(ql:quickload '(fiveam str cl-ppcre arrows uiop))


(setf markers
      (loop for line in (uiop:read-file-lines "eg-in")
            for (sx sy bx by) = (multiple-value-bind (match values)
                                    (cl-ppcre:scan-to-strings "Sensor at x=(-?\\d+), y=\(-?\\d+\): closest beacon is at x=(-?\\d+), y=(-?\\d+)"
                                                              line)
                                  (map 'list #'parse-integer values))
            nconc (list (cons sx sy) (cons bx by))))

(defun bounds (markers)
  (list (list
         (loop for (x . y) in markers minimize x)
         (loop for (x . y) in markers maximize x))
        (list
         (loop for (x . y) in markers minimize y)
         (loop for (x . y) in markers maximize y))))

(defun grid (bounds)
  (destructuring-bind ((xmin xmax) (ymin ymax)) bounds
    (make-array (* (- xmax xmin -1) (- ymax ymin -1)) :initial-element 0 :element-type '(unsigned-byte 2))))

(defun in-grid (bounds)
  (destructuring-bind ((xmin xmax) (ymin ymax)) bounds
    (let ((stride (- xmax xmin -1)))
      (lambda (x y)
        (when (and (<= xmin x xmax) (<= ymin y ymax))
          (+ (- x xmin) (* (- y ymin) stride)))))))


(defun draw-grid (grid stride)
  (let ((out (make-string-output-stream)))
    (loop for elt across grid
          for idx from 0
          do (progn (when (= 0 (mod idx stride)) (terpri out))
                    (princ (case elt
                             (0 ".")
                             (1 "S")
                             (2 "B")) out)))
    (get-output-stream-string out)))

(let* ((bounds (bounds markers))
       (loc (in-grid bounds))
       (grid (grid bounds)))
  (loop for ((sx . sy) (bx . by)) on markers by #'cddr
        do (progn (princ (list sx sy bx by))
                  (setf (aref grid (funcall loc sx sy)) 1)
                  (setf (aref grid (funcall loc bx by)) 2)))
  (destructuring-bind ((xmin xmax) a) bounds
    (princ (draw-grid grid (- xmax xmin -1)))
    )
  )