/***************************************************************************
 kscripts.c.c Copyright (C) 1999 Christoph Reichenbach


 This program may be modified and copied freely according to the terms of
 the GNU general public license (GPL), as long as the above copyright
 notice and the licensing information contained herein are preserved.

 Please refer to www.gnu.org for licensing details.

 This work is provided AS IS, without warranty of any kind, expressed or
 implied, including but not limited to the warranties of merchantibility,
 noninfringement, and fitness for a specific purpose. The author will not
 be held liable for any damage caused by this work or derivatives of it.

 By using this source code, you agree to the licensing terms as stated
 above.


 Please contact the maintainer for bug reports or inquiries.

 Current Maintainer:

    Christoph Reichenbach (CJR) [jameson@linuxgames.com]

***************************************************************************/

#include "sci/include/sciresource.h"
#include "sci/include/engine.h"
#include "sci/engine/kernel_types.h"

reg_t
read_selector(state_t *s, reg_t object, selector_t selector_id, const char *file, int line)
{
	reg_t *address;

	if (lookup_selector(s, object, selector_id, &address, NULL) != SELECTOR_VARIABLE)
		return NULL_REG;
	else
		return *address;
}


void
write_selector(state_t *s, reg_t object, selector_t selector_id, reg_t value,
	       const char *fname, int line)
{
	reg_t *address;

	if ((selector_id < 0) || (selector_id > s->selector_names_nr)) {
		SCIkwarn(SCIkWARNING, "Attempt to write to invalid selector %d of"
			 " object at "PREG" (%s L%d).\n", selector_id,
			 PRINT_REG(object), fname, line);
		return;
	}

	if (lookup_selector(s, object, selector_id, &address, NULL) != SELECTOR_VARIABLE)
		SCIkwarn(SCIkWARNING, "Selector '%s' of object at %04x could not be"
			 " written to (%s L%d)\n",
			 s->selector_names[selector_id], object, fname, line);
	else
		*address = value;

}

int
invoke_selector(state_t *s, reg_t object, int selector_id, int noinvalid, int kfunct,
		stack_ptr_t k_argp, int k_argc, /* Kernel function argp/argc */
		const char *fname, int line, int argc, ...)
{
	va_list argp;
	int i;
	int framesize = 2 + 1 * argc;
	reg_t address;
	int slc_type;
	stack_ptr_t stackframe = k_argp + k_argc;

	exec_stack_t *xstack; /* Execution stack */

	stackframe[0] = make_reg(0, selector_id);  /* The selector we want to call */
	stackframe[1] = make_reg(0, argc); /* Argument count */

	slc_type = lookup_selector(s, object, selector_id, NULL, &address);

	if (slc_type == SELECTOR_NONE) {
		SCIkwarn(SCIkERROR, "Selector '%s' of object at "PREG" could not be invoked (%s L%d)\n",
			 s->selector_names[selector_id], PRINT_REG(object), fname, line);
		if (noinvalid == 0)
			KERNEL_OOPS("Not recoverable: VM was halted\n");
		return 1;
	}
	if (slc_type == SELECTOR_VARIABLE) /* Swallow silently */
		return 0;

	va_start(argp, argc);
	for (i = 0; i < argc; i++) {
		reg_t arg = va_arg(argp, reg_t);
		stackframe[2 + i] = arg; /* Write each argument */
	}
	va_end(argp);

	/* Write "kernel" call to the stack, for debugging: */
	xstack = add_exec_stack_entry(s, NULL_REG, NULL, NULL_REG,
				      k_argc, k_argp - 1, 0, NULL_REG,
				      s->execution_stack_pos, SCI_XS_CALLEE_LOCALS);
	xstack->selector = -42 - kfunct; /* Evil debugging hack to identify kernel function */
	xstack->type = EXEC_STACK_TYPE_KERNEL;

	/* Now commit the actual function: */
	xstack = send_selector(s, object, object,
			       stackframe, framesize, stackframe);

	xstack->sp += argc+2;
	xstack->fp += argc+2;

	run_vm(s, 0); /* Start a new vm */

	--(s->execution_stack_pos); /* Get rid of the extra stack entry */

	return 0;
}


int
is_object(state_t *s, reg_t object)
{
	return obj_get(s, object) != NULL;
}


/* kLoad(restype, resnrs ... ):
** Loads arbitrary resources of type 'restype' with resource numbers 'resnrs'
** This implementation ignores all resource numbers except the first one.
*/
reg_t
kLoad(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	int restype = KP_UINT(argv[0]);
	int resnr = KP_UINT(argv[1]);

	if (restype == sci_memory)/* Request to dynamically allocate hunk memory for later use */
		return kalloc(s, "kLoad()", resnr);
	
	return make_reg(0, ((restype << 11) | resnr)); /* Return the resource identifier as handle */
}

reg_t
kLock(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	int restype = UKPV(0)&0x7f;
	int resnr = UKPV(1);
	int state = argc > 2 ? UKPV(2) : 1;

	resource_t *which;

	switch (state)
	{
	case 1 :
		scir_find_resource(s->resmgr, restype, resnr, 1);
		break;
	case 0 :
		which = scir_find_resource(s->resmgr, restype, resnr, 0);
		scir_unlock_resource(s->resmgr, which, resnr, restype);
		break;
	}
	return s->r_acc;
}

/* kUnload():
** Unloads an arbitrary resource of type 'restype' with resource numbber 'resnr'
*/
reg_t
kUnLoad(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	int restype = KP_UINT(argv[0]);
	reg_t resnr = argv[1];

	if (restype == sci_memory)
		kfree(s, resnr);

	return s->r_acc;
}


reg_t
kClone(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	reg_t parent_addr = argv[0];
	object_t *parent_obj = obj_get(s, parent_addr);
	reg_t clone_addr;
	clone_t *clone_obj; /* same as object_t* */
	int varblock_size;


	if (!parent_obj) {
		SCIkwarn(SCIkERROR, "Attempt to clone non-object/class at "PREG" failed", PRINT_REG(parent_addr));
		return NULL_REG;
	}

