/*
    * Copyright (C) 2019 Alberto Irurueta Carro (alberto@irurueta.com)
    *
    * 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.irurueta.navigation.inertial;
  
  import com.irurueta.units.Distance;
  import com.irurueta.units.DistanceConverter;
  import com.irurueta.units.DistanceUnit;
  
  import java.io.Serial;
  import java.io.Serializable;
  import java.util.Objects;
  
  /**
   * Contains radii of curvature of the WGS84 ellipsoid at a given latitude.
   */
  public class RadiiOfCurvature implements Serializable, Cloneable {
  
      /**
       * Serialization version. This is used to ensure compatibility of deserialization of permanently stored serialized
       * instances.
       */
      @Serial
      private static final long serialVersionUID = 0L;
  
      /**
       * Meridian radius of curvature expressed in meters (m).
       * This is the radius of curvature for north-south motion.
       * It is the radius of curvature of a meridian, a cross-section of the ellipsoid
       * surface in the north-down plane, at the point of interest (a given latitude).
       * This is the same as the radius of the best-fitting circle to the meridian
       * ellipse at the point of interest.
       * The meridian radius of curvature varies with latitude and is smallest at the
       * equator, where the geocentric radius is largest, and largest at the poles.
       */
      private double rn;
  
      /**
       * Transverse radius of curvature expressed in meters (m).
       * This is the radius of curvature for east-west motion.
       * This is also known as the normal radius of curvature or prime vertical radius
       * of curvature.
       * It is the radius of curvature of a cross-section of the ellipsoid surface in
       * the east-down plane at the point of interest.
       * This is the vertical plane perpendicular to the meridian plane and is not
       * the plane of constant latitude.
       * The transverse radius of curvature varies with latitude and is smallest at the
       * equator. It is also equal to the length of the normal from a point on the
       * surface to the polar axis.
       */
      private double re;
  
      /**
       * Constructor.
       */
      public RadiiOfCurvature() {
      }
  
      /**
       * Constructor.
       *
       * @param rn meridian radius of curvature expressed in meters (m).
       * @param re transverse radius of curvature expressed in meters (m).
       */
      public RadiiOfCurvature(final double rn, final double re) {
          setValues(rn, re);
      }
  
      /**
       * Constructor.
       *
       * @param rnDistance meridian radius of curvature.
       * @param reDistance transverse radius of curvature.
       */
      public RadiiOfCurvature(final Distance rnDistance, final Distance reDistance) {
          setValues(rnDistance, reDistance);
      }
  
      /**
       * Constructor.
       *
       * @param input instance to copy data from.
       */
      public RadiiOfCurvature(final RadiiOfCurvature input) {
          copyFrom(input);
      }
  
     /**
      * Gets meridian radius of curvature expressed in meters (m).
      * This is the radius of curvature for north-south motion.
      * It is the radius of curvature of a meridian, a cross-section of the ellipsoid
      * surface in the north-down plane, at the point of interest (a given latitude).
      * This is the same as the radius of the best-fitting circle to the meridian
      * ellipse at the point of interest.
      * The meridian radius of curvature varies with latitude and is smallest at the
      * equator, where the geocentric radius is largest, and largest at the poles.
      *
      * @return meridian radius of curvature expressed in meters (m).
      */
     public double getRn() {
         return rn;
     }
 
     /**
      * Sets meridian radius of curvature expressed in meters (m).
      * This is the radius of curvature for north-south motion.
      * It is the radius of curvature of a meridian, a cross-section of the ellipsoid
      * surface in the north-down plane, at the point of interest (a given latitude).
      * This is the same as the radius of the best-fitting circle to the meridian
      * ellipse at the point of interest.
      * The meridian radius of curvature varies with latitude and is smallest at the
      * equator, where the geocentric radius is largest, and largest at the poles.
      *
      * @param rn meridian radius of curvature expressed in meters (m).
      */
     public void setRn(final double rn) {
         this.rn = rn;
     }
 
