/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.persistence;

import org.waveprotocol.box.server.persistence.AttachmentStore.AttachmentData;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.waveprotocol.wave.model.id.IdConstants;
import org.waveprotocol.wave.model.id.WaveId;
import org.waveprotocol.wave.model.id.WaveletId;
import org.waveprotocol.wave.model.id.WaveletName;
import org.waveprotocol.wave.model.waveref.InvalidWaveRefException;
import org.waveprotocol.wave.model.waveref.WaveRef;
import org.waveprotocol.wave.util.escapers.jvm.JavaWaverefEncoder;
import org.waveprotocol.wave.util.logging.Log;

/**
 * Some utility methods for managing attachment data objects
 *
 * @author josephg@gmail.com (Joseph Gentle)
 */
public class AttachmentUtil {
  private static final Log LOG = Log.get(AttachmentUtil.class);

  private AttachmentUtil() {}

  /**
   * Write an input stream to an output stream. This will often be useful for
   * implementors of AttachmentData.writeDataTo().
   *
   * @param source The InputStream to read from
   * @param dest The OutputStream to write to
   * @throws IOException
   */
  public static void writeTo(InputStream source, OutputStream dest) throws IOException {
    byte[] buffer = new byte[256];
    int length;
    while ((length = source.read(buffer)) != -1) {
      dest.write(buffer, 0, length);
    }
  }

  /**
   * Write the attachment out to a string.
   *
   * @param encoding The string encoding format of the data. Eg, "UTF-8".
   * @return A string representation of the attachment data.
   * @throws IOException
   */
  public static String writeAttachmentDataToString(
      AttachmentData data, String encoding) throws IOException {
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    writeTo(data.getInputStream(), stream);
    return stream.toString(encoding);
  }

  /**
   * Decode wavelet name.
   *
   * @param waveRefStr encoded name.
   * @return WaveletName object.
   */
  public static WaveletName waveRef2WaveletName(String waveRefStr) {
    WaveRef waveRef = null;
    try {
      waveRef = JavaWaverefEncoder.decodeWaveRefFromPath(waveRefStr);
    } catch (InvalidWaveRefException e) {
      LOG.warning("Cannot decode: " + waveRefStr, e);
      return null;
    }

    WaveId waveId = waveRef.getWaveId();
    WaveletId waveletId =
        waveRef.getWaveletId() != null ? waveRef.getWaveletId() : WaveletId.of(waveId.getDomain(),
            IdConstants.CONVERSATION_ROOT_WAVELET);

    WaveletName waveletName = WaveletName.of(waveId, waveletId);
    return waveletName;
  }

}