;;;; This file is part of LilyPond, the GNU music typesetter.
;;;;
;;;; Copyright (C) 1998--2012 Han-Wen Nienhuys <hanwen@xs4all.nl>
;;;;		     Jan Nieuwenhuizen <janneke@gnu.org>
;;;;                 Neil Puttock <n.puttock@gmail.com>
;;;;                 Carl Sorensen <c_sorensen@byu.edu>
;;;;
;;;; LilyPond is free software: you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; the Free Software Foundation, either version 3 of the License, or
;;;; (at your option) any later version.
;;;;
;;;; LilyPond is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;;; GNU General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU General Public License
;;;; along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.

;; TODO: should link back into user manual.

(define (mm-rest-child-list music)
  "Generate events for multimeasure rests,
to be used by the sequential-iterator"
  (let ((location (ly:music-property music 'origin))
	(duration (ly:music-property music 'duration)))
    (list (make-music 'BarCheck
		      'origin location)
	  (make-event-chord (cons (make-music 'MultiMeasureRestEvent
					      'origin location
					      'duration duration)
				  (ly:music-property music 'articulations)))
	  (make-music 'BarCheck
		      'origin location))))

(define (make-volta-set music)
  (let* ((alts (ly:music-property music 'elements))
         (lalts (length alts))
         (times (ly:music-property music 'repeat-count)))
    (map (lambda (x y)
           (make-music
             'SequentialMusic
             'elements
               ;; set properties for proper bar numbering
               (append
                 (list (make-music 'AlternativeEvent
                                   'alternative-dir (if (= y 0)
                                                        -1
                                                        0)
                                   'alternative-increment
                                     (if (= 0 y)
                                         (1+ (- times
                                                lalts))
                                             1)))
                       (list x)
                       (if (= y (1- lalts))
                           (list (make-music 'AlternativeEvent
                                             'alternative-dir 1
                                             'alternative-increment 0))
                           '()))))
         alts
         (iota lalts))))

(define (make-ottava-set music)
  "Set context properties for an ottava bracket."
  (let ((octavation (ly:music-property music 'ottava-number)))

    (list (context-spec-music
	   (make-apply-context
	    (lambda (context)
	      (let ((offset (* -7 octavation))
		    (string (assoc-get octavation '((2 . "15ma")
						    (1 . "8va")
						    (0 . #f)
						    (-1 . "8vb")
						    (-2 . "15mb")))))
		(set! (ly:context-property context 'middleCOffset) offset)
		(set! (ly:context-property context 'ottavation) string)
		(ly:set-middle-C! context))))
	   'Staff))))

(define (make-time-signature-set music)
  "Set context properties for a time signature."
  (let* ((num (ly:music-property music 'numerator))
         (den (ly:music-property music 'denominator))
         (structure (ly:music-property music 'beat-structure))
         (fraction (cons num den)))
    (list (descend-to-context
            (context-spec-music
              (make-apply-context
                (lambda (context)
                  (let* ((time-signature-settings
                          (ly:context-property context 'timeSignatureSettings))
                         (my-base-fraction
                           (base-fraction fraction time-signature-settings))
                         (my-beat-structure
                           (if (null? structure)
                               (beat-structure my-base-fraction
                                               fraction
                                               time-signature-settings)
                               structure))
                         (beaming-exception
                           (beam-exceptions fraction time-signature-settings))
                         (new-measure-length (ly:make-moment num den)))
                     (ly:context-set-property!
                       context 'timeSignatureFraction fraction)
                     (ly:context-set-property!
                       context 'baseMoment (fraction->moment my-base-fraction))
                     (ly:context-set-property!
                       context 'beatStructure my-beat-structure)
                     (ly:context-set-property!
                       context 'beamExceptions beaming-exception)
                     (ly:context-set-property!
                       context 'measureLength new-measure-length))))
                'Timing)
            'Score))))