/*
    * 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.datamodel.metadata;
  
  import java.util.ArrayList;
  import java.util.Objects;
  import java.util.stream.Collectors;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.jdom2.Element;
  import org.jdom2.Namespace;
  import org.mycore.common.MCRCalendar;
  import org.mycore.common.MCRException;
  
  import com.ibm.icu.util.Calendar;
  import com.ibm.icu.util.GregorianCalendar;
  
  /**
   * This class implements all methods for handling the MCRMetaHistoryDate
   * part of a metadata object. It uses the GPL licensed ICU library of IBM.
   * 
   * @author Juergen Vogler
   * @author Jens Kupferschmidt
   * @author Thomas Junge
   * @version $Revision$ $Date$
   * @see <a href="http://www.icu-project.org/">http://www.icu-project.org/</a>
   */
  public class MCRMetaHistoryDate extends MCRMetaDefault {
  
      /** Logger */
      private static final Logger LOGGER = LogManager.getLogger();
  
      /** The maximal length of 'text' */
      public static final int MCRHISTORYDATE_MAX_TEXT = 512;
  
      // Data of this class
      private ArrayList<MCRMetaHistoryDateText> texts;
  
      private Calendar von;
  
      private Calendar bis;
  
      private int ivon;
  
      private int ibis;
  
      private String calendar;
  
      /**
       * This is the constructor. <br>
       * The language element was set to configured default. The text element is
       * set to an empty string. The calendar is set to 'Gregorian Calendar'. The
       * von value is set to MIN_JULIAN_DAY_NUMBER, the bis value is set to
       * MAX_JULIAN_DAY_NUMBER;
       */
      public MCRMetaHistoryDate() {
          super();
          texts = new ArrayList<>();
          calendar = MCRCalendar.CALENDARS_LIST.get(0);
          setDefaultVon();
          setDefaultBis();
      }
  
      /**
       * This is the constructor. <br>
       * The language element was set. If the value of <em>default_lang</em> is
       * null, empty or false <b>en </b> was set. The subtag element was set to
       * the value of <em>subtag</em>. If the value of <em>subtag</em>
       * is null or empty an exception was thrown. The type element was set to
       * the value of <em>type</em>, if it is null, an empty string was set
       * to the type element.<br>
       * The text element is set to an empty string. The calendar is set to 'Gregorian Calendar'. The von value 
       * is set to MIN_JULIAN_DAY_NUMBER, the bis value is set to MAX_JULIAN_DAY_NUMBER;
       * @param subtag      the name of the subtag
       * @param type        the optional type string
       * @param inherted    a value &gt;= 0
       *
       * @exception MCRException if the parameter values are invalid
       */
      public MCRMetaHistoryDate(String subtag, String type, int inherted) throws MCRException {
          super(subtag, null, type, inherted);
          texts = new ArrayList<>();
         calendar = MCRCalendar.CALENDARS_LIST.get(0);
         setDefaultVon();
         setDefaultBis();
     }
 
     /**
      * This method set the text field for the default language. If data exists,
      * it overwrites the value of text.
      * 
      * @param text
      *            the text string for a date or range
      */
     @Deprecated
     public final void setText(String text) {
         setText(text, lang);
     }
 
     /**
      * This method set the text field for the given language. If data exists, it
      * overwrites the value of text.
      * 
      * @param text
      *            the text string for a date or range
      * @param lang
      *            the language of the text in the ISO format
      */
     public final void setText(String text, String lang) {
         if (text == null || text.length() == 0) {
             LOGGER.warn("The text field of MCRMeataHistoryDate is empty.");
             return;
         }
         if (text.length() <= MCRHISTORYDATE_MAX_TEXT) {
             text = text.trim();
         } else {
             text = text.substring(0, MCRHISTORYDATE_MAX_TEXT);
         }
         if (lang == null || lang.length() == 0) {
             addText(text, this.lang);
         } else {
             addText(text, lang);
         }
     }
 
     /**
      * This method add a MCRMetaHistoryDateTexts instance to the ArrayList of
      * texts.
      * 
      * @param text
      *            the text- String
      * @param lang
      *            the lang- String
      */
 
     public final void addText(String text, String lang) {
         if (text == null || text.length() == 0) {
             LOGGER.warn("The text field of MCRMeataHistoryDate is empty.");
             return;
         }
         if (lang == null || lang.length() == 0) {
             LOGGER.warn("The lang field of MCRMeataHistoryDate is empty.");
             return;
         }
         for (int i = 0; i < texts.size(); i++) {
             if (texts.get(i).getLang().equals(lang)) {
                 texts.remove(i);
                 break;
             }
         }
         texts.add(new MCRMetaHistoryDateText(text, lang));
     }
 
