/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file newgrf_cargo.cpp Implementation of NewGRF cargoes. */

#include "stdafx.h"
#include "debug.h"
#include "newgrf_spritegroup.h"

static uint32 CargoGetRandomBits(const ResolverObject *object)
{
	return 0;
}


static uint32 CargoGetTriggers(const ResolverObject *object)
{
	return 0;
}


static void CargoSetTriggers(const ResolverObject *object, int triggers)
{
	return;
}


static uint32 CargoGetVariable(const ResolverObject *object, byte variable, uint32 parameter, bool *available)
{
	DEBUG(grf, 1, "Unhandled cargo variable 0x%X", variable);

	*available = false;
	return UINT_MAX;
}


static const SpriteGroup *CargoResolveReal(const ResolverObject *object, const RealSpriteGroup *group)
{
	/* Cargo action 2s should always have only 1 "loaded" state, but some
	 * times things don't follow the spec... */
	if (group->num_loaded > 0) return group->loaded[0];
	if (group->num_loading > 0) return group->loading[0];

	return NULL;
}


static void NewCargoResolver(ResolverObject *res, const CargoSpec *cs)
{
	res->GetRandomBits = &CargoGetRandomBits;
	res->GetTriggers   = &CargoGetTriggers;
	res->SetTriggers   = &CargoSetTriggers;
	res->GetVariable   = &CargoGetVariable;
	res->ResolveRealMethod = &CargoResolveReal;

	res->u.cargo.cs = cs;

	res->callback        = CBID_NO_CALLBACK;
	res->callback_param1 = 0;
	res->callback_param2 = 0;
	res->ResetState();

	res->grffile         = cs->grffile;
}


SpriteID GetCustomCargoSprite(const CargoSpec *cs)
{
	const SpriteGroup *group;
	ResolverObject object;

	NewCargoResolver(&object, cs);

	group = SpriteGroup::Resolve(cs->group, &object);
	if (group == NULL) return 0;

	return group->GetResult();
}


uint16 GetCargoCallback(CallbackID callback, uint32 param1, uint32 param2, const CargoSpec *cs)
{
	ResolverObject object;
	const SpriteGroup *group;

	NewCargoResolver(&object, cs);
	object.callback = callback;
	object.callback_param1 = param1;
	object.callback_param2 = param2;

	group = SpriteGroup::Resolve(cs->group, &object);
	if (group == NULL) return CALLBACK_FAILED;

	return group->GetCallbackResult();
}

/**
 * Translate a GRF-local cargo slot/bitnum into a CargoID.
 * @param cargo   GRF-local cargo slot/bitnum.
 * @param grffile Originating GRF file.
 * @param usebit  Defines the meaning of \a cargo for GRF version < 7.
 *                If true, then \a cargo is a bitnum. If false, then \a cargo is a cargoslot.
 *                For GRF version >= 7 \a cargo is always a translated cargo bit.
 * @return CargoID or CT_INVALID if the cargo is not available.
 */
CargoID GetCargoTranslation(uint8 cargo, const GRFFile *grffile, bool usebit)
{
	/* Pre-version 7 uses the 'climate dependent' ID in callbacks and properties, i.e. cargo is the cargo ID */
	if (grffile->grf_version < 7 && !usebit) return cargo;

	/* Other cases use (possibly translated) cargobits */

	if (grffile->cargo_list.Length() > 0) {
		/* ...and the cargo is in bounds, then get the cargo ID for
		 * the label */
		if (cargo < grffile->cargo_list.Length()) return GetCargoIDByLabel(grffile->cargo_list[cargo]);
	} else {
		/* Else the cargo value is a 'climate independent' 'bitnum' */
		return GetCargoIDByBitnum(cargo);
	}
	return CT_INVALID;
}