import graphlib.edges.DirectedEdge;
import graphlib.graphs.DirectedGraph;
import graphlib.nodes.Node;
import graphlib.util.Graphs;
import org.junit.Assert;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

import java.util.Arrays;


public class SimpleTest {

    private static KortstePaden kp;

    @BeforeClass
    public static void initClass() {
        kp = new BellmanFordKortstePaden();
    }

    private DirectedGraph graph;

    @Before
    public void init() {
        graph = new DirectedGraph();
        for(int i = 0; i < 4; i++) {
            graph.addNode(new Node("n" + i));
        }

        DirectedEdge e01 = new DirectedEdge(graph.getNode("n0"), graph.getNode("n1"), 50);
        DirectedEdge e03 = new DirectedEdge(graph.getNode("n0"), graph.getNode("n3"), -34);
        DirectedEdge e02 = new DirectedEdge(graph.getNode("n0"), graph.getNode("n2"), 20);
        DirectedEdge e13 = new DirectedEdge(graph.getNode("n1"), graph.getNode("n3"), 10);
        DirectedEdge e23 = new DirectedEdge(graph.getNode("n2"), graph.getNode("n3"), 15);

        graph.addEdge(e01);
        graph.addEdge(e02);
        graph.addEdge(e03);
        graph.addEdge(e13);
        graph.addEdge(e23);
    }

    @Test
    public void testSameNode() {
        Assert.assertEquals(Arrays.asList(graph.getNode("n0")), kp.kortstePad(Graphs.unmodifiableDirectedGraph(graph), graph.getNode("n0"), graph.getNode("n0")));
    }

    @Test
    public void testPath01() {
        Assert.assertEquals(Arrays.asList(graph.getNode("n0"), graph.getNode("n1")), kp.kortstePad(Graphs.unmodifiableDirectedGraph(graph), graph.getNode("n0"), graph.getNode("n1")));
    }

    @Test
    public void testPath02() {
        Assert.assertEquals(Arrays.asList(graph.getNode("n0"), graph.getNode("n2")), kp.kortstePad(Graphs.unmodifiableDirectedGraph(graph), graph.getNode("n0"), graph.getNode("n2")));
    }

    @Test
    public void testPath03() {
        Assert.assertEquals(Arrays.asList(graph.getNode("n0"), graph.getNode("n3")), kp.kortstePad(Graphs.unmodifiableDirectedGraph(graph), graph.getNode("n0"), graph.getNode("n3")));
    }

    @Test
    public void testPath13() {
        graph.addEdge(new DirectedEdge(graph.getNode("n1"), graph.getNode("n0"), 40));
        Assert.assertEquals(Arrays.asList(graph.getNode("n1"), graph.getNode("n0"), graph.getNode("n3")), kp.kortstePad(Graphs.unmodifiableDirectedGraph(graph), graph.getNode("n1"), graph.getNode("n3")));
    }

    @Test(expected = KortstePaden.UnreachableDestinationException.class)
    public void testUnreachableNode() {
        kp.kortstePad(Graphs.unmodifiableDirectedGraph(graph), graph.getNode("n1"), graph.getNode("n2"));
    }

    @Test(expected = KortstePaden.NegativeCycleException.class)
    public void testNegativeCycle() {
        graph.addEdge(new DirectedEdge(graph.getNode("n3"), graph.getNode("n0"), -34));
        kp.kortstePad(Graphs.unmodifiableDirectedGraph(graph), graph.getNode("n0"), graph.getNode("n1"));
    }
    
}