/**
* This method accepts a position and returns an ArrayList made up of four or less cells that are
* 1) neighbors, 2) not null and 3) within the boundaries of the grid.
*
* @param p position to validate
* @return validated list of neighbors that are not null and within boundaries
*/
private ArrayList<Position> getValidatedNeighbors(Position p) {
// Set boundaries
int r = p.getRow();
int c = p.getCol();
int maxColIndex = getWidth() - 1;
int maxRowIndex = getHeight() - 1;
int minIndex = 0;
// Create new positions for each neighbor
Position above = new Position(r - 1, c);
Position below = new Position(r + 1, c);
Position left = new Position(r, c - 1);
Position right = new Position(r, c + 1);
Position[] temp = {above, below, left, right};
ArrayList<Position> validated = new ArrayList<Position>();
// If within boundaries and not null, add neighbor to validated
for (int i = 0; i < 4; i++) {
if (temp[i].getRow() > maxRowIndex || temp[i].getRow() < minIndex) {
temp[i] = null;
} else if (temp[i].getCol() > maxColIndex || temp[i].getCol() < minIndex) {
temp[i] = null;
}
if (temp[i] != null) {
validated.add(temp[i]);
}
}
return validated;
}
@Override
public ArrayList<Position> determineCellsToCollapse() {
ArrayList<Position> cellsToCollapse = new ArrayList<Position>();
for (int row = 0; row < getHeight(); row++) {
for (int col = 0; col < getWidth(); col++) {
if (getGridIcon(row, col) != null) {
Position focus = new Position(row, col);
int r = focus.getRow();
int c = focus.getCol();
// Bounds checking, returns neighbors that are not null and within the grid
ArrayList<Position> neighbors = getValidatedNeighbors(focus);
GridCell center = getGridIcon(r, c);
GridCell[] cells = new GridCell[neighbors.size()];
ArrayList<Position> posMatches = new ArrayList<Position>();
for (int i = 0; i < neighbors.size(); i++) {
cells[i] = getGridIcon(neighbors.get(i).getRow(), neighbors.get(i).getCol());
if (center.matches(cells[i])) {
posMatches.add(neighbors.get(i));
}
}
// Store position matches here until we know that there are at least two matches for the
// cell
if (posMatches.size() >= 2) {
posMatches.add(focus);
cellsToCollapse.addAll(posMatches);
posMatches.clear();
}
}
}
}
score += cellsToCollapse.size();
return cellsToCollapse;
}