     /**
      * This method return the MCRMetaHistoryDateTexts instance with the
      * corresponding language.
      * 
      * @param lang
      *            the language String in ISO format
      * @return an instance of MCRMetaHistoryDateTexts or null
      */
     public final MCRMetaHistoryDateText getText(String lang) {
         if (lang == null) {
             return null;
         }
         return texts.stream()
             .filter(text -> text.getLang().equals(lang))
             .findFirst()
             .orElse(null);
     }
 
     /**
      * This method return the MCRMetaHistoryDateTexts instance of the indexed
      * element of the ArrayList.
      * 
      * @param index
      *            the index of ArryList texts
      * @return an instance of MCRMetaHistoryDateTexts or null
      */
     public final MCRMetaHistoryDateText getText(int index) {
         if (index >= 0 && index < texts.size()) {
             return texts.get(index);
         }
         return null;
     }
 
     /**
      * This method read the ArryList texts
      * 
      * @return an ArrayList of MCRMetaHistoryDateTexts instances
      */
     public final ArrayList<MCRMetaHistoryDateText> getTexts() {
         return texts;
     }
 
     /**
      * This method read the size of texts
      * 
      * @return the size of the ArrayList of language dependence texts
      */
     public final int textSize() {
         return texts.size();
     }
 
     /**
      * The method set the calendar String value.
      * 
      * @param calstr
      *            the calendar as String, one of CALENDARS.
      */
     public final void setCalendar(String calstr) {
         if (calstr == null || calstr.trim().length() == 0 || (!MCRCalendar.CALENDARS_LIST.contains(calstr))) {
             calendar = MCRCalendar.TAG_GREGORIAN;
             LOGGER.warn("The calendar field of MCRMeataHistoryDate is set to default " + MCRCalendar.TAG_GREGORIAN
                 + ".");
             return;
         }
         calendar = calstr;
     }
 
     /**
      * The method set the calendar String value.
      * 
      * @param calendar
      *            the date of the calendar.
      */
     public final void setCalendar(Calendar calendar) {
         this.calendar = MCRCalendar.getCalendarTypeString(calendar);
     }
 
     /**
      * The method set the von values to the default.
      */
     public final void setDefaultVon() {
         von = new GregorianCalendar();
         von.set(Calendar.JULIAN_DAY, MCRCalendar.MIN_JULIAN_DAY_NUMBER);
         ivon = MCRCalendar.MIN_JULIAN_DAY_NUMBER;
     }
 
     /**
      * The method set the bis values to the default.
      */
     public final void setDefaultBis() {
         bis = new GregorianCalendar();
         bis.set(Calendar.JULIAN_DAY, MCRCalendar.MAX_JULIAN_DAY_NUMBER);
         ibis = MCRCalendar.MAX_JULIAN_DAY_NUMBER;
     }
 
     /**
      * This method set the von to the given date of a supported calendar.
      * 
      * @param calendar
      *            the date of a ICU supported calendar.
      */
     public final void setVonDate(Calendar calendar) {
         if (calendar == null) {
             setDefaultVon();
             LOGGER.warn("The calendar to set 'von' is null, default is set.");
         } else {
             von = calendar;
             ivon = von.get(Calendar.JULIAN_DAY);
         }
     }
 
     /**
      * This method set the von to the given date.
      * 
      * @param date
      *            a date string
      * @param calendar
      *            the calendar as String, one of CALENDARS.
      */
     public final void setVonDate(String date, String calendar) {
         try {
             von = MCRCalendar.getHistoryDateAsCalendar(date, false, calendar);
             ivon = von.get(Calendar.JULIAN_DAY);
         } catch (Exception e) {
             e.printStackTrace();
             LOGGER.warn("The von date {} for calendar {} is false. Set to default!", date, calendar);
             setDefaultVon();
         }
     }
 
     /**
      * This method set the bis to the given date of a supported calendar.
      * 
      * @param calendar
      *            the date of a ICU supported calendar
      */
     public final void setBisDate(Calendar calendar) {
         if (calendar == null) {
             setDefaultBis();
             LOGGER.warn("The calendar to set 'bis' is null, default is set.");
         } else {
             bis = calendar;
             ibis = bis.get(Calendar.JULIAN_DAY);
         }
     }
 
     /**
      * This method set the bis to the given date.
      * 
      * @param date
      *            a date string
      * @param calendar
      *            the calendar as String, one of CALENDARS.
      */
     public final void setBisDate(String date, String calendar) {
         Calendar c = bis;
         try {
             c = MCRCalendar.getHistoryDateAsCalendar(date, true, calendar);
         } catch (Exception e) {
             LOGGER.warn("The bis date {} for calendar {} is false.", date, calendar);
             c = null;
         }
         setBisDate(c);
     }
 
