(defmodule Bench
  (system-include "bench.h")

  (register get-time-elapsed (Fn [] Double))

  (defn get-unit [n]
    (cond
      (> n 1000.0) (String.append (Double.str n) "µs")
      (> n 1000000.0) (String.append (Double.str (/ n 1000.0)) "ms")
      (> n 1000000000.0) (String.append (Double.str (/ n 1000000.0)) "s")
      (String.append (Double.str (/ n 1000000000.0)) "s")))

  (defn print [title n]
    (let [unit (get-unit n)]
      (do
        (IO.println title)
        (IO.println &unit))))

  (defn ns-iter-inner [f k]
    (let [start (get-time-elapsed)]
      (do
        (for [i 0 n] (f))
        (Double.- (Bench.get-time-elapsed) before))))

  (defn dbl-cmp [a b]
    (Double.- a b))

  (defn winsorize [samples pct]
    (let [tmp (Array.sort samples dbl-cmp)
      ; and now?
      ))

  (defn bench [f]
    (let [ns (ns-iter-inner f 1)
          ns-target-total 1000000.0
          n (Double./ ns-target-total (if (> 1 ns) 1 ns))
          n (if (> 1 n) 1 n)
          total 0
          samples []]
      (while (< total 3000000000)
        (let [loop-start (get-time-elapsed)]
          (do
            (for [i 0 50]
              (set! &samples &(Array.push-back (Double./ (ns-iter-inner f n) n))))
            ; and now?
            ))))))

(defmacro benchn [n form]
  (list 'let ['before (Bench.get-time-elapsed)
              'times []]
    (list 'do
      (list 'for ['i 0 n]
        (list 'let ['before-once (Bench.get-time-elapsed)]
          (list 'do
            form
            (list 'set! &times (Array.push-back (Array.copy &times) (Double.- (get-time-elapsed) before-once))))))
      (list 'let ['total (Double.- (Bench.get-time-elapsed) before)
                  'per (list 'Double./ 'total (list 'Double.from-int n))]
        (do
          (Bench.print "Total time elapsed: " total)
          (Bench.print "Time elapsed per run (average): " per)
          (Bench.print "Best case: " (Statistics.min &times))
          (Bench.print "Worst case: " (Statistics.max &times))
          (Bench.print "Standard deviation: " (Statistics.stdev &times)))))))