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

  Copyright (C) 2006--2020 Han-Wen Nienhuys <hanwen@lilypond.org>
      2007--2008 Rune Zedeler
      2008       Joe Neeman <joeneeman@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/>.
*/

#include "scale.hh"
#include "protected-scm.hh"

#include <limits>

using std::vector;

/*
  todo: put string <-> pitch here too.
*/
LY_DEFINE (ly_make_scale, "ly:make-scale",
           1, 0, 0, (SCM steps),
           "Create a scale."
           "  The argument is a vector of rational numbers, each of which"
           " represents the number of 200 cent tones of a pitch above the"
           " tonic.")
{
  bool type_ok = scm_is_vector (steps);

  vector<Rational> tones;
  if (type_ok)
    {
      vsize len = scm_c_vector_length (steps);
      for (vsize i = 0; i < len; i++)
        {
          SCM step = scm_c_vector_ref (steps, i);
          type_ok = type_ok && scm_is_rational (step);
          if (type_ok)
            {
              Rational from_c (scm_to_int (scm_numerator (step)),
                               scm_to_int (scm_denominator (step)));
              tones.push_back (from_c);
            }
        }
    }

  SCM_ASSERT_TYPE (type_ok, steps, SCM_ARG1, __FUNCTION__, "vector of rational");

  return (new Scale (tones))->unprotect ();
}

Scale *default_global_scale = 0;
Protected_scm default_global_scale_scm (SCM_BOOL_F);

// TODO: This is somewhat fishy: pitches protect their scale via a
// mark_smob hook.  But since pitches are of Simple_smob variety, they
// are unknown to GUILE unless a smobbed_copy has been created.  So
// changing the default scale might cause some existing pitches to
// lose their scale's protection.

LY_DEFINE (ly_default_scale, "ly:default-scale",
           0, 0, 0, (),
           "Get the global default scale.")
{
  return default_global_scale_scm;
}

LY_DEFINE (ly_set_default_scale, "ly:set-default-scale",
           1, 0, 0, (SCM scale),
           "Set the global default scale.  This determines the tuning of"
           " pitches with no accidentals or key signatures.  The first"
           " pitch is C.  Alterations are calculated relative to this"
           " scale.  The number of pitches in this scale determines the"
           " number of scale steps that make up an octave.  Usually the"
           " 7-note major scale.")
{
  LY_ASSERT_SMOB (Scale, scale, 1);

  default_global_scale_scm = scale;
  default_global_scale = unsmob<Scale> (scale);

  return SCM_UNSPECIFIED;
}

int
Scale::step_count () const
{
  return static_cast<int> (step_tones_.size ());
}

Rational
Scale::tones_at_step (int step, int octave) const
{
  int normalized_step = normalize_step (step);

  octave += (step - normalized_step) / step_count ();

  // There are 6 tones in an octave.
  return step_tones_[normalized_step] + Rational (octave * 6);
}

Rational
Scale::step_size (int step) const
{
  int normalized_step = normalize_step (step);

  // Wrap around if we are asked for the final note of the
  // scale (6 is the number of tones of the octave above the
  // first note).
  if (normalized_step + 1 == step_count ())
    return Rational (6) - step_tones_[normalized_step];

  return step_tones_[normalized_step + 1] - step_tones_[normalized_step];
}

int
Scale::normalize_step (int step) const
{
  int ret = step % step_count ();
  if (ret < 0)
    ret += step_count ();

  return ret;
}

Scale::Scale (vector<Rational> const &tones)
{
  assert (tones.size () <= std::numeric_limits<int>::max ());
  step_tones_ = tones;

  smobify_self ();
}

Scale::Scale (Scale const &src)
  : Smob<Scale> ()
{
  step_tones_ = src.step_tones_;
  smobify_self ();
}

Scale::~Scale ()
{
}
