#lang racket

(require (planet clements/rsound)
         (planet clements/rsound/draw)
         ffi/vector)

(define song-chunk
  (rs-read/clip
   "/Users/clements/clements/teaching/video-game-music/earworm-2011.wav"
   0 (* 44100 30)))

#;(play song-chunk)

(define msr signal->rsound)

(define (quantize q num)
  (/ (/ (floor (* q (* num 32768.0))) q) 32768.0))

;; given a sound and a multiplier, do "fake resampling"
;; by choosing a rounded sample from the original

;; given a factor and a sound, resample the sound (using simple rounding)
;; to obtain a new one. Using e.g. factor of 2 will make the sound one
;; octave higher and half as long.
(define (my-resample sound new-freq q)
  (define factor (let ([ans (/ new-freq (rsound-sample-rate sound))])
                   (printf "~s\n" ans)
                   ans))
  (define (left i) (quantize 
                    q
                    (rs-ith/left sound 
                                 (inexact->exact (floor 
                                                  (/ (floor (* factor i))
                                                     factor))))))
  (define (right i) (quantize
                     q
                     (rs-ith/right sound 
                                   (inexact->exact (floor
                                                    (/ (floor (* factor i)) 
                                                       factor))))))
  (parameterize ([default-sample-rate 
                   (rsound-sample-rate sound)])
    (signals->rsound (rs-frames sound)
                     left
                     right)))


(define start-clip (* 10 44100))

(rs-draw (clip song-chunk start-clip (+ start-clip 500)))

(define s (my-resample song-chunk 44100 1.0))

(rs-draw (clip s start-clip (+ start-clip 500)))
(play s)