(load "../common.scm")

(define (read-starting-positions filename)
  (call-with-input-file
    filename
    (lambda (file)
      (let* [(player-1 (begin
			 (get-string-n file (string-length "Player 1 starting position: "))
			 (get-number file)))
	     (player-2 (begin
			 (get-string-n file (string-length "Player 2 starting position: "))
			 (get-number file)))]
	; subtracting one to play with a board numbered 0..9 instead of 1..10, just easier
	(values (- player-1 1) (- player-2 1))))))

(define (deterministic-dice)
  (let [(value -1)]
    (lambda ()
      (set! value (mod (+ value 1) 100))
      (+ value 1))))

(define (roll! position-score dice)
  (set-car! position-score (mod (+ (car position-score) (dice) (dice) (dice)) 10))
  (set-cdr! position-score (+ (car position-score) (cdr position-score) 1)))

(define (play-deterministic position-1 position-2)
  (let [(player-1 (cons position-1 0))
	(player-2 (cons position-2 0))
	(dice (deterministic-dice))
	(rolls 0)]
    (let loop ()
      (roll! player-1 dice)
      (set! rolls (+ rolls 3))
      (if (>= (cdr player-1) 1000)
	(* (cdr player-2) rolls)
	(begin
	  (roll! player-2 dice)
	  (set! rolls (+ rolls 3))
	  (if (>= (cdr player-1) 1000)
	    (* (cdr player-1) rolls)
	    (loop)))))))

(define (dirac-dice outcome)
  (let [(next outcome)]
    (lambda ()
      (if (null? next)
	#f
	(let [(value (car next))]
	  (set! next (cdr next))
	  value)))))

(define (play-dirac position-1 position-2)
  (let [(player-1 (list (cons position-1 0)))
	(player-2 (list (cons position-2 0)))
	(wins-1 0)
	(wins-2 0)]
    (let loop ()
      'no-idea-yet)))

(let-values [((position-1 position-2) (read-starting-positions "input"))]
  (printf "part 1:~% Rolls * Opponent Score = ~a~%"
	  (play-deterministic position-1 position-2))
  (printf "part 2:~% Max Winning Universes: ~a~%"
	  (play-dirac position-1 position-2)))