/*
  key-item.cc -- implement Key_signature_interface

  source file of the GNU LilyPond music typesetter

  (c) 1996--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>

  keyplacement by Mats Bengtsson
*/

#include "item.hh"

#include "stencil.hh"
#include "output-def.hh"
#include "font-interface.hh"
#include "staff-symbol-referencer.hh"
#include "lookup.hh"
#include "lily-guile.hh"
#include "lily-proto.hh"
#include "accidental-interface.hh"

struct Key_signature_interface
{
  DECLARE_SCHEME_CALLBACK (print, (SCM ));

  static bool has_interface (Grob*);
};


/*
  FIXME: too much hardcoding here.
 */
const int FLAT_TOP_PITCH=2; /* fes,ges,as and bes typeset in lower octave */
const int SHARP_TOP_PITCH=4; /*  ais and bis typeset in lower octave */

/*
  TODO: look this up. I'm not sure where the naturals ought to go. 
 */
const int NATURAL_TOP_PITCH = 4;  




/*
  FIXME: key-item should just get a list of (position, acc), and leave
  the thinking to other parties.

  - TODO: put this in Scheme

  TODO: can  we do without c0pos? it's partly musical. 

*/
int
alteration_pos  (SCM what, int alter, int c0p)
{
  if (scm_is_pair (what))
    return scm_to_int (scm_car (what)) * 7 + scm_to_int (scm_cdr (what)) + c0p;

  int p = scm_to_int (what);

  // Find the c in the range -4 through 2
  int from_bottom_pos = c0p + 4;
  from_bottom_pos = from_bottom_pos%7;
  from_bottom_pos = (from_bottom_pos + 7)%7; // Precaution to get positive.
  int c0 = from_bottom_pos - 4;

    
  if ((alter <0 && ((p>FLAT_TOP_PITCH) || (p+c0>4)) && (p+c0>1))
      || (alter >0 && ((p > SHARP_TOP_PITCH) || (p+c0>5)) && (p+c0>2))
      || (alter == 0 && ((p > NATURAL_TOP_PITCH) || (p + c0>5)) && (p + c0>2)))
    {
      p -= 7; /* Typeset below c_position */
    }
  
  /* Provide for the four cases in which there's a glitch 
       it's a hack, but probably not worth  
       the effort of finding a nicer solution.
       --dl. */
  if (c0==2 && alter >0 && p==3)
    p -= 7;
  if (c0==-3 && alter>0 && p==-1)
    p += 7;
  if (c0==-4 && alter<0 && p==-1)
    p += 7;
  if (c0==-2 && alter<0 && p==-3)
    p += 7;
    
  return p + c0;
}

/*
  TODO
  - space the `natural' signs wider
 */
MAKE_SCHEME_CALLBACK (Key_signature_interface,print,1);
SCM
Key_signature_interface::print (SCM smob)
{
  Grob*me =unsmob_grob (smob);

  Real inter = Staff_symbol_referencer::staff_space (me)/2.0;

  SCM scm_style = me->get_property ("style");
  String style;
  if (scm_is_symbol (scm_style))
    {
      style = ly_symbol2string (scm_style);
    }
  else
    {
      style = "";
    }

  SCM newas = me->get_property ("new-accidentals");  
  Stencil mol;

  SCM c0s = me->get_property ("c0-position");
  int c0p = 0;
  if (scm_is_number (c0s))
    c0p = scm_to_int (c0s);

  /*
    SCM lists are stacks, so we work from right to left, ending with
    the cancellation signature.
  */

  Font_metric *fm = Font_interface::get_default_font (me);
  for (SCM s = newas; scm_is_pair (s); s = scm_cdr (s))
    {
      int alteration = scm_to_int (scm_cdar (s));
      String font_char =
	Accidental_interface::get_fontcharname (style, alteration);
      Stencil acc (fm->find_by_name ("accidentals-" + font_char));

      if (acc.is_empty ())
	{
	  me->warning (_f ("accidental `%s' not found", font_char));
	}
      else
	{
	  SCM what = scm_caar (s);
	  int pos = alteration_pos (what, alteration, c0p);
	  acc.translate_axis (pos * inter, Y_AXIS);
	  mol.add_at_edge (X_AXIS, LEFT, acc, 0, 0);
	}
    }

  Item *it = dynamic_cast<Item*> (me) ;
  if (it->break_status_dir () != RIGHT)
    {
      SCM old = me->get_property ("old-accidentals");
      
      Stencil natural;
      if (scm_is_pair (old))
	natural=Font_interface::get_default_font (me)->
	    find_by_name (String ("accidentals-") + style + String ("0"));
      

      int last_pos = -100;
      for (; scm_is_pair (old); old = scm_cdr (old))
        {
	  SCM found = scm_assoc (scm_caar (old), newas);
	  if (found == SCM_BOOL_F
	      || scm_cdr (found) != scm_cdar (old))
	    {
	      SCM what = scm_caar (old);
	      int alteration = 0;
	      int pos = alteration_pos (what, alteration, c0p);

	      Stencil m = natural;
              m.translate_axis (pos* inter, Y_AXIS);

	      /*
		The natural sign (unlike flat & sharp)
		has vertical edges on both sides. A little padding is
		needed to prevent collisions.
	       */
	      Real padding = 0.0;
	      if (last_pos < pos + 2
		  &&  last_pos> pos - 6)
		padding = 0.3;
	      
	      mol.add_at_edge (X_AXIS, LEFT, m, padding, 0);
	      last_pos = pos;
            }
        }
    }

  mol.align_to (X_AXIS, LEFT);
  
  return mol.smobbed_copy ();
}

ADD_INTERFACE (Key_signature_interface, "key-signature-interface",
  "A group of accidentals, to be printed as signature sign.",
  "style c0-position old-accidentals new-accidentals");
