/*
  Implement storage and manipulation of grob properties.
*/

#include <cstring>

#include "main.hh"
#include "input.hh"
#include "pointer-group-interface.hh"
#include "misc.hh"
#include "paper-score.hh"
#include "output-def.hh"
#include "spanner.hh"
#include "international.hh"
#include "item.hh"
#include "misc.hh"
#include "item.hh"
#include "program-option.hh"
#include "profile.hh"
#include "simple-closure.hh"
#include "warn.hh"
#include "protected-scm.hh"

Protected_scm grob_property_callback_stack = SCM_EOL;

extern bool debug_property_callbacks;

#ifndef NDEBUG
static void
print_property_callback_stack ()
{
  int frame = 0;
  for (SCM s = grob_property_callback_stack; scm_is_pair (s); s = scm_cdr (s))
    message (_f ("%d: %s", frame++, ly_scm_write_string (scm_car (s)).c_str ()));
}
#endif

static SCM modification_callback = SCM_EOL;
static SCM cache_callback = SCM_EOL;


/*

FIXME: this should use ly:set-option interface instead.

*/

LY_DEFINE (ly_set_grob_modification_callback, "ly:set-grob-modification-callback",
	   1, 0, 0, (SCM cb),
	   "Specify a procedure that will be called every time LilyPond"
	   " modifies a grob property.  The callback will receive as"
	   " arguments the grob that is being modified, the name of the"
	   " C++ file in which the modification was requested, the line"
	   " number in the C++ file in which the modification was requested,"
	   " the name of the function in which the modification was"
	   " requested, the property to be changed, and the new value for"
	   " the property.")
{
  modification_callback =  (ly_is_procedure (cb)) ? cb : SCM_BOOL_F;
  return SCM_UNSPECIFIED;
}

LY_DEFINE (ly_set_property_cache_callback, "ly:set-property-cache-callback",
	   1, 0, 0, (SCM cb),
	   "Specify a procedure that will be called whenever lilypond"
	   " calculates a callback function and caches the result.  The"
	   " callback will receive as arguments the grob whose property it"
	   " is, the name of the property, the name of the callback that"
	   " calculated the property, and the new (cached) value of the"
	   " property.")
{
  cache_callback =  (ly_is_procedure (cb)) ? cb : SCM_BOOL_F;
  return SCM_UNSPECIFIED;
}


void
Grob::instrumented_set_property (SCM sym, SCM v,
				 char const *file,
				 int line,
				 char const *fun)
{
#ifndef NDEBUG
  if (ly_is_procedure (modification_callback))
    scm_apply_0 (modification_callback,
		 scm_list_n (self_scm (),
			     scm_from_locale_string (file),
			     scm_from_int (line),
			     scm_from_locale_string (fun),
			     sym, v, SCM_UNDEFINED));
#else
  (void) file;
  (void) line;
  (void) fun;
#endif
  
  internal_set_property (sym, v);
}

SCM
Grob::get_property_alist_chain (SCM def) const
{
  return scm_list_n (mutable_property_alist_,
		     immutable_property_alist_,
		     def,
		     SCM_UNDEFINED);
}

extern void check_interfaces_for_property (Grob const *me, SCM sym);

void
Grob::internal_set_property (SCM sym, SCM v)
{
  internal_set_value_on_alist (&mutable_property_alist_,
			       sym, v);

}

void
Grob::internal_set_value_on_alist (SCM *alist, SCM sym, SCM v)
{
  /* Perhaps we simply do the assq_set, but what the heck. */
  if (!is_live ())
    return;

  if (do_internal_type_checking_global)
    {
      if (!ly_is_procedure (v)
	  && !is_simple_closure (v)
	  && v != ly_symbol2scm ("calculation-in-progress"))
	type_check_assignment (sym, v, ly_symbol2scm ("backend-type?"));

      check_interfaces_for_property (this, sym);
    }

  *alist = scm_assq_set_x (*alist, sym, v);
}

SCM
Grob::internal_get_property_data (SCM sym) const
{
#ifndef NDEBUG
  if (profile_property_accesses)
    note_property_access (&grob_property_lookup_table, sym);
#endif
  
