/*
  This file is part of LilyPond, the GNU music typesetter.

  Copyright (C) 1997--2020 Han-Wen Nienhuys <hanwen@xs4all.nl>

  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/>.
*/

#include "engraver.hh"

#include "context.hh"
#include "grob-properties.hh"
#include "international.hh"
#include "music.hh"
#include "paper-column.hh"
#include "score-engraver.hh"
#include "spanner.hh"
#include "stream-event.hh"
#include "warn.hh"

Engraver_group *
Engraver::get_group () const
{
  // safe: Engravers belong to Engraver_groups
  return static_cast<Engraver_group *> (Translator::get_group ());
}

void
Engraver::announce_grob (Grob_info inf, Context *reroute_context)
{
  get_group ()->announce_grob (inf, START, reroute_context);
}

void
Engraver::announce_end_grob (Grob_info inf, Context *reroute_context)
{
  get_group ()->announce_grob (inf, STOP, reroute_context);
}

Grob_info
Engraver::make_grob_info (Grob *e, SCM cause)
{
  /* TODO: Remove Music code when it's no longer needed */
  if (Music *m = unsmob<Music> (cause))
    {
      cause = m->to_event ()->unprotect ();
    }
  if (scm_is_null (get_property (e, "cause"))
      && (unsmob<Stream_event> (cause) || unsmob<Grob> (cause)))
    set_property (e, "cause", cause);

  return Grob_info (this, e);
}

/*
  CAUSE is the object (typically a Stream_event object)  that
  was the reason for making E.
*/
void
Engraver::announce_grob (Grob *e, SCM cause)
{
  announce_grob (make_grob_info (e, cause));
}

/*
  CAUSE is the object (typically a grob or stream-event object) that
  was the reason for ending E.  */
void
Engraver::announce_end_grob (Grob *e, SCM cause)
{
  announce_end_grob (make_grob_info (e, cause));
}

Engraver::Engraver (Context *c)
  : Translator (c)
{
}

#ifdef DEBUG
static SCM creation_callback = SCM_EOL;
LY_DEFINE (ly_set_grob_creation_callback, "ly:set-grob-creation-callback",
           1, 0, 0, (SCM cb),
           "Specify a procedure that will be called every time a new grob"
           " is created.  The callback will receive as arguments the grob"
           " that was created, the name of the C++ source file that caused"
           " the grob to be created, and the corresponding line number in"
           " the C++ source file.")
{
  LY_ASSERT_TYPE (ly_is_procedure, cb, 1);

  creation_callback = cb;

  return SCM_UNSPECIFIED;
}
#endif

Grob *
Engraver::internal_make_grob (SCM symbol,
                              SCM cause,
                              char const *file,
                              int line,
                              char const *fun)
{
#ifndef DEBUG
  (void)file;
  (void)line;
  (void)fun;
#endif

  SCM props = Grob_property_info (context (), symbol).updated ();
  Grob *grob = 0;
  if (!scm_is_pair (props))
    {
      programming_error (to_string ("No grob definition found for `%s’.",
                                    ly_symbol2string (symbol).c_str ()));
      grob = new Item (SCM_EOL);
    }
  else
    {
      SCM handle = scm_sloppy_assq (ly_symbol2scm ("meta"), props);
      SCM klass = scm_cdr (scm_sloppy_assq (ly_symbol2scm ("class"), scm_cdr (handle)));

      if (scm_is_eq (klass, ly_symbol2scm ("Item")))
        grob = new Item (props);
      else if (scm_is_eq (klass, ly_symbol2scm ("Spanner")))
        grob = new Spanner (props);
      else if (scm_is_eq (klass, ly_symbol2scm ("Paper_column")))
        grob = new Paper_column (props);
    }
  assert (grob);
  announce_grob (grob, cause);

#ifdef DEBUG
  if (ly_is_procedure (creation_callback))
    scm_call_4 (creation_callback,
                grob->self_scm (), scm_from_utf8_string (file),
                to_scm (line), scm_from_ascii_string (fun));
#endif

  return grob;
}

Item *
Engraver::internal_make_item (SCM x, SCM cause,
                              char const *file, int line, char const *fun)
{
  Item *it = dynamic_cast<Item *> (internal_make_grob (x, cause, file, line, fun));
  assert (it);
  return it;
}

Paper_column *
Engraver::internal_make_column (SCM x, char const *file, int line, char const *fun)
{
  return dynamic_cast<Paper_column *> (internal_make_grob (x, SCM_EOL, file, line, fun));
}

Spanner *
Engraver::internal_make_spanner (SCM x, SCM cause,
                                 char const *file, int line, char const *fun)
{
  Spanner *sp = dynamic_cast<Spanner *> (internal_make_grob (x, cause, file, line, fun));
  assert (sp);
  return sp;
}

bool
ly_is_grob_cause (SCM obj)
{
  return unsmob<Grob> (obj) || unsmob<Stream_event> (obj) || scm_is_null (obj);
}
