/*******************************************************************************
 * Copyright 2013 SAP AG
 * 
 * Licensed under the Apache 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://www.apache.org/licenses/LICENSE-2.0
 * 
 * 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 com.sap.core.odata.core.ep.producer;

import java.util.Locale;

import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;

import com.sap.core.odata.api.edm.Edm;
import com.sap.core.odata.core.ep.util.FormatXml;

public class XmlErrorDocumentProducer {

  public void writeErrorDocument(final XMLStreamWriter writer, final String errorCode, final String message, final Locale locale, final String innerError) throws XMLStreamException {
    writer.writeStartDocument();
    writer.writeStartElement(FormatXml.M_ERROR);
    writer.writeDefaultNamespace(Edm.NAMESPACE_M_2007_08);
    writer.writeStartElement(FormatXml.M_CODE);
    if (errorCode != null) {
      writer.writeCharacters(errorCode);
    }
    writer.writeEndElement();
    writer.writeStartElement(FormatXml.M_MESSAGE);
    if (locale != null) {
      writer.writeAttribute(Edm.PREFIX_XML, Edm.NAMESPACE_XML_1998, FormatXml.XML_LANG, getLocale(locale));
    } else {
      writer.writeAttribute(Edm.PREFIX_XML, Edm.NAMESPACE_XML_1998, FormatXml.XML_LANG, "");
    }
    if (message != null) {
      writer.writeCharacters(message);
    }
    writer.writeEndElement();

    if (innerError != null) {
      writer.writeStartElement(FormatXml.M_INNER_ERROR);
      writer.writeCharacters(innerError);
      writer.writeEndElement();
    }

    writer.writeEndDocument();
  }

  /**
   * Gets language and country as defined in RFC 4646 based on {@link Locale}.
   */
  private String getLocale(final Locale locale) {
    if (locale.getCountry().isEmpty()) {
      return locale.getLanguage();
    } else {
      return locale.getLanguage() + "-" + locale.getCountry();
    }
  }

}