/*
  vaticana-ligature-engraver.cc -- implement Vaticana_ligature_engraver
  
  source file of the GNU LilyPond music typesetter
  
  (c)  2003 Juergen Reuter <reuter@ipd.uka.de>
 */

#include "gregorian-ligature-engraver.hh"
#include "gregorian-ligature.hh"
#include "vaticana-ligature.hh"
#include "item.hh"
#include "spanner.hh"
#include "staff-symbol-referencer.hh"
#include "font-interface.hh"
#include "warn.hh"
#include "paper-def.hh"
#include "paper-column.hh"

/*
 * This class implements the notation specific aspects of Vaticana
 * style ligatures for Gregorian chant notation.
 */

class Vaticana_ligature_engraver : public Gregorian_ligature_engraver
{

private:
  bool is_stacked_head (int prefix_set,
			int context_info);
  Real align_heads (Array<Grob_info> primitives,
		    Real flexa_width,
		    Real thickness);

public:
  TRANSLATOR_DECLARATIONS(Vaticana_ligature_engraver);

protected:
  virtual Spanner *create_ligature_spanner ();
  virtual void transform_heads (Spanner *ligature,
				Array<Grob_info> primitives);
};

Vaticana_ligature_engraver::Vaticana_ligature_engraver ()
{
}

Spanner *
Vaticana_ligature_engraver::create_ligature_spanner ()
{
  return new Spanner (get_property ("VaticanaLigature"));
}

bool
Vaticana_ligature_engraver::is_stacked_head (int prefix_set,
					     int context_info)
{
      bool is_stacked_b;

      // upper head of pes is stacked upon lower head of pes ...
      is_stacked_b = context_info & PES_UPPER;

      // ... unless this note starts a flexa
      if (context_info & FLEXA_LEFT)
	is_stacked_b = false;

      // ... or another pes
      if (context_info & PES_LOWER)
	is_stacked_b = false;

      // ... or the previous note is a semivocalis or inclinatum
      if (context_info & AFTER_DEMINUTUM)
	is_stacked_b = false;

      // auctum head is never stacked upon preceding note
      if (prefix_set & AUCTUM)
	is_stacked_b = false;

      // virga is never stacked upon preceding note
      if (prefix_set & VIRGA)
	is_stacked_b = false;

      // oriscus is never stacked upon preceding note
      if (prefix_set & ORISCUS)
	is_stacked_b = false;

      if ((prefix_set & DEMINUTUM) &&
	  !(prefix_set & INCLINATUM) &&
	  (context_info & FLEXA_RIGHT))
	is_stacked_b = true; // semivocalis head of deminutus form

      return is_stacked_b;
}

/*
 * When aligning the heads, sometimes extra space is needed, e.g. to
 * avoid clashing with the appendix of an adjacent notehead or with an
 * adjacent notehead itself if it has the same pitch.  Extra space is
 * added at most once between to heads.
 */
bool
need_extra_space (int prev_prefix_set, int prefix_set,
		  int context_info, int delta_pitch)
{
  if (prev_prefix_set & VIRGA)
    /*
     * After a virga, make a an additional small space such that the
     * appendix on the right side of the head does not touch the
     * following head.
     */
    return true;

  if ((prefix_set & INCLINATUM) &&
	   !(prev_prefix_set & INCLINATUM))
    /*
     * Always start a series of inclinatum heads with an extra space.
     */
    return true;

  if ((context_info & FLEXA_LEFT) && !(context_info & PES_UPPER))
    /*
     * Before a flexa (but not within a torculus), make a an
     * additional small space such that the appendix on the left side
     * of the flexa does not touch the this head.
     */
    return true;

  if (delta_pitch == 0)
    /*
     * If there are two adjacent noteheads with the same pitch, add
     * additional small space between them, such that they do not
     * touch each other.
     */
    return true;

  return false;
}

Real
Vaticana_ligature_engraver::align_heads (Array<Grob_info> primitives,
					 Real flexa_width,
					 Real thickness)
{
  if (!primitives.size ())
    {
      programming_error ("Vaticana_ligature: "
			 "empty ligature [ignored]");
      return 0.0;
    }

