/**
 * 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.wave.model.wave.data.impl;

import org.waveprotocol.wave.model.id.WaveId;
import org.waveprotocol.wave.model.id.WaveletId;
import org.waveprotocol.wave.model.util.CollectionUtils;
import org.waveprotocol.wave.model.util.Preconditions;
import org.waveprotocol.wave.model.wave.data.ObservableWaveletData;
import org.waveprotocol.wave.model.wave.data.WaveViewData;

import java.util.Collection;
import java.util.Collections;
import java.util.Map;

/**
 * A skeleton implementation of {@link WaveViewData}.
 *
 */
public class WaveViewDataImpl implements WaveViewData {

  /** The wave id */
  private final WaveId id;

  /** Wavelets in this wave. */
  private final Map<WaveletId, ObservableWaveletData> wavelets = CollectionUtils.newHashMap();

  private WaveViewDataImpl(WaveId id) {
    this.id = id;
  }

  /**
   * Creates an empty wave.
   *
   * @param id wave id
   */
  public static WaveViewDataImpl create(WaveId id) {
    return new WaveViewDataImpl(id);
  }

  /**
   * Creates a wave with some initial state.
   *
   * @param id wave id
   * @param wavelets initial wavelet data
   */
  public static WaveViewDataImpl create(
      WaveId id, Collection<? extends ObservableWaveletData> wavelets) {
    WaveViewDataImpl wave = new WaveViewDataImpl(id);
    for (ObservableWaveletData wavelet : wavelets) {
      wave.addWavelet(wavelet);
    }
    return wave;
  }

  @Override
  public WaveId getWaveId() {
    return id;
  }

  @Override
  public Iterable<? extends ObservableWaveletData> getWavelets() {
    return Collections.unmodifiableCollection(wavelets.values());
  }

  @Override
  public ObservableWaveletData getWavelet(WaveletId waveletId) {
    return wavelets.get(waveletId);
  }

  @Override
  public void addWavelet(ObservableWaveletData wavelet) {
    WaveletId waveletId = wavelet.getWaveletId();
    Preconditions.checkArgument(
        !wavelets.containsKey(waveletId), "Duplicate wavelet id: %s", waveletId);
    wavelets.put(waveletId, wavelet);
  }

  @Override
  public void removeWavelet(WaveletId waveletId) {
    if (wavelets.remove(waveletId) == null) {
      throw new IllegalArgumentException(waveletId + " is not present");
    }
  }
}