/** Copyright by Barry G. Becker, 2000-2011. Licensed under MIT License: http://www.opensource.org/licenses/MIT */
package com.barrybecker4.game.twoplayer.go.board.elements.position;
import com.barrybecker4.common.format.FormatUtil;
import com.barrybecker4.game.common.board.BoardPosition;
import com.barrybecker4.game.twoplayer.go.board.GoBoard;
import com.barrybecker4.game.twoplayer.go.board.elements.IGoMember;
import com.barrybecker4.game.twoplayer.go.board.elements.eye.IGoEye;
import com.barrybecker4.game.twoplayer.go.board.elements.group.IGoGroup;
import com.barrybecker4.game.twoplayer.go.board.elements.string.IGoString;
/**
* The GoBoardPosition describes the physical marker at a location on the board.
* It can be empty or occupied. If occupied, then it is either black or white and has a string owner.
* A GoBoardPosition may have an eye owner if it is part of a group's eye.
*
* @author Barry Becker
*/
public final class GoBoardPosition extends BoardPosition
implements IGoMember {
/** the string (connected set of stones) to which this stone belongs. */
private IGoString string_;
/**
* if non-null then this position belongs to an eye string.
* The group owner of the eye is different than the owner of the string.
*/
private IGoEye eye_;
/**
* when true the stone has been visited already during a search.
* This is a temporary state that is used for some traversal operations.
*/
private boolean visited_;
/** the amount this position contributes to the overall score. */
private double scoreContribution_ = 0.0;
/**
* create a new go stone.
* @param row location.
* @param col location.
* @param string the string that this stone belongs to.
* @param stone the stone at this position if there is one (use null if no stone).
*/
public GoBoardPosition( int row, int col, IGoString string, GoStone stone) {
super( row, col, stone );
string_ = string;
eye_ = null;
visited_ = false;
}
/**
* Create a deep copy of this position.
*/
public GoBoardPosition(GoBoardPosition pos) {
this( pos.location_.getRow(), pos.location_.getCol(), pos.string_,
(pos.piece_ == null) ? null : (GoStone)pos.piece_.copy());
pos.setEye(getEye());
setVisited(pos.isVisited());
}
/**
* @return copy of this position.
*/
@Override
public GoBoardPosition copy() {
return new GoBoardPosition(this);
}
/**
* @param string the string owner we are assign to this stone.
*/
public void setString( IGoString string ) {
string_ = string;
}
/**
* @return the string owner for this stone.
* There may be none if its blank and part of an eye, in that case null is returned.
*/
public IGoString getString() {
return string_;
}
/**
* @return the group owner.
* There is only one group owner that has the same ownership (color) as this stone.
* The stone may also belong to to an eye in an opponent group, however.
*/
public IGoGroup getGroup() {
if (string_ != null)
return string_.getGroup();
if (eye_ != null) {
return eye_.getGroup();
}
return null;
}
/**
* @param eye the eye owner this space is to be assigned to
*/
public void setEye(IGoEye eye ) {
eye_ = eye;
}
/**
* @return the eye that this space belongs to. May be null if no eye owner.
*/
public IGoEye getEye() {
return eye_;
}
/**
*
* @return true if the string this stone belongs to is in atari
*/
public boolean isInAtari(GoBoard b) {
return (getString() != null && getString().getNumLiberties(b) == 1);
}
public void setVisited( boolean visited ) {
visited_ = visited;
}
public boolean isVisited() {
return visited_;
}
/**
* @return true if this position is part of an eye.
*/
public boolean isInEye() {
return eye_!=null;
}
/**
* we must recalculate the number of liberties every time because it changes often.
* @return the number of liberties the specified position has.
*/
public int getNumLiberties( GoBoard board ) {
int numLiberties = 0;
int row = getRow();
int col = getCol();
if ( row > 1 && board.getPosition( row - 1, col ).isUnoccupied() )
numLiberties++;
if ( row < board.getNumRows() && board.getPosition( row + 1, col ).isUnoccupied() )
numLiberties++;
if ( col > 1 && board.getPosition( row, col - 1 ).isUnoccupied() )
numLiberties++;
if ( col < board.getNumCols() && board.getPosition( row, col + 1 ).isUnoccupied() )
numLiberties++;
return numLiberties;
}
/**
* make it show an empty board position.
*/
public void clear(GoBoard board) {
IGoString string = getString();
if (string != null) {
string.remove(this, board);
} else {
assert isUnoccupied();
}
clear();
}
/**
* make it show an empty board position.
*/
@Override
public void clear() {
super.clear();
setString(null);
setEye(null);
scoreContribution_ = 0;
setVisited(false);
}
/**
* @return a string representation of the go board position
*/
@Override
public String getDescription() {
return super.getDescription()+ " score:"+ FormatUtil.formatNumber(scoreContribution_);
}
/**
* @return a string representation of the go board position
*/
@Override
public String toString() {
return super.toString()+ " s:"+ FormatUtil.formatNumber(scoreContribution_) + " hc:"+hashCode();
}
public double getScoreContribution() {
return scoreContribution_;
}
public void setScoreContribution(double scoreContribution) {
this.scoreContribution_ = scoreContribution;
}
}