/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "ultima/nuvie/core/nuvie_defs.h"
#include "ultima/nuvie/actors/actor.h"
#include "ultima/nuvie/core/map.h"
#include "ultima/nuvie/pathfinder/path.h"
#include "ultima/nuvie/pathfinder/sched_path_finder.h"

namespace Ultima {
namespace Nuvie {

/* NOTE: Path_type must always be valid. */
SchedPathFinder::SchedPathFinder(Actor *a, MapCoord g, Path *path_type)
	: ActorPathFinder(a, g), prev_step_i(0), next_step_i(0) {
	new_search(path_type);
	assert(search && actor);
}

SchedPathFinder::~SchedPathFinder() {

}

bool SchedPathFinder::get_next_move(MapCoord &step) {
	// jump to goal if both locations are off-screen
	if (!goal.is_visible() && !loc.is_visible()) {
		if (check_loc(goal)) {
			search->delete_path();
			step = goal;
			return true;
		}
	}

	if (!search->have_path())
		if (!find_path())
			return false;
	step = search->get_step(next_step_i); // have a path, take a step
	return true;
}

bool SchedPathFinder::find_path() {
	if (search->have_path())
		search->delete_path();
	if (!search->path_search(loc, goal)) {
		DEBUG(0, LEVEL_WARNING, "actor %d failed to find a path to %x,%x\n", actor->get_actor_num(), goal.x, goal.y);
		return false;
	}
	prev_step_i = next_step_i = 0;
	incr_step(); // the first step is the start location, so skip it
	return true;
}

/* Returns true if actor location is correct. */
bool SchedPathFinder::is_location_in_path() {
	const MapCoord &prev_step = search->get_step(prev_step_i);
	return (loc == prev_step);
}

/* Update previous and next steps in path. */
void SchedPathFinder::incr_step() {
	const MapCoord &prev_loc = search->get_step(prev_step_i);
	const MapCoord &next_loc = search->get_step(next_step_i);
	const MapCoord &last_loc = search->get_last_step();
	if (prev_loc != last_loc) {
		if (prev_loc != next_loc) // prev_step is going to stay behind next_step
			++prev_step_i;
		if (next_loc != last_loc)
			++next_step_i;
	}
}

void SchedPathFinder::actor_moved() {
	update_location();
	if (search->have_path())
		incr_step();
}

/* Don't bother moving around other actors. They will probably move soon. */
bool SchedPathFinder::check_loc(const MapCoord &locPos) {
	return actor->check_move(locPos.x, locPos.y, locPos.z, ACTOR_IGNORE_OTHERS);
}

} // End of namespace Nuvie
} // End of namespace Ultima