/*
    * Portions of this software was developed by employees of the National Institute
    * of Standards and Technology (NIST), an agency of the Federal Government and is
    * being made available as a public service. Pursuant to title 17 United States
    * Code Section 105, works of NIST employees are not subject to copyright
    * protection in the United States. This software may be subject to foreign
    * copyright. Permission in the United States and in foreign countries, to the
    * extent that NIST may hold copyright, to use, copy, modify, create derivative
    * works, and distribute this software and its documentation without fee is hereby
   * granted on a non-exclusive basis, provided that this notice and disclaimer
   * of warranty appears in all copies.
   *
   * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
   * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
   * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
   * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
   * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
   * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
   * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
   * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
   * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
   * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
   * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
   */
  
  package gov.nist.secauto.metaschema.core.metapath.item.atomic;
  
  import gov.nist.secauto.metaschema.core.metapath.function.ArithmeticFunctionException;
  import gov.nist.secauto.metaschema.core.metapath.function.FunctionUtils;
  import gov.nist.secauto.metaschema.core.metapath.function.InvalidValueForCastFunctionException;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  
  import java.math.BigDecimal;
  import java.math.BigInteger;
  import java.math.MathContext;
  import java.math.RoundingMode;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  public interface INumericItem extends IAnyAtomicItem {
  
    @NonNull
    static INumericItem cast(@NonNull IAnyAtomicItem item) throws InvalidValueForCastFunctionException {
      INumericItem retval;
      if (item instanceof INumericItem) {
        retval = (INumericItem) item;
      } else {
        try {
          retval = IDecimalItem.valueOf(item.asString());
        } catch (NumberFormatException ex) {
          throw new InvalidValueForCastFunctionException(ex);
        }
      }
      return retval;
    }
  
    @NonNull
    BigDecimal asDecimal();
  
    @NonNull
    BigInteger asInteger();
  
    boolean toEffectiveBoolean();
  
    /**
     * Get the absolute value of the item.
     *
     * @return this item negated if this item is negative, or the item otherwise
     */
    @NonNull
    INumericItem abs();
  
    /**
     * Round the value to the whole number closest to positive infinity.
     *
     * @return the rounded value
     */
    @NonNull
    IIntegerItem ceiling();
  
    /**
     * Round the value to the whole number closest to negative infinity.
     *
     * @return the rounded value
     */
    @NonNull
    IIntegerItem floor();
  
    @NonNull
    default INumericItem round() {
      return round(IIntegerItem.ZERO);
    }
  
    @NonNull
    default INumericItem round(@NonNull IIntegerItem precisionItem) {
      int precision;
      try {
        precision = FunctionUtils.asInteger(precisionItem);
     } catch (ArithmeticException ex) {
       throw new ArithmeticFunctionException(ArithmeticFunctionException.OVERFLOW_UNDERFLOW_ERROR,
           "Numeric operation overflow/underflow.", ex);
     }
     INumericItem retval;
     if (precision >= 0) {
       // round to precision decimal places
       if (this instanceof IIntegerItem) {
         retval = this;
       } else {
         // IDecimalItem
         BigDecimal value = this.asDecimal();
         if (value.signum() == -1) {
           retval = IDecimalItem.valueOf(
               ObjectUtils.notNull(
                   value.round(new MathContext(precision + value.precision() - value.scale(), RoundingMode.HALF_DOWN))));
         } else {
           retval = IDecimalItem.valueOf(
               ObjectUtils.notNull(
                   value.round(new MathContext(precision + value.precision() - value.scale(), RoundingMode.HALF_UP))));
         }
       }
     } else {
       // round to a power of 10
       BigInteger value = this.asInteger();
       BigInteger divisor = BigInteger.TEN.pow(0 - precision);
 
       @NonNull BigInteger result;
       if (divisor.compareTo(value.abs()) > 0) {
         result = ObjectUtils.notNull(BigInteger.ZERO);
       } else {
         BigInteger remainder = value.mod(divisor);
         BigInteger lessRemainder = value.subtract(remainder);
         BigInteger halfDivisor = divisor.divide(BigInteger.TWO);
         result = ObjectUtils.notNull(
             remainder.compareTo(halfDivisor) >= 0 ? lessRemainder.add(divisor) : lessRemainder);
       }
       retval = IIntegerItem.valueOf(result);
     }
     return retval;
   }
 }