RandomWalkStateHandler.java

package net.scapeemulator.game.model.npc.stateful.handler;

import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.Set;

import net.scapeemulator.game.model.Position;
import net.scapeemulator.game.model.area.Area;
import net.scapeemulator.game.model.mob.Direction;
import net.scapeemulator.game.model.npc.stateful.StateHandler;
import net.scapeemulator.game.model.npc.stateful.impl.NormalNPC;

/**
 * @author Hadyn Richard
 */
public final class RandomWalkStateHandler extends StateHandler<NormalNPC> {

    private final static Random random = new Random();

    @Override
    public void handle(NormalNPC npc) {

        /* Get the amount of steps that the NPC will walk if possible */
        int iterations = random.nextInt(2) + 1;

        Position currentPosition = npc.getPosition();

        Set<Position> oldPositions = new HashSet<>();
        oldPositions.add(currentPosition);
        Area bounds = npc.getWalkingBounds();

        for (int i = 0; i < iterations; i++) {

            List<Position> positions = Direction.getNearbyTraversableTiles(currentPosition, npc.getSize());
            // Remove all the positions that are not within bounds or previously used
            Iterator<Position> iterator = positions.iterator();
            while (iterator.hasNext()) {
                Position position = iterator.next();
                if (!bounds.allWithinArea(position, npc.getSize(), 0, true) || oldPositions.contains(position)) {
                    iterator.remove();
                }
            }

            Position[] array = positions.toArray(new Position[0]);
            if (array.length > 0) {
                Position position = array[random.nextInt(array.length)];
                npc.getWalkingQueue().addPoint(position);
                oldPositions.add(position);
                currentPosition = position;
            }
        }
    }
}