/// Returns one of:
/// 0 fragments
/// 1 additive or subtractive fragment
/// Both
/// </summary>
/// <param name="romanNumeral"></param>
/// <param name="value"></param>
/// <returns></returns>
private static List<RomanNumeralFragment> GetFragmentsForRomanNumeral(RomanNumeral romanNumeral, int value)
{
var result = new List<RomanNumeralFragment>();
var count = GetFullNumeralCount(value, romanNumeral);
var fragmentString = GetAdditiveFragmentString(count, romanNumeral);
if (fragmentString.Length > 0)
{
var fragment = new RomanNumeralFragment(fragmentString);
result.Add(fragment);
value = value - fragment.Value;
}
var subtractiveFragment = GetSubtractiveFragment(romanNumeral, value);
if (subtractiveFragment != null)
{
result.Add(subtractiveFragment);
}
return result;
}
/// <summary>
/// Returns a subtractive fragment using the specified roman numeral. Returns null if not needed
/// </summary>
/// <param name="currentRomanNumeral"></param>
/// <param name="value"></param>
/// <returns></returns>
private static RomanNumeralFragment GetSubtractiveFragment(RomanNumeral currentRomanNumeral, int value)
{
RomanNumeralFragment fragment = null;
// check if value if difference is greater than numeral minus C
if ((value > (int)RomanNumeral.C) && (value >= ((int)currentRomanNumeral - (int)RomanNumeral.C)))
{
// if greater, we need to use a C subtractive fragment
fragment = new RomanNumeralFragment(GetSubtractiveFragmentString(RomanNumeral.C, currentRomanNumeral));
}
// if false, check for X and I using rules above
else if ((value > (int)RomanNumeral.X) && (value >= ((int)currentRomanNumeral - (int)RomanNumeral.X)))
{
// if greater, we need to use a X subtractive fragment
fragment = new RomanNumeralFragment(GetSubtractiveFragmentString(RomanNumeral.X, currentRomanNumeral));
}
else if ((value > (int)RomanNumeral.I) && (value >= ((int)currentRomanNumeral - (int)RomanNumeral.I)))
{
// if greater, we need to use a I subtractive fragment
fragment = new RomanNumeralFragment(GetSubtractiveFragmentString(RomanNumeral.I, currentRomanNumeral));
}
return fragment;
}
