package nl.camilstaps.cs.graphs;

import java.util.ArrayList;
import java.util.List;

/**
 * A Node is a simple point in a graph, with references to its neighbours. It holds an integer 'content' which can act
 * as an identifier.
 *
 * @author Camil Staps
 */
public class Node implements Comparable<Node> {
    private final int content;
    private final List<Node> neighbours = new ArrayList<>();

    public Node(int content) {
        this.content = content;
    }

    public int getDegree() {
        return neighbours.size();
    }

    public List<Node> getNeighbourhood() {
        return neighbours;
    }

    public List<Node> getInclusiveNeighbourhood() {
        List<Node> nb = new ArrayList<>();
        nb.add(this);
        nb.addAll(neighbours);
        return nb;
    }

    public List<Node> getSecondNeighbourhood() {
        List<Node> nb = new ArrayList<>();
        for (Node n : getNeighbourhood())
            for (Node n2 : n.getNeighbourhood())
                if (!nb.contains(n2))
                    nb.add(n2);
        nb.remove(this);
        return nb;
    }

    public boolean dominates(Node b) {
        for (Node nb : getInclusiveNeighbourhood())
            if (!b.getInclusiveNeighbourhood().contains(nb))
                return false;
        return true;
    }

    public boolean neighbourhoodsDisjoint(Node b) {
        return neighbourhoodIntersection(b).isEmpty();
    }

    public List<Node> neighbourhoodIntersection(Node b) {
        List<Node> intersection = new ArrayList<>();
        for (Node n : neighbours)
            if (b.getNeighbourhood().contains(n))
                intersection.add(n);
        return intersection;
    }

    public String toString() {
        return "<" + content + ">";
    }

    /**
     * Nodes are equal if their identifiers are equal
     * @param another
     * @return
     */
    public boolean equals(Object another) {
        return !(another == null || another.getClass() != this.getClass()) &&
                content == (((Node) another).content);
    }

    @Override
    public int compareTo(Node node) {
        return node == null ? 1 : Integer.compare(neighbours.size(), node.neighbours.size());
    }
}