#include "video-widget.hpp"

#include "compat/check-visible.hpp"
#include "compat/math.hpp"

#include <cstddef>
#include <cstring>

#ifdef OTR_VIDEO_HAS_OPENCV
#   include <opencv2/imgproc.hpp>
#endif

#include <QPainter>

void cv_video_widget::init_image_nolock()
{
    texture = QImage(W, H, QImage::Format_ARGB32);
    texture.setDevicePixelRatio(devicePixelRatioF());
}

cv_video_widget::cv_video_widget(QWidget* parent) : QWidget(parent)
{
    W = width(); H = height();
    init_image_nolock(); texture.fill(Qt::gray);

    connect(&timer, &QTimer::timeout, this, &cv_video_widget::update_and_repaint, Qt::DirectConnection);
    timer.start(65);
}

#ifdef OTR_VIDEO_HAS_OPENCV
void cv_video_widget::update_image(const cv::Mat& frame)
{
    QMutexLocker l(&mtx);

    if (freshp)
        return;

    if (W < 1 || H < 1 || frame.rows < 1 || frame.cols < 1)
        return;

    cv::Mat const* __restrict frame_scaled = nullptr;

    if (frame3.cols != W || frame3.rows != H)
    {
        frame3 = cv::Mat(H, W, frame.type());
        frame2 = cv::Mat(H, W, CV_8UC4);

        if (!frame2.isContinuous() || !frame3.isContinuous())
            std::abort();
    }

    if (frame.cols != W || frame.rows != H)
    {
        cv::resize(frame, frame3, { W, H }, 0, 0, cv::INTER_NEAREST);
        frame_scaled = &frame3;
    }
    else if (!frame.isContinuous())
    {
        frame.copyTo(frame3);
        frame_scaled = &frame3;
    }
    else
        frame_scaled = &frame;

    freshp = true;

    int color_cvt = 0;
    constexpr int nchannels = 4;

    switch (frame_scaled->channels())
    {
    case 1:
        color_cvt = cv::COLOR_GRAY2BGRA;
        break;
    case 3:
        color_cvt = cv::COLOR_BGR2BGRA;
        break;
    case nchannels:
        break;
    default:
        unreachable();
        break;
    }

    cv::Mat const* frame_color;

    if (color_cvt != cv::COLOR_COLORCVT_MAX)
    {
        cv::cvtColor(*frame_scaled, frame2, color_cvt);
        frame_color = &frame2;
    }
    else
        frame_color = frame_scaled;

    int stride = frame_color->step.p[0], rows = frame_color->rows;
    int nbytes = rows * stride;
    vec.resize(nbytes); vec.shrink_to_fit();
    std::memcpy(vec.data(), frame_color->data, nbytes);

    texture = QImage((const unsigned char*) vec.data(), W, H, stride, QImage::Format_ARGB32);
    texture.setDevicePixelRatio(devicePixelRatioF());
}
#endif

void cv_video_widget::update_image(const QImage& img)
{
    QMutexLocker l(&mtx);

    if (freshp)
        return;
    freshp = true;

    unsigned nbytes = (unsigned)(img.bytesPerLine() * img.height());
    vec.resize(nbytes); vec.shrink_to_fit();
    std::memcpy(vec.data(), img.constBits(), nbytes);

    texture = QImage((const unsigned char*) vec.data(), img.width(), img.height(), img.bytesPerLine(), img.format());
    texture.setDevicePixelRatio(devicePixelRatioF());
}

void cv_video_widget::paintEvent(QPaintEvent*)
{
    QMutexLocker foo(&mtx);

    if (texture.width() != W || texture.height() != H)
    {
        init_image_nolock();
        texture.fill(Qt::gray);
    }

    QPainter painter(this);
    painter.drawImage(rect(), texture);
}

void cv_video_widget::update_and_repaint()
{
    if (!check_is_visible())
        return;

    QMutexLocker l(&mtx);

    if (freshp)
    {
        freshp = false;
        repaint();
    }
}

void cv_video_widget::resizeEvent(QResizeEvent*)
{
    QMutexLocker l(&mtx);
    double dpr = devicePixelRatioF();
    W = iround(width() * dpr);
    H = iround(height() * dpr);
    init_image_nolock();
}

void cv_video_widget::get_preview_size(int& w, int& h)
{
    QMutexLocker l(&mtx);
    w = W; h = H;
}