; ranks are 1-13 with 1 being two, 12 being king, and 13 being ace
; there are no suits, flushes, or ace-to-four straights
; takes a list of card ranks and returns the value of the best poker 
; hand which can be made with them
; returned list is hand type followed by cards in descending order
; all sorting is done highest to lowest
(
    (include *standard-cl-22*)
    (include sort.clinc)
    (include deep_compare.clinc)
    (include filtermap.clinc)
    (include slice.clinc)
    (include max.clinc)
    (defconstant FIVE_OF_A_KIND 10)
    (defconstant STRAIGHT_FLUSH 9)
    (defconstant FOUR_OF_A_KIND 8)
    (defconstant FULL_HOUSE 7)
    (defconstant FLUSH 6)
    (defconstant STRAIGHT 5)
    (defconstant THREE_OF_A_KIND 4)
    (defconstant TWO_PAIR 3)
    (defconstant PAIR 2)
    (defconstant HIGH_CARD 1)
    (defun straight_high_inner (ranks last count)
        (if (not ranks)
            ; at the end of the list
            0
            (if (= last (f ranks))
                ; skip identical cards
                (straight_high_inner (r ranks) started_ace last count)
                ; if the partial straight continues
                (if (= (f ranks) (- last 1))
                    (if (= count 4)
                        ; found a straight, add 3 to last because next and last are included
                        (+ last 3)
                        ; keep looking for a straight with the count going up by one
                        (straight_high_inner (r ranks) started_ace (f ranks) (+ count 1))
                    )
                    ; reset the count
                    (straight_high_inner (r ranks) started_ace (f ranks) 1)
                )
            )
        )
    )
    ; returns the high card of a straight or 0 if there isn't any
    ; ranks must be sorted in descending order
    (defun straight_high (ranks)
        (straight_high_inner (ranks (= (f ranks) 13) 0 0))
    )
    (defun group_by_count_inner (items last count)
        (if (not items)
            0
            (if (= (f items) last)
                (group_by_count_inner (r items) last (+ count 1))
                (assign val (group_by_count_inner (r items) (f items) 1)
                    (if last
                        (c (c count last) val)
                        val
                    )
                )
            )
        )
    )
    (defun group_by_count (items)
        (group_by_count_inner items 0 0)
    )
    (defun space_hand_calc (cards)
        (assign 
            rest (lambda (x) (r x))
            greater (lambda (x y) (> x y))
            ranks (sort greater cards)
            sh (straight_high ranks)
            max_straight (if sh
                (list STRAIGHT sh)
                0
            )
            groups (sort deep> (group_by_count ranks))
            (top_count . top_card) (f groups)
            (second_count . second_card) (f (r groups))
            topcards (map rest groups)
            max_group (if (= top_count 1)
                (c HIGH_CARD (slice topcards 5))
                (if (= top_count 2)
                    (if (= second_count 1)
                        (c PAIR (slice topcards 4))
                        (c TWO_PAIR (slice topcards 3))
                    )
                    (if (= top_count 3)
                        (if (= second_count 1)
                            (c THREE_OF_A_KIND (slice topcards 3))
                            (c FULL_HOUSE (slice topcards 2))
                        )
                        (if (= top_count 4)
                            (c FOUR_OF_A_KIND (slice topcards 2))
                            (c FIVE_OF_A_KIND (slice topcards 1))
                        )
                    )
                )
            )
            (max deep< (list max_straight max_group))
        )
    )
)