MoonIllumination.getClosestPhase() returns the closest phase of the enum

shred · Jun 5, 2021 · f8ba2d1 · f8ba2d1
1 parent a901760
commit f8ba2d1
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diff --git a/src/main/java/org/shredzone/commons/suncalc/MoonIllumination.java b/src/main/java/org/shredzone/commons/suncalc/MoonIllumination.java
@@ -88,6 +88,9 @@ public double getFraction() {
     /**
      * Moon phase. Starts at {@code -180.0} (new moon, waxing), passes {@code 0.0} (full
      * moon) and moves toward {@code 180.0} (waning, new moon).
+     * <p>
+     * Note that for historical reasons, the range of this phase is different to the
+     * moon phase angle used in {@link MoonPhase}.
      */
     public double getPhase() {
         return phase;
@@ -106,6 +109,16 @@ public double getAngle() {
         return angle;
     }
 
+    /**
+     * The closest {@link MoonPhase.Phase} that is matching the moon's angle.
+     *
+     * @return Closest {@link MoonPhase.Phase}
+     * @since 2.12
+     */
+    public MoonPhase.Phase getClosestPhase() {
+        return MoonPhase.Phase.toPhase(phase + 180.0);
+    }
+
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();

diff --git a/src/test/java/org/shredzone/commons/suncalc/MoonIlluminationTest.java b/src/test/java/org/shredzone/commons/suncalc/MoonIlluminationTest.java
@@ -18,6 +18,7 @@
 
 import org.assertj.core.data.Offset;
 import org.junit.Test;
+import org.shredzone.commons.suncalc.MoonPhase.Phase;
 
 /**
  * Unit tests for {@link MoonIllumination}.
@@ -35,6 +36,7 @@ public void testNewMoon() {
         assertThat(mi.getFraction()).as("fraction").isCloseTo(0.0, ERROR);
         assertThat(mi.getPhase()).as("phase").isCloseTo(176.0, ERROR); // -180.0
         assertThat(mi.getAngle()).as("angle").isCloseTo(1.8, ERROR);
+        assertThat(mi.getClosestPhase()).as("MoonPhase.Phase").isEqualTo(Phase.NEW_MOON);
     }
 
     @Test
@@ -46,6 +48,7 @@ public void testWaxingHalfMoon() {
         assertThat(mi.getFraction()).as("fraction").isCloseTo(0.5, ERROR);
         assertThat(mi.getPhase()).as("phase").isCloseTo(-90.0, ERROR);
         assertThat(mi.getAngle()).as("angle").isCloseTo(-66.9, ERROR);
+        assertThat(mi.getClosestPhase()).as("MoonPhase.Phase").isEqualTo(Phase.FIRST_QUARTER);
     }
 
     @Test
@@ -57,6 +60,7 @@ public void testFullMoon() {
         assertThat(mi.getFraction()).as("fraction").isCloseTo(1.0, ERROR);
         assertThat(mi.getPhase()).as("phase").isCloseTo(-3.2, ERROR); // 0.0
         assertThat(mi.getAngle()).as("angle").isCloseTo(-7.0, ERROR);
+        assertThat(mi.getClosestPhase()).as("MoonPhase.Phase").isEqualTo(Phase.FULL_MOON);
     }
 
     @Test
@@ -68,6 +72,7 @@ public void testWaningHalfMoon() {
         assertThat(mi.getFraction()).as("fraction").isCloseTo(0.5, ERROR);
         assertThat(mi.getPhase()).as("phase").isCloseTo(90.0, ERROR);
         assertThat(mi.getAngle()).as("angle").isCloseTo(68.1, ERROR);
+        assertThat(mi.getClosestPhase()).as("MoonPhase.Phase").isEqualTo(Phase.LAST_QUARTER);
     }
 
 }