  /*
   * The paper column where we put the whole ligature into.
   */
  Paper_column *column =
    dynamic_cast<Item*> (primitives[0].grob_)->get_column ();

  Real join_thickness =
    thickness * column->get_paper ()->get_realvar (ly_symbol2scm ("linethickness"));

  /*
   * Amount of extra space two put between some particular
   * configurations of adjacent heads.
   *
   * TODO: make this a property of primtive grobs.
   */
  Real extra_space = 4.0 * join_thickness;

  /*
   * Keep track of the total width of the ligature.
   */
  Real ligature_width = 0.0;

  Item *prev_primitive = 0;
  int prev_prefix_set = 0;
  for (int i = 0; i < primitives.size (); i++)
    {
      Item *primitive = dynamic_cast<Item*> (primitives[i].grob_);
      int prefix_set =
	gh_scm2int (primitive->get_grob_property ("prefix-set"));
      int context_info =
	gh_scm2int (primitive->get_grob_property ("context-info"));

      /*
       * Get glyph_name, delta_pitch and context_info for this head.
       */

      SCM glyph_name_scm = primitive->get_grob_property ("glyph-name");
      if (glyph_name_scm == SCM_EOL)
	{
	  primitive->programming_error ("Vaticana_ligature:"
					"undefined glyph-name -> "
					"ignoring grob");
	  continue;
	}
      String glyph_name = ly_scm2string (glyph_name_scm);

      int delta_pitch = 0;
      if (prev_primitive) /* urgh, need prev_primitive only here */
	{
	  SCM delta_pitch_scm = prev_primitive->get_grob_property ("delta-pitch");
	  if (delta_pitch_scm != SCM_EOL)
	    {
	      delta_pitch = gh_scm2int (delta_pitch_scm);
	    }
	  else
	    {
	      primitive->programming_error ("Vaticana_ligature:"
					    "delta-pitch undefined -> "
					    "ignoring grob");
	      continue;
	    }
	}

      /*
       * Now determine width and x-offset of head.
       */

      Real head_width;
      Real x_offset;

      if (context_info & STACKED_HEAD)
	{
	  /*
	   * This head is stacked upon the previous one; hence, it
	   * does not contribute to the total width of the ligature,
	   * and its width is assumed to be 0.0.  Moreover, it is
	   * shifted to the left by its width such that the right side
	   * of this and the other head are horizontally aligned.
	   */
	  head_width = 0.0;
	  x_offset = join_thickness -
	    Font_interface::get_default_font (primitive)->
	    find_by_name ("noteheads-" + glyph_name).extent (X_AXIS).length ();
	}
      else if (!String::compare (glyph_name, "flexa") ||
	       !String::compare (glyph_name, ""))
	{
	  /*
	   * This head represents either half of a flexa shape.
	   * Hence, it is assigned half the width of this shape.
	   */
	  head_width = 0.5 * flexa_width;
	  x_offset = 0.0;
	}
      else
	{
	  /*
	   * This is a regular head, placed right to the previous one.
	   * Retrieve its width from corresponding font.
	   */
	  head_width =
	    Font_interface::get_default_font (primitive)->
	    find_by_name ("noteheads-" + glyph_name).extent (X_AXIS).length ();
	  x_offset = 0.0;
	}

      /*
       * Save the head's final x-offset.
       */
      primitive->set_grob_property ("x-offset",
				    gh_double2scm (x_offset));

