package btools.util;

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class CheapAngleMeterTest {
  static int toOsmLon(double lon) {
    return (int) ((lon + 180.) / CheapRuler.ILATLNG_TO_LATLNG + 0.5);
  }

  static int toOsmLat(double lat) {
    return (int) ((lat + 90.) / CheapRuler.ILATLNG_TO_LATLNG + 0.5);
  }

  @Test
  public void testCalcAngle() {
    CheapAngleMeter am = new CheapAngleMeter();
    // Segment ends
    int lon0, lat0, lon1, lat1, lon2, lat2;

    lon0 = toOsmLon(2.317126);
    lat0 = toOsmLat(48.817927);
    lon1 = toOsmLon(2.317316);
    lat1 = toOsmLat(48.817978);
    lon2 = toOsmLon(2.317471);
    lat2 = toOsmLat(48.818043);
    assertEquals(
      "Works for an angle between -pi/4 and pi/4",
      -10.,
      am.calcAngle(lon0, lat0, lon1, lat1, lon2, lat2),
      0.05 * 10.
    );

    lon0 = toOsmLon(2.317020662874013);
    lat0 = toOsmLat(48.81799440182911);
    lon1 = toOsmLon(2.3169460585876327);
    lat1 = toOsmLat(48.817812421536644);
    lon2 = lon0;
    lat2 = lat0;
    assertEquals(
      "Works for an angle between 3*pi/4 and 5*pi/4",
      180.,
      am.calcAngle(lon0, lat0, lon1, lat1, lon2, lat2),
      0.05 * 180.
    );

    lon0 = toOsmLon(2.317112);
    lat0 = toOsmLat(48.817802);
    lon1 = toOsmLon(2.317632);
    lat1 = toOsmLat(48.817944);
    lon2 = toOsmLon(2.317673);
    lat2 = toOsmLat(48.817799);
    assertEquals(
      "Works for an angle between -3*pi/4 and -pi/4",
      100.,
      am.calcAngle(lon0, lat0, lon1, lat1, lon2, lat2),
      0.1 * 100.
    );

    lon0 = toOsmLon(2.317128);
    lat0 = toOsmLat(48.818072);
    lon1 = toOsmLon(2.317532);
    lat1 = toOsmLat(48.818108);
    lon2 = toOsmLon(2.317497);
    lat2 = toOsmLat(48.818264);
    assertEquals(
      "Works for an angle between pi/4 and 3*pi/4",
      -100.,
      am.calcAngle(lon0, lat0, lon1, lat1, lon2, lat2),
      0.1 * 100.
    );
  }

  @Test
  public void testCalcAngle2() {
    CheapAngleMeter am = new CheapAngleMeter();
    int lon1 = 8500000;
    int lat1 = 49500000;

    double[] lonlat2m = CheapRuler.getLonLatToMeterScales(lat1);
    double lon2m = lonlat2m[0];
    double lat2m = lonlat2m[1];

    for (double afrom = -175.; afrom < 180.; afrom += 10.) {
      double sf = Math.sin(afrom * Math.PI / 180.);
      double cf = Math.cos(afrom * Math.PI / 180.);

      int lon0 = (int) (0.5 + lon1 - cf * 150. / lon2m);
      int lat0 = (int) (0.5 + lat1 - sf * 150. / lat2m);

      for (double ato = -177.; ato < 180.; ato += 10.) {
        double st = Math.sin(ato * Math.PI / 180.);
        double ct = Math.cos(ato * Math.PI / 180.);

        int lon2 = (int) (0.5 + lon1 + ct * 250. / lon2m);
        int lat2 = (int) (0.5 + lat1 + st * 250. / lat2m);

        double a1 = afrom - ato;
        if (a1 > 180.) a1 -= 360.;
        if (a1 < -180.) a1 += 360.;
        double a2 = am.calcAngle(lon0, lat0, lon1, lat1, lon2, lat2);
        double c1 = Math.cos(a1 * Math.PI / 180.);
        double c2 = am.getCosAngle();

        assertEquals("angle mismatch for afrom=" + afrom + " ato=" + ato, a1, a2, 0.2);
        assertEquals("cosinus mismatch for afrom=" + afrom + " ato=" + ato, c1, c2, 0.001);
      }
    }
  }

}