/*
 * Copyright 2012 Sebastian Annies, Hamburg
 *
 * 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.googlecode.mp4parser.authoring.builder;

import com.googlecode.mp4parser.authoring.Movie;
import com.googlecode.mp4parser.authoring.Track;

import java.util.Arrays;

/**
 * This <code>FragmentIntersectionFinder</code> cuts the input movie in 2 second
 * snippets.
 */
public class TwoSecondIntersectionFinder implements FragmentIntersectionFinder {
    private int fragmentLength = 2;
    private Movie movie;


    public TwoSecondIntersectionFinder(Movie movie, int fragmentLength) {
        this.movie = movie;
        this.fragmentLength = fragmentLength;
    }


    /**
     * {@inheritDoc}
     */
    public long[] sampleNumbers(Track track) {
        double trackLength = 0;
        for (Track thisTrack : movie.getTracks()) {
            double thisTracksLength = thisTrack.getDuration() / thisTrack.getTrackMetaData().getTimescale();
            if (trackLength < thisTracksLength) {
                trackLength = thisTracksLength;
            }
        }

        int fragmentCount = (int) Math.ceil(trackLength / fragmentLength) - 1;
        fragmentCount = Math.min(fragmentCount, track.getSamples().size());
        if (fragmentCount < 1) {
            fragmentCount = 1;
        }

        long fragments[] = new long[fragmentCount];
        Arrays.fill(fragments, -1);
        fragments[0] = 1;

        long time = 0;
        int samples = 0;
        for (long delta : track.getSampleDurations()) {
            int currentFragment = (int) (time / track.getTrackMetaData().getTimescale() / fragmentLength) + 1;
            if (currentFragment >= fragments.length) {
                break;
            }
            fragments[currentFragment] = samples++ + 1;
            time += delta;
        }
        long last = samples + 1;
        // fill all -1 ones.
        for (int i = fragments.length - 1; i >= 0; i--) {
            if (fragments[i] == -1) {
                fragments[i] = last;
            }
            last = fragments[i];
        }
        return fragments;

    }

}
