Nim Challenge

package gr.sullenart.games.nimchallenge.gameengine;

import java.util.Random;
import java.util.Vector;

//import android.util.Log;

public class NimEngine {

	private static Random random = new Random();

	private int boardSize;

	private boolean lastWins;
	
	public NimEngine(int boardSize, boolean lastWins) {
		this.boardSize = boardSize;
		this.lastWins = lastWins;
	}

	private boolean gameFinished = false;

	public boolean isGameFinished() {
		return gameFinished;
	}

	/*private Vector<int[]> getGameRows(int [] boardTable) {
		Vector<int[]> rows = new Vector<int[]>();

		boolean isPegFound;
		int start = 0, stop = 0;
		for (int r=0; r<boardSize; r++) {
			isPegFound = false;
			for (int c=0; c<boardSize; c++) {
				if (boardTable[r*boardSize + c] != 0 && !isPegFound) {
					isPegFound = true;
					start = r*boardSize + c;
					stop = start;
				}
				else if (boardTable[r*boardSize + c] != 0) {
					stop = r*boardSize + c;
				}
				else if (isPegFound &&
							(boardTable[r*boardSize + c] == 0 || c == (boardSize - 1)))
					{
					isPegFound = false;
					rows.add(new int [] {start, stop});
				}
			}
		}

		return rows;
	}*/

	private boolean evaluate(int [] boardTable)
	{
	    int [] sets = new int[boardSize];
	    int row, column, count;

	    for(int i=0; i<boardSize; i++) {
	    	sets[i] = 0;
	    }

	    for(row=0;row<boardSize;row++) {
	        count = 0;
	        for(column=0;column<boardSize;column++) {
	            if (boardTable[row*boardSize+column]==1) {
	                count++;
	            }
	            else if (boardTable[row*boardSize+column]==0 && count > 0) {
	                sets[count-1]++;
	                count = 0;
	            }
	        }
	        if (count > 0) {
	            sets[count-1]++;
	        }
	    }

	    if (!lastWins) {
	    	boolean onlyOnes = true;
		    for(int i=1;i<boardSize;i++) {
		        if (sets[i] > 0) {
		        	onlyOnes = false;
		        	break;
		        }
		    }
		    if (onlyOnes) {
		    	return sets[0] % 2 == 1;
		    }
	    }
	    
	    int result = 0;
	    for(int i=0;i<boardSize;i++) {
	        if (sets[i]%2!=0) {
	            result^=(i+1);
	        }
	    }

	    return result == 0;
	}


	private int getRemainingPegsCount(int [] boardTable)
	{
	    int count = 0;
		for(int i=0;i<boardSize*boardSize;i++) {
	        if (boardTable[i]!=0)
	            count++;
	    }
	    return count;
	}


	public Vector<Integer> getMove(int [] boardTable) {
		gameFinished = false;

		int remainingPegsCount = getRemainingPegsCount(boardTable);
		if (remainingPegsCount == 0) {
			gameFinished = true;
			return null;
		}
		Vector<int [] > moves = new Vector<int[]>();


		int [] tempBoard = new int [boardTable.length];
	    for(int i=0;i<boardSize*boardSize;i++) {
	        tempBoard[i] = boardTable[i];
	    }

	    int count = 0;
	    int moveCount = 0;
	    int selectedMove = 0;
	    int  winningMoveCount = 0;
	    for(int row=0;row<boardSize;row++) {
	        count = 0;
	        for(int column=0;column<boardSize;column++) {
	            if (boardTable[row*boardSize+column]==1) {
	                count++;
	            }
	            else {
	                count=0;
	            }

	            if (count > 0) {
	                moveCount++;
	                int [] move = new int[count];
	                int j = count - 1;
	                for(int i=row*boardSize+column; i>(row*boardSize+column-count);i--) {
	                    tempBoard[i] = 0;
	                    move[j--] = i;
	                }
	                moves.add(move);
	                if (evaluate(tempBoard)) {
	                    if (selectedMove == 0) {
	                        selectedMove = moveCount;
	                    }
	                    else {
	                        if (Math.random()>0.5)
	                        {
	                            selectedMove = moveCount;
	                        }
	                    }
	                    winningMoveCount++;
	                }
	                for(int i=row*boardSize+column;i>row*boardSize+column-count;i--) {
	                    tempBoard[i] = 1;
	                }
	            }
	        }
	    }

	    if (winningMoveCount == 0) {
	        selectedMove = random.nextInt(moveCount) + 1;
	    }

	    Vector<Integer> result = new Vector<Integer>();
	    for(int i: moves.get(selectedMove-1)) {
	    	result.add(i);
	    	boardTable[i] = 0;
	    }
	    gameFinished = remainingPegsCount == result.size();
		return result;
	}
}