/**
 * Copyright (C) 2003-2008 eXo Platform SAS.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or (at your option) any later version.
 * 
 * This program 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 this program; if not, see<http://www.gnu.org/licenses/>.
 */

package org.etk.core.rest.impl.provider;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.nio.charset.Charset;

import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.Provider;

import org.etk.core.rest.provider.EntityProvider;


@Provider
public class ReaderEntityProvider implements EntityProvider<Reader> {

  /**
   * {@inheritDoc}
   */
  public boolean isReadable(Class<?> type,
                            Type genericType,
                            Annotation[] annotations,
                            MediaType mediaType) {
    return type == Reader.class;
  }

  /**
   * {@inheritDoc}
   */
  public Reader readFrom(Class<Reader> type,
                         Type genericType,
                         Annotation[] annotations,
                         MediaType mediaType,
                         MultivaluedMap<String, String> httpHeaders,
                         InputStream entityStream) throws IOException {
    String cs = mediaType != null ? mediaType.getParameters().get("charset") : null;
    return new InputStreamReader(entityStream, cs != null ? Charset.forName(cs)
                                                         : IOHelper.DEFAULT_CHARSET);
  }

  /**
   * {@inheritDoc}
   */
  public long getSize(Reader t,
                      Class<?> type,
                      Type genericType,
                      Annotation[] annotations,
                      MediaType mediaType) {
    return -1;
  }

  /**
   * {@inheritDoc}
   */
  public boolean isWriteable(Class<?> type,
                             Type genericType,
                             Annotation[] annotations,
                             MediaType mediaType) {
    return Reader.class.isAssignableFrom(type);
  }

  /**
   * {@inheritDoc}
   */
  public void writeTo(Reader t,
                      Class<?> type,
                      Type genericType,
                      Annotation[] annotations,
                      MediaType mediaType,
                      MultivaluedMap<String, Object> httpHeaders,
                      OutputStream entityStream) throws IOException {
    Writer out = new OutputStreamWriter(entityStream);
    try {
      IOHelper.write(t, out);
    } finally {
      out.flush();
      t.close();
    }
  }

}