using System;
using System.Collections.Generic;
using System.Linq;
using HeuristicLab.Algorithms.ParameterlessPopulationPyramid;
using HeuristicLab.Random;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace ParameterlessPopulationPyramid.Test {
  [TestClass]
  public class LinkageTreeTest {
    private static int Length = 9;
    private static bool[][] solutions = new bool[][] {
    new bool[] { true, true, false, false, false, false, false, false, false }, // 110000000
    new bool[] { false, false, true, true, false, false, false, false, false }, // 001100000
    new bool[] { false, false, false, false, true, true, false, false, false }, // 000011000
    new bool[] { false, false, false, false, false, false, true, true, true },  // 000000111
    new bool[] { true, true, true, true, false, false, false, false, false },   // 111100000
    new bool[] { true, true, true, true, true, true, true, true, true },        // 111111111
    };

    private static int[][] correctClusters = new int[][] {
      new int[] { 2, 3 },
      new int[] { 4, 5 },
      new int[] { 0, 1 },
      new int[] { 6, 7, 8 },
      new int[] { 0, 1, 2, 3},
      new int[] { 4, 5, 6, 7, 8},
    };

    [TestMethod]
    public void LinkageTreeTestAdd() {
      LinkageTree tree = new LinkageTree(Length);
      tree.Add(solutions[0]);
      tree.Add(solutions[1]);
      PrivateObject hidden = new PrivateObject(tree);
      int[][][] result = (int[][][])hidden.GetField("occurances");
      Assert.AreEqual(1, result[1][0][0]); // Positions 0 and 1 had value 00 exactly once
      Assert.AreEqual(2, result[Length - 1][Length - 2][0]); // Positions 0 and 1 had value 00 exactly once
      Assert.AreEqual(0, result[Length - 1][Length - 2][1]); // Positions 7 and 8 never had value 10
      Assert.AreEqual(1, result[1][0][3]); // Positions 0 and 1 had value 11 exactly once
    }

    [TestMethod]
    public void LinkageTreeTestEntropyDistance() {
      LinkageTree tree = new LinkageTree(Length);
      PrivateObject hidden = new PrivateObject(tree);
      // No information should result in a distance of 0
      Assert.AreEqual((double)0, hidden.Invoke("EntropyDistance", new object[] { 0, 1 }));
      foreach (var solution in solutions) {
        tree.Add(solution);
      }
      // Check that 0 and 1 are closer than 0 and 2
      var linked = (double)hidden.Invoke("EntropyDistance", new object[] { 0, 1 });
      var unlinked = (double)hidden.Invoke("EntropyDistance", new object[] { 0, 2 });
      Assert.IsTrue(linked < unlinked);

      // Reversing the arguments should not change the result
      var forward = hidden.Invoke("EntropyDistance", new object[] { Length - 1, Length - 2 });
      var backward = hidden.Invoke("EntropyDistance", new object[] { Length - 2, Length - 1 });
      Assert.AreEqual(forward, backward);
    }

    [TestMethod]
    public void LinkageTreeTestRebuild() {
      LinkageTree tree = new LinkageTree(Length);
      foreach (var solution in solutions) {
        tree.Add(solution);
      }
      MersenneTwister rand = new MersenneTwister(123);
      tree.Rebuild(rand);
      PrivateObject hidden = new PrivateObject(tree);
      var ordering = (List<int>)hidden.GetField("clusterOrdering");
      var clusters = (List<int>[])hidden.GetField("clusters");
      int[][] comparable = new int[ordering.Count][];
      for (int i = 0; i < ordering.Count; i++) {
        var found = clusters[ordering[i]].ToArray();
        Array.Sort(found);
        Assert.IsTrue(correctClusters[i].SequenceEqual(found));
      }
    }
  }
}