#ifndef PPJ_ENKA_H
#define PPJ_ENKA_H

#include <set>
#include <map>
#include <string>

using namespace std;

class State {
  public:
    void addTrans(char letter, State* next) {
      trans[letter].insert(next);
    }

    set <State*> getNext (char letter) {
      return trans[letter];
    }

  private:
    map <char, set <State*> > trans;
};

/**
 * This class only keeps pointers to start state and to end state.
 * It provides convinient ways to build Enka, through operators.
 *
 */
class Enka {
  public:
    const static char EPS = 0; //  value used for eps transitions

    /**
     * Constructs an automata that only accepts empty string.
     */
    Enka();

    /**
     * Constructs an automata that only accepts the letter 'letter'.
     */
    Enka(char letter);

    /**
     * Evaluates if a string is accepted by this automata.
     * @return  True if word is accepted
     *          False otherwise
     */
    bool evaluate(string word);

    /**
     * Creates automata that accepts left | right (or).
     */
    Enka operator +(const Enka& right);


    State* startState;
    State* endState; //  endState is always considered acceptable


  private:
    set <State*> currStates;

    Enka(State* s, State* v) {
      startState = s;
      endState = v;
    }

    void makeTransition(char letter);
    void addEpsClosure();
};

#endif