     /**
      * Gets transverse radius of curvature expressed in meters (m).
      * This is the radius of curvature for east-wet motion.
      * This is also known as the normal radius of curvature or prime vertical radius
      * of curvature.
      * It is the radius of curvature of a cross-section of the ellipsoid surface in
      * the east-down plane at the point of interest.
      * This is the vertical plane perpendicular to the meridian plane and is not
      * the plane of constant latitude.
      * The transverse radius of curvature varies with latitude and is smallest at the
      * equator. It is also equal to the length of the normal from a point on the
      * surface to the polar axis.
      *
      * @return transverse radius of curvature expressed in meters (m).
      */
     public double getRe() {
         return re;
     }
 
     /**
      * Sets transverse radius of curvature expressed in meters (m).
      * This is the radius of curvature for east-wet motion.
      * This is also known as the normal radius of curvature or prime vertical radius
      * of curvature.
      * It is the radius of curvature of a cross-section of the ellipsoid surface in
      * the east-down plane at the point of interest.
      * This is the vertical plane perpendicular to the meridian plane and is not
      * the plane of constant latitude.
      * The transverse radius of curvature varies with latitude and is smallest at the
      * equator. It is also equal to the length of the normal from a point on the
      * surface to the polar axis.
      *
      * @param re transverse radius of curvature expressed in meters (m).
      */
     public void setRe(final double re) {
         this.re = re;
     }
 
     /**
      * Sets radii of curvature.
      *
      * @param rn meridian radius of curvature expressed in meters (m).
      * @param re transverse radius of curvature expressed in meters (m).
      */
     public void setValues(final double rn, final double re) {
         this.rn = rn;
         this.re = re;
     }
 
     /**
      * Gets meridian radius of curvature.
      * This is the radius of curvature for north-south motion.
      * It is the radius of curvature of a meridian, a cross-section of the ellipsoid
      * surface in the north-down plane, at the point of interest (a given latitude).
      * This is the same as the radius of the best-fitting circle to the meridian
      * ellipse at the point of interest.
      * The meridian radius of curvature varies with latitude and is smallest at the
      * equator, where the geocentric radius is largest, and largest at the poles.
      *
      * @param result instance where meridian radius of curvature will be stored.
      */
     public void getRnDistance(final Distance result) {
         result.setValue(rn);
         result.setUnit(DistanceUnit.METER);
     }
 
     /**
      * Gets meridian radius of curvature.
      * This is the radius of curvature for north-south motion.
      * It is the radius of curvature of a meridian, a cross-section of the ellipsoid
      * surface in the north-down plane, at the point of interest (a given latitude).
      * This is the same as the radius of the best-fitting circle to the meridian
      * ellipse at the point of interest.
      * The meridian radius of curvature varies with latitude and is smallest at the
      * equator, where the geocentric radius is largest, and largest at the poles.
      *
      * @return meridian radius of curvature.
      */
     public Distance getRnDistance() {
         return new Distance(rn, DistanceUnit.METER);
     }
 
     /**
      * Sets meridian radius of curvature.
      * This is the radius of curvature for north-south motion.
      * It is the radius of curvature of a meridian, a cross-section of the ellipsoid
      * surface in the north-down plane, at the point of interest (a given latitude).
      * This is the same as the radius of the best-fitting circle to the meridian
      * ellipse at the point of interest.
      * The meridian radius of curvature varies with latitude and is smallest at the
      * equator, where the geocentric radius is largest, and largest at the poles.
      *
      * @param rnDistance meridian radius of curvature to be set.
      */
     public void setRnDistance(final Distance rnDistance) {
         rn = DistanceConverter.convert(rnDistance.getValue().doubleValue(), rnDistance.getUnit(), DistanceUnit.METER);
     }
 
     /**
      * Gets transverse radius or curvature.
      * This is the radius of curvature for east-wet motion.
      * This is also known as the normal radius of curvature or prime vertical radius
      * of curvature.
      * It is the radius of curvature of a cross-section of the ellipsoid surface in
      * the east-down plane at the point of interest.
      * This is the vertical plane perpendicular to the meridian plane and is not
      * the plane of constant latitude.
      * The transverse radius of curvature varies with latitude and is smallest at the
      * equator. It is also equal to the length of the normal from a point on the
      * surface to the polar axis.
      *
      * @param result instance where transverse radius of curvature will be stored.
      */
     public void getReDistance(final Distance result) {
         result.setValue(re);
         result.setUnit(DistanceUnit.METER);
     }
 
