(system-include "carp_int.h")

(doc Int "is the default integral data type.")
(defmodule Int
  (register + (λ [Int Int] Int))
  (register - (λ [Int Int] Int))
  (register * (λ [Int Int] Int))
  (register / (λ [Int Int] Int))
  (register < (λ [Int Int] Bool))
  (register > (λ [Int Int] Bool))
  (register = (λ [Int Int] Bool))
  (register copy (λ [&Int] Int))
  (register inc (λ [Int] Int))
  (register dec (λ [Int] Int))
  (register neg (λ [Int] Int))
  (register mod (λ [Int Int] Int))

  (doc to-int "acts as the identity function to implement the interface.")
  (sig to-int (Fn [Int] Int))
  (defn to-int [a] a)

  (doc from-int "acts as the identity function to implement the interface.")
  (sig from-int (Fn [Int] Int))
  (defn from-int [a] a)

  (implements + Int.+)
  (implements - Int.-)
  (implements * Int.*)
  (implements / Int./)
  (implements < Int.<)
  (implements > Int.>)
  (implements = Int.=)
  (implements copy Int.copy)
  (implements inc Int.inc)
  (implements dec Int.dec)
  (implements neg Int.neg)
  (implements mod Int.mod)
  (implements to-int Int.to-int)
  (implements from-int Int.from-int)
)

(defmodule Int
  (register MAX Int "CARP_INT_MAX")
  (register MIN Int "CARP_INT_MIN")
  (register bit-shift-left (λ [Int Int] Int))
  (register bit-shift-right (λ [Int Int] Int))
  (register bit-and (λ [Int Int] Int))
  (register bit-or (λ [Int Int] Int))
  (register bit-xor (λ [Int Int] Int))
  (register bit-not (λ [Int] Int))
  (implements bit-shift-left Int.bit-shift-left)
  (implements bit-shift-right Int.bit-shift-right)
  (implements bit-and Int.bit-and)
  (implements bit-or Int.bit-or)
  (implements bit-xor Int.bit-xor)
  (implements bit-not Int.bit-not)

  (doc abs "The absolute value (removes the negative sign) of an Int.")
  (register abs (λ [Int] Int))
  (implements abs Int.abs)

  (defn even? [a] (= (mod a 2) 0))
  (defn odd? [a] (not (even? a)))

  (defn zero []
    0)
  (implements zero Int.zero)

  (defn add-ref [x y]
    (Int.+ @x @y))

  ;; Move to generic math module?
  (defn clamp [min, max, val]
    (if (> val max)
      max
      (if (< val min)
        min
        val)))

  (doc pow "Raise x to the power of y.")
  (defn pow [x y]
    (let-do [r 1]
      (while (/= y 0)
        (do
          (when (/= (bit-and y 1) 0)
            (set! r (* r x)))
          (set! y (/ y 2))
          (set! x (* x x))))
      r))

  (doc positive-mod "Like mod but always returns a positive answer.")
  (defn positive-mod [k n]
    (let [r (Int.mod k n)]
      (if (> 0 r)
        (+ r n)
        r)))

  (implements add-ref Int.add-ref)
  (implements pow Int.pow)
)

(defmodule IntRef
  (defn = [a b]
    (Int.= @a @b))
  (implements = IntRef.=)

  (defn < [a b]
    (Int.< @a @b))
  (implements < IntRef.<)

  (defn > [a b]
    (Int.> @a @b))
  (implements > IntRef.>)
)