/**
    *
    * Copyright (C) 2011 Cloud Conscious, LLC. <info@cloudconscious.com>
    *
    * ====================================================================
    * 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.jclouds.date.internal;
  import static org.jclouds.date.internal.DateUtils.trimNanosToMillis;
  import static org.jclouds.date.internal.DateUtils.trimTZ;
  
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.Locale;
  import java.util.SimpleTimeZone;
  
  import org.jclouds.date.DateService;
  
  /**
   * 
   * uses {@link SimpleDateFormat} internally.
   * 
   * @author Adrian Cole
   * @author James Murty
   */
  public class SimpleDateFormatDateService implements DateService {
  
     /*
      * Use default Java Date/SimpleDateFormat classes for date manipulation, but be *very* careful to
      * guard against the lack of thread safety.
      */
     // @GuardedBy("this")
     private static final SimpleDateFormat iso8601SecondsSimpleDateFormat = new SimpleDateFormat(
              "yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US);
  
     // @GuardedBy("this")
     private static final SimpleDateFormat iso8601SimpleDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
              Locale.US);
  
     // @GuardedBy("this")
     private static final SimpleDateFormat rfc822SimpleDateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z",
              Locale.US);
  
     // @GuardedBy("this")
     private static final SimpleDateFormat cSimpleDateFormat = new SimpleDateFormat("EEE MMM dd HH:mm:ss '+0000' yyyy",
              Locale.US);
  
     static {
        iso8601SimpleDateFormat.setTimeZone(new SimpleTimeZone(0, "GMT"));
        iso8601SecondsSimpleDateFormat.setTimeZone(new SimpleTimeZone(0, "GMT"));
        rfc822SimpleDateFormat.setTimeZone(new SimpleTimeZone(0, "GMT"));
        cSimpleDateFormat.setTimeZone(new SimpleTimeZone(0, "GMT"));
     }
  
     public final Date fromSeconds(long seconds) {
        return new Date(seconds * 1000);
     }
  
     public final String cDateFormat(Date date) {
        synchronized (cSimpleDateFormat) {
           return cSimpleDateFormat.format(date);
        }
     }
  
     public final String cDateFormat() {
        return cDateFormat(new Date());
     }
  
     public final Date cDateParse(String toParse) {
        synchronized (cSimpleDateFormat) {
           try {
              return cSimpleDateFormat.parse(toParse);
           } catch (ParseException e) {
              throw new RuntimeException(e);
           }
        }
     }
  
     public final String rfc822DateFormat(Date date) {
        synchronized (rfc822SimpleDateFormat) {
           return rfc822SimpleDateFormat.format(date);
        }
     }
  
     public final String rfc822DateFormat() {
        return rfc822DateFormat(new Date());
     }
 
    public final Date rfc822DateParse(String toParse) {
       synchronized (rfc822SimpleDateFormat) {
          try {
             return rfc822SimpleDateFormat.parse(toParse);
          } catch (ParseException e) {
             throw new RuntimeException(e);
          }
       }
    }
 
    public final String iso8601SecondsDateFormat() {
       return iso8601SecondsDateFormat(new Date());
    }
 
    public final String iso8601DateFormat(Date date) {
       synchronized (iso8601SimpleDateFormat) {
          return iso8601SimpleDateFormat.format(date);
       }
    }
 
    public final String iso8601DateFormat() {
       return iso8601DateFormat(new Date());
    }
 
    public final Date iso8601DateParse(String toParse) {
       toParse = trimTZ(toParse);
       toParse = trimNanosToMillis(toParse);
       synchronized (iso8601SimpleDateFormat) {
          try {
             return iso8601SimpleDateFormat.parse(toParse);
          } catch (ParseException e) {
             throw new RuntimeException(e);
          }
       }
    }
 
    public final Date iso8601SecondsDateParse(String toParse) {
       toParse = trimTZ(toParse);
       synchronized (iso8601SecondsSimpleDateFormat) {
          try {
             return iso8601SecondsSimpleDateFormat.parse(toParse);
          } catch (ParseException e) {
             throw new RuntimeException(e);
          }
       }
    }
 
    @Override
    public String iso8601SecondsDateFormat(Date date) {
       synchronized (iso8601SecondsSimpleDateFormat) {
          return iso8601SecondsSimpleDateFormat.format(date);
       }
    }
 
 }