SimpleFireSpreadStrategy.java

package model;

import util.Position;
import java.util.*;

public class SimpleFireSpreadStrategy implements Strategy {
    private final Set<Position> firePositions;
    private final Map<Position, List<Position>> neighbors;
    private final Set<Position> mountainPositions;
    private final Set<Position> roadPositions;
    private final Set<Position> rocksPositions;
    private final int step;

    public SimpleFireSpreadStrategy(Set<Position> firePositions, Map<Position, List<Position>> neighbors,Set<Position> moutainsPositions,Set<Position> roadPositions,Set<Position> rocksPositions, int step) {
        this.firePositions = firePositions;
        this.neighbors = neighbors;
        this.mountainPositions = moutainsPositions;
        this.roadPositions = roadPositions;
        this.rocksPositions = rocksPositions;
        this.step = step;
    }

    @Override
    public List<Position> update() {
        if(step %2 != 0){
            return Collections.emptyList();
        }
        List<Position> modifiedPositions = new ArrayList<>();
        Set<Position> newFirePositions = new HashSet<>();

        for (Position firePosition : firePositions) {
            spreadFire(firePosition, newFirePositions);
        }
        firePositions.addAll(newFirePositions);
        modifiedPositions.addAll(newFirePositions);
        return modifiedPositions;
    }
    private void spreadFire(Position firePosition, Set<Position> newFirePositions) {
        List<Position> potentialPositions = neighbors.getOrDefault(firePosition, Collections.emptyList());
        for (Position potentialPosition : potentialPositions) {
            if (canPropagateTo(potentialPosition)) {
                newFirePositions.add(potentialPosition);
            }
        }
    }
    private boolean canPropagateTo(Position newPosition) {
        if(mountainPositions.contains(newPosition) || roadPositions.contains(newPosition)){
            return false;
        }
        if (rocksPositions.contains(newPosition)){
            return step % 4 ==0;
        }
        return true;
    }

    @Override
    public List<Position> getModelPositions() {
        throw new UnsupportedOperationException("Fire positions can't be accessed as Model Positions.");
    }

    @Override
    public Set<Position> getFirePositions() {
        return firePositions;
    }
}