package au.gov.amsa.navigation;
   
   import java.util.concurrent.TimeUnit;
   
   import com.google.common.base.Optional;
   
   import au.gov.amsa.navigation.VesselPosition.NavigationalStatus;
   import au.gov.amsa.risky.format.AisClass;
   import au.gov.amsa.risky.format.Fix;
  import au.gov.amsa.risky.format.HasFix;
  import rx.functions.Func1;
  
  public class VesselPositions {
  
      private static final double KNOTS_TO_METRES_PER_SECOND = 1852.0 / TimeUnit.HOURS.toSeconds(1);
  
      // TODO unit test
      public static VesselPosition toVesselPosition(Fix fix, Optional<?> data) {
          return VesselPosition.builder().id(new Mmsi(fix.mmsi())).lat(fix.lat()).lon(fix.lon())
                  .time(fix.time()).cls(fix.aisClass() == AisClass.A ? VesselClass.A : VesselClass.B)
                  .cogDegrees(toDouble(fix.courseOverGroundDegrees()))
                  .headingDegrees(toDouble(fix.headingDegrees()))
                  .speedMetresPerSecond(
                          multiply(fix.speedOverGroundKnots(), KNOTS_TO_METRES_PER_SECOND))
                  .navigationalStatus(fix.navigationalStatus().isPresent()
                          ? NavigationalStatus.values()[fix.navigationalStatus().get().ordinal()]
                          : NavigationalStatus.NOT_DEFINED)
                  .positionAisNmea(Optional.<String> absent())
                  .shipStaticAisNmea(Optional.<String> absent())
                  // set data
                  .data(data)
                  // build
                  .build();
      }
  
      public static Func1<HasFix, VesselPosition> TO_VESSEL_POSITION = fix -> toVesselPosition(
              fix.fix(), Optional.absent());
  
      public static <T extends HasFix> Func1<T, VesselPosition> toVesselPosition(
              final Func1<T, Optional<?>> dataExtractor) {
          return fix -> toVesselPosition(fix.fix(), dataExtractor.call(fix));
      }
  
      private static Optional<Double> toDouble(Optional<Float> value) {
          if (!value.isPresent())
              return Optional.absent();
          else
              return Optional.of((double) value.get());
      }
  
      private static Optional<Double> multiply(Optional<Float> value, double factor) {
          if (!value.isPresent())
              return Optional.absent();
          else
              return Optional.of((double) value.get() * factor);
      }
  
  }