#include "RPN.hpp"

RPN::RPN(){}

RPN::RPN(const RPN &other)
{
	this->_stack = other._stack;
}

RPN &RPN::operator=(const RPN &other)
{
	this->_stack = other._stack;
	return (*this);
}

RPN::~RPN(){}

int RPN::compute(const std::string &string)
{
	std::istringstream iss(string);
	std::string token;
	std::string ops = "+-*/";
	int b;
	int a;
	while (iss >> token)
	{
		if (token.size() == 1)
		{
			if (isdigit(token[0]))
				_stack.push(token[0] - '0');
			else if (ops.find(token[0]) != std::string::npos)
			{
				if (_stack.size() <= 1)
					throw std::runtime_error("Error");
				b = _stack.top();
				_stack.pop();
				a = _stack.top();
				_stack.pop();
				switch (token[0])
				{
				case '+':
					_stack.push(a + b);
					break;
				case '-':
					_stack.push(a - b);
					break;
				case '*':
					_stack.push(a * b);
					break;
				case '/':
					if (b == 0)
						throw std::runtime_error("Error");
					_stack.push(a / b);
					break;
				}
			}
			else
				throw std::runtime_error("Error");
		}
		else
			throw std::runtime_error("Error");
	}
	if (_stack.size() != 1)
		throw std::runtime_error("Error");
	return _stack.top();
}