//    This file is part of Motion Watch.

//    Motion Watch is free software: you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    (at your option) any later version.

//    Motion Watch is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.

#include "mo_detect.h"

bool imgDiff(const Mat &prev, const Mat &next, int &score, shared_t *share)
{
    Mat prevGray;
    Mat nextGray;

    cvtColor(prev, prevGray, COLOR_BGR2GRAY);
    cvtColor(next, nextGray, COLOR_BGR2GRAY);

    Mat diff;

    absdiff(prevGray, nextGray, diff);
    threshold(diff, diff, share->pixThresh, 255, THRESH_BINARY);

    score = countNonZero(diff);

    detLog("diff_score: " + QString::number(score) + " thresh: " + QString::number(share->imgThresh), share);

    return score >= share->imgThresh;
}

bool moDetect(const QString &buffFile, QThread *thr, shared_t *share)
{
    auto score = 0;
    auto mod   = false;

    detLog("stream_clip: " + buffFile, share);

    VideoCapture capture;

    if (!capture.open(buffFile.toUtf8().data(), CAP_FFMPEG))
    {
        thr->usleep(500);

        capture.open(buffFile.toUtf8().data(), CAP_FFMPEG);
    }

    if (capture.isOpened())
    {
        Mat prev;
        Mat next;

        int fps = capture.get(cv::CAP_PROP_FPS);

        for (auto gap = 0, frm = fps; capture.grab(); ++gap, ++frm)
        {
            if (frm == fps) thr->sleep(1); frm = 1;

            if (prev.empty())
            {
                capture.retrieve(prev);
            }
            else if (gap == (share->frameGap - 1))
            {
                capture.retrieve(next);

                if (!next.empty())
                {
                    if (imgDiff(prev, next, score, share))
                    {
                        mod = true;

                        if (share->maxScore <= score)
                        {
                            share->maxScore = score;

                            resize(next, share->curEvent.thumbnail, Size(720, 480), INTER_LINEAR);
                        }
                    }
                }

                prev = next.clone();
                gap  = 0;

                next.release();
            }
            else
            {
                capture.grab();
            }
        }
    }
    else
    {
        detLog("err: failed to open: " + buffFile + " after 500 msecs. giving up.", share);
    }

    capture.release();

    return mod;
}