// Copyright Contributors to the Open Shading Language project.
// SPDX-License-Identifier: BSD-3-Clause
// https://github.com/AcademySoftwareFoundation/OpenShadingLanguage

#include <algorithm>

#include <QAction>
#include <QLabel>
#include <QLayout>
#include <QString>

#include <OSL/oslconfig.h>
#include <OpenImageIO/imagebuf.h>
#include <OpenImageIO/strutil.h>

OIIO_NAMESPACE_BEGIN

namespace Strutil {

template<typename T>
inline std::string
to_string(const T& value);

template<>
inline std::string
to_string(const QString& value)
{
    return value.toUtf8().data();
}

}  // end namespace Strutil
OIIO_NAMESPACE_END



OSL_NAMESPACE_ENTER
namespace QtUtils {


template<typename OBJ, typename ACT>
QAction*
add_action(OBJ* obj, const std::string& name, const std::string& label,
           const std::string& hotkey = "", ACT trigger_action = nullptr)
{
    QAction* act = new QAction(label.size() ? label.c_str() : name.c_str(),
                               obj);
    if (hotkey.size())
        act->setShortcut(QString(hotkey.c_str()));
    if (trigger_action)
        connect(act, &QAction::triggered, obj, trigger_action);
    return act;
}



// Remove and delete any widgets within the layout.
inline void
clear_layout(QLayout* lay)
{
    QLayoutItem* child;
    while ((child = lay->takeAt(0)) != 0) {
        delete (child->widget());
        delete child;
    }
}



// Create a label whose text is given by std::format-style arguments (type
// safe). The label will be "autotext" which means it will auto-detect RTF and
// render a subset of HTML formatting. For example, "<i>blah</i>" will
// render the 'blah' in italics.
template<typename... Args>
inline QLabel*
make_qlabelfmt(const char* fmt, const Args&... args)
{
    std::string text = OIIO::Strutil::fmt::format(fmt, args...);
    auto label       = new QLabel(text.c_str());
    label->setTextFormat(Qt::AutoText);
    return label;
}



// Make a QImage that "wraps" the pixels of the ImageBuf. The ImageBuf MUST
//  * Be 3 or 4 channel, uint8 pixels
//  * Outlive the lifetime of the QImage, without having anything done
//    to it that will reallocate its memory.
inline QImage
ImageBuf_to_QImage(const OIIO::ImageBuf& ib)
{
    using namespace OIIO;
    if (ib.storage() == ImageBuf::UNINITIALIZED)
        return {};

    const ImageSpec& spec(ib.spec());
    QImage::Format format = QImage::Format_Invalid;
    if (spec.format == TypeDesc::UINT8) {
        if (spec.nchannels == 3)
            format = QImage::Format_RGB888;
        else if (spec.nchannels == 4)
            format = QImage::Format_RGBA8888;
    }
    if (format == QImage::Format_Invalid)
        return {};

    if (ib.cachedpixels())
        const_cast<ImageBuf*>(&ib)->make_writeable(true);
    return QImage((const uchar*)ib.localpixels(), spec.width, spec.height,
                  (int)spec.scanline_bytes(), format);
}



/// QtUtils::DoubleSpinBox is an improved QDoubleSpinBox with the following
/// enhancements:
/// * Default range is -1e6 to 1e6 (allows negatives and bigger values than
///   regular QDoubleSpinBox, unless you restrict the range further).
/// * Default single-step size is not fixed, but gets bigger or smaller
///   based on the current value. That makes it easier to make fine
///   adjustments especially near zero.
/// * KeyboardTracking turned off by default, so if you edit the value as
///   text, the change doesn't take effect until you hit enter or focus
///   on a different widget.
class DoubleSpinBox final : public QDoubleSpinBox {
public:
    typedef QDoubleSpinBox parent_t;

    DoubleSpinBox(double val, QWidget* parent = nullptr)
        : QDoubleSpinBox(parent)
    {
        setValue(val);
        setDecimals(3);
        setMaximumWidth(100);
        setRange(-1e6, 1e6);
        setAccelerated(true);
        setKeyboardTracking(false);
        variable_step_size();  // defaults
        set_step_size(value());
    }

#if 1
    virtual void stepBy(int steps)
    {  // override to adjust step size
        set_step_size(value());
        parent_t::stepBy(steps);
    }
#endif

    void fixed_step_size(double step = 1.0)
    {
        m_variable_step_digits = 1;
        m_fixed_step           = step;
    }

    void variable_step_size(int digits = 1, double minstep = 1e-3)
    {
        m_variable_step_digits = digits;
        m_variable_min_step    = minstep;
    }

    void valueChanged(double v)
    {
        set_step_size(v);
        parent_t::valueChanged(v);
    }

private:
    void set_step_size(double valsize)
    {
        double ss = m_fixed_step;
        if (m_variable_step_digits) {
            ss        = m_variable_min_step;
            double av = std::fabs(valsize);
            for (int d = 6; d > -4; --d) {
                double p = pow(10.0, double(d));
                if (av > p * 1.1) {
                    ss = p * pow(0.1, double(m_variable_step_digits));
                    setDecimals(abs(d) + 3);
                    break;
                }
            }
            ss = std::max(ss, m_variable_min_step);
        }
        setSingleStep(ss);
    }

    double m_fixed_step        = 1.0;
    double m_variable_min_step = 1e-3;
    int m_variable_step_digits = 1;
};



}  // end namespace QtUtils
OSL_NAMESPACE_EXIT
