//main******************************************************************************************************
//cplusplus.com/forum/beginner/75558
#include <iostream>
#include "RomanInt.h"

int main()
{
    RomanInt RInt;

    do
    {
        std::cout << "Enter a roman numeral: ";
        std::cin >> RInt;
    }
    while (true);

}
//RomanInt.h************************************************************************************************
#ifndef ROMANINT_H
#define ROMANINT_H
#include <string>
#include <iostream>
#include <cstdlib>
#include <algorithm>

class RomanInt
{
public:
    RomanInt (std::string RNum = "");
    void PrintRoman(int);
private:
    void Convert (std::string RNum);
    int ValueOf (char RChar);
    bool IsValid (std::string RNum);

    friend std::istream& operator>> (std::istream& is, RomanInt& RInt);

    std::string RomanNumeral;
    int DecimalNumeral;
};
#endif
//RomanInt.cpp**********************************************************************************************
#include "RomanInt.h"

RomanInt::RomanInt (std::string RNum) :
RomanNumeral (RNum)
{
    if (RNum != "") Convert (RNum);
}

void RomanInt::Convert (std::string RNum)
{
    int DecimalNumeral = 0;
    bool isOdd = 0;
    int ValueL;
    int ValueR;

    for (unsigned int i = 0; i < RNum.length(); i++)
    {
        if (RNum.length() % 2 && i == 0) // is odd and first number
        {
            isOdd = 1;
            DecimalNumeral += ValueOf (RNum[0]);
        }
        else
        {
            ValueL = ValueOf (RNum[RNum.length() - i - 2 + isOdd]); //shortcut and easier on the eyes
            ValueR = ValueOf (RNum[RNum.length() - i - 1 + isOdd]);

            if (ValueL < ValueR) DecimalNumeral += (ValueR - ValueL);
            else DecimalNumeral += (ValueL + ValueR);

            i++; //do it in groups of 2
        }
    }
    std::cout << RNum << " = " << DecimalNumeral << std::endl;
}

int RomanInt::ValueOf (char RChar)
{
    switch (RChar)
    {
    case 'I': return 1;
    case 'V': return 5;
    case 'X': return 10;
    case 'L': return 50;
    case 'C': return 100;
    case 'D': return 500;
    case 'M': return 1000;
    default:
        std::cout << RChar << " should not be in the ValueOf function, something broke" << std::endl;
        exit (1); //terminate
    }

    return -10000; //shouldn't ever be called, but just in case some weird shit goes on.
}

void RomanInt::PrintRoman(int var)
{
    if (var == 0) std::cout << RomanNumeral << std::endl; //why? don't ask me, part of the exercise
    else std::cout << DecimalNumeral << std::endl; //why? don't ask me, part of the exercise
}

bool RomanInt::IsValid (std::string RNum)
{
    for (unsigned int i = 0; i < RNum.length(); i++)
    {
        if ( (RNum[i] != 'I' && RNum[i] != 'V' && RNum[i] != 'X' && RNum[i] != 'L' && RNum[i] != 'C' && RNum[i] != 'D' && RNum[i] != 'M'))
            return false; // only accept IVXLCDM
        else if ( (RNum.length() >= 4 && i <= RNum.length() - 4) && (RNum[i] == RNum[i+1]) && (RNum[i+1] == RNum[i+2]) && (RNum[i+2] == RNum[i+3]))
            return false; // no more than 3 of the same character in a row
    }

    return true;
}

std::istream& operator>> (std::istream& is, RomanInt& RInt)
{
    std::string RNum;
    is >> RNum; //get input
    std::transform (RNum.begin(), RNum.end(), RNum.begin(), ::toupper); //fix lowercase

    if (RInt.IsValid (RNum)) //check we can convert it
    {
        RInt.RomanNumeral = RNum;
        RInt.Convert (RNum);
    }
    else std::cout << "Invalid Numeral " << RNum << " entered\n" << std::endl;

    return is;
}