public class Life implements ILife {
  private int width;
  private int height;
  private boolean[][] grid;

  public static void main(String[] args) {
    Life l = new Life(new String[]{
            "     ",
            "     ",
            " *** ",
            "     ",
            "     "
    });
    l = (Life) l.nextGeneration();
  }

  public Life() {
    this.width = 5;
    this.height = 5;
    this.grid = new boolean[width][height];
    nukeAll();
  }

  public Life(String[] setup) {
    this.height = setup.length;
    this.width = setup[0].length();
    this.grid = new boolean[width][height];

    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        if (setup[y].charAt(x) == '*') {
          setAlive(x, y);
        }
      }
    }
  }

  @Override
  public void nukeAll() {
    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        grid[x][y] = false;
      }
    }
  }

  @Override
  public void setAlive(int x, int y) {
    if (isInBounds(x, y)) {
      grid[x][y] = true;
    }
  }

  @Override
  public void setDead(int x, int y) {
  }

  @Override
  public boolean isAlive(int x, int y) {
    return isInBounds(x, y) && grid[x][y];
  }

  @Override
  public ILife nextGeneration() {
    Life newLife = new Life();
    newLife.width = this.width;
    newLife.height = this.height;
    newLife.grid = new boolean[width][height];

    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        int neighbors = countAliveNeighbors(x, y);

        if (isAlive(x, y)) {
          if (neighbors < 2 || neighbors > 3) {
            newLife.setDead(x, y);
          } else {
            newLife.setAlive(x, y);
          }
        } else {
          if (neighbors == 3) {
            newLife.setAlive(x, y);
          }
        }
      }
    }
    return newLife;
  }

  private int countAliveNeighbors(int x, int y) {
    int count = 0;
    for (int dy = -1; dy <= 1; dy++) {
      for (int dx = -1; dx <= 1; dx++) {
        if (dx == 0 && dy == 0) continue;
        if (isAlive(x + dx, y + dy)) count++;
      }
    }
    return count;
  }

  private boolean isInBounds(int x, int y) {
    return x >= 0 && x < width && y >= 0 && y < height;
  }
}