#include <iostream>
#include "processor.h"
#include "unexpectedValue.h"

int Processor::eval()
{ 
  try {
    return E();
  }catch( UnexpectedValue & e) {
    cerr << "Error: \n";
    cerr << str << '\n';
    for (int i=0 ; i < pos; i++) cerr << ' ';
    cerr << "^\n";
    cerr << "Se esperaba "<<e.getmsg()<< endl;
    return 0;
  }
}

int Processor::E()
{
  try {
    int t = T();
    return Ep(t);
  } catch(UnexpectedValue &e) {
    throw e;
  }
}

int Processor::Ep(int tl)
{
  int tr;
  char op;
  try {
    while(str[pos]==' ') pos++;  // saltamos espacios en blanco
    op=str[pos];
    if (op!='+' && op!='-') return tl;
    pos++;
    tr = T();
    switch(op) {
    case '+': return(Ep(tl+tr));
    case '-': return(Ep(tl-tr));
    }
  } catch(UnexpectedValue &e) {
    throw e;
  }
}

int Processor::T() 
{
  try {
    int f = F();
    return (Tp(f));
  }catch(UnexpectedValue &e){
    throw e;
  }
}

int Processor::Tp(int fl) 
{
  int fr;
  char op;

  try {
    while(str[pos]==' ') pos++;  // saltamos espacios en blanco
    op=str[pos];
    if (op!='*') return fl;
    pos++;
    fr = F();
    switch(op) {
    case '*': return(Tp(fl*fr));
    }  
  }catch(UnexpectedValue &e) {
    throw e;
  }
}

int Processor::F() 
{
  char op;
  int result;

  while(str[pos]==' ') pos++;  // saltamos espacios en blanco
  op=str[pos];
  if (op == '(') {
    pos++;
    result= E();
    while(str[pos]==' ') pos++;  // saltamos espacios en blanco
    if (str[pos]==')' ) {
      pos++;
      return result;
    }
    else throw UnexpectedValue(" )" ,pos);
  }
  else {
    char digit;
    int number=0;
    while(str[pos]==' ') pos++;  // saltamos espacios en blanco
    if ((str[pos]<'0') || ('9' < str[pos]))
      throw UnexpectedValue("un digito",pos);
    while (('0'<=str[pos]) &&(str[pos]<='9')){
      number=number*10+str[pos]-'0';
      pos++;
    }
    return number;
  }
}