/**
 * Copyright 2010 Google Inc.
 *
 *  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 org.waveprotocol.box.server.robots.operations;

import com.google.wave.api.InvalidRequestException;
import com.google.wave.api.JsonRpcConstant.ParamsProperty;
import com.google.wave.api.OperationRequest;
import com.google.wave.api.data.converter.ContextResolver;
import com.google.wave.api.data.converter.EventDataConverter;
import com.google.wave.api.event.WaveletFetchedEvent;
import com.google.wave.api.impl.EventMessageBundle;
import com.google.wave.api.impl.WaveletData;

import org.waveprotocol.box.server.robots.OperationContext;
import org.waveprotocol.box.server.robots.util.ConversationUtil;
import org.waveprotocol.box.server.robots.util.OperationUtil;
import org.waveprotocol.wave.model.conversation.Conversation;
import org.waveprotocol.wave.model.conversation.ObservableConversation;
import org.waveprotocol.wave.model.wave.ParticipantId;
import org.waveprotocol.wave.model.wave.Wavelet;
import org.waveprotocol.wave.model.wave.opbased.OpBasedWavelet;

/**
 * {@link OperationService} for the "fetchWave" operation.
 *
 * @author ljvderijk@google.com (Lennard de Rijk)
 */
public class FetchWaveService implements OperationService {

  private FetchWaveService() {
  }

  @Override
  public void execute(
      OperationRequest operation, OperationContext context, ParticipantId participant)
      throws InvalidRequestException {
    OpBasedWavelet wavelet = context.openWavelet(operation, participant);
    ObservableConversation conversation =
        context.openConversation(operation, participant).getRoot();

    EventMessageBundle messages =
        mapWaveletToMessageBundle(context.getConverter(), participant, wavelet, conversation);

    String rootBlipId = ConversationUtil.getRootBlipId(conversation);
    String message = OperationUtil.getOptionalParameter(operation, ParamsProperty.MESSAGE);

    WaveletFetchedEvent event =
        new WaveletFetchedEvent(null, null, participant.getAddress(), System.currentTimeMillis(),
            message, rootBlipId, messages.getWaveletData(), messages.getBlipData(),
            messages.getThreads(), null, null);

    context.processEvent(operation, event);
  }

  /**
   * Maps a wavelet and its conversation to a new {@link EventMessageBundle}.
   *
   * @param converter to convert to API objects.
   * @param participant the participant who the bundle is for.
   * @param wavelet the wavelet to put in the bundle.
   * @param conversation the conversation to put in the bundle.
   */
  private EventMessageBundle mapWaveletToMessageBundle(EventDataConverter converter,
      ParticipantId participant, Wavelet wavelet, Conversation conversation) {
    EventMessageBundle messages = new EventMessageBundle(participant.getAddress(), "");
    WaveletData waveletData = converter.toWaveletData(wavelet, conversation, messages);
    messages.setWaveletData(waveletData);
    ContextResolver.addAllBlipsToEventMessages(messages, conversation, wavelet, converter);
    return messages;
  }

  public static FetchWaveService create() {
    return new FetchWaveService();
  }
}