package mini2;

import api.ITransform;

/**
 * Transformation implementing Conway's Game of Life.
 * All cells have value 0 or 1. The new value is based on the center 
 * cell along with the sum S of its eight neighbors, according to 
 * the rules:
 * <ul>
 *   <li>if S is less than 2 the result is 0
 *   <li>if S is greater than 3 the result is 0
 *   <li>if the center cell is 1 and S is 2 or 3, the result is 1
 *   <li>if the center cell is 0 and S is exactly 3, the result is 1
 * </ul>
 * See
 * http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life
 *
 * <p>
 * The radius is 1 and the <code>isWrapped()</code> method 
 * always returns true.
 */
public class ConwayTransform implements ITransform
{

  @Override
  public int apply(int[][] elements){
	  // TODO
	  if(elements.length != (2 * getRadius() + 1) || elements[0].length != (2 * getRadius() + 1)){
		  throw new IllegalArgumentException();
	  }
	  int sum = 0;
	  for(int i = 0; i < elements.length; i++){
		  for(int j = 0; j < elements[0].length; j++){
			  if(elements[i][j] == 1){
				  sum++;
			  }
		  }
	  }
	  int center = elements[1][1];
	  sum = sum - center;
	  if(sum < 2){
		  return 0;
	  }
	  if(sum > 3){
		  return 0;
	  }
	  if(center == 1 && (sum == 2 || sum == 3)){
		  return 1;
	  }
	  if(center == 0 && sum == 3){
		  return 1;
	  }
	  return 0;
  }

  @Override
  public int getRadius()
  {
    return 1;
  }

  @Override
  public boolean isWrapped()
  {
    return true;
  }
  
}