;nyquist plug-in
;version 3
;type generate
;categories "http://lv2plug.in/ns/lv2core#GeneratorPlugin"
;name "Click Track..."
;action "Generating Click Track..."
;info "by Dominic Mazzoni, modified by David R. Sky and Steve Daulton.\nReleased under terms of the GNU General Public License version 2.\nFor help, select one of two help screens in 'Action choice' below."

;; Released under terms of the GNU General Public License version 2:
;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html .
;; original clicktrack.ny by Dominic Mazzoni,
;; modified by David R. Sky and Steve Daulton.
;; Minimum Audacity version: 1.3.4
;;
;; bug fixes and restructured by Steve Daulton Sept 2011.
;; string input verification added by Steve Daulton, 2009.
;; added click pitch [user request] and sound types fields September 2007 (D.R.Sky).
;; added optional total click track duration field [requested by Mike Mullins]
;; June 2009 (D.R.Sky).
;; added individual click duration field [requested by Quinto Milana]
;; June 2009 (D.R.Sky).
;;
;; Drip sound generator by Paul Beach,
;; used with permission.
;;
;; Thanks very much to Gale Andrews, who gave extensive visual feedback
;; and suggestions!

;control action "Action choice" choice "Generate track, help screen 1, help screen 2" 0
;control tempo "Tempo [beats per minute]" real "30 - 300 beats/minute" 120 30 300
;control sig "Beats per measure [bar]" int "1 - 20 beats/measure" 4 1 20
;control measures "Number of measures [bars]" int "1 - 1000 bars" 16 1 1000
;control click-track-dur "Optional click track duration [minutes seconds]" string "Whole numbers only" ""  
;control ticklen "Individual click duration [milliseconds]" int "1 - 100 ms" 10 1 100
;control offset "Start time offset [seconds]" real "0 - 30 seconds" 0 0 30
;control click-type "Click sound" choice "ping,noise,tick" 0
;control q "Noise click resonance - discernable pitch [q]" int "1 - 20" 1 1 20
;control high "MIDI pitch of strong click" int "18 - 116" 92 18 116
;control low "MIDI pitch of weak click" int "18 - 116" 80 18 116


(defun help1 ()
  (format nil
"Click Track Generator help - screen 1 of 2

Generates a click track at the selected tempo, beats per
measure, and either number of measures or track duration,
using selected click sound.

'Tempo': number of beats (clicks) per minute.

'Beats per measure (bar)': For example, 3/4 time means one
strong click then two others to form one bar, repeated
depending on 'number of measures' or 'click track duration'.

'Optional click track duration': If you enter a value into this
field, either [minutes seconds] (separated by a space), or
[seconds], the generated click track will be at or slightly
longer than this duration: the end of the track is extended
into a whole measure if the entered duration does not
produce this. Use whole numbers only.

If you enter a value into this field, the 'number of measures'
value will be ignored.

To generate click track or view help screen 2,
restart Click Track and select from 'Action choice'.")) ;end of help1


(defun help2 ()
  (format nil
"Click Track Generator help - screen 2 of 2

'Individual click duration': the duration of each individual
click, minimum of 1 millisecond (ms) to maximum of 100 ms.

'Start time offset': makes the click track start at a later
time than the very beginning (zero seconds), maximum
of 30 seconds.

'Click sound': choose between ping, noise or tick sound
for clicks.

'Noise click resonance': the higher this value, the more
clearly noise clicks have a tone.

'MIDI pitch of strong/weak click': MIDI values indicate\nwhat pitch to use. C-notes are:

24, 36, 48, 60 (middle C), 72, 84, 96, 108.
C# (C-sharp) above middle C is 61.

To generate click track or view help screen 1,
restart Click Track and select from 'Action choice'.")) ;end of help 2


;Check function: returns 1 on error
;min and max are allowable min and max values for arg
(defun check (arg min max)
  (if (and (>= arg min) (<= arg max)) 0 1))


;Function to convert a string into a list
(defun string-to-list (string)
  (read (make-string-input-stream (format nil "(~a)" string))))


(defun round-up (x)
  (if (> x (truncate x))
    (truncate (1+ x))
    (truncate x)))


(defun m-s-to-seconds (mslist)
  (if (= (length mslist) 1)
    ;just seconds
    (first mslist)
    ;minutes and seconds
    (+ (* 60 (first mslist))(second mslist))))


;Function to generate drip sound clicks
;code by Paul Beach www.proviewlandscape.com/liss/
;stretch-abs function makes this sound more like 'tick' sounds.
;limit hz to nyquist frequency.
(defun drip (p) ;p is pitch in hz
  (let* ((maxhz (/ *sound-srate* 2.1))
        (hz1 (min maxhz (* 2.40483  p)))
        (hz2 (min maxhz (* 5.52008  p)))
        (hz3 (min maxhz (* 8.653  p)))
        (hz4 (min maxhz (* 11.8  p))))
    (lp 
      (stretch-abs 1
        (mult (exp-dec 0 0.015 0.25) 
          (sim
            (mult (hzosc hz1) 0.5)
            (mult (hzosc hz2)  0.25)
            (mult (hzosc hz3)  0.125)
            (mult (hzosc hz4)  0.0625))))
    440)))


;Function used to normalize noise and tick clicks
;this function is necessary because filtering 
;changes amplitude of filtered noise clicks
(defun normalize (sound)
  (scale (/ (peak sound ny:all)) sound))


