/** Copyright by Barry G. Becker, 2000-2011. Licensed under MIT License: http://www.opensource.org/licenses/MIT */
package com.barrybecker4.game.twoplayer.go.board.update;
import com.barrybecker4.game.common.GameContext;
import com.barrybecker4.game.twoplayer.go.board.GoBoard;
import com.barrybecker4.game.twoplayer.go.board.analysis.neighbor.NeighborType;
import com.barrybecker4.game.twoplayer.go.board.elements.position.GoBoardPosition;
import com.barrybecker4.game.twoplayer.go.board.elements.position.GoBoardPositionSet;
import com.barrybecker4.game.twoplayer.go.board.elements.string.GoString;
import com.barrybecker4.game.twoplayer.go.board.elements.string.GoStringSet;
import com.barrybecker4.game.twoplayer.go.board.elements.string.IGoString;
import com.barrybecker4.game.twoplayer.go.board.move.GoCaptureList;
import com.barrybecker4.game.twoplayer.go.board.move.GoMove;
/**
* Responsible for updating a go board after making a move.
*
* @author Barry Becker
*/
public class PostMoveUpdater extends PostChangeUpdater {
/**
* Update the board information data after a stone has been played.
* @param board board that changed.
* @param captureCounter captureCounter added or removed during the change
*/
PostMoveUpdater(GoBoard board, CaptureCounts captureCounter) {
super(board, captureCounter);
}
/**
* Update the board after move has been played.
* @param move the move that was just made.
*/
@Override
public void update(GoMove move) {
clearEyes();
GoBoardPosition stone = (GoBoardPosition) (getBoard().getPosition(move.getToLocation()));
board_.adjustLiberties(stone);
GoCaptureList captures = determineCaptures(stone);
move.setCaptures(captures);
updateStringsAfterMove(stone);
captures.removeFromBoard(getBoard());
assert (stone.getString().getNumLiberties(getBoard()) > 0):
"The placed stone " + stone + " has no liberties "+stone.getGroup() +"\n"+ getBoard().toString();
updateGroupsAfterMove(stone);
captureCounter_.updateCaptures(move, true);
}
/**
* Determine a list of enemy stones that are captured when this stone is played on the board.
* In other words determine all opponent strings (at most 4) whose last liberty is at the new stone location.
* @param stone stone that was just placed and caused stones to be captured (if any)
* @return list of captured stones. Empty if no captures.
*/
private GoCaptureList determineCaptures(GoBoardPosition stone) {
profiler_.startFindCaptures();
assert ( stone != null );
GoBoardPositionSet nbrs = nbrAnalyzer_.getNobiNeighbors( stone, NeighborType.ENEMY );
GoCaptureList captureList = new GoCaptureList();
// keep track of the strings captured so we don't capture the same one twice
GoStringSet capturedStrings = new GoStringSet();
for (GoBoardPosition enbr : nbrs) {
assert (enbr.isOccupied()): "enbr=" + enbr;
IGoString str = enbr.getString();
assert ( str.isOwnedByPlayer1() != stone.getPiece().isOwnedByPlayer1()):
"The "+str+" is not an enemy of "+stone;
assert ( str.size() > 0 ) : "Sting has 0 stones:" + str;
if ( str.getNumLiberties(getBoard()) == 0 && !capturedStrings.contains(str) ) {
capturedStrings.add( str );
// we need to add copies so that when the original stones on the board are
// changed we don't change the captures.
captureList.addCaptures(str.getMembers());
}
}
profiler_.stopFindCaptures();
return captureList;
}
/**
* Examine the neighbors of this added stone and determine how the strings have changed.
* For strings: examine the strongly connected neighbors. If more than one string borders, then
* we merge the strings. If only one borders, then we add this stone to that string. If no strings
* touch the added stone, then we create a new string containing only this stone.
* @param stone the stone that was just placed on the board.
*/
private void updateStringsAfterMove( GoBoardPosition stone ) {
profiler_.startUpdateStringsAfterMove();
GoBoardPositionSet nbrs = nbrAnalyzer_.getNobiNeighbors( stone, NeighborType.FRIEND );
if ( nbrs.size() == 0 ) {
// there are no strongly connected neighbors, create a new string
new GoString( stone, getBoard()); // stone points to the new string
}
else {
updateNeighborStringsAfterMove(stone, nbrs);
}
cleanupGroups();
profiler_.stopUpdateStringsAfterMove();
}
/**
* There is at least one neighbor string, so we will join to it/them.
* @param stone position where we just placed a stone.
* @param nbrs neighbors
*/
private void updateNeighborStringsAfterMove(GoBoardPosition stone, GoBoardPositionSet nbrs) {
GoBoardPosition nbrStone = nbrs.getOneMember();
GoString str = (GoString) nbrStone.getString();
str.addMember( stone, getBoard() );
getAllGroups().debugPrint( 3, "groups before merging:", true, true);
if ( nbrs.size() > 1 ) {
mergeStringsIfNeeded(str, nbrs);
}
}
/**
* Then we probably need to merge the strings.
* We will not, for example, if we are completing a clump of four.
*/
private void mergeStringsIfNeeded(GoString str, GoBoardPositionSet nbrs) {
for (GoBoardPosition nbrStone: nbrs ) {
// if its the same string then there is nothing to merge
IGoString nbrString = nbrStone.getString();
if ( str != nbrString ) {
str.merge(nbrString, getBoard());
}
}
}
/**
* First remove all the groups on the board.
* Then for each stone, find its group and add that new group to the board's group list.
* Continue until all stone accounted for.
* @param pos the stone that was just placed on the board.
*/
private void updateGroupsAfterMove(GoBoardPosition pos) {
profiler_.startUpdateGroupsAfterMove();
if (GameContext.getDebugMode() > 1) {
getAllGroups().confirmAllStonesInUniqueGroups();
}
profiler_.startRecreateGroupsAfterMove();
recreateGroupsAfterChange();
profiler_.stopRecreateGroupsAfterMove();
// verify that the string to which we added the stone has at least one liberty
assert (pos.getString().getNumLiberties(getBoard()) > 0):
"The placed stone "+pos+" has no liberties "+pos.getGroup();
////if ( GameContext.getDebugMode() > 1 )
////validator_.consistencyCheck(pos);
profiler_.stopUpdateGroupsAfterMove();
}
}