	SCIkdebug(SCIkMEM, "Attempting to clone from "PREG"\n", PRINT_REG(parent_addr));

	clone_obj = sm_alloc_clone(&s->seg_manager, &clone_addr);

	if (!clone_obj) {
		SCIkwarn(SCIkERROR, "Cloning "PREG" failed-- internal error!\n", PRINT_REG(parent_addr));
		return NULL_REG;
	}

	memcpy(clone_obj, parent_obj, sizeof(clone_t));
	clone_obj->flags = 0;
	varblock_size = parent_obj->variables_nr * sizeof(reg_t);
	clone_obj->variables = (reg_t*)sci_malloc(varblock_size);
	memcpy(clone_obj->variables, parent_obj->variables, varblock_size);

	/* Mark as clone */
	clone_obj->variables[SCRIPT_INFO_SELECTOR].offset = SCRIPT_INFO_CLONE;
	clone_obj->variables[SCRIPT_SPECIES_SELECTOR] = clone_obj->pos;
	if (IS_CLASS(parent_obj))
		clone_obj->variables[SCRIPT_SUPERCLASS_SELECTOR] = parent_obj->pos;
	sm_increment_lockers(&s->seg_manager, parent_obj->pos.segment, SEG_ID);
	sm_increment_lockers(&s->seg_manager, clone_obj->pos.segment, SEG_ID);

	return clone_addr;
}


extern void
_k_view_list_mark_free(state_t *s, reg_t off); /* kgraphics.c */

reg_t
kDisposeClone(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	reg_t victim_addr = argv[0];
	clone_t *victim_obj = obj_get(s, victim_addr);
	word underBits;

	if (!victim_obj) {
		SCIkwarn(SCIkERROR, "Attempt to dispose non-class/object at "PREG"\n",
			 PRINT_REG(victim_addr));
		return s->r_acc;
	}

	if (victim_obj->variables[SCRIPT_INFO_SELECTOR].offset != SCRIPT_INFO_CLONE) {
		/*  SCIkwarn("Attempt to dispose something other than a clone at %04x\n", offset); */
		/* SCI silently ignores this behaviour; some games actually depend on it */
		return s->r_acc;
	}

	underBits = GET_SEL32V(victim_addr, underBits);
	if (underBits) {
		SCIkwarn(SCIkWARNING,"Clone "PREG" was cleared with underBits set\n", PRINT_REG(victim_addr));
	}
#if 0
	if (s->dyn_views) {  /* Free any widget associated with the clone */
		gfxw_widget_t *widget = gfxw_set_id(gfxw_remove_ID(s->dyn_views, offset), GFXW_NO_ID);

		if (widget && s->bg_widgets)
			s->bg_widgets->add(GFXWC(s->bg_widgets), widget);
	}
#endif

	victim_obj->flags |= OBJECT_FLAG_FREED;

	_k_view_list_mark_free(s, victim_addr); /* Free on view list, if neccessary */ 

	return s->r_acc;
}


/* kScriptID(script, index):
** Returns script dispatch address index in the supplied script
*/
reg_t
kScriptID(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	int script = KP_UINT(argv[0]);
	int index = KP_UINT(KP_ALT(1, NULL_REG));

	seg_id_t scriptid = script_get_segment(s, script, SCRIPT_GET_LOAD);
	script_t *scr;

	if (argv[0].segment)
		return argv[0];

	if (!scriptid)
		return NULL_REG;

	scr = &(s->seg_manager.heap[scriptid]->data.script);

	if (!scr->exports_nr) {
		SCIkdebug(SCIkERROR, "Script 0x%x does not have a dispatch table\n", script);
		return NULL_REG;
	}

	if (index > scr->exports_nr) {
		SCIkwarn(SCIkERROR, "Dispatch index too big: %d > %d\n",
			 index, scr->exports_nr);
		return NULL_REG;
	}

	return make_reg(scriptid, sm_validate_export_func(&s->seg_manager, index, scriptid));
}


reg_t
kDisposeScript(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	int script = argv[0].offset;
	
	/* Work around QfG1 graveyard bug */
	if (argv[0].segment) return s->r_acc;

	if (sm_script_is_loaded(&(s->seg_manager), script, SCRIPT_ID))
        {
	    int id = sm_seg_get(&(s->seg_manager), script);
	    
	    if (s->execution_stack[s->execution_stack_pos].addr.pc.segment != id)
		    sm_set_lockers(&(s->seg_manager), 1, script, SCRIPT_ID);
	}

	script_uninstantiate(s, script);
	s->execution_stack_pos_changed = 1;
	return s->r_acc;
}

int
is_heap_object(state_t *s, reg_t pos)
{
	object_t *obj = obj_get(s, pos);
	return (obj != NULL
		&& (!(obj->flags & OBJECT_FLAG_FREED))
		&& (!sm_script_is_marked_as_deleted(&s->seg_manager, pos.segment)));
}

reg_t
kIsObject(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	if (argv[0].offset == 0xffff) /* Treated specially */
		return NULL_REG;
	else
		return make_reg(0, is_heap_object(s, argv[0]));
}

reg_t
kRespondsTo(state_t *s, int funct_nr, int argc, reg_t *argv)
{
	reg_t obj = argv[0];
	int selector = KP_UINT(argv[1]);

	return make_reg(0, is_heap_object(s, obj)
			&& lookup_selector(s, obj, selector, NULL, NULL) != SELECTOR_NONE);
}