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/*
 * Copyright 2010 eBusinessInformation
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.excilys.blog.refactoring.fixed;

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

import junit.framework.Assert;

import org.junit.Before;
import org.junit.Test;

import com.excilys.blog.refactoring.GeoPoint;
import com.excilys.blog.refactoring.HullHelper;

public class FixedInitialHullHelperTest {

    private HullHelper hullHelper;

    @Before
    public void setup() {
        hullHelper = new FixedInitialHullHelper();
    }

    /* BEHAVIOR TESTS */

    @Test
    public void threePointsHullContainsAllPoints() {
        Set<GeoPoint> points = createThreePointsSet();

        List<GeoPoint> convexHull = hullHelper.computeConvexHull(points);

        for (GeoPoint point : points) {
            Assert.assertTrue("Each point should be part of the hull", convexHull.contains(point));
        }
    }

    @Test
    public void hullLoopsOnItself() {
        Set<GeoPoint> points = createThreePointsSet();

        List<GeoPoint> convexHull = hullHelper.computeConvexHull(points);

        Assert.assertEquals("Hull should contain one more point to loop", points.size() + 1, convexHull.size());

        Assert.assertSame("First point should be last point", convexHull.get(0), convexHull.get(convexHull.size() - 1));
    }

    @Test
    public void hullExcludesInnerPoints() {
        GeoPoint inner = new GeoPoint(0, 0);
        Set<GeoPoint> points = createTriangleSetAroundInner(inner);

        List<GeoPoint> convexHull = hullHelper.computeConvexHull(points);

        Assert.assertFalse("Hull should not contain inner point", convexHull.contains(inner));

    }

    @Test
    public void hullIncludesOuterPoints() {
        GeoPoint inner = new GeoPoint(0, 0);
        Set<GeoPoint> points = createTriangleSetAroundInner(inner);

        List<GeoPoint> convexHull = hullHelper.computeConvexHull(points);

        for (GeoPoint point : points) {
            if (point != inner) {
                Assert.assertTrue("Hull should contain all outer points", convexHull.contains(point));
            }
        }
    }

    @Test
    public void twoPointsHullContainsAllPoints() {

        final Set<GeoPoint> points = createTwoPointsSet();

        List<GeoPoint> convexHull = hullHelper.computeConvexHull(points);

        for (GeoPoint point : points) {
            Assert.assertTrue("Each point should be part of the hull", convexHull.contains(point));
        }
    }

    @Test
    public void twoPointsHullLoopsOnItself() {
        Set<GeoPoint> points = createTwoPointsSet();

        List<GeoPoint> convexHull = hullHelper.computeConvexHull(points);

        Assert.assertEquals("Hull should contain one more point to loop", points.size() + 1, convexHull.size());

        Assert.assertSame("First point should be last point", convexHull.get(0), convexHull.get(convexHull.size() - 1));
    }

    @Test
    public void rotationAntiClockWise() {
        Set<GeoPoint> points = new HashSet<GeoPoint>();

        GeoPoint northWest = new GeoPoint(10, 5);
        GeoPoint southWest = new GeoPoint(0, 0);
        GeoPoint southEast = new GeoPoint(5, 10);
        GeoPoint northEast = new GeoPoint(15, 15);

        points.add(northWest);
        points.add(southWest);
        points.add(southEast);
        points.add(northEast);

        List<GeoPoint> convexHull = hullHelper.computeConvexHull(points);

        Assert.assertSame("rotation should be anti clockwise", southWest, convexHull.get(0));
        Assert.assertSame("rotation should be anti clockwise", southEast, convexHull.get(1));
        Assert.assertSame("rotation should be anti clockwise", northEast, convexHull.get(2));
        Assert.assertSame("rotation should be anti clockwise", northWest, convexHull.get(3));

    }

    @Test
    public void pointsWithSameLongitude() {
        Set<GeoPoint> points = new HashSet<GeoPoint>();

        GeoPoint northWest = new GeoPoint(10, 5);
        GeoPoint southWest = new GeoPoint(0, 0);
        GeoPoint southEast = new GeoPoint(5, 10);
        GeoPoint northEast = new GeoPoint(15, 10);

        points.add(northWest);
        points.add(southWest);
        points.add(southEast);
        points.add(northEast);

        List<GeoPoint> hull = hullHelper.computeConvexHull(points);

        Assert.assertEquals(5, hull.size());
    }

    /* ERROR TESTS */

    @Test(expected = IllegalArgumentException.class)
    public void emptyPointsThrowsIllegalArgumentException() {
        hullHelper.computeConvexHull(new HashSet<GeoPoint>());
        Assert.fail("Empty set should throw an IllegalArgumentException");
    }

    @Test(expected = IllegalArgumentException.class)
    public void pointsNullThrowsIllegalArgumentException() {
        hullHelper.computeConvexHull(null);
        Assert.fail("Null set should throw an IllegalArgumentException");
    }

    @Test
    public void onePointReturnsOnePointList() {
        Set<GeoPoint> points = new HashSet<GeoPoint>();
        GeoPoint geoPoint = new GeoPoint(10, 10);
        points.add(geoPoint);
        List<GeoPoint> hull = hullHelper.computeConvexHull(points);
        Assert.assertEquals(1, hull.size());
        Assert.assertSame(geoPoint, hull.get(0));
    }

    /* HELPER METHODS */

    private Set<GeoPoint> createTwoPointsSet() {
        Set<GeoPoint> points = new HashSet<GeoPoint>();
        points.add(new GeoPoint(0, 0));
        points.add(new GeoPoint(0, 10));
        return points;
    }

    private Set<GeoPoint> createThreePointsSet() {
        Set<GeoPoint> points = new HashSet<GeoPoint>();
        points.add(new GeoPoint(0, 0));
        points.add(new GeoPoint(0, 10));
        points.add(new GeoPoint(10, 0));
        return points;
    }

    private Set<GeoPoint> createTriangleSetAroundInner(GeoPoint inner) {

        double latitude = inner.getLatitude();
        double longitude = inner.getLongitude();

        Set<GeoPoint> points = new HashSet<GeoPoint>();

        points.add(inner);
        points.add(new GeoPoint(latitude - 10, longitude - 10));
        points.add(new GeoPoint(latitude + 10, longitude - 10));
        points.add(new GeoPoint(latitude, longitude + 10));

        return points;
    }
}