import java.util.*;
/**
 * This class defines what a move is and provides methods for 
 * generating moves for a player or for a piece.
 * There are two fields, both ints, start and end.
 * start is the number of position of the piece before the move is made, while
 * end is the number of the position where the piece ends up after making
 * the move.
 */

public class aMove{
    private int start;
    private int end;

    /**
     * The start and end are both initialized to -1.  This is an ileagal move.
     */
    public aMove(){
	this.start =-1;
	this.end = -1;
    }
    /**
     * Start is set to be i, and end is set to be j.
     * There is no checking as to whether this move is legal.
     */
    public aMove(int i, int j){
	this.start =i;
	this.end =j;
    }

    /**
     * Start is set to be i, and end is set to be j.
     * There is no checking as to whether this move is legal.
     */
    public void Set(int i, int j){
	start =i;
	end =j;
    }
    /**
     * Returns start
    */
    public int GetStart(){
	return start;
    }
    /** 
     * Returns end
     */
    public int GetEnd(){
	return end;
    }

    /**
     * Given a CheckerBoard and a player, returns a LinkedList of aMoves
     * that includes all legal moves (but no jumps) that the player can make.
     *  @parameters player must be either 'p' or 'o'.
     */
    static public LinkedList GetMoves(CheckerBoard b, char c){
	LinkedList l = new LinkedList();
	int i;
	char player;

	if(c=='p'||c=='P'){ player ='p';}
	else {
	    if (c=='o'||c=='O') {player = 'o';}
	    else{player ='e';}
	}

	switch(player){
	case 'p':
	    for(i=0;i<32;i++){
		if(b.Piece(i)=='p'||b.Piece(i)=='P'){
		    l.addAll(GetMoves(b,i));
		}
	    }
	    break;
	case 'o':
	    for(i=0;i<32;i++){
		if(b.Piece(i)=='o'||b.Piece(i)=='O'){
		    l.addAll(GetMoves(b,i));
		}
	    }
	    break;
	default:
	    break;
	}
	return l;
	
    }

    /**
     * Given a checkerboard and an int specifying a board position, returns 
     * a LinkedList of all possible moves (but no jumps) that can be made
     * by the piece in that position.
     */

    static public LinkedList GetMoves(CheckerBoard b, int pos){
	LinkedList l = new LinkedList();
	ArrayList nbrs = new ArrayList();
	char piece;
	int size,i,place;
	aMove m;

	//	System.out.println("The position is " + pos);
	piece = b.board[pos].piece;
	//	System.out.println("The piece is " + piece);
	nbrs = b.board[pos].GetNeighbours();
	switch(piece){
	case 'e':
	    break;
	case 'p':
	    /* process neighbours */
	    size = nbrs.size();
	    for(i=0;i<size;i++){
		place = ((Integer)nbrs.get(i)).intValue();
		if(b.isEmpty(place)&&(place>pos)){
		    /* there is a move */
		    m = new aMove(pos,place);
		    l.add(m);
		}
	    }
	    
	    break;
	case 'o':
	    /* process neighbours */
	    size = nbrs.size();
	    for(i=0;i<size;i++){
		place = ((Integer)nbrs.get(i)).intValue();
		if((b.isEmpty(place))&&(place<pos)){
		    /* there is a move */
		    m = new aMove(pos,place);
		    l.add(m);
		}
	    }
	    
	    break;
	case 'O': case 'P':
	    size = nbrs.size();
	    for(i=0;i<size;i++){
		place = ((Integer)nbrs.get(i)).intValue();
		if(b.isEmpty(place)){
		    /* there is a move */
		    m = new aMove(pos,place);
		    l.add(m);
		}
	    }
	    
	    break;


	default:
	    break;
	}

	return l;
    }
    /**
     * Given a CheckerBoard and an aMove, returns a new CheckerBoard
     * where the move has been  executed.
     */

    static public CheckerBoard MakeMove(CheckerBoard b, aMove m){
	CheckerBoard newb = new CheckerBoard();
	int i;
	char piece;
	int end;
	/* 1. Copy the old board*/
	for(i=0;i<32;i++){
	    newb.SetPiece(i,b.Piece(i));
	}
	/* 2. Make move */
	piece = b.Piece(m.GetStart());
	end = m.GetEnd();

	newb.SetPiece(m.GetStart(),'e');
	/* check to see if piece is being crowned */
	//	System.out.println("End is  "+ end);
	newb.SetPiece(end,piece);
	if(end>27 && piece=='p'){
	    newb.SetPiece(end,'P');
	}

	if(end<5 && end>-1 && piece =='o'){
	    newb.SetPiece(end,'O');
	}
	
	//newb.SetPiece(m.GetEnd(),piece);
	//newb.SetPiece(m.GetStart(),'e');
	return newb;
    }


}