/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.mods;
  
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.Locale;
  import java.util.Map;
  import java.util.TimeZone;
  
  import org.mycore.datamodel.common.MCRISO8601Date;
  
  /**
   * Different supported MODS date formats.
   * @author Thomas Scheffler
   * @since 2015.03
   *
   */
  public enum MCRMODSDateFormat {
      iso8601("iso8601", null),
      w3cdtf_10("w3cdtf-10", "yyyy-MM-dd"),
      w3cdtf_19("w3cdtf-19",
          "yyyy-MM-dd'T'HH:mm:ss"),
      marc_4("marc-4", "yyyy"),
      iso8601_4("iso8601-4", "yyyy"),
      iso8601_7("iso8601-7",
          "yyyy-MM"),
      iso8601_8("iso8601-8", "yyyyMMdd"),
      iso8601_15("iso8601-15", "yyyyMMdd'T'HHmmss"),
  
      // Try to guess encoding from date length 
      unknown_4("unknown-4", "yyyy"),
      unknown_8("unknown-8", "yyyyMMdd"),
      unknown_10("unknown-10",
          "yyyy-MM-dd"),
      unknown_19("unknown-19", "yyyy-MM-dd'T'HH:mm:ss"),
      unknown_15("unknown-15", "yyyyMMdd'T'HHmmss");
  
      private static volatile Map<String, MCRMODSDateFormat> encodingToFormatMap;
  
      private String encoding, attributeValue;
  
      private String dateFormat;
  
      boolean dateOnly;
  
      static final TimeZone MODS_TIMEZONE = TimeZone.getTimeZone("UTC");
  
      static final Locale DATE_LOCALE = Locale.ROOT;
  
      MCRMODSDateFormat(String encoding, String dateFormat) {
          this.encoding = encoding;
          this.attributeValue = encoding == "iso8601" ? encoding : encoding.split("-")[0];
          this.dateFormat = dateFormat;
          this.dateOnly = dateFormat != null && !dateFormat.endsWith("ss"); //see above
      }
  
      public static MCRMODSDateFormat getFormat(String encoding) {
          if (encodingToFormatMap == null) {
              initMap();
          }
          return encodingToFormatMap.get(encoding);
      }
  
      private static void initMap() {
          Map<String, MCRMODSDateFormat> encodingToFormatMap = new HashMap<>();
          for (MCRMODSDateFormat f : values()) {
              encodingToFormatMap.put(f.encoding, f);
          }
          MCRMODSDateFormat.encodingToFormatMap = encodingToFormatMap;
      }
  
      public String getEncoding() {
          return encoding;
      }
  
      public boolean isDateOnly() {
          return dateOnly;
      }
  
      public String asEncodingAttributeValue() {
         return attributeValue;
     }
 
     public Date parseDate(String text) throws ParseException {
         if (this == iso8601) {
             MCRISO8601Date isoDate = new MCRISO8601Date(text);
             return isoDate.getDate();
         }
         return getDateFormat().parse(text);
     }
 
     public String formatDate(Date date) {
         if (this == iso8601) {
             MCRISO8601Date isoDate = new MCRISO8601Date();
             isoDate.setDate(date);
             return isoDate.getISOString();
         }
         return getDateFormat().format(date);
     }
 
     public SimpleDateFormat getDateFormat() {
         SimpleDateFormat dateFormat = new SimpleDateFormat(this.dateFormat, MCRMODSDateFormat.DATE_LOCALE);
         dateFormat.setTimeZone(MCRMODSDateFormat.MODS_TIMEZONE);
         return dateFormat;
     }
 }