import graphlib.edges.DirectedEdge;
import graphlib.graphs.DirectedMultiGraph;
import graphlib.nodes.Node;
import graphlib.paths.Walk;
import graphlib.util.Graphs;

import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;

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


public class SimpleTest {

    public static Cycle c;

    @BeforeClass
    public static void init() {
        c = new EulerianCycle();
    }

    @Test
    public void test1() {
        DirectedMultiGraph<String> graph = new DirectedMultiGraph<>();
        graph.addNode(new Node<>("n1"));
        graph.addNode(new Node<>("n2"));
        graph.addNode(new Node<>("n3"));

        graph.addEdge(new DirectedEdge<>(graph.getNode("n1"), graph.getNode("n2")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n2"), graph.getNode("n3")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n1")));

        Walk<String> euler = c.createCircuit(Graphs.unmodifiableDirectedMultiGraph(graph));
        check(euler, graph);
    }

    @Test
    public void test2() {
        DirectedMultiGraph<String> graph = new DirectedMultiGraph<>();
        graph.addNode(new Node<>("n1"));
        graph.addNode(new Node<>("n2"));
        graph.addNode(new Node<>("n3"));
        graph.addNode(new Node<>("n4"));
        graph.addNode(new Node<>("n5"));
        graph.addNode(new Node<>("n6"));

        graph.addEdge(new DirectedEdge<>(graph.getNode("n1"), graph.getNode("n2")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n2"), graph.getNode("n3")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n1")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n2"), graph.getNode("n5")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n5"), graph.getNode("n4")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n4"), graph.getNode("n2")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n6")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n6"), graph.getNode("n5")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n5"), graph.getNode("n3")));

        Walk<String> euler = c.createCircuit(Graphs.unmodifiableDirectedMultiGraph(graph));
        check(euler, graph);
    }

    @Test
    public void test3() {
        DirectedMultiGraph<String> graph = new DirectedMultiGraph<>();
        graph.addNode(new Node<>("n1"));
        graph.addNode(new Node<>("n2"));
        graph.addNode(new Node<>("n3"));
        graph.addNode(new Node<>("n4"));

        graph.addEdge(new DirectedEdge<>(graph.getNode("n1"), graph.getNode("n2")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n1"), graph.getNode("n4")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n2"), graph.getNode("n3")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n2"), graph.getNode("n3")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n1")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n4")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n3")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n4"), graph.getNode("n1")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n4"), graph.getNode("n2")));

        Walk<String> euler = c.createCircuit(Graphs.unmodifiableDirectedMultiGraph(graph));
        check(euler, graph);
    }

    @Test
    public void test4() {
        DirectedMultiGraph<String> graph = new DirectedMultiGraph<>();
        graph.addNode(new Node<>("n1"));
        graph.addNode(new Node<>("n2"));
        graph.addNode(new Node<>("n3"));

        graph.addEdge(new DirectedEdge<>(graph.getNode("n1"), graph.getNode("n2")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n1"), graph.getNode("n3")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n2"), graph.getNode("n1")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n2"), graph.getNode("n3")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n1")));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n3"), graph.getNode("n2")));

        Walk<String> euler = c.createCircuit(Graphs.unmodifiableDirectedMultiGraph(graph));
        check(euler, graph);
    }

    @Test
    public void test5() {
        DirectedMultiGraph<String> graph = new DirectedMultiGraph<>();
        graph.addNode(new Node<>("n1"));
        graph.addEdge(new DirectedEdge<>(graph.getNode("n1"), graph.getNode("n1")));

        Walk<String> euler = c.createCircuit(Graphs.unmodifiableDirectedMultiGraph(graph));
        check(euler, graph);
    }

    public void check(Walk<String> walk, DirectedMultiGraph<String> graph) {
        // lijst waaruit de gebruikte bogen worden verwijderd
        Set<DirectedEdge<String>> usedEdges = new HashSet<>(graph.getAllEdges());
        Iterator<Node<String>> it = walk.iterator();
        Node<String> first = null, second;
        if(it.hasNext()) {
            first = it.next();
        }
        while(it.hasNext()) {
            second = it.next();
            List<DirectedEdge<String>> edges = graph.getEdges(first, second);
            // controleert of de gegeven boog wel in de graaf aanwezig is
            Assert.assertFalse("Je gebruikt een boog (" + first + "," + second + "), maar deze is niet in de graaf aanwezig.", edges.isEmpty());
            int i = 0;
            boolean found = false;
            // zoekt de juiste boog (indien een boog meerdere keren aanwezig is)
            while(!found && i < edges.size()) {
                if (usedEdges.contains(graph.getEdges(first, second).get(i))) {
                    found = true;
                } else {
                    i++;
                }
            }
            // indien i==edges.size(), dan is de boog al eens gebruikt en al verwijderd uit de lijst usedEdges
            Assert.assertTrue("Je gebruikt de boog (" + first + "," + second + ") meerdere keren.",i < edges.size());
            usedEdges.remove(graph.getEdges(first, second).get(i));
            first = second;
        }
        // de bogen die nog aanwezig zijn in usedEdges zijn nog niet gebruikt in het pad
        Assert.assertTrue("De bogen " + usedEdges + " zijn niet gebruikt in jouw pad.", usedEdges.isEmpty());
    }
    
}