#ifndef STATE_H
#define STATE_H
///////////////////////////////////////////////////////////////
//  state2.h   - defines states in terms of the events       //
//               that trigger transitions to another state   //
//                                                           //
//  ver 1.0      Adds hooks for new state                    //
//  Language:    Visual C++, ver 5.0                         //
//  Platform:    Micron Dual Pentium 200, NT 4.0             //
//  Application: Design Patterns - property pattern, Su98    //
//  Author:      Jim Fawcett, CST 2-187, (314) 443-3948      //
//               fawcett@neptune.syr.edu                     //
///////////////////////////////////////////////////////////////

#include <vector>
#include <cstdlib>

using namespace std;

// an extensible enumeration of states
  const int numStates = 5;
  const int onFF = 0;
  const int goUp = 1;
  const int onSF = 2;
  const int goDn = 3;
  const int newS = 4;

class ElevBase {

public:
  static  ElevBase* getRegistered(int n) { 
    
    if(n<0 || numStates<=n) {
      cout << "  unknown state\n\n"; exit(1);
    }
    return registry[n]; }

  virtual ElevBase* upButton() { return newEvent(); }

  virtual ElevBase* dnButton() { return newEvent(); }

  virtual ElevBase*  arrived() { return newEvent(); }

  virtual ElevBase* newEvent() { return this; }
    // this is a hook to add in new events
  
protected:
  static vector<ElevBase*> registry;  
  // shared by all elevator states

};

template <class DerivedState> class ElevState : public ElevBase {

public:
  ElevBase* makeState(int s) {
    if(s<0) { cout << "  not a valid state\n"; exit(1); }
    ElevBase* pElevBase;
    return (pElevBase = registry[s] = new DerivedState);
  }
};

//

///////////////////////////////////////////////////////////////
//  property classes                                         //
///////////////////////////////////////////////////////////////

//----< on the first floor >-----------------------------------

class onFirstFloor  : public ElevState<onFirstFloor> {

public:
  ~onFirstFloor() { delete registry[onFF]; }

  ElevBase* upButton() { 
    cout << "  going up\n"; return registry[goUp]; 
  }
};

//----< going up to second floor >-----------------------------

class goingUp       : public ElevState<goingUp> {

public:
  ~goingUp() { delete registry[goUp]; }

  ElevBase* arrived() { 
    cout << "  arrived on second floor\n"; return registry[onSF]; 
  }
};

//----< on the second floor >----------------------------------

class onSecondFloor : public ElevState<onSecondFloor> {

public:
  ~onSecondFloor() { delete registry[onSF]; }

  ElevBase* dnButton() { 
    cout << "  going down\n"; return registry[goDn]; 
  }
};

//----< going down to first floor >----------------------------

class goingDown     : public ElevState<goingDown> {

public:
  ~goingDown() { delete registry[goDn]; }

  ElevBase* arrived() { 
    cout << "  arrived on first floor\n"; return registry[onFF]; 
  }
};

#endif