/*
    * 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.bibtex;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Locale;
  
  import org.jaxen.JaxenException;
  import org.jdom2.Element;
  import org.mycore.common.MCRException;
  import org.mycore.common.xml.MCRNodeBuilder;
  
  import bibtex.dom.BibtexAbstractValue;
  import bibtex.dom.BibtexEntry;
  
  /**
   * Transforms a single BibTeX field to a MODS element.
   *
   * @author Frank L\u00FCtzenkirchen
   */
  class MCRFieldTransformer {
  
      static final String AS_NEW_ELEMENT = "[999]";
  
      protected String field;
  
      MCRFieldTransformer(String field) {
          this.field = field;
      }
  
      String getField() {
          return field;
      }
  
      /** Converts german umlauts and other special LaTeX characters */
      protected String normalizeValue(String value) {
          return value.replaceAll("\\s+", " ").trim().replace("{\\\"a}", "\u00e4").replace("{\\\"o}", "\u00f6")
              .replace("{\\\"u}", "\u00fc").replace("{\\\"A}", "\u00c4").replace("{\\\"O}", "\u00d6")
              .replace("{\\\"U}", "\u00dc").replace("{\\ss}", "\u00df").replace("\\\"a", "\u00e4")
              .replace("\\\"o", "\u00f6").replace("\\\"u", "\u00fc").replace("\\\"A", "\u00c4")
              .replace("\\\"O", "\u00d6").replace("\\\"U", "\u00dc").replace("{\\'a}", "\u00e1")
              .replace("{\\'e}", "\u00e9").replace("{\\'i}", "\u00ed").replace("{\\'o}", "\u00f3")
              .replace("{\\'u}", "\u00fa").replace("{\\`a}", "\u00e0").replace("{\\`e}", "\u00e8")
              .replace("{\\`i}", "\u00ec").replace("{\\`o}", "\u00f2").replace("{\\`u}", "\u00f9")
              .replace("{\\'\\i}", "\u00ed").replace("{\\`\\i}", "\u00ec").replace("{", "").replace("}", "")
              .replace("---", "-").replace("--", "-");
      }
  
      void transformField(BibtexEntry entry, Element parent) {
          for (BibtexAbstractValue value : getFieldValues(entry, field)) {
              buildField(value, parent);
          }
      }
  
      private List<BibtexAbstractValue> getFieldValues(BibtexEntry entry, String field) {
          List<BibtexAbstractValue> fieldValues = entry.getFieldValuesAsList(field);
          if (fieldValues == null) {
              fieldValues = entry.getFieldValuesAsList(field.toUpperCase(Locale.ROOT));
          }
          return fieldValues == null ? Collections.emptyList() : fieldValues;
      }
  
      void buildField(BibtexAbstractValue value, Element parent) {
          String type = value.getClass().getSimpleName();
          MCRMessageLogger.logMessage("Field " + field + " returns unsupported abstract value of type " + type, parent);
      }
  
      static Element buildElement(String xPath, String content, Element parent) {
          try {
              return new MCRNodeBuilder().buildElement(xPath, content, parent);
          } catch (JaxenException ex) {
              throw new MCRException("Unable to build field " + xPath, ex);
          }
      }
  }