/**
 * 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.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
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
@Consumes({ MediaType.APPLICATION_JSON })
@Produces({ MediaType.APPLICATION_JSON })
public class JsonEntityProvider implements EntityProvider<Object> {
  
  // It is common task for #isReadable() and #isWriteable
  // TODO Not sure it is required but ...
  // Investigation about checking can type be write as JSON (useful JSON).
  // Probably should be better added this checking in JSON framework.
  // Or probably enough check only content type 'application/json'
  // and if this content type set trust it and try parse/write

  /**
   * {@inheritDoc}
   */
  public boolean isReadable(Class<?> type,
                            Type genericType,
                            Annotation[] annotations,
                            MediaType mediaType) {
    // say as support all objects, see _TODO_ above
    return Object.class.isAssignableFrom(type);
  }

  /**
   * {@inheritDoc}
   */
  public Object readFrom(Class<Object> type,
                         Type genericType,
                         Annotation[] annotations,
                         MediaType mediaType,
                         MultivaluedMap<String, String> httpHeaders,
                         InputStream entityStream) throws IOException {
    try {
      //JsonParser jsonParser = new JsonParserImpl();
      //JsonHandler jsonHandler = new JsonDefaultHandler();
      //jsonParser.parse(entityStream, jsonHandler);
      //JsonValue jsonValue = jsonHandler.getJsonObject();
      // jsonValue can be null if stream empty
      //if (jsonValue == null)
        return null;
      //return new BeanBuilder().createObject(type, jsonValue);
    } catch (Exception e) {
      throw new IOException("Can't read from input stream " + e);
    }
  }

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

  /**
   * {@inheritDoc}
   */
  public boolean isWriteable(Class<?> type,
                             Type genericType,
                             Annotation[] annotations,
                             MediaType mediaType) {
    // say as support all objects, see _TODO_ above
    return Object.class.isAssignableFrom(type);
  }

  /**
   * {@inheritDoc}
   */
  public void writeTo(Object t,
                      Class<?> type,
                      Type genericType,
                      Annotation[] annotations,
                      MediaType mediaType,
                      MultivaluedMap<String, Object> httpHeaders,
                      OutputStream entityStream) throws IOException {
    /*
    try {
      JsonValue jv = new JsonGeneratorImpl().createJsonObject(t);
      JsonWriter jsonWriter = new JsonWriterImpl(entityStream);
      jv.writeTo(jsonWriter);
      jsonWriter.flush();
    } catch (JsonException e) {
      throw new IOException("Can't write to output stream " + e);
    }*/

  }

}