     /**
      * This method get the 'calendar' text element.
      * 
      * @return the calendar string
      */
     public final String getCalendar() {
         return calendar;
     }
 
     /**
      * This method get the von element as ICU-Calendar.
      * 
      * @return the date
      */
     public final Calendar getVon() {
         return von;
     }
 
     /**
      * This method return the von as string.
      * 
      * @return the date
      */
     public final String getVonToString() {
         return MCRCalendar.getCalendarDateToFormattedString(von);
     }
 
     /**
      * This method get the ivon element as Julian Day integer.
      * 
      * @return the date
      */
     public final int getIvon() {
         return ivon;
     }
 
     /**
      * This method get the bis element as ICU-Calendar.
      * 
      * @return the date
      */
     public final Calendar getBis() {
         return bis;
     }
 
     /**
      * This method return the bis as string.
      * 
      * @return the date
      */
     public final String getBisToString() {
         return MCRCalendar.getCalendarDateToFormattedString(bis);
     }
 
     /**
      * This method get the ibis element as Julian Day integer.
      * 
      * @return the date
      */
     public final int getIbis() {
         return ibis;
     }
 
     /**
      * This method reads the XML input stream part from a DOM part for the
      * metadata of the document.
      * 
      * @param element
      *            a relevant JDOM element for the metadata
      */
     @Override
     public void setFromDOM(Element element) {
         super.setFromDOM(element);
         texts.clear(); // clear
 
         for (Element textElement : element.getChildren("text")) {
             String text = textElement.getText();
             String lang = textElement.getAttributeValue("lang", Namespace.XML_NAMESPACE);
             if (lang != null) {
                 setText(text, lang);
             } else {
                 setText(text);
             }
         }
         setCalendar(element.getChildTextTrim("calendar"));
         setVonDate(element.getChildTextTrim("von"), calendar);
         setBisDate(element.getChildTextTrim("bis"), calendar);
         /** 
          * If dates higher than 1582 and calendar is Julian the calendar must switch to 
          * Gregorian cause the date transforming is implicit in the calendar methods. In
          * other cases before 1582 both calendar are equal.
          * */
         if (calendar.equals(MCRCalendar.TAG_JULIAN)) {
             calendar = MCRCalendar.TAG_GREGORIAN;
         }
     }
 
     /**
      * This method creates a XML stream for all data in this class, defined by
      * the MyCoRe XML MCRMetaHistoryDate definition for the given subtag.
      * 
      * @exception MCRException
      *                if the content of this class is not valid
      * @return a JDOM Element with the XML MCRMetaHistoryDate part
      */
     @Override
     public Element createXML() throws MCRException {
         Element elm = super.createXML();
         for (MCRMetaHistoryDateText text : texts) {
             Element elmt = new Element("text");
             elmt.addContent(text.getText());
             elmt.setAttribute("lang", text.getLang(), Namespace.XML_NAMESPACE);
             elm.addContent(elmt);
         }
         elm.addContent(new Element("calendar").addContent(calendar));
 
         elm.addContent(new Element("ivon").addContent(Integer.toString(ivon)));
         elm.addContent(new Element("von").addContent(getVonToString()));
 
         elm.addContent(new Element("ibis").addContent(Integer.toString(ibis)));
         elm.addContent(new Element("bis").addContent(getBisToString()));
         return elm;
     }
 
     /**
      * Validates this MCRMetaHistoryDate. This method throws an exception if:
      * <ul>
      * <li>the subtag is not null or empty</li>
      * <li>the lang value was supported</li>
      * <li>the inherited value is lower than zero</li>
      * <li>the number of texts is 0 (empty texts are delete)</li>
      * <li>von is null or bis is null or calendar is null</li>
      * </ul>
      * 
      * @throws MCRException the MCRMetaHistoryDate is invalid
      */
     @Override
     public void validate() throws MCRException {
         super.validate();
         texts.removeIf(textItem -> !textItem.isValid());
         if (texts.size() == 0) {
             throw new MCRException(getSubTag() + ": no texts defined");
         }
         if (von == null || bis == null || calendar == null) {
             throw new MCRException(getSubTag() + ": von,bis or calendar are null");
         }
         if (ibis < ivon) {
             Calendar swp = (Calendar) von.clone();
             setVonDate((Calendar) bis.clone());
             setBisDate(swp);
         }
     }
 
