//****************************************************************//
//                                                                //
// Copyright (c) 1997.                                            //
//      Dr. Michael A. Redmond                                    //
//                                                                //
// This software may not be distributed further without permission from     //
// Dr Michael A. Redmond.                                         //
//                                                                //
// This software is distributed WITHOUT ANY WARRANTY. No claims are made    //
// as to its functionality or purpose.                            //
//                                                                //
// Title: Tw_Peg.h
// Description: abstraction for twixt peg, includes position and color
// Author: Dr Michael A. Redmond                            //
// Date: 2/11/97                                                  //
//                                                                //
//            Overcommented because also explaining the language as well
//            as the program
//
//****************************************************************//

// tw-peg.h: declaration of Tw_Peg ADT
// conditional compilation to avoid trying to include same thing twice
#ifndef TW_PEG_H
#define TW_PEG_H

#include <iostream.h>
#include "point.h"   
#include "tw-color.h"   

const int badrow = -1;
const int badcol = -1;

// Tw_Peg ADT: class description
// Defines class and its interface to the world
//    implementation is in tw-peg.cpp
class Tw_Peg {
        // public interface can be used by anybody
        friend class Tw_Board;  // Tw_Board needs access to GetPosition
        friend class Tw_Link;  // Tw_Link needs access to GetPosition
	public: // member functions
		// constructors - prob shouldn't provide second - can 
                //    be simulated using Tw_Peg(Point(row,column),col);
		Tw_Peg();
		Tw_Peg(Point pos, Tw_Color col = empty);
		Tw_Peg(int row, int column, Tw_Color col = empty);
		// inspectors               
                //    report back if a position is free
                bool PositionFree() const;
                //    report back what color is in the position
                Tw_Color WhatColor() const;
                //    report all offsets from the position
                //        without concern for legality
                void AllOffsets(Point neighbors[]) const;
		// mutators -  establish new values of attributes (data members)
                //   if the position is free fill with specified color
                //        and return true otherwise return false
		bool AcceptPeg(Tw_Color col);
		// facilitators
                //    place peg on a board should go under board
                //    form a link should go under link
                //    check two pegs to see if they are appropriate
                //    distance apart to form a link
                bool LegalLinkOffset(const Tw_Peg peg2) const;
                //    determines if two pegs are equal
                bool PegEqual(const Tw_Peg peg2) const;
		// some stream facilitators
                // write to stream
		void Insert(ostream &sout) const;
                // read from stream
		void Extract(istream &sin);
        // protected interface can be used by objects that are in class,
        //    and objects that are in a subtype class (derived class)
	protected:
		// inspectors
                //    return values of attributes (data members)
		Point GetPosition() const;
		Tw_Color GetPegColor() const;
		// mutators
                //    establish new values of attributes (data members)
		void SetPosition(Point pos);
		void SetPegColor(Tw_Color col);
                // facilitators
        // private members can only be used by other member functions and
        //    operators of this class
        //    typically all attributes (data members) go here
	private:
		// data members
		Point position;
		Tw_Color colorv;
};

// below overloads standard c++ operators so that they can be used 
// with tw_peg class objects, so syntax is like with ints floats etc
//
// Tw_Peg ADT: auxiliary operator description

ostream& operator<<(ostream &sout, const Tw_Peg &s);
istream& operator>>(istream &sin, Tw_Peg &r);
bool operator==(const Tw_Peg &left, const Tw_Peg &right);

#endif