      /*
       * If the head is the 2nd head of a pes or flexa (but not a
       * flexa shape), mark this head to be joined with the left-side
       * neighbour head (i.e. the previous head) by a vertical beam.
       */
      if ((context_info & PES_UPPER) ||
	  ((context_info & FLEXA_RIGHT) &&
	   !(context_info & PES_LOWER)))
	{
	  if (!prev_primitive)
	    {
	      primitive->programming_error ("vaticana ligature: add-join: "
					    "missing previous primitive");
	    }
	  else
	    {
	      prev_primitive->set_grob_property ("add-join",
						 gh_bool2scm(true));

	      /*
	       * Create a small overlap of adjacent heads so that the join
	       * can be drawn perfectly between them.
	       */
	      ligature_width -= join_thickness;
	    }
	}
      else if (!String::compare (glyph_name, ""))
	{
	  /*
	   * This is the 2nd (virtual) head of flexa shape.  Join it
	   * tightly with 1st head, i.e. do *not* add additional
	   * space, such that next head will not be off from the flexa
	   * shape.
	   */
	}

      if (need_extra_space (prev_prefix_set, prefix_set,
			    context_info, delta_pitch))
	ligature_width += extra_space;

      /*
       * Horizontally line-up this head to form a ligature.
       */
      get_set_column (primitive, column);
      primitive->translate_axis (ligature_width, X_AXIS);
      ligature_width += head_width;

      prev_primitive = primitive;
      prev_prefix_set = prefix_set;
    }

  /*
   * Add extra horizontal padding space after ligature, such that
   * neighbouring ligatures do not touch each other.
   */
  ligature_width += extra_space;

  return ligature_width;
}

/*
 * Depending on the typographical features of a particular ligature
 * style, some prefixes may be ignored.  In particular, if a curved
 * flexa shape is produced, any prefixes to either of the two
 * contributing heads that would select a head other than punctum, is
 * by definition ignored.
 *
 * This function prints a warning, if the given primitive is prefixed
 * such that a head other than punctum would be chosen, if this
 * primitive were engraved as a stand-alone head.
 */
void
check_for_prefix_loss (Item *primitive)
{
  int prefix_set =
    gh_scm2int (primitive->get_grob_property ("prefix-set"));
  if (prefix_set & ~PES_OR_FLEXA)
    {
      String prefs = Gregorian_ligature::prefixes_to_str (primitive);
      primitive->warning (_f ("ignored prefix(es) `%s' of this head according "
			      "to restrictions of the selected ligature style",
			      prefs.to_str0 ()));
    }
}

void
Vaticana_ligature_engraver::transform_heads (Spanner *ligature,
					     Array<Grob_info> primitives)
{
  Real flexa_width;
  SCM flexa_width_scm = ligature->get_grob_property ("flexa-width");
  if (flexa_width_scm != SCM_EOL)
    {
      flexa_width = gh_scm2double (flexa_width_scm);
    }
  else
    {
      ligature->programming_error ("Vaticana_ligature_engraver:"
				   "flexa-width undefined; "
				   "assuming 2.0 staff space");
      flexa_width =
	2.0 * Staff_symbol_referencer::staff_space (ligature);
    }

  Real thickness;
  SCM thickness_scm = ligature->get_grob_property ("thickness");
  if (thickness_scm != SCM_EOL)
    {
      thickness = gh_scm2double (thickness_scm);
    }
  else
    {
      ligature->programming_error ("Vaticana_ligature_engraver:"
				   "thickness undefined; assuming 1.0");
      thickness = 1.0;
    }

  Item *prev_primitive = 0;
  int prev_prefix_set = 0;
  int prev_context_info = 0;
  int prev_delta_pitch = 0;
  String prev_glyph_name = "";
  for (int i = 0; i < primitives.size(); i++) {
    Item *primitive = dynamic_cast<Item*> (primitives[i].grob_);

    int delta_pitch;
    SCM delta_pitch_scm = primitive->get_grob_property ("delta-pitch");
    if (delta_pitch_scm != SCM_EOL)
      {
	delta_pitch = gh_scm2int (delta_pitch_scm);
      }
    else
      {
	primitive->programming_error ("Vaticana_ligature:"
				      "delta-pitch undefined -> "
				      "ignoring grob");
	continue;
      }

