/*   
  volta-engraver.cc --  implement Volta_engraver
  
  source file of the GNU LilyPond music typesetter
  
  (c) 2000--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
  
 */

#include "engraver.hh"
#include "translator-group.hh"
#include "volta-bracket.hh"
#include "item.hh"
#include "note-column.hh"
#include "bar-line.hh"
#include "side-position-interface.hh"
#include "warn.hh"
#include "staff-symbol.hh"

/*
  Create Volta spanners, by reading repeatCommands  property, usually
  set by Unfolded_repeat_iterator.
 */
class Volta_engraver : public Engraver
{
public:
  TRANSLATOR_DECLARATIONS(Volta_engraver);
protected:

  virtual void acknowledge_grob (Grob_info);
  virtual void finalize ();
  virtual void stop_translation_timestep ();
  virtual void process_music ();
  virtual void process_acknowledged_grobs ();
  
  Moment started_mom_;
  Spanner *volta_span_;
  Spanner *end_volta_span_;
  SCM staff_;
  SCM start_string_;
};

Volta_engraver::Volta_engraver ()
{
  staff_ = SCM_EOL;
  volta_span_ = 0;
  end_volta_span_ = 0;
}


void
Volta_engraver::process_music ()
{
  if (unsmob_grob (staff_)
      && !to_boolean (get_property ("voltaOnThisStaff")))
    {
      /*
	TODO: this does weird things when you open a piece with a
	volta spanner.
	
       */
      SCM staffs = get_property ("stavesFound");

      /*
	only put a volta on the top staff.
	
	May be this is a bit convoluted, and we should have a single
	volta engraver in score context or somesuch.
	
      */
      if (!gh_pair_p (staffs))
	programming_error ("Huh? Volta engraver can't find staffs?");
      else if (ly_car (scm_last_pair (staffs)) != staff_)
	return ;
    }
	
  
  SCM cs = get_property ("repeatCommands");

  bool  end = false;
  start_string_ = SCM_EOL;
  while (gh_pair_p (cs))
    {
      SCM c = ly_car (cs);

      if (gh_pair_p (c)
	  && ly_car (c) == ly_symbol2scm ("volta")
	  && gh_pair_p (ly_cdr (c)))
	{
	  if (ly_cadr (c) ==  SCM_BOOL_F)
	    end = true;
	  else
	    start_string_ = ly_cadr (c);
	}
      
      cs = ly_cdr (cs);
    }

  if (volta_span_)
    {
      SCM l (get_property ("voltaSpannerDuration"));
      Moment now = now_mom ();
  
      bool early_stop = unsmob_moment (l)
	&& *unsmob_moment (l) <= now - started_mom_;
      
      end = end || early_stop;
    }

  
  if (end && !volta_span_)
    {
      warning (_ ("No volta spanner to end")); // fixme: be more verbose.
    }
  else if (end)
    {
      end_volta_span_ = volta_span_;
      volta_span_ =0;
    }

  if (volta_span_ && 
      (gh_string_p (start_string_) || gh_pair_p (start_string_)))
    {
      warning (_ ("Already have a volta spanner.  Stopping that one prematurely."));
      
      if (end_volta_span_)
	{
	  warning (_ ("Also have a stopped spanner.  Giving up."));
	  return ;
	}

      end_volta_span_ = volta_span_;
      volta_span_ = 0;
    }
}

/*
  this could just as well be done in process_music (), but what the hack.
 */
void
Volta_engraver::process_acknowledged_grobs ()
{
  if (!volta_span_ && 
      (gh_string_p (start_string_) || gh_pair_p (start_string_)))
    {
      started_mom_ = now_mom () ;

      volta_span_ = new Spanner (get_property ("VoltaBracket"));

      announce_grob (volta_span_, SCM_EOL);
      volta_span_->set_grob_property ("text", start_string_);
    }
}

void
Volta_engraver::acknowledge_grob (Grob_info i)
{
  if (Item* item = dynamic_cast<Item*> (i.grob_))
    {
      if (Note_column::has_interface (item))
	{
	  if (volta_span_)
	    Volta_bracket_interface::add_column (volta_span_,item);
	}
      if (Bar_line::has_interface (item))
	{
	  if (volta_span_)
	    Volta_bracket_interface::add_bar (volta_span_, item);
	  if (end_volta_span_)
	    Volta_bracket_interface::add_bar (end_volta_span_ , item);
	}
    }
  else if (Staff_symbol::has_interface (i.grob_))
    {
      /*
	We only want to know about a single staff: then we add to the
	support.  */
      if (staff_ != SCM_EOL)
	staff_ = SCM_UNDEFINED;

      if (staff_ != SCM_UNDEFINED)
	staff_ = i.grob_->self_scm();
    }
}

void
Volta_engraver::finalize ()
{
  if (volta_span_)
    {
      typeset_grob (volta_span_);
    }
  if (end_volta_span_)
    {
      typeset_grob (end_volta_span_);
    }
}



void 
Volta_engraver::stop_translation_timestep ()
{
  if (end_volta_span_)
    {
      typeset_grob (end_volta_span_);
      end_volta_span_ =0;
    }
}

/*
  TODO: should attach volta to paper-column if no bar is found.
 */

ENTER_DESCRIPTION(Volta_engraver,
/* descr */       "Make volta brackets",
/* creats*/       "VoltaBracket",
/* accepts */     "",
/* acks  */       "bar-line-interface staff-symbol-interface note-column-interface",
/* reads */       "repeatCommands voltaSpannerDuration stavesFound",
/* write */       "");
