#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
#include "chemlib.h"

using namespace std;

elreader::elreader(string s)
{ line = s + "_";
  pos = 0; }

char elreader::getnext()
{ if (pos >= line.length())
    return '_';
  char c = line[pos];
  pos = pos + 1;
  return c; }

char elreader::peeknext()
{ if (pos >= line.length())
    return '_';
  return line[pos]; }

string elreader::readsym()
{ string ans = "";
  char c1 = getnext();
  if (isupper(c1))
  { char c2 = peeknext();
    if (islower(c2))
    { getnext();
      return ans + c1 + c2; } 
    return ans + c1; }
  cout << "readsym doesn't understand \"" << c1 << "\"\n";
  return "_"; }

int elreader::readnum()
{ int value = 0;
  while (isdigit(peeknext()))
  { int dig = getnext();
    value = value * 10 + dig - '0'; }      // could use digittoint()
  return value; }

item elreader::readpart()
{ item result;
  char c = peeknext();
  if (isdigit(c))
  { result.type = 'N';
    result.i = readnum(); }
  else if (isalpha(c))
  { result.type = 'S';
    result.s = readsym(); }
  else if (c == '_')
    result.type = c;
  else if (c == '(' || c == ')')
  { result.type = getnext(); }
  else
  { cout << "Unexpected in formula: " << c << "\n";
    result.type = 'X'; }
  return result; } 

element::element()
{ }

element::element(int an, string sy, string nm, double aw)
{ atno = an;
  atwt = aw;
  symbol = sy;
  name = nm; }

ostream & operator<<(ostream & os, const element & e)
{ os << e.atno   << " " 
     << e.name   << " " 
     << e.atwt   << " " 
     << e.symbol << "\n"; }

void element::print()
{ cout << *this; }


ptable::ptable()
{ max = 150;
  num = 0;
  T[0] = element(0, "Q", "Nosuchthingium", 0.0); }

void ptable::read_table()
{ ifstream elfile("elements.txt");
  if (elfile.fail())
  { cerr << "could not open elements.txt\n";
    return; }

  while (true)
  { string n, s;
    double a;

    elfile >> s >> n >> a;
    if (elfile.fail())
      break;

    num = num + 1;
    if (num >= max)
    { cerr << "too many elements\n";
      exit(1); }

    T[num] = element(num, s, n, a); }

  elfile.close();
  cout << num << " elements read\n"; }

element ptable::find_sym(const string & sy)
{ int i = 1;
  while (i <= num)
  { if (T[i].symbol == sy)
      return T[i];
    i = i + 1; }
  return T[0]; }