    /* retrieve & complete prefix_set and context_info */
    int prefix_set =
      gh_scm2int (primitive->get_grob_property ("prefix-set"));
    int context_info =
      gh_scm2int (primitive->get_grob_property ("context-info"));
    if (is_stacked_head (prefix_set, context_info))
      {
	context_info |= STACKED_HEAD;
	primitive->set_grob_property ("context-info",
				      gh_int2scm (context_info));
      }

    /*
     * Now determine which head to typeset (this is context sensitive
     * information, since it depends on neighbouring heads; therefore,
     * this decision must be made here in the engraver rather than in
     * the backend).
     */
    String glyph_name;
    if (prefix_set & VIRGA)
      {
	glyph_name = "vaticana_punctum";
	primitive->set_grob_property ("add-stem", gh_bool2scm(true));
      }
    else if (prefix_set & QUILISMA)
      glyph_name = "vaticana_quilisma";
    else if (prefix_set & ORISCUS)
      glyph_name = "solesmes_oriscus";
    else if (prefix_set & STROPHA)
      if (prefix_set & AUCTUM)
	glyph_name = "solesmes_stropha_aucta";
      else glyph_name = "solesmes_stropha";
    else if (prefix_set & INCLINATUM)
      if (prefix_set & AUCTUM)
	glyph_name = "solesmes_incl_auctum";
      else if (prefix_set & DEMINUTUM)
	glyph_name = "solesmes_incl_parvum";
      else
	glyph_name = "vaticana_inclinatum";
    else if (prefix_set & DEMINUTUM)
      if (i == 0)
	{
	  // initio debilis
	  glyph_name = "vaticana_reverse_plica";
	}
      else if (prev_delta_pitch > 0)
	{
	  // epiphonus
	  if (!(prev_context_info & FLEXA_RIGHT))
	    /* correct head of previous primitive */
	    if (prev_delta_pitch > 1)
	      prev_glyph_name = "vaticana_epiphonus";
	    else
	      prev_glyph_name = "vaticana_vepiphonus";
	  glyph_name = "vaticana_plica";
	}
      else // (prev_delta_pitch <= 0)
	{
	  // cephalicus
	  if (!(prev_context_info & FLEXA_RIGHT))
	    /* correct head of previous primitive */
	    {
	      if (i > 1)
		{
		  /* cephalicus head with fixed size cauda */
		  prev_glyph_name = "vaticana_inner_cephalicus";
		}
	      else
		{
		  /* cephalicus head without cauda */
		  prev_glyph_name = "vaticana_cephalicus";
		}

	      /*
	       * Flexa has no variable size cauda if its left head is
	       * stacked on the right head.  This is true for
	       * cephalicus.  Hence, remove the cauda.
	       *
	       * Urgh: for the current implementation, this rule only
	       * applies for cephalicus; but it is a fundamental rule.
	       * Therefore, the following line of code should be
	       * placed somewhere else.
	       */
	      prev_primitive->set_grob_property ("add-cauda",
						 gh_bool2scm(false));
	    }
	  glyph_name = "vaticana_reverse_plica";
	}
    else if (prefix_set & (CAVUM | LINEA))
      if ((prefix_set & CAVUM) && (prefix_set & LINEA))
	glyph_name = "vaticana_linea_punctum_cavum";
      else if (prefix_set & CAVUM)
	glyph_name = "vaticana_punctum_cavum";
      else
	glyph_name = "vaticana_linea_punctum";
    else if (prefix_set & AUCTUM)
      if (prefix_set & ASCENDENS)
	glyph_name = "solesmes_auct_asc";
      else
	glyph_name = "solesmes_auct_desc";
    else if ((context_info & STACKED_HEAD) &&
	     (context_info & PES_UPPER))
      if (prev_delta_pitch > 1)
	glyph_name = "vaticana_upes";
      else
	glyph_name = "vaticana_vupes";
    else
      glyph_name = "vaticana_punctum";

