#include "evaluate_prefix.h"
#include <bits/stdc++.h>

Expression::Expression(std::string text) {
  mText = text;
  dubina = 0;
  mNextToken = 0;
}

Expression::Token Expression::getToken() {
  Expression::Token t;
  t.value = 0;

  while (mNextToken < mText.size() && mText[mNextToken] == ' ') mNextToken++;

  if (mNextToken == mText.size()) {
    throw std::runtime_error("nema vise tokena");
  }

  if (mText[mNextToken] == '+' || mText[mNextToken] == '-' || mText[mNextToken] == '^' || mText[mNextToken] == '*' || mText[mNextToken] == '/') {
    t.type = binaryOp;
    t.symbol = mText[mNextToken];
    mNextToken++;
  }
  else if (mText[mNextToken] == '~') {
    t.type = unaryOp;
    t.symbol = mText[mNextToken];
    mNextToken++;
  }
  else if (mText[mNextToken] >= '0' && mText[mNextToken] <= '9') {
    t.type = operand;

    while (mNextToken < mText.size() && mText[mNextToken] >= '0' && mText[mNextToken] <= '9') {
      t.value *= 10;
      t.value += mText[mNextToken] - '0';
      mNextToken++;
    }
  }
  else {
    throw std::runtime_error("nepoznati znak");
  }

  while (mNextToken < mText.size() && mText[mNextToken] == ' ') mNextToken++;

  return t;
}

Expression::Value Expression::evaluate() {
  dubina++;
  int ret;
  Expression::Token t = this->getToken();

  std::cout << dubina << " " << t.type << " " << t.symbol << ' ' << t.value << '\n';

  if (t.type == unaryOp) {
    ret = -(this->evaluate());
  }
  if (t.type == binaryOp) {
    if (t.symbol == '+') {
      ret = (this->evaluate()) + (this->evaluate());
    }
    else if (t.symbol == '-') {
      ret = (this->evaluate()) - (this->evaluate());
    }
    else if (t.symbol == '^') {
      int a = (this->evaluate());
      int b = (this->evaluate());
      int ret = 1;
      std::cout << "pote " << a << " " << b << '\n';

      while (b--) ret *= a;
      std::cout << "ret = " << ret << '\n';
    }
    else if (t.symbol == '*') {
      ret = (this->evaluate()) * (this->evaluate());
    }
    else if (t.symbol == '/') {
      ret = (this->evaluate()) / (this->evaluate());
    }
    std::cout << "ret = " << ret << '\n';
  }
  if (t.type == operand) {
    ret = t.value;
  }
  dubina--;

  std::cout << "dubina i ret " << dubina << " " << ret << '\n';

  if (!dubina && mNextToken != mText.size())
    throw std::runtime_error("previse znakova");

  return ret;
}