/* 
 * Copyright (c) 2019 Stephane Lenclud
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 */

#include "preview.h"

#include "compat/math.hpp"

#include <opencv2/imgproc.hpp>


namespace EasyTracker
{


    Preview& Preview::operator=(const cv::Mat& aFrame)
    {
        //TODO: Assert if channel size is neither one nor two

        // Make sure our frame channel is 8 bit
        size_t channelSize = aFrame.elemSize1();
        if (channelSize == 2)
        {
            // First resample to 8-bits            
            double min = std::numeric_limits<uint16_t>::min();
            double max = std::numeric_limits<uint16_t>::max();
            //cv::minMaxLoc(raw, &min, &max); // Should we use 16bit min and max instead?
            // For scalling to have more precission in the range we are interrested in
            //min = max - 255;
            // See: https://stackoverflow.com/questions/14539498/change-type-of-mat-object-from-cv-32f-to-cv-8u/14539652
            aFrame.convertTo(iFrameChannelSizeOne, CV_8U, 255.0 / (max - min), -255.0*min / (max - min));
        }
        else
        {
            iFrameChannelSizeOne = aFrame;
        }

        // Make sure our frame is RGB
        // Make an extra copy if needed
        int channelCount = iFrameChannelSizeOne.channels();
        if (channelCount == 1)
        {
            // Convert to RGB
            cv::cvtColor(iFrameChannelSizeOne, iFrameRgb, cv::COLOR_GRAY2BGR);
        }
        else if (channelCount == 3)
        {
            iFrameRgb = iFrameChannelSizeOne;
        }
        else
        {
            eval_once(qDebug() << "tracker/easy: camera frame depth not supported" << aFrame.channels());
            return *this;
        }


        return *this;
    }

    Preview::Preview(int w, int h)
    {
        ensure_size(frame_out, w, h, CV_8UC4);
        ensure_size(iFrameResized, w, h, CV_8UC3);

        iFrameResized.setTo(cv::Scalar(0, 0, 0));
    }

    QImage Preview::get_bitmap()
    {
        int stride = frame_out.step.p[0];

        if (stride < 64 || stride < frame_out.cols * 4)
        {
            eval_once(qDebug() << "bad stride" << stride
                << "for bitmap size" << iFrameResized.cols << iFrameResized.rows);
            return QImage();
        }

        // Resize if needed
        const bool need_resize = iFrameRgb.cols != frame_out.cols || iFrameRgb.rows != frame_out.rows;
        if (need_resize)
        {
            cv::resize(iFrameRgb, iFrameResized, cv::Size(frame_out.cols, frame_out.rows), 0, 0, cv::INTER_NEAREST);
        }
        else
        {
            iFrameRgb.copyTo(iFrameResized);
        }

        cv::cvtColor(iFrameResized, frame_out, cv::COLOR_BGR2BGRA);

        return QImage((const unsigned char*)frame_out.data,
            frame_out.cols, frame_out.rows,
            stride,
            QImage::Format_ARGB32);
    }

    void Preview::draw_head_center(numeric_types::f x, numeric_types::f y)
    {
        int px = iround(x), py = iround(y);

        constexpr int len = 9;

        static const cv::Scalar color(0, 255, 255);
        cv::line(iFrameRgb,
            cv::Point(px - len, py),
            cv::Point(px + len, py),
            color, 2);
        cv::line(iFrameRgb,
            cv::Point(px, py - len),
            cv::Point(px, py + len),
            color, 2);
    }

    void Preview::ensure_size(cv::Mat& frame, int w, int h, int type)
    {
        if (frame.cols != w || frame.rows != h)
            frame = cv::Mat(h, w, type);
    }

}