public class Snake {

	private int snakeLength;
	private Position[] snakeBody;

	public Snake(int row, int col) {
		snakeLength = 1;
		snakeBody = new Position[5];
		Position initial = new Position(row, col);
		snakeBody[0] = initial;
	}

	public int getLength() {
		return snakeLength;
	}

	public Position getPosition(int index) {
		if(index < 0 || index >= snakeLength) {
			return null;
		}
		return snakeBody[index];
	}

	public void shrink() {
		snakeLength = snakeLength - 1;
	}

	public boolean snakePosition(Position pos) {
		for(int i = 0; i <= snakeBody.length-1;i++) {
			if (snakeBody[0] != null) {
				boolean isEqual = pos.equals(snakeBody[0]);
				if (isEqual == true) {
					return true;
				}
			}
		}
		return false;
	}

	public Position newHeadPosition(String direction) {
		Position pos = snakeBody[0];
		int currentCol = pos.getCol();
		int currentRow = pos.getRow();
		if(direction == "up") {
			pos = new Position(currentRow-1,currentCol);
		}
		if(direction == "down") {
			pos = new Position(currentRow+1,currentCol);
		}
		if(direction == "left") {
			pos = new Position(currentRow,currentCol-1);
		}
		if(direction == "right") {
			pos = new Position(currentRow,currentCol+1);
		}
		return pos;
	}

	public void moveSnake(String direction) {
		for(int i = 1; i < snakeLength - 2; i++) {
			snakeBody[i] = snakeBody[i-1];
		}
		Position newHead = newHeadPosition(direction);
		snakeBody[0] = newHead;
	}

	public void grow(String direction) {
		if(snakeLength <= snakeBody.length) {
			snakeLength = snakeLength + 1;
			snakeBody[0] = newHeadPosition(direction);
			for(int i = 1; i < snakeLength; i++) {
				snakeBody[i] = snakeBody[i-1];
			}
		} else {
			increaseArraySize();
			grow(direction);
		}
	}

	private void increaseArraySize() {
		Position[] newArray = new Position[snakeLength*2];
		snakeLength = snakeLength * 2;
		for (int i = 0; i < snakeBody.length; i++) {
			   newArray[i] = snakeBody[i];
			}
		snakeBody = newArray;
	}

	public static void main (String[] args) {
		Snake theSnake = new Snake(2,1);
		theSnake.snakePosition(new Position(0,1));

	}
}