/*
    *  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.chrono;
  
  import java.util.Locale;
  
  import org.joda.time.DateTimeConstants;
  import org.joda.time.DateTimeFieldType;
  import org.joda.time.DurationField;
  import org.joda.time.DurationFieldType;
  import org.joda.time.field.BaseDateTimeField;
  import org.joda.time.field.FieldUtils;
  import org.joda.time.field.UnsupportedDurationField;
  
  /**
   * Provides time calculations for the era component of time.
   *
   * @author Stephen Colebourne
   * @author Brian S O'Neill
   * @since 1.0
   */
  final class GJEraDateTimeField extends BaseDateTimeField {
      
      /** Serialization version */
      private static final long serialVersionUID = 4240986525305515528L;
  
      private final BasicChronology iChronology;
  
      /**
       * Restricted constructor
       */
      GJEraDateTimeField(BasicChronology chronology) {
          super(DateTimeFieldType.era());
          iChronology = chronology;
      }
  
      public boolean isLenient() {
          return false;
      }
  
      /**
       * Get the Era component of the specified time instant.
       * 
       * @param instant  the time instant in millis to query.
       */
      public int get(long instant) {
          if (iChronology.getYear(instant) <= 0) {
              return DateTimeConstants.BCE;
          } else {
              return DateTimeConstants.CE;
          }
      }
  
      public String getAsText(int fieldValue, Locale locale) {
          return GJLocaleSymbols.forLocale(locale).eraValueToText(fieldValue);
      }
  
      /**
       * Set the Era component of the specified time instant.
       * 
       * @param instant  the time instant in millis to update.
       * @param era  the era to update the time to.
       * @return the updated time instant.
       * @throws IllegalArgumentException  if era is invalid.
       */
      public long set(long instant, int era) {
          FieldUtils.verifyValueBounds(this, era, DateTimeConstants.BCE, DateTimeConstants.CE);
              
          int oldEra = get(instant);
          if (oldEra != era) {
              int year = iChronology.getYear(instant);
              return iChronology.setYear(instant, -year);
          } else {
              return instant;
          }
      }
  
      public long set(long instant, String text, Locale locale) {
          return set(instant, GJLocaleSymbols.forLocale(locale).eraTextToValue(text));
      }
  
      public long roundFloor(long instant) {
          if (get(instant) == DateTimeConstants.CE) {
              return iChronology.setYear(0, 1);
          } else {
              return Long.MIN_VALUE;
         }
     }
 
     public long roundCeiling(long instant) {
         if (get(instant) == DateTimeConstants.BCE) {
             return iChronology.setYear(0, 1);
         } else {
             return Long.MAX_VALUE;
         }
     }
 
     public long roundHalfFloor(long instant) {
         // In reality, the era is infinite, so there is no halfway point.
         return roundFloor(instant);
     }
 
     public long roundHalfCeiling(long instant) {
         // In reality, the era is infinite, so there is no halfway point.
         return roundFloor(instant);
     }
 
     public long roundHalfEven(long instant) {
         // In reality, the era is infinite, so there is no halfway point.
         return roundFloor(instant);
     }
 
     public DurationField getDurationField() {
         return UnsupportedDurationField.getInstance(DurationFieldType.eras());
     }
 
     public DurationField getRangeDurationField() {
         return null;
     }
 
     public int getMinimumValue() {
         return DateTimeConstants.BCE;
     }
 
     public int getMaximumValue() {
         return DateTimeConstants.CE;
     }
 
     public int getMaximumTextLength(Locale locale) {
         return GJLocaleSymbols.forLocale(locale).getEraMaxTextLength();
     }
 
     /**
      * Serialization singleton
      */
     private Object readResolve() {
         return iChronology.era();
     }
 }