package org.djutils.math.functions;
   
   import java.util.Objects;
   import java.util.SortedSet;
   
   import org.djutils.exceptions.Throw;
   
   /**
    * Quotient.java.
   * <p>
   * Copyright (c) 2024-2025 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
   * for project information <a href="https://djutils.org" target="_blank"> https://djutils.org</a>. The DJUTILS project is
   * distributed under a three-clause BSD-style license, which can be found at
   * <a href="https://djutils.org/docs/license.html" target="_blank"> https://djutils.org/docs/license.html</a>.
   * </p>
   * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
   * @author <a href="https://github.com/peter-knoppers">Peter Knoppers</a>
   * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
   */
  public class Quotient implements MathFunction
  {
      /** The numerator of this Quotient. */
      private final MathFunction numerator;
  
      /** The denominator of this Quotient. */
      private final MathFunction denominator;
  
      /**
       * Construct a new Quotient; division of two <code>MathFunction</code>s, generally <code>numerator / denominator</code>.
       * @param numerator the numerator part of the division (the part above the division line)
       * @param denominator the denominator of the division (the part below the division line)
       * @throws NullPointerException when <code>numerator</code>, or <code>denominator</code> is <code>null</code>
       */
      public Quotient(final MathFunction numerator, final MathFunction denominator)
      {
          Throw.whenNull(numerator, "numerator");
          Throw.whenNull(denominator, "denominator");
          this.numerator = numerator;
          this.denominator = denominator;
      }
  
      @Override
      public double get(final double x)
      {
          return this.numerator.get(x) / this.denominator.get(x);
      }
  
      @Override
      public MathFunction getDerivative()
      {
          Quotient result = new Quotient(
                  new Sum(new Product(this.numerator.getDerivative(), this.denominator),
                          new Product(this.numerator.scaleBy(-1), this.denominator.getDerivative())),
                  new Product(this.denominator, this.denominator));
          return result.simplify();
      }
  
      @Override
      public MathFunction simplify()
      {
          if (this.denominator instanceof Constant)
          {
              return this.numerator.scaleBy(1.0 / this.denominator.get(0));
          }
          MathFunction divideResult = this.numerator.mergeDivide(this.denominator);
          return divideResult != null ? divideResult : this;
      }
  
      @Override
      public MathFunction scaleBy(final double factor)
      {
          return new Quotient(this.numerator.scaleBy(factor), this.denominator);
      }
  
      @Override
      public int sortPriority()
      {
          return 102;
      }
  
      @Override
      public int compareWithinSubType(final MathFunction other)
      {
          Throw.when(!(other instanceof Quotient), IllegalArgumentException.class, "other is of wrong type");
          Quotient otherQuotient = (Quotient) other;
          int result = this.denominator.compareTo(otherQuotient.denominator);
          if (result != 0)
          {
              return result;
          }
          return this.numerator.compareTo(otherQuotient.numerator);
      }
  
      @Override
      public KnotReport getKnotReport(final Interval<?> interval)
      {
          return KnotReport.UNKNOWN;
      }
  
     @Override
     public SortedSet<Double> getKnots(final Interval<?> interval)
     {
         throw new UnsupportedOperationException(
                 "Cannot report knots in because I do not know where the numerator function is negative or zero");
     }
 
     @Override
     public String toString()
     {
         StringBuilder result = new StringBuilder();
         result.append("(");
         result.append(this.numerator.toString());
         result.append(")/(");
         result.append(this.denominator.toString());
         result.append(")");
         return result.toString();
     }
 
     @Override
     public int hashCode()
     {
         return Objects.hash(this.denominator, this.numerator);
     }
 
     @SuppressWarnings("checkstyle:needbraces")
     @Override
     public boolean equals(final Object obj)
     {
         if (this == obj)
             return true;
         if (obj == null)
             return false;
         if (getClass() != obj.getClass())
             return false;
         Quotient other = (Quotient) obj;
         return Objects.equals(this.denominator, other.denominator) && Objects.equals(this.numerator, other.numerator);
     }
 
 }