/*
 * Copyright (C) 2017 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 com.google.android.exoplayer2.text.ssa;

import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.text.Cue;
import com.google.android.exoplayer2.text.Subtitle;
import com.google.android.exoplayer2.util.Assertions;
import com.google.android.exoplayer2.util.Util;
import java.util.Collections;
import java.util.List;

/**
 * A representation of an SSA/ASS subtitle.
 */
/* package */ final class SsaSubtitle implements Subtitle {

  private final Cue[] cues;
  private final long[] cueTimesUs;

  /**
   * @param cues The cues in the subtitle. Null entries may be used to represent empty cues.
   * @param cueTimesUs The cue times, in microseconds.
   */
  public SsaSubtitle(Cue[] cues, long[] cueTimesUs) {
    this.cues = cues;
    this.cueTimesUs = cueTimesUs;
  }

  @Override
  public int getNextEventTimeIndex(long timeUs) {
    int index = Util.binarySearchCeil(cueTimesUs, timeUs, false, false);
    return index < cueTimesUs.length ? index : C.INDEX_UNSET;
  }

  @Override
  public int getEventTimeCount() {
    return cueTimesUs.length;
  }

  @Override
  public long getEventTime(int index) {
    Assertions.checkArgument(index >= 0);
    Assertions.checkArgument(index < cueTimesUs.length);
    return cueTimesUs[index];
  }

  @Override
  public List<Cue> getCues(long timeUs) {
    int index = Util.binarySearchFloor(cueTimesUs, timeUs, true, false);
    if (index == -1 || cues[index] == null) {
      // timeUs is earlier than the start of the first cue, or we have an empty cue.
      return Collections.emptyList();
    } else {
      return Collections.singletonList(cues[index]);
    }
  }

}
