/*
 * Licensed to The Apereo Foundation under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 *
 * The Apereo Foundation licenses this file to you under the Educational
 * Community 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://opensource.org/licenses/ecl2.txt
 *
 * 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.opencastproject.security.api;

import org.opencastproject.util.XmlSafeParser;

import org.apache.commons.io.IOUtils;
import org.xml.sax.SAXException;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.io.Writer;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

/**
 * Marshals and unmarshalls {@link User}s to/from XML.
 */
public final class UserParser {

  private static final JAXBContext jaxbContext;

  static {
    try {
      jaxbContext = JAXBContext.newInstance("org.opencastproject.security.api", UserParser.class.getClassLoader());
    } catch (JAXBException e) {
      throw new IllegalStateException(e);
    }
  }

  /**
   * Disallow construction of this utility class.
   */
  private UserParser() {
  }

  public static User fromXml(String xml) {
    InputStream in = null;
    try {
      in = IOUtils.toInputStream(xml);
      Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
      return unmarshaller.unmarshal(XmlSafeParser.parse(in), JaxbUser.class).getValue();
    } catch (JAXBException e) {
      throw new IllegalStateException(e.getLinkedException() != null ? e.getLinkedException() : e);
    } catch (IOException | SAXException e) {
      throw new IllegalStateException((Throwable) e);
    } finally {
      IOUtils.closeQuietly(in);
    }
  }

  public static String toXml(User user) {
    try {
      Marshaller marshaller = jaxbContext.createMarshaller();
      Writer writer = new StringWriter();
      marshaller.marshal(user, writer);
      return writer.toString();
    } catch (JAXBException e) {
      throw new IllegalStateException(e.getLinkedException() != null ? e.getLinkedException() : e);
    }
  }

}
