/* Copyright 2002-2022 CS GROUP
    * Licensed to CS GROUP (CS) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * CS licenses this file to You 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 org.orekit.time;
  
  
  import org.junit.After;
  import org.junit.Assert;
  import org.junit.Before;
  import org.junit.Test;
  import org.orekit.Utils;
  import org.orekit.utils.Constants;
  import org.orekit.utils.IERSConventions;
  
  
  public class GMSTScaleTest {
  
      @Test
      // reference: http://www.astro.umd.edu/~jph/GST_eqn.pdf
      public void testReference() {
          Assert.assertEquals("GMST", gmst.toString());
          AbsoluteDate date = new AbsoluteDate(2001, 10, 3, 6, 30, 0.0,
                                               TimeScalesFactory.getUT1(IERSConventions.IERS_2010, true));
          DateTimeComponents gmstComponents = date.getComponents(gmst);
          Assert.assertEquals(2001,  gmstComponents.getDate().getYear());
          Assert.assertEquals( 10,   gmstComponents.getDate().getMonth());
          Assert.assertEquals(  3,   gmstComponents.getDate().getDay());
          Assert.assertEquals(  7,   gmstComponents.getTime().getHour());
          Assert.assertEquals( 18,   gmstComponents.getTime().getMinute());
          Assert.assertEquals(8.329, gmstComponents.getTime().getSecond(), 4.0e-4);
      }
  
      @Test
      public void testSymmetry() {
          for (double dt = -10000; dt < 10000; dt += 123.456789) {
              AbsoluteDate date = AbsoluteDate.J2000_EPOCH.shiftedBy(dt * Constants.JULIAN_DAY);
              double dt1 = gmst.offsetFromTAI(date);
              DateTimeComponents components = date.getComponents(gmst);
              double dt2 = gmst.offsetToTAI(components.getDate(), components.getTime());
              Assert.assertEquals( 0.0, dt1 + dt2, 1.0e-10);
          }
      }
  
      @Test
      public void testDuringLeap() {
          final TimeScale utc   = TimeScalesFactory.getUTC();
          final TimeScale scale = gmst;
          final AbsoluteDate before = new AbsoluteDate(new DateComponents(1983, 06, 30),
                                                       new TimeComponents(23, 59, 59),
                                                       utc);
          final AbsoluteDate during = before.shiftedBy(1.25);
          Assert.assertEquals(61, utc.minuteDuration(during));
          Assert.assertEquals(1.0, utc.getLeap(during), 1.0e-10);
          Assert.assertEquals(60, scale.minuteDuration(during));
          Assert.assertEquals(0.0, scale.getLeap(during), 1.0e-10);
      }
  
      @Before
      public void setUp() {
          Utils.setDataRoot("regular-data");
          gmst = TimeScalesFactory.getGMST(IERSConventions.IERS_2010, false);
      }
  
      @After
      public void tearDown() {
          gmst = null;
      }
  
      private TimeScale gmst;
  
  }