Advent of code 2019/11

Ajax Direct

class Robot extends Intcode
{
    public function __construct($ops, $start)
    {
        parent::__construct($ops);

        $this->grid = new Grid();
        $this->grid->set([0, 0], $start);
        $this->pos  = xy([0, 0]);
        $this->dir  = 0; // [up, right, down, left]
        $this->mode = 0; // [write, move]
    }

    /**
     * Output a value
     *
     * @param int $value
     * @return void
     */
    public function sendOutput($value)
    {
        if ($this->mode) {
            // Rotate + Move
            $this->dir = Math::mod($this->dir + ((int) $value * 2) - 1, 4);
            $this->pos->direction(["up", "right", "down", "left"][$this->dir]);
        } else {
            // Write
            $this->grid->set($this->pos, $value ? 1 : 0);
        }

        $this->mode = ($this->mode + 1) % 2;
    }

    /**
     * Get an input
     *
     * @return int
     */
    public function getInput()
    {
        if ($this->grid->get($this->pos)) {
            return 1;
        } else {
            return 0;
        }
    }

    /**
     * Return the grid
     *
     * @return Grid
     */
    public function onStop()
    {
        return $this->grid;
    }
}

// ==================================================
// > PART 1
// ==================================================
$solution_1 = (new Robot($input, 0))->run()->cells()->count();

// ==================================================
// > PART 2
// ==================================================
$solution_2 = (new Robot($input, 1))->run()
    ->fillVoid(" ")->rows->callEach()->join("")->callEach()->replace(["0", "1"], [" ", "#"])->join("<br>");