/*   
  staff-side.cc --  implement Staff_side_element
  
  source file of the GNU LilyPond music typesetter
  
  (c) 1998--2002 Han-Wen Nienhuys <hanwen@cs.uu.nl>
  
 */
#include <math.h>		// ceil.

#include "side-position-interface.hh"
#include "debug.hh"
#include "warn.hh"
#include "dimensions.hh"
#include "staff-symbol-referencer.hh"
#include "group-interface.hh"
#include "directional-element-interface.hh"

void
Side_position_interface::add_support (Grob*me, Grob*e)
{
  Pointer_group_interface::add_grob (me, ly_symbol2scm ("side-support-elements"), e);
}



Direction
Side_position_interface::get_direction (Grob*me)
{
  SCM d = me->get_grob_property ("direction");
  if (ly_dir_p (d) && to_dir (d))
    return to_dir (d);

  Direction relative_dir = Direction (1);
  SCM reldir = me->get_grob_property ("side-relative-direction");	// should use a lambda.
  if (ly_dir_p (reldir))
    {
      relative_dir = to_dir (reldir);
    }
  
  SCM other_elt = me->get_grob_property ("direction-source");
  Grob * e = unsmob_grob (other_elt);
  if (e)
    {
      return (Direction) (relative_dir * Directional_element_interface::get (e));
    }
  
  return CENTER;
}
  

MAKE_SCHEME_CALLBACK (Side_position_interface,aligned_on_support_extents, 2);
SCM
Side_position_interface::aligned_on_support_extents (SCM element_smob, SCM axis)
{
  Grob *me = unsmob_grob (element_smob);
  Axis a = (Axis) gh_scm2int (axis);

  return general_side_position (me, a, true);
}


/*
 Puts the element next to the support, optionally taking in
 account the extent of the support.
*/
SCM
Side_position_interface::general_side_position (Grob * me, Axis a, bool use_extents)
{


  /*
    As this is only used as a callback, this is called only once. We
    could wipe SIDE-SUPPORT-ELEMENTS after we retrieve it to conserve
    memory; however -- we should look more into benefits of such actions?

    The benefit is small, it seems: total GC times taken don't
    differ. Would this also hamper Generational GC ?
    
  */
  SCM support = me->get_grob_property ("side-support-elements");
  Grob *common = common_refpoint_of_list (support, me->get_parent (a), a);
  
  Interval dim;
  for (SCM s = support; s != SCM_EOL; s = ly_cdr (s))
    {
      Grob * e  = unsmob_grob (ly_car (s));
      if (e)
	if (use_extents)
	  dim.unite (e->extent (common, a));
	else
	  {
	    Real x = e->relative_coordinate (common, a);
	    dim.unite (Interval (x,x));
	  }
    }

  if (dim.empty_b ())
    {
      dim = Interval (0,0);
    }

  Direction dir = Side_position_interface::get_direction (me);
    
  Real off =  me->get_parent (a)->relative_coordinate (common, a);
  SCM minimum = me->remove_grob_property ("minimum-space");

  Real total_off = dim.linear_combination (dir) + off;
  SCM padding = me->remove_grob_property ("padding");
  if (gh_number_p (padding))
    {
      total_off += gh_scm2double (padding) * dir;
    }

  if (gh_number_p (minimum) 
      && dir
      && total_off * dir < gh_scm2double (minimum))
    {
      total_off = gh_scm2double (minimum) * dir;
    }

  if (fabs (total_off) > 100 CM)
    programming_error ("Huh ? Improbable staff side dim.");

  return gh_double2scm (total_off);
}

/*
  Cut & paste (ugh.)
 */
MAKE_SCHEME_CALLBACK (Side_position_interface,aligned_on_support_refpoints,2);
SCM
Side_position_interface::aligned_on_support_refpoints (SCM smob, SCM axis)
{
  Grob *me = unsmob_grob (smob);
  Axis a = (Axis) gh_scm2int (axis);

  return  general_side_position (me, a, false); 
}




Real
directed_round (Real f, Direction d)
{
  if (d < 0)
    return floor (f);
  else
    return ceil (f);
}

/*
  Callback that quantises in staff-spaces, rounding in the direction
  of the elements "direction" elt property.

