/*
 * Copyright (C) 2022 The Android Open Source Project
 *
 * 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 androidx.media3.common.text;

import android.graphics.Bitmap;
import android.os.Bundle;
import androidx.annotation.Nullable;
import androidx.media3.common.Timeline;
import androidx.media3.common.util.BundleCollectionUtil;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
import com.google.common.collect.ImmutableList;
import java.util.ArrayList;
import java.util.List;

/** Class to represent the state of active {@link Cue Cues} at a particular time. */
public final class CueGroup {

  /** An empty group with no {@link Cue Cues} and presentation time of zero. */
  @UnstableApi
  public static final CueGroup EMPTY_TIME_ZERO =
      new CueGroup(ImmutableList.of(), /* presentationTimeUs= */ 0);

  /**
   * The cues in this group.
   *
   * <p>This list is in ascending order of priority. If any of the cue boxes overlap when displayed,
   * the {@link Cue} nearer the end of the list should be shown on top.
   *
   * <p>This list may be empty if the group represents a state with no cues.
   */
  public final ImmutableList<Cue> cues;

  /**
   * The presentation time of the {@link #cues}, in microseconds.
   *
   * <p>This time is an offset from the start of the current {@link Timeline.Period}.
   */
  @UnstableApi public final long presentationTimeUs;

  /** Creates a CueGroup. */
  @UnstableApi
  public CueGroup(List<Cue> cues, long presentationTimeUs) {
    this.cues = ImmutableList.copyOf(cues);
    this.presentationTimeUs = presentationTimeUs;
  }

  private static final String FIELD_CUES = Util.intToStringMaxRadix(0);
  private static final String FIELD_PRESENTATION_TIME_US = Util.intToStringMaxRadix(1);

  @UnstableApi
  public Bundle toBundle() {
    Bundle bundle = new Bundle();
    bundle.putParcelableArrayList(
        FIELD_CUES,
        BundleCollectionUtil.toBundleArrayList(
            filterOutBitmapCues(cues), Cue::toBinderBasedBundle));
    bundle.putLong(FIELD_PRESENTATION_TIME_US, presentationTimeUs);
    return bundle;
  }

  /** Restores a {@code final CueGroup} from a {@link Bundle}. */
  @UnstableApi
  public static CueGroup fromBundle(Bundle bundle) {
    @Nullable ArrayList<Bundle> cueBundles = bundle.getParcelableArrayList(FIELD_CUES);
    List<Cue> cues =
        cueBundles == null
            ? ImmutableList.of()
            : BundleCollectionUtil.fromBundleList(Cue::fromBundle, cueBundles);
    long presentationTimeUs = bundle.getLong(FIELD_PRESENTATION_TIME_US);
    return new CueGroup(cues, presentationTimeUs);
  }

  /**
   * Filters out {@link Cue} objects containing {@link Bitmap}. It is used when transferring cues
   * between processes to prevent transferring too much data.
   */
  private static ImmutableList<Cue> filterOutBitmapCues(List<Cue> cues) {
    ImmutableList.Builder<Cue> builder = ImmutableList.builder();
    for (int i = 0; i < cues.size(); i++) {
      if (cues.get(i).bitmap != null) {
        continue;
      }
      builder.add(cues.get(i));
    }
    return builder.build();
  }
}