     /**
      * clone of this instance
      * 
      * you will get a (deep) clone of this element
      * 
      * @see java.lang.Object#clone()
      */
     @Override
     public MCRMetaHistoryDate clone() {
         MCRMetaHistoryDate clone = (MCRMetaHistoryDate) super.clone();
 
         clone.texts = this.texts.stream().map(MCRMetaHistoryDateText::clone)
             .collect(Collectors.toCollection(ArrayList::new));
         clone.bis = (Calendar) this.bis.clone();
         clone.von = (Calendar) this.von.clone();
         clone.ibis = this.ibis;
         clone.ivon = this.ivon;
         clone.calendar = this.calendar;
 
         return clone;
     }
 
     /**
      * This method put debug data to the logger (for the debug mode).
      */
     @Override
     public void debug() {
         if (LOGGER.isDebugEnabled()) {
             super.debugDefault();
             for (MCRMetaHistoryDateText text : texts) {
                 LOGGER.debug("Text / lang         = {} / {}", text.getText(), text.getLang());
             }
             LOGGER.debug("Calendar           = {}", calendar);
             LOGGER.debug("Von (String)       = {}", getVonToString());
             LOGGER.debug("Von (JulianDay)    = {}", ivon);
             LOGGER.debug("Bis (String)       = {}", getBisToString());
             LOGGER.debug("Bis (JulianDay)    = {}", ibis);
             LOGGER.debug("");
         }
     }
 
     /**
      * This method compares this instance with a MCRMetaHistoryDate object
      */
     @Override
     public boolean equals(Object obj) {
         if (!super.equals(obj)) {
             return false;
         }
         final MCRMetaHistoryDate other = (MCRMetaHistoryDate) obj;
         boolean fieldTest = Objects.equals(this.calendar, other.calendar) && Objects.equals(this.ivon, other.ivon);
         boolean textTest = equalText(other.getTexts());
         return fieldTest && textTest;
     }
 
     private boolean equalText(ArrayList<MCRMetaHistoryDateText> objtexts) {
         boolean testflag = true;
         int size = texts.size() < objtexts.size() ? texts.size() : objtexts.size();
         for (int i = 0; i < size; i++) {
             testflag &= texts.get(i).equals(objtexts.get(i));
         }
         return testflag;
     }
 
     /**
      * This class describes the structure of pair of language an text. The
      * language notation is in the ISO format.
      * 
      */
     public static class MCRMetaHistoryDateText implements Cloneable {
         private String text;
 
         private String lang;
 
         public MCRMetaHistoryDateText() {
             text = "";
             lang = DEFAULT_LANGUAGE;
         }
 
         public MCRMetaHistoryDateText(String text, String lang) {
             setText(text, lang);
         }
 
         /**
          * This method get the text element as String.
          * 
          * @return the text
          */
 
         public String getText() {
             return text;
         }
 
         /**
          * This method get the language element as String of ISO code.
          * 
          * @return the language
          */
         public String getLang() {
             return lang;
         }
 
         /**
          * This method set the text element with the corresponding language.
          * 
          * @param text
          *            the text String
          * @param lang
          *            the language String
          */
         public void setText(String text, String lang) {
             if (lang == null || lang.length() == 0) {
                 this.lang = DEFAULT_LANGUAGE;
             } else {
                 this.lang = lang;
             }
             if (text == null || text.length() == 0) {
                 this.text = "";
             } else {
                 this.text = text;
             }
         }
 
         /**
          * This method set the text element.
          * 
          * @param text
          *            the text String of a date value
          */
         @Deprecated
         public void setText(String text) {
             if (text == null || text.length() == 0) {
                 this.text = "";
             } else {
                 this.text = text;
             }
         }
 
         /**
          * This method set the lang element.
          * 
          * @param lang
          *            the language String of a date value
          */
         @Deprecated
         public void setLang(String lang) {
             if (lang == null || lang.length() == 0) {
                 this.lang = DEFAULT_LANGUAGE;
             } else {
                 this.lang = lang;
             }
         }
 
         /**
          * This method validate the content. If lang and text are not empty, it return true otherwise it return false.
          * 
          * @return true if the content is valid.
          */
         public boolean isValid() {
             return !(lang.length() == 0 || text.length() == 0);
         }
 
         /**
          * This method check the equivalence of lang and text between this object
          * and a given MCRMetaHistoryDateText object.
          * 
          * @param obj a MCRMetaHistoryDateText instance
          * @return true if both parts are equal
          */
         public boolean equals(MCRMetaHistoryDateText obj) {
             return lang.equals(obj.getLang()) && text.equals(obj.getText());
         }
 
         @Override
         protected MCRMetaHistoryDateText clone() {
             MCRMetaHistoryDateText clone = null;
             try {
                 clone = (MCRMetaHistoryDateText) super.clone();
             } catch (Exception e) {
                 // this can not happen!
             }
 
             clone.text = this.text;
             clone.lang = this.lang;
 
             return clone;
         }
     }
 }