/*  Part of XPCE --- The SWI-Prolog GUI toolkit

    Author:        Jan Wielemaker and Anjo Anjewierden
    E-mail:        jan@swi.psy.uva.nl
    WWW:           http://www.swi.psy.uva.nl/projects/xpce/
    Copyright (c)  1985-2002, University of Amsterdam
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in
       the documentation and/or other materials provided with the
       distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.
*/

#include <h/kernel.h>
#include <h/interface.h>
#include <h/graphics.h>


status
initialiseHost(Host h, Name which)
{ assign(h, system, which);
  assign(h, callBack, ON);
  assign(h, language, NAME_prolog);
  assign(h, messages, newObject(ClassChain, EAV));

  succeed;
}


static status
callHostv(Host host, Name selector, int argc, Any *argv)
{ status rval;
  int n;

  for(n=0; n<argc; n++)
    if ( isObject(argv[n]) )
      addCodeReference(argv[n]);

  rval = hostSend(host, selector, argc, argv);

  for(n=0; n<argc; n++)
    if ( isObject(argv[n]) && !isFreedObj(argv[n]) )
      delCodeReference(argv[n]);

  return rval;
}


static Any
getCallHostv(Host host, Name selector, int argc, Any *argv)
{ Any rval;
  int n;

  for(n=0; n<argc; n++)
    if ( isObject(argv[n]) )
      addCodeReference(argv[n]);

  rval = hostGet(host, selector, argc, argv);

  for(n=0; n<argc; n++)
    if ( isObject(argv[n]) && !isFreedObj(argv[n]) )
      delCodeReference(argv[n]);

  return rval;
}


static status
catchAllHostv(Host h, Name selector, int argc, Any *argv)
{ if ( h->callBack == ON )
  { status rval;

    if ( !(rval = callHostv(h, selector, argc, argv)) &&
    	 PCE->last_error == NAME_noBehaviour )
      assign(PCE, last_error, NIL);

    return rval;
  } else
  { ArgVector(av, argc+2);
    int ac;

    av[0] = h; av[1] = (Any) selector;
    for(ac=0; ac < argc; ac++)
      av[ac+2] = argv[ac];

    return appendChain(h->messages, newObjectv(ClassMessage, argc+2, av));
  }
}


static Any
getCatchAllHostv(Host h, Name selector, int argc, Any *argv)
{ Any rval;

  if ( h->callBack == OFF )
  { errorPce(h, NAME_noCallBack);
    fail;
  }

  if ( !(rval = getCallHostv(h, selector, argc, argv)) &&
        PCE->last_error == NAME_noBehaviour )
    assign(PCE, last_error, NIL);

  answer(rval);
}


static Message
getMessageHost(Host h)
{ Message msg;
  BoolObj oldBack = h->callBack;

  assign(h, callBack, OFF);

  for (;;)
  { if ( (msg = getHeadChain(h->messages)) )
    { assign(h, callBack, oldBack);

      addCodeReference(msg);
      deleteHeadChain(h->messages);
      delCodeReference(msg);
      pushAnswerObject(msg);

      answer(msg);
    }

    dispatchDisplayManager(TheDisplayManager(), DEFAULT, DEFAULT);
  }
}


		 /*******************************
		 *	 CLASS DECLARATION	*
		 *******************************/

/* Type declarations */

static char *T_name_any_XXX[] =
        { "name", "any|host_data ..." };
static char *T_name_unchecked_XXX[] =
        { "name", "unchecked ..." };
static char *T_sendCall[] =
	{ "name|host_data", "unchecked ..." };

/* Instance Variables */

static vardecl var_host[] =
{ IV(NAME_language, "{prolog,lisp,c}", IV_BOTH,
     NAME_host, "Host language pce is connected to"),
  IV(NAME_system, "name", IV_BOTH,
     NAME_host, "Identifier name of host language"),
  IV(NAME_callBack, "bool", IV_BOTH,
     NAME_callback, "Queue messages or invoke asynchronously"),
  IV(NAME_messages, "chain*", IV_GET,
     NAME_callback, "Message queue")
};

/* Send Methods */

static senddecl send_host[] =
{ SM(NAME_initialise, 1, "name=name", initialiseHost,
     DEFAULT, "Create host from name"),
  SM(NAME_call, 2, T_sendCall, callHostv,
     NAME_callback, "Invoke a host defined send operation"),
  SM(NAME_catchAll, 2, T_name_any_XXX, catchAllHostv,
     NAME_callback, "Call procedure on host")
};

/* Get Methods */

static getdecl get_host[] =
{ GM(NAME_call, 2, "unchecked", T_name_unchecked_XXX, getCallHostv,
     NAME_callback, "Invoke a host defined get_method"),
  GM(NAME_catchAll, 2, "any", T_name_any_XXX, getCatchAllHostv,
     NAME_callback, "Call function on host"),
  GM(NAME_message, 0, "message", NULL, getMessageHost,
     NAME_callback, "Read next message from queue")
};

/* Resources */

#define rc_host NULL
/*
static classvardecl rc_host[] =
{
};
*/

/* Class Declaration */

static Name host_termnames[] = { NAME_system };

ClassDecl(host_decls,
          var_host, send_host, get_host, rc_host,
          1, host_termnames,
          "$Rev$");

status
makeClassHost(Class class)
{ declareClass(class, &host_decls);
  saveStyleClass(class, NAME_external);

  HOST = globalObject(NAME_host, ClassHost, NAME_unknown, EAV);
  protectObject(HOST);

  succeed;
}


Host
HostObject()
{ if ( HOST )
    return HOST;

  return findGlobal(NAME_host);
}