/*
    *  Copyright 2001-2005 Stephen Colebourne
    *
    *  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 org.joda.time.field;
  
  import org.joda.time.DateTimeField;
  import org.joda.time.DateTimeFieldType;
  import org.joda.time.DurationField;
  
  /**
   * Generic offset adjusting datetime field.
   * <p>
   * OffsetDateTimeField is thread-safe and immutable.
   * 
   * @author Brian S O'Neill
   * @since 1.0
   */
  public class OffsetDateTimeField extends DecoratedDateTimeField {
      private static final long serialVersionUID = 3145790132623583142L;
  
      private final int iOffset;
  
      private final int iMin;
      private final int iMax;
  
      /**
       * Constructor.
       * 
       * @param field  the field to wrap, like "year()".
       * @param offset  offset to add to field values
       * @throws IllegalArgumentException if offset is zero
       */
      public OffsetDateTimeField(DateTimeField field, int offset) {
          this(field, (field == null ? null : field.getType()), offset, Integer.MIN_VALUE, Integer.MAX_VALUE);
      }
  
      /**
       * Constructor.
       * 
       * @param field  the field to wrap, like "year()".
       * @param type  the field type this field actually uses
       * @param offset  offset to add to field values
       * @throws IllegalArgumentException if offset is zero
       */
      public OffsetDateTimeField(DateTimeField field, DateTimeFieldType type, int offset) {
          this(field, type, offset, Integer.MIN_VALUE, Integer.MAX_VALUE);
      }
  
      /**
       * Constructor.
       * 
       * @param field  the field to wrap, like "year()".
       * @param type  the field type this field actually uses
       * @param offset  offset to add to field values
       * @param minValue  minimum allowed value
       * @param maxValue  maximum allowed value
       * @throws IllegalArgumentException if offset is zero
       */
      public OffsetDateTimeField(DateTimeField field, DateTimeFieldType type, int offset,
                                 int minValue, int maxValue) {
          super(field, type);
                  
          if (offset == 0) {
              throw new IllegalArgumentException("The offset cannot be zero");
          }
  
          iOffset = offset;
  
          if (minValue < (field.getMinimumValue() + offset)) {
              iMin = field.getMinimumValue() + offset;
          } else {
              iMin = minValue;
          }
          if (maxValue > (field.getMaximumValue() + offset)) {
              iMax = field.getMaximumValue() + offset;
          } else {
              iMax = maxValue;
          }
      }
  
      /**
       * Get the amount of offset units from the specified time instant.
       * 
       * @param instant  the time instant in millis to query.
       * @return the amount of units extracted from the input.
       */
      public int get(long instant) {
         return super.get(instant) + iOffset;
     }
 
     /**
      * Add the specified amount of offset units to the specified time
      * instant. The amount added may be negative.
      * 
      * @param instant  the time instant in millis to update.
      * @param amount  the amount of units to add (can be negative).
      * @return the updated time instant.
      */
     public long add(long instant, int amount) {
         instant = super.add(instant, amount);
         FieldUtils.verifyValueBounds(this, get(instant), iMin, iMax);
         return instant;
     }
 
     /**
      * Add the specified amount of offset units to the specified time
      * instant. The amount added may be negative.
      * 
      * @param instant  the time instant in millis to update.
      * @param amount  the amount of units to add (can be negative).
      * @return the updated time instant.
      */
     public long add(long instant, long amount) {
         instant = super.add(instant, amount);
         FieldUtils.verifyValueBounds(this, get(instant), iMin, iMax);
         return instant;
     }
 
     /**
      * Add to the offset component of the specified time instant,
      * wrapping around within that component if necessary.
      * 
      * @param instant  the time instant in millis to update.
      * @param amount  the amount of units to add (can be negative).
      * @return the updated time instant.
      */
     public long addWrapField(long instant, int amount) {
         return set(instant, FieldUtils.getWrappedValue(get(instant), amount, iMin, iMax));
     }
 
     /**
      * Set the specified amount of offset units to the specified time instant.
      * 
      * @param instant  the time instant in millis to update.
      * @param value  value of units to set.
      * @return the updated time instant.
      * @throws IllegalArgumentException if value is too large or too small.
      */
     public long set(long instant, int value) {
         FieldUtils.verifyValueBounds(this, value, iMin, iMax);
         return super.set(instant, value - iOffset);
     }
 
     public boolean isLeap(long instant) {
         return getWrappedField().isLeap(instant);
     }
 
     public int getLeapAmount(long instant) {
         return getWrappedField().getLeapAmount(instant);
     }
 
     public DurationField getLeapDurationField() {
         return getWrappedField().getLeapDurationField();
     }
 
     /**
      * Get the minimum value for the field.
      * 
      * @return the minimum value
      */
     public int getMinimumValue() {
         return iMin;
     }
 
     /**
      * Get the maximum value for the field.
      * 
      * @return the maximum value
      */
     public int getMaximumValue() {
         return iMax;
     }
     
     public long roundFloor(long instant) {
         return getWrappedField().roundFloor(instant);
     }
 
     public long roundCeiling(long instant) {
         return getWrappedField().roundCeiling(instant);
     }
 
     public long roundHalfFloor(long instant) {
         return getWrappedField().roundHalfFloor(instant);
     }
 
     public long roundHalfCeiling(long instant) {
         return getWrappedField().roundHalfCeiling(instant);
     }
 
     public long roundHalfEven(long instant) {
         return getWrappedField().roundHalfEven(instant);
     }
 
     public long remainder(long instant) {
         return getWrappedField().remainder(instant);
     }
 
     /**
      * Returns the offset added to the field values.
      * 
      * @return the offset
      */
     public int getOffset() {
         return iOffset;
     }
 }