;; Error Checking
(defun errorcheck ()
  ; tempo
  (if (= (check tempo 30 300) 1)
    (setq error-msg (strcat error-msg (format nil
"Tempo ~a outside valid range 30 to 300 bpm
" tempo))))

  ;beats per measure
  (if (= (check sig 1 20) 1)
    (setq error-msg (strcat error-msg (format nil
"Beats per measure ~a outside valid range 1 to 20
" sig))))

  ;number of measures
  (if (= (check measures 1 1000) 1)
    (setq error-msg (strcat error-msg (format nil
"Number of measures ~a outside valid range 1 to 1000
" measures))))

  ;time start offset
  (if (= (check offset 0 30) 1)
    (setq error-msg (strcat error-msg (format nil
"Time offset ~a outside valid range 0 to 30 seconds
" offset))))

  ; q
  (if (= (check q 1 20) 1)
    (setq error-msg (strcat error-msg (format nil
"Filter quality q ~a outside valid range 1 to 20
" q))))

  ;high MIDI pitch
  (if (= (check high 18 116) 1)
    (setq error-msg (strcat error-msg (format nil
"High MIDI pitch ~a outside valid range 18 to 116
" high))))

  ;low MIDI pitch
  (if (= (check low 18 116) 1)
    (setq error-msg (strcat error-msg (format nil
"Low MIDI pitch ~a outside valid range 18 to 116
" low))))

  ;validate string
  (if (> (length m-s) 0) ;if at least one item
    (cond
      ((or 
        (> (length m-s) 2) ;there are more than 2 items or
        (not (integerp (first m-s))) ;first is not an integer or
        (and (= (length m-s) 2)(not (integerp (second m-s))))) ;second is not an integer
      (setq error-msg (strcat error-msg (format nil 
"If used, 'Optional click track duration' must be 
entered as either one number [seconds], or two 
numbers [minutes seconds] separated by a space.
Use whole numbers only.~%"))))
      ;one or two integers
      ((and 
          (= (length m-s) 1) ;one integer and
          (= (check (first m-s) 0 3660) 1)) ;outside valid range
        (setq error-msg (strcat error-msg (format nil 
"~a seconds is outside valid range 0 to 3660~%" (first m-s)))))
      ;one or two integers
      ((and
        (= (length m-s) 2) ;2 integers and
        (or
          (= (check (first m-s) 0 60) 1) ;1st is outside valid range or
          (= (check (second m-s) 0 59) 1))) ;2nd is outside valid range or
        (setq error-msg (strcat error-msg (format nil 
"~a is outside valid range 0 to [60 59]~%"
    m-s))))))) ;end of error checking


;Function to make click
(defun click (type accent)
  (setq pitch (if (= accent 1) high low))
  (setq amp (if (= accent 1) 0.75 0.5))
  (stretch-abs ticklen 
    ;pwl is used to add 5ms fade-in and fade-out of clicks
    (mult 
      (control-srate-abs *sound-srate*
        (pwl 0.005 amp 0.995 amp 1))
      (case type
        (0 (osc pitch)) ;ping click
        (1 (normalize (lowpass2 (noise 1) (step-to-hz pitch) q))) ;noise click
        (2 (normalize (drip (step-to-hz pitch)))))))) ;tick click
        

;Function to make one measure
(defun makemeasure ()
  (setf measure (click click-type 1)) ;accented click
  (dotimes (x (- sig 1))
    (setf measure (sim measure
      (at (* beatlen (+ x 1))                 
        (click click-type 0)))))) ;unaccented clicks
        

;Function to loop measures
(defun loop (bar number sig beatlen)
  (do* ((result bar) ;initialise result
        (count 1 (setq count (1+ count))))
        ((= count number) result) ;up to number of measures and return result
    (setq mtime (* count sig beatlen)) ;set time for next measure				
    (setf result (sim result (at mtime (cue bar))))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; START MAIN PROGRAM
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
      
;view 1 of 2 help screens, or generate click track
(cond ;'master' cond
  ((= action 1)(help1)); display help screen 1
  ((= action 2)(help2)) ; display help screen 2
  (t ;Run Program
    (setq len (/ (* 60.0 *sound-srate* sig measures) tempo))
    (setq error-msg "") ;initialize error-msg	
    
    ;convert minutes-seconds string to a list
    ;for example, "4 30" becomes (4 30)
    (setf m-s (string-to-list click-track-dur))

    ;run error checks on input values
    (errorcheck)

    (if (= (length error-msg) 0) ;if no errors, generate Click Track
      (progn
        ; duration of 1 click, originally statically 0.01 s
        (setf ticklen (* (max 1 (min 100 ticklen)) 0.001))
        (setf beatlen (/ 60.0 tempo))
        
        ;call function to make one measure
        (makemeasure)
    
        ;calculate measures from text input (if used)
        (if m-s (setq measures 
          (/ (m-s-to-seconds m-s)(* sig beatlen))))

        ;round up number of measures
        (setq measures (round-up measures))

        ;loop measures
        (setf clicktrack (loop measure measures sig beatlen))
      
        ;add time offset and beatlen of silence to clicktrack,
        (seq (s-rest offset) ;offset
          (cue clicktrack) ;click track
          (s-rest(- beatlen ticklen)))) ;trailing silence
      ;Else error message
      (setq error-msg (strcat (format nil
"Error.~%You have entered at least one invalid value:~%~%") error-msg)))))