/*
    * ModeShape (http://www.modeshape.org)
    * See the COPYRIGHT.txt file distributed with this work for information
    * regarding copyright ownership.  Some portions may be licensed
    * to Red Hat, Inc. under one or more contributor license agreements.
    * See the AUTHORS.txt file in the distribution for a full listing of 
    * individual contributors. 
    *
    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
   * is licensed to you under the terms of the GNU Lesser General Public License as
   * published by the Free Software Foundation; either version 2.1 of
   * the License, or (at your option) any later version.
   *
   * ModeShape is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this software; if not, write to the Free
   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
   */
  package org.modeshape.common.math;
  
  import java.math.BigDecimal;
  import java.util.Comparator;
  import java.util.Random;
  import net.jcip.annotations.Immutable;
  
  /**
   * The {@link MathOperations math operations} for integer numbers.
   */
  @Immutable
  public class IntegerOperations implements MathOperations<Integer>, Comparator<Integer> {
  
      public Class<Integer> getOperandClass() {
          return Integer.class;
      }
  
      public Integer add( Integer value1,
                          Integer value2 ) {
          if (value1 == null) return value2 != null ? value2 : createZeroValue();
          if (value2 == null) return value1;
          return value1 + value2;
      }
  
      public Integer subtract( Integer value1,
                               Integer value2 ) {
          if (value1 == null) return negate(value2);
          if (value2 == null) return value1;
          return value1 - value2;
      }
  
      public Integer multiply( Integer value1,
                               Integer value2 ) {
          if (value1 == null || value2 == null) return createZeroValue();
          return value1 * value2;
      }
  
      public double divide( Integer value1,
                            Integer value2 ) {
          if (value1 == null || value2 == null) throw new IllegalArgumentException();
          return value1 / value2;
      }
  
      public Integer negate( Integer value ) {
          if (value == null) return createZeroValue();
          return value * -1;
      }
  
      public Integer increment( Integer value ) {
          if (value == null) return createZeroValue();
          return value + 1;
      }
  
      public Integer maximum( Integer value1,
                              Integer value2 ) {
          if (value1 == null) return value2;
          if (value2 == null) return value1;
          return Math.max(value1, value2);
      }
  
      public Integer minimum( Integer value1,
                              Integer value2 ) {
          if (value1 == null) return value2;
          if (value2 == null) return value1;
          return Math.min(value1, value2);
      }
  
      public int compare( Integer value1,
                          Integer value2 ) {
          if (value1 == null) return value2 != null ? -1 : 0;
          if (value2 == null) return 1;
          return value1.compareTo(value2);
      }
  
      public BigDecimal asBigDecimal( Integer value ) {
          return value != null ? new BigDecimal(value) : null;
     }
 
     public Integer fromBigDecimal( BigDecimal value ) {
         return value != null ? value.intValue() : null;
     }
 
     public Integer createZeroValue() {
         return 0;
     }
 
     public Integer create( int value ) {
         return value;
     }
 
     public Integer create( long value ) {
         return (int)value;
     }
 
     public Integer create( double value ) {
         return (int)value;
     }
 
     public double sqrt( Integer value ) {
         return Math.sqrt(value);
     }
 
     public Comparator<Integer> getComparator() {
         return this;
     }
 
     public Integer random( Integer minimum,
                            Integer maximum,
                            Random rng ) {
         Integer difference = subtract(maximum, minimum);
         return minimum + rng.nextInt(difference);
     }
 
     public double doubleValue( Integer value ) {
         return value.doubleValue();
     }
 
     public float floatValue( Integer value ) {
         return value.floatValue();
     }
 
     public int intValue( Integer value ) {
         return value.intValue();
     }
 
     public long longValue( Integer value ) {
         return value.longValue();
     }
 
     public short shortValue( Integer value ) {
         return value.shortValue();
     }
 
     public int getExponentInScientificNotation( Integer value ) {
         int v = Math.abs(value);
         int exp = 0;
         if (v > 1) {
             while (v >= 10) {
                 v /= 10;
                 ++exp;
             }
         }
         return exp;
     }
 
     public Integer roundUp( Integer value,
                             int decimalShift ) {
         if (value == 0) return 0;
         if (decimalShift >= 0) return value;
         int shiftedValueP5 = Math.abs(value);
         for (int i = 0; i != (-decimalShift - 1); ++i)
             shiftedValueP5 /= 10;
         shiftedValueP5 += 5l;
         int shiftedValue = shiftedValueP5 / 10;
         if (shiftedValue * 10l - shiftedValueP5 >= 5) ++shiftedValue;
         shiftedValue *= Long.signum(value);
         for (int i = 0; i != -decimalShift; ++i)
             shiftedValue *= 10;
         return shiftedValue;
     }
 
     public Integer roundDown( Integer value,
                               int decimalShift ) {
         if (value == 0) return 0;
         if (decimalShift >= 0) return value;
         int shiftedValue = Math.abs(value);
         for (int i = 0; i != -decimalShift; ++i)
             shiftedValue /= 10;
         shiftedValue *= Long.signum(value);
         for (int i = 0; i != -decimalShift; ++i)
             shiftedValue *= 10;
         return shiftedValue;
     }
 
     public Integer keepSignificantFigures( Integer value,
                                            int numSigFigs ) {
         if (numSigFigs < 0) return value;
         if (numSigFigs == 0) return 0;
         int currentExp = getExponentInScientificNotation(value);
         int decimalShift = -currentExp + numSigFigs - 1;
         return roundUp(value, decimalShift);
     }
 }