;; ganoi.mut : Good ol towers of hanoi done "graphically"
;; Usage:
;;      (hanoi <n>)
;;          <n> - an integer number of discs
;; C Durland	Public Domain

(include me2.h)

(defun 
  hanoi  MAIN
  {
    (int DISKS)

    (if (or (> (DISKS (convert-to NUMBER (ask "DISKS (max 9) = "))) 9)
	    (< DISKS 1))
	{ (msg "Bogus number of disks")(done) })
    (set-up DISKS)
    (transfer 0 1 2 DISKS)
    (buffer-modified -1 FALSE)
    (msg "done.")
  }
  transfer (from to via)(int n)
  {
    (if (== n 1)(move-disk from to)
    {
      (transfer from via to (- n 1))
      (move-disk from to)
      (transfer via to from (- n 1))
    })
  }
)

(array int Pegs 3 20)	; (Pegs n 0) ==> count
(defun set-up (int disks)
{
  (int n)

  (Pegs 0 0 disks)(Pegs 1 0 (Pegs 2 0 0))
  (n 1)(while (<= n disks){(Pegs 0 n (- disks n -1))(+= n 1)})
  (switch-to-buffer "HANOI")
  (clear-buffer)
  (insert-text
"              A                        B                        C")
  (newline)(n 10)
  (while (>= (n (- n 1)) 0)
  {
    (insert-text
"              |                        |                        |        ")
    (newline)
  })
    (insert-text
"     ====================     ====================     ====================")
  (n 1)
  (while 
  {
    (put-a-disk (Pegs 0 n)(Pegs 0 n) n 0)
    (<= (+= n 1) disks)
  } ())
})

(defun
  move-disk (int from to)
  {
    (int a b d)
;(msg "move-disk: " (arg 0) " " (arg 1) " " (Pegs 0 0) " " (Pegs 1 0) " " (Pegs 2 0))(getchar)
    (a (Pegs from 0))(b (+ (Pegs to 0) 1)) (d (Pegs from a))
    (Pegs from 0 (- a 1))(Pegs to b d)(Pegs to 0 b)
    (put-a-disk " "  d a from)(put-a-disk d d b to)
  }
  post (int n)
  {
    (switch n
      0 15
      1 40
      2 65
    )
  }
  move-to (int row col) { (goto-line row)(current-column col) }
  put-a-disk	; input: disk character, number of characters, row, post
    (dchar)(int dn drow dpost)
  {
    (int row col n)
;(msg "put-a-disk \""(arg 0)"\" "(arg 1)" "(arg 2)" "(arg 3))(getchar)
    (row (- 12 drow))(col (post dpost))
    (n (+ (* 2 dn) 1))
    (move-to row (- col (/ n 2)))
    (while (<= 0 (n (- n 1))){(insert-text dchar)(delete-character)})
    (move-to row col)(delete-character)(insert-text "|")
    (update)
  }
)