  SCM handle = scm_sloppy_assq (sym, mutable_property_alist_);
  if (handle != SCM_BOOL_F)
    return scm_cdr (handle);

  handle = scm_sloppy_assq (sym, immutable_property_alist_);

  if (do_internal_type_checking_global && scm_is_pair (handle))
    {
      SCM val = scm_cdr (handle);
      if (!ly_is_procedure (val) && !is_simple_closure (val))
	type_check_assignment (sym, val, ly_symbol2scm ("backend-type?"));

      check_interfaces_for_property (this, sym);
    }
  
  return (handle == SCM_BOOL_F) ? SCM_EOL : scm_cdr (handle);
}

SCM
Grob::internal_get_property (SCM sym) const
{
  SCM val = get_property_data (sym);

#ifndef NDEBUG
  if (val == ly_symbol2scm ("calculation-in-progress"))
    {
      programming_error (_f ("cyclic dependency: calculation-in-progress encountered for #'%s (%s)",
			     ly_symbol2string (sym).c_str (),
			     name ().c_str ()));
      if (debug_property_callbacks)
	{
	  message ("backtrace: ");
	  print_property_callback_stack ();
	}
    }
#endif
  
  if (ly_is_procedure (val)
      || is_simple_closure (val))
    {
      Grob *me = ((Grob*)this);
      val = me->try_callback_on_alist (&me->mutable_property_alist_, sym, val);
    }
  
  return val;
}

SCM
Grob::try_callback_on_alist (SCM *alist, SCM sym, SCM proc)
{      
  SCM marker = ly_symbol2scm ("calculation-in-progress");
  /*
    need to put a value in SYM to ensure that we don't get a
    cyclic call chain.
  */
  *alist = scm_assq_set_x (*alist, sym, marker);

#ifndef NDEBUG
  if (debug_property_callbacks)
    grob_property_callback_stack = scm_cons (scm_list_3 (self_scm (), sym, proc), grob_property_callback_stack);
#endif

  SCM value = SCM_EOL;
  if (ly_is_procedure (proc))
    value = scm_call_1 (proc, self_scm ());
  else if (is_simple_closure (proc))
    {
      value = evaluate_with_simple_closure (self_scm (),
					    simple_closure_expression (proc),
					    false, 0, 0);
    }
  
#ifndef NDEBUG
  if (debug_property_callbacks)
    grob_property_callback_stack = scm_cdr (grob_property_callback_stack);
#endif
	  
  /*
    If the function returns SCM_UNSPECIFIED, we assume the
    property has been set with an explicit set_property ()
    call.
  */
  if (value == SCM_UNSPECIFIED)
    {
      value = get_property_data (sym);
      assert (value == SCM_EOL || value == marker);
      if (value == marker)
	*alist = scm_assq_remove_x (*alist, marker);
    }
  else
    {
#ifndef NDEBUG
      if (ly_is_procedure (cache_callback))
	scm_apply_0 (cache_callback,
		     scm_list_n (self_scm (),
				 sym,
				 proc,
				 value,
				 SCM_UNDEFINED));
#endif
      internal_set_value_on_alist (alist, sym, value);
    }
  
  return value;
}

void
Grob::internal_set_object (SCM s, SCM v)
{
  /* Perhaps we simply do the assq_set, but what the heck. */
  if (!is_live ())
    return;

  object_alist_ = scm_assq_set_x (object_alist_, s, v);
}

void
Grob::internal_del_property (SCM sym)
{
  mutable_property_alist_ = scm_assq_remove_x (mutable_property_alist_, sym);
}

SCM
Grob::internal_get_object (SCM sym) const
{
  if (profile_property_accesses)
    note_property_access (&grob_property_lookup_table, sym);

  SCM s = scm_sloppy_assq (sym, object_alist_);
  
  if (s != SCM_BOOL_F)
    {
      SCM val = scm_cdr (s);
      if (ly_is_procedure (val)
	  || is_simple_closure (val))
	{
	  Grob *me = ((Grob*)this);
	  val = me->try_callback_on_alist (&me->object_alist_, sym, val);
	}
      
      return val;
    }

  return SCM_EOL;
}

bool
Grob::is_live () const
{
  return scm_is_pair (immutable_property_alist_);
}

bool
Grob::internal_has_interface (SCM k)
{
  return scm_c_memq (k, interfaces_) != SCM_BOOL_F;
}

SCM
call_pure_function (SCM unpure, SCM args, int start, int end)
{
  SCM scm_call_pure_function = ly_lily_module_constant ("call-pure-function");

  return scm_apply_0 (scm_call_pure_function,
		      scm_list_4 (unpure, args, scm_from_int (start), scm_from_int (end)));
}