     /**
      * Gets transverse radius of curvature.
      * This is the radius of curvature for east-wet motion.
      * This is also known as the normal radius of curvature or prime vertical radius
      * of curvature.
      * It is the radius of curvature of a cross-section of the ellipsoid surface in
      * the east-down plane at the point of interest.
      * This is the vertical plane perpendicular to the meridian plane and is not
      * the plane of constant latitude.
      * The transverse radius of curvature varies with latitude and is smallest at the
      * equator. It is also equal to the length of the normal from a point on the
      * surface to the polar axis.
      *
      * @return transverse radius of curvature.
      */
     public Distance getReDistance() {
         return new Distance(re, DistanceUnit.METER);
     }
 
     /**
      * Sets transverse radius of curvature.
      * This is the radius of curvature for east-wet motion.
      * This is also known as the normal radius of curvature or prime vertical radius
      * of curvature.
      * It is the radius of curvature of a cross-section of the ellipsoid surface in
      * the east-down plane at the point of interest.
      * This is the vertical plane perpendicular to the meridian plane and is not
      * the plane of constant latitude.
      * The transverse radius of curvature varies with latitude and is smallest at the
      * equator. It is also equal to the length of the normal from a point on the
      * surface to the polar axis.
      *
      * @param reDistance transverse radius of curvature to be set.
      */
     public void setReDistance(final Distance reDistance) {
         re = DistanceConverter.convert(reDistance.getValue().doubleValue(), reDistance.getUnit(), DistanceUnit.METER);
     }
 
     /**
      * Sets radii of curvature.
      *
      * @param rnDistance meridian radius of curvature.
      * @param reDistance transverse radius of curvature.
      */
     public void setValues(final Distance rnDistance, final Distance reDistance) {
         setRnDistance(rnDistance);
         setReDistance(reDistance);
     }
 
     /**
      * Copies this instance data into provided instance.
      *
      * @param output destination instance where data will be copied to.
      */
     public void copyTo(final RadiiOfCurvature output) {
         output.rn = rn;
         output.re = re;
     }
 
     /**
      * Copies data of provided instance into this instance.
      *
      * @param input instance to copy data from.
      */
     public void copyFrom(final RadiiOfCurvature input) {
         rn = input.rn;
         re = input.re;
     }
 
     /**
      * Computes and returns hash code for this instance. Hash codes are almost unique
      * values that are useful for fast classification and storage of objects in collections.
      *
      * @return Hash code.
      */
     @Override
     public int hashCode() {
         return Objects.hash(rn, re);
     }
 
     /**
      * Checks if provided object is a RadiiOfCurvature instance having exactly the same
      * contents as this instance.
      *
      * @param obj object to be compared.
      * @return true if both objects are considered to be equal, false otherwise.
      */
     @Override
     public boolean equals(final Object obj) {
         if (obj == null) {
             return false;
         }
         if (obj == this) {
             return true;
         }
         if (!(obj instanceof RadiiOfCurvature)) {
             return false;
         }
 
         //noinspection PatternVariableCanBeUsed
         final var other = (RadiiOfCurvature) obj;
         return equals(other);
     }
 
     /**
      * Checks if provided instance has exactly the same contents as this instance.
      *
      * @param other instance to be compared.
      * @return true if both instances are considered to be equal, false otherwise.
      */
     public boolean equals(final RadiiOfCurvature other) {
         return equals(other, 0.0);
     }
 
     /**
      * Checks if provided instance has contents similar to this instance up to provided
      * threshold value.
      *
      * @param other     instance to be compared.
      * @param threshold maximum allowed difference between radii values.
      * @return true if both instances are considered to be equal (up to provided
      * threshold), false otherwise.
      */
     public boolean equals(final RadiiOfCurvature other, final double threshold) {
         if (other == null) {
             return false;
         }
 
         return Math.abs(rn - other.rn) <= threshold && Math.abs(re - other.re) <= threshold;
     }
 
     /**
      * Makes a copy of this instance.
      *
      * @return a copy of this instance.
      * @throws CloneNotSupportedException if clone fails for some reason.
      */
     @Override
     protected Object clone() throws CloneNotSupportedException {
         final var result = (RadiiOfCurvature) super.clone();
         copyTo(result);
         return result;
     }
 }