  Only rounds when we're inside the staff, as determined by
  Staff_symbol_referencer::staff_radius () */
MAKE_SCHEME_CALLBACK (Side_position_interface,quantised_position,2);
SCM
Side_position_interface::quantised_position (SCM element_smob, SCM)
{
  Grob *me = unsmob_grob (element_smob);
  
  
  Direction d = Side_position_interface::get_direction (me);

  if (Staff_symbol_referencer::has_interface (me))
    {
      Real p = Staff_symbol_referencer::position_f (me);
      Real rp = directed_round (p, d);
      Real rad = Staff_symbol_referencer::staff_radius (me) *2 ;
      int ip = int (rp);

      if (abs (ip) <= rad && Staff_symbol_referencer::on_staffline (me,ip))
	{
	  ip += d;
	  rp += d;
	}

      return gh_double2scm ((rp - p) * Staff_symbol_referencer::staff_space (me) / 2.0);
    }
  return gh_double2scm (0.0);
}

/*
  Position next to support, taking into account my own dimensions and padding.
 */
MAKE_SCHEME_CALLBACK (Side_position_interface,aligned_side,2);
SCM
Side_position_interface::aligned_side (SCM element_smob, SCM axis)
{
  Grob *me = unsmob_grob (element_smob);
  Axis a = (Axis) gh_scm2int (axis);
  
  Direction d = Side_position_interface::get_direction (me);
  
  Real o = gh_scm2double (aligned_on_support_extents (element_smob,axis));

  Interval iv =  me->extent (me, a);

  if (!iv.empty_b ())
    {
      if (!d)
	{
	  programming_error ("Direction unknown, but aligned-side wanted.");
	  d = DOWN;
	}
      o += - iv[-d];

      SCM pad = me->get_grob_property ("padding");
      if (gh_number_p (pad))
	o += d *gh_scm2double (pad) ; 
    }
  return gh_double2scm (o);
}

void
Side_position_interface::add_staff_support (Grob*me)
{
  Grob* st = Staff_symbol_referencer::staff_symbol_l (me);
  if (st && get_axis (me) == Y_AXIS)
    {
      add_support (me,st);
    }
}

void
Side_position_interface::set_axis (Grob*me, Axis a)
{
  me->add_offset_callback (Side_position_interface::aligned_side_proc, a);
}



// ugh. doesn't cactch all variants. 
Axis
Side_position_interface::get_axis (Grob*me)
{
  if (me->has_offset_callback_b (Side_position_interface::aligned_side_proc, X_AXIS)
      || me->has_offset_callback_b (Side_position_interface::aligned_side_proc , X_AXIS))
    return X_AXIS;

  
  return Y_AXIS;
}

void
Side_position_interface::set_direction (Grob*me, Direction d)
{
  me->set_grob_property ("direction", gh_int2scm (d));
}

void
Side_position_interface::set_minimum_space (Grob*me, Real m)
{
  me->set_grob_property ("minimum-space", gh_double2scm (m));
}

void
Side_position_interface::set_padding (Grob*me, Real p)
{
  me->set_grob_property ("padding", gh_double2scm (p));
}


bool
Side_position_interface::supported_b (Grob*me) 
{
  SCM s = me->get_grob_property ("side-support-elements"); 
  return gh_pair_p (s);
}




ADD_INTERFACE (Side_position_interface,"side-position-interface",
  "Position a victim object (this one) next to other objects (the support).
#'direction = where to put the victim object (left or right?)
",
  "side-support-elements direction-source direction side-relative-direction minimum-space padding");
