// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include <qpydesignerextensions.h>

#include <QtCore/QCoreApplication>
#include <QtCore/QVariant>

#include <shiboken.h>
#include <bindingmanager.h>

static QString pyStringToQString(PyObject *s)
{
    const char *utf8 = _PepUnicode_AsString(s);
    return utf8 ? QString::fromUtf8(utf8) : QString();
}

// Return a string from keyword argument dict
static QString kwdString(PyObject *kwds, PyObject *key)
{
    QString result;
    if (PyDict_Contains(kwds, key)) {
        if (auto value = PyDict_GetItem(kwds, key))
            result = pyStringToQString(value);
    }
    return result;
}

// Return a bool from keyword argument dict
static bool kwdBool(PyObject *kwds, PyObject *key)
{
    bool result = false;
    if (PyDict_Contains(kwds, key)) {
        if (auto value = PyDict_GetItem(kwds, key))
            result = PyObject_IsTrue(value);
    }
    return result;
}

// PyDesignerCustomWidget: A custom widget registered by type
// (similar to what is done by QUiLoader.registerCustomWidget()).
class PyDesignerCustomWidget : public QDesignerCustomWidgetInterface
{
public:
    explicit PyDesignerCustomWidget(PyObject *pyTypeObject) :
        m_pyTypeObject(pyTypeObject) {}

    QString name() const override;
    QString group() const override { return m_group; }
    QString toolTip() const override { return m_toolTip; }
    QString whatsThis() const  override { return toolTip(); }
    QString includeFile() const override { return m_includeFile; }
    QIcon icon() const override { return m_icon; }
    bool isContainer() const override { return m_container; }

    QWidget *createWidget(QWidget *parent) override;

    bool isInitialized() const  override { return m_core != nullptr; }
    void initialize(QDesignerFormEditorInterface *core) override;

    QString domXml() const override { return m_domXml; }

    void setGroup(const QString &group) { m_group = group; }
    void setToolTip(const QString &toolTip) { m_toolTip = toolTip; }
    void setIncludeFile(const QString &includeFile) { m_includeFile = includeFile; }
    void setIcon(const QIcon &icon) { m_icon = icon; }
    void setDomXml(const QString &domXml) { m_domXml = domXml; }
    void setContainer(bool container) { m_container = container; }

private:
    const char *utf8Name() const;

    QDesignerFormEditorInterface *m_core = nullptr;
    QString m_group;
    QString m_toolTip;
    QString m_includeFile;
    QIcon m_icon;
    QString m_domXml;
    PyObject *m_pyTypeObject = nullptr;
    bool m_container = false;
};

const char *PyDesignerCustomWidget::utf8Name() const
{
    return reinterpret_cast<PyTypeObject *>(m_pyTypeObject)->tp_name;
}

QString PyDesignerCustomWidget::name() const
{
    return QString::fromUtf8(utf8Name());
}

QWidget *PyDesignerCustomWidget::createWidget(QWidget *parent)
{
    // This is a copy of the similar function used for QUiLoader
    // (see sources/pyside6/plugins/uitools/customwidget.cpp)
    // Create a python instance and return cpp object
    PyObject *pyParent = nullptr;
    bool unknownParent = false;
    if (parent) {
        pyParent = reinterpret_cast<PyObject *>(Shiboken::BindingManager::instance().retrieveWrapper(parent));
        if (pyParent) {
            Py_INCREF(pyParent);
        } else {
            static Shiboken::Conversions::SpecificConverter converter("QWidget*");
            pyParent = converter.toPython(&parent);
            unknownParent = true;
        }
    } else {
        Py_INCREF(Py_None);
        pyParent = Py_None;
    }

    Shiboken::AutoDecRef pyArgs(PyTuple_New(1));
    PyTuple_SET_ITEM(pyArgs, 0, pyParent); // tuple will keep pyParent reference

    // Call python constructor
    auto result = reinterpret_cast<SbkObject *>(PyObject_CallObject(m_pyTypeObject, pyArgs));
    if (!result) {
        qWarning("Unable to create a Python custom widget of type \"%s\".", utf8Name());
        PyErr_Print();
        return nullptr;
    }

    if (unknownParent) // if parent does not exist in python, transfer the ownership to cpp
        Shiboken::Object::releaseOwnership(result);
    else
        Shiboken::Object::setParent(pyParent, reinterpret_cast<PