/*
    * 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.common.content;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.UnsupportedEncodingException;
  import java.security.MessageDigest;
  
  import org.jdom2.output.Format;
  import org.mycore.common.MCRConstants;
  import org.mycore.common.config.MCRConfiguration2;
  import org.mycore.common.content.streams.MCRMD5InputStream;
  
  /**
   * Reads MCRContent from an XML document.
   * Provides functionality to output XML using different formatters. 
   * 
   * @author Frank L\u00FCtzenkichen
   */
  public abstract class MCRXMLContent extends MCRContent {
  
      /** 
       * The default format used when outputting XML as a byte stream.
       * By default, content is outputted using {@link MCRConstants#DEFAULT_ENCODING}.
       * If MCR.IFS2.PrettyXML=true, a pretty format with indentation is used. 
       */
      protected static Format defaultFormat;
  
      static {
          boolean prettyXML = MCRConfiguration2.getBoolean("MCR.IFS2.PrettyXML").orElse(true);
          defaultFormat = prettyXML ? Format.getPrettyFormat().setIndent("  ") : Format.getRawFormat();
          defaultFormat.setEncoding(MCRConstants.DEFAULT_ENCODING);
      }
  
      /** The default format used when outputting this XML as a byte stream */
      protected Format format = defaultFormat;
  
      public MCRXMLContent() {
          try {
              this.setEncoding(MCRConstants.DEFAULT_ENCODING);
          } catch (UnsupportedEncodingException e) {
              throw new RuntimeException(e);
          }
      }
  
      /** 
       * Sets the format used when outputting XML as a byte stream. 
       * By default, content is outputted using {@link MCRConstants#DEFAULT_ENCODING}.
       * If MCR.IFS2.PrettyXML=true, a pretty format with indentation is used. 
       */
      public void setFormat(Format format) {
          this.format = format;
      }
  
      @Override
      public InputStream getInputStream() throws IOException {
          return new ByteArrayInputStream(asByteArray());
      }
  
      @Override
      public MCRContent ensureXML() {
          return this;
      }
  
      @Override
      public String getMimeType() throws IOException {
          return super.getMimeType() == null ? "text/xml" : super.getMimeType();
      }
  
      @Override
      public long length() throws IOException {
          return asByteArray().length;
      }
  
      @Override
      public String getETag() throws IOException {
          MessageDigest md5Digest = MCRMD5InputStream.buildMD5Digest();
          byte[] byteArray = asByteArray();
          md5Digest.update(byteArray, 0, byteArray.length);
          byte[] digest = md5Digest.digest();
          String md5String = MCRMD5InputStream.getMD5String(digest);
         return '"' + md5String + '"';
     }
 
     @Override
     public void setEncoding(String encoding) throws UnsupportedEncodingException {
         super.setEncoding(encoding);
         this.format = format.clone();
         format.setEncoding(encoding);
     }
 }