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

(defun data (filename)
  (with-open-file (in filename)
    (loop for line = (read-line in nil nil)
          while line
          collect (cl-ppcre:register-groups-bind (val (#'parse-integer flow) others)
                      ("Valve (\\w+) has flow rate=(\\d+); tunnels? leads? to valves? (.+)" line)
                    `(,(intern val) ,flow ,@(mapcar #'intern (cl-ppcre:split ", " others)))))))


(defun next-steps (current graph paths)
  (flet ((appropriate (next)
           (and (not (gethash next paths)) ;; not visited
                (setf (gethash next paths) (cons next (gethash current paths))))))
    (remove-if-not #'appropriate (cddr (assoc current graph :test #'eq)))))

(defun shortest-path (graph from to)
  (let ((paths (make-hash-table :test #'eq)))
    (setf (gethash from paths) (list from))
    (labels ((traverse (queue paths)
               (unless (null queue)
                 (let ((next (next-steps (car queue) graph paths)))
                   (unless (member to next :test #'eq)
                     (traverse (append (cdr queue) next) paths))))))
      (traverse (list from) paths))
    ;; (loop for k being the hash-keys in paths using (hash-value v)
    ;;       do (format t "~a=>~a~%" k v))
    (gethash to paths)))

(defun path-release (path)
  (loop for ((name flow) . distance) in path
        sum (1+ distance) into runtime
        sum (* flow (- 30 runtime)) into release
        finally (return release)))

(= 340 (path-release '(((a 5) . 1) ((b 8) . 2))))
(shortest-path (data "eg-in") 'AA 'CC)

(defun next-options (current graph visited)
  (flet ((appropriate (next)
           (and (not (gethash next paths)) ;; not visited
                (setf (gethash next paths) (cons next (gethash current paths))))))
    (remove-if-not #'appropriate (cddr (assoc current graph :test #'eq))))
  )
q
(let* ((graph (data "eg-in"))
       (interesting (remove-if #'zerop graph :key #'cadr))
       (open nil))

  (sort
   (mapcar (lambda (node)
             (cons (subseq node 0 2)
                   (length (shortest-path graph 'aa (car node)))))
           interesting)
   #'>
   :key (lambda (destination)
          (destructuring-bind ((name flow) . distance) destination
            ;; because start is in path take that as valve opening time
            (- flow distance))))
  )

(adjoin 'c '(b c))