;;;; This file is part of LilyPond, the GNU music typesetter.
;;;;
;;;; Copyright (C) 2005--2011 Erik Sandberg <mandolaerik@gmail.com>
;;;;
;;;; 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/>.


(use-modules (srfi srfi-1))

;; Event class hierarchy. Each line is on the form (Parent . (List of children))
(define event-classes
  '((() . (StreamEvent))
    (StreamEvent .
		 (RemoveContext ChangeParent Override Revert UnsetProperty
				SetProperty music-event OldMusicEvent CreateContext Prepare
				OneTimeStep Finish))
    (music-event . (annotate-output-event footnote-event
		    arpeggio-event breathing-event extender-event span-event
      rhythmic-event dynamic-event break-event label-event percent-event
      key-change-event string-number-event stroke-finger-event tie-event
      part-combine-event part-combine-force-event
      beam-forbid-event script-event tempo-change-event
      tremolo-event bend-after-event fingering-event glissando-event
      harmonic-event hyphen-event laissez-vibrer-event mark-event
      multi-measure-text-event note-grouping-event
      pes-or-flexa-event repeat-tie-event spacing-section-event
      layout-instruction-event completize-extender-event break-span-event))

    (layout-instruction-event . (apply-output-event))
    (script-event . (articulation-event text-script-event))
    (part-combine-event . (solo-one-event solo-two-event unisono-event))
    (break-event . (line-break-event page-break-event page-turn-event))
    (dynamic-event . (absolute-dynamic-event))
    (span-event . (span-dynamic-event beam-event episema-event ligature-event
			 pedal-event phrasing-slur-event slur-event staff-span-event
			 text-span-event trill-span-event tremolo-span-event
			 tuplet-span-event))
    (span-dynamic-event . (decrescendo-event crescendo-event))
    (break-span-event . (break-dynamic-span-event))
    (pedal-event . (sostenuto-event sustain-event una-corda-event))
    (rhythmic-event . (lyric-event melodic-event multi-measure-rest-event
				   double-percent-event percent-event
				   repeat-slash-event rest-event
				   skip-event bass-figure-event))
    (melodic-event . (cluster-note-event note-event))
    (() . (Announcement))
    (Announcement . (AnnounceNewContext))
    ))

;; Maps event-class to a list of ancestors (inclusive)
(define ancestor-lookup (make-hash-table 11))

;; Each class will be defined as
;; (class parent grandparent .. )
;; so that (eq? (cdr class) parent) holds.
(for-each
 (lambda (rel)
   (for-each
    (lambda (type)
      (hashq-set! ancestor-lookup type
		  (cons type (hashq-ref ancestor-lookup (car rel) '()))))
    (cdr rel)))
 event-classes)

(define-public (define-event-class leaf heritage)
  (cond
   ((not (eq? leaf (car heritage)))
    (ly:warning (_ "All classes must be the last in their matrilineal line.")))
   ((not (equal? (cdr heritage)
                 (list-head (hashq-ref ancestor-lookup (cadr heritage) '())
                            (length (cdr heritage)))))
    (ly:warning (_ "All classes must have a well-defined pedigree in the existing class hierarchy.")))
   (else (hashq-set! ancestor-lookup
                     leaf
                     (cons leaf
                           (hashq-ref ancestor-lookup
                                      (cadr heritage)
                                      '()))))))

;; TODO: Allow entering more complex classes, by taking unions.
(define-public (ly:make-event-class leaf)
 (hashq-ref ancestor-lookup leaf))

(define-public (ly:in-event-class? ev cl)
  "Does event @var{ev} belong to event class @var{cl}?"
  (memq cl (ly:make-event-class (ly:event-property ev 'class))))

;; does this exist in guile already?
(define (map-tree f t)
  (cond
   ((list? t)
    (map (lambda (x) (map-tree f x)) t))
   ((pair? t)
    (cons (map-tree f (car t)) (map-tree f (cdr t))))
   (else (f t))))

;; expand each non-leaf subtree to (root . children), recursively
(define (expand-event-tree root)
  (let ((children (assq root event-classes)))
    (if children
	(cons root (map expand-event-tree (cdr children)))
	root)))

;; All leaf event classes that no translator listens to
;; directly.  Avoids printing a warning.
(define unlistened-music-event-classes
  '(harmonic-event line-break-event page-break-event page-turn-event label-event
		   solo-one-event solo-two-event skip-event unisono-event
		   part-combine-force-event break-dynamic-span-event))

;; produce neater representation of music event tree.
;; TODO: switch to this representation for the event-classes list?
(define music-event-tree (expand-event-tree 'music-event))
(define (sort-tree t)
  (define (stringify el)
	      (if (symbol? el)
		  (symbol->string el)
		  (symbol->string (first el))))
  (if (list? t)
      (sort (map (lambda (el)
		   (if (list? el)
		       (cons (car el) (sort-tree (cdr el)))
		       el))
		 t)
	    (lambda (a b) (string<? (stringify a) (stringify b))))
      t))

;;(use-modules (ice-9 pretty-print))
;;(pretty-print (cons (car music-event-tree) (sort-tree (cdr music-event-tree))))

;; check that the music event tree corresponds well with the set of
;; available translators; print warnings otherwise.
(map-tree (lambda (sym)
	    (if (and (symbol? sym)
		     (not (ly:is-listened-event-class sym))
		     (not (assq sym event-classes))
		     (not (memq sym unlistened-music-event-classes)))
		(ly:programming-error (_ "event class ~A seems to be unused") sym)))
	  music-event-tree)

(map (lambda (sym)
       (if (not (pair? (ly:make-event-class sym)))
	   ;; should be programming-error
	   (ly:error (_ "translator listens to nonexisting event class ~A") sym)))
     (ly:get-listened-event-classes))

(defmacro-public make-stream-event (expr)
  (Stream_event::undump (primitive-eval (list 'quasiquote expr))))

(define* (simplify e)
  (cond
   ;; Special case for lists reduces stack consumption.
   ((list? e) (map simplify e))
   ((pair? e) (cons (simplify (car e))
		    (simplify (cdr e))))
   ((ly:stream-event? e)
    (list 'unquote (list 'make-stream-event (simplify (Stream_event::dump e)))))
   ((ly:music? e)
    (list 'unquote (music->make-music e)))
   ((ly:moment? e)
    (list 'unquote `(ly:make-moment
		     ,(ly:moment-main-numerator e)
		     ,(ly:moment-main-denominator e)
		     . ,(if (eq? 0 (ly:moment-grace-numerator e))
			    '()
			    (list (ly:moment-grace-numerator e)
				  (ly:moment-grace-denominator e))))))
   ((ly:duration? e)
    (list 'unquote `(ly:make-duration
		     ,(ly:duration-log e)
		     ,(ly:duration-dot-count e)
		     ,(car (ly:duration-factor e))
		     ,(cdr (ly:duration-factor e)))))
   ((ly:pitch? e)
    (list 'unquote `(ly:make-pitch
		     ,(ly:pitch-octave e)
		     ,(ly:pitch-notename e)
		     ,(ly:pitch-alteration e))))
   ((ly:input-location? e)
    (list 'unquote '(ly:dummy-input-location)))
   (#t e)))

(define-public (ly:simplify-scheme e)
  (list 'quasiquote (simplify e)))
