#include "stretchpanel.h"
#include <QVBoxLayout>
#include <QDebug>
#include <QPushButton>
#include "imageringlist.h"

const float BLACK_POINT_SIGMA = -2.8f;
const float MAD_TO_SIGMA = 1.4826f;
const float TARGET_BACKGROUND = 0.25f;

float MTF(float x, float m)
{
    if(x < 0)return 0;
    if(x > 1)return 1;
    return ((m - 1) * x) / ((2 * m - 1) * x - m);
}

StretchPanel::StretchPanel(QWidget *parent) : QWidget(parent)
{
    QHBoxLayout *layout = new QHBoxLayout(this);
    setLayout(layout);

    m_stfSlider = new STFSlider(this);
    layout->addWidget(m_stfSlider);
    connect(m_stfSlider, SIGNAL(paramChanged(float, float, float)), this, SIGNAL(paramChanged(float,float,float)));

    QPushButton *resetButton = new QPushButton(tr("Reset STF"), this);
    resetButton->setSizePolicy(QSizePolicy::Maximum, QSizePolicy::Maximum);
    layout->addWidget(resetButton);
    connect(resetButton, SIGNAL(pressed()), this, SLOT(resetMTF()));
}

void StretchPanel::imageLoaded(Image *img)
{
    if(img)
    {
        if(img->rawImage())
        {
            double mean, stdDev, median;
            img->rawImage()->imageStats(&mean, &stdDev, &median, nullptr, nullptr);
            median /= 65536;
            double mad = img->rawImage()->MAD() / 65536;
            float bp = median + mad * BLACK_POINT_SIGMA * MAD_TO_SIGMA;
            float mid = MTF(median - bp, TARGET_BACKGROUND);
            m_stfSlider->setMTFParams(bp, mid, 1.0f);
            emit paramChanged(m_stfSlider->blackPoint(), m_stfSlider->midPoint(), 1.0f);
        }
    }
}

void StretchPanel::resetMTF()
{
    m_stfSlider->setMTFParams(0, 0.5, 1);
    emit paramChanged(0, 0.5, 1);
}