    /*
     * This head needs a cauda, if it starts a flexa, is not the upper
     * head of a pes, and if it is a punctum.
     */
    if ((context_info & FLEXA_LEFT) && !(context_info & PES_UPPER))
      if (!String::compare (glyph_name, "vaticana_punctum"))
	primitive->set_grob_property ("add-cauda", gh_bool2scm(true));

    /*
     * Execptional rule for porrectus:
     *
     * If the current head is preceded by a \flexa and succeded by a
     * \pes (e.g. "a \flexa g \pes a"), then join the current head and
     * the previous head into a single curved flexa shape.
     */
    if ((context_info & FLEXA_RIGHT) && (context_info & PES_LOWER))
      {
	check_for_prefix_loss (prev_primitive);
	prev_glyph_name = "flexa";
	prev_primitive->set_grob_property ("flexa-height",
					   gh_int2scm (prev_delta_pitch));
	prev_primitive->set_grob_property ("flexa-width",
					   gh_double2scm (flexa_width));
	bool add_cauda = !(prev_prefix_set && PES_OR_FLEXA);
	prev_primitive->set_grob_property ("add-cauda",
					   gh_bool2scm (add_cauda));
	check_for_prefix_loss (primitive);
	glyph_name = "";
	primitive->set_grob_property ("flexa-width",
				      gh_double2scm (flexa_width));
      }

    /*
     * Exceptional rule for pes:
     *
     * If this head is stacked on the previous one due to a \pes, then
     * set the glyph of the previous head to that for this special
     * case, thereby avoiding potential vertical collision with the
     * current head.
     */
    if (prefix_set & PES_OR_FLEXA)
      {
	if ((context_info & PES_UPPER) && (context_info & STACKED_HEAD))
	  {
	    if (!String::compare (prev_glyph_name, "vaticana_punctum"))
	      if (prev_delta_pitch > 1)
		prev_glyph_name = "vaticana_lpes";
	      else
		prev_glyph_name = "vaticana_vlpes";
	  }
      }

    if (prev_primitive)
      prev_primitive->set_grob_property ("glyph-name",
					 scm_makfrom0str (prev_glyph_name.to_str0 ()));

    /*
     * In the backend, flexa shapes and joins need to know about line
     * thickness.  Hence, for simplicity, let's distribute the
     * ligature grob's value for thickness to each ligature head (even
     * if not all of them need to know).
     */
    primitive->set_grob_property ("thickness", gh_double2scm (thickness));

    prev_primitive = primitive;
    prev_prefix_set = prefix_set;
    prev_context_info = context_info;
    prev_delta_pitch = delta_pitch;
    prev_glyph_name = glyph_name;
  }

  prev_primitive->set_grob_property ("glyph-name",
				     scm_makfrom0str (prev_glyph_name.to_str0 ()));

#if 0
  Real ligature_width =
#endif

  align_heads (primitives, flexa_width, thickness);

#if 0 // experimental code to collapse spacing after ligature
  /* TODO: set to max(old/new spacing-increment), since other
     voices/staves also may want to set this property. */
  Item *first_primitive = dynamic_cast<Item*> (primitives[0].grob_);
  Paper_column *paper_column = first_primitive->get_column();
  paper_column->warning (_f ("Vaticana_ligature_engraver: "
			     "setting `spacing-increment = %f': ptr=%ul",
			     ligature_width, paper_column));
  paper_column->
    set_grob_property("forced-spacing", gh_double2scm (ligature_width));
#endif
}


ENTER_DESCRIPTION (Vaticana_ligature_engraver,
/* descr */       "Handles ligatures by glueing special ligature heads together.",
/* creats*/       "VaticanaLigature",
/* accepts */     "ligature-event abort-event",
/* acks  */      "note-head-interface rest-interface",
/* reads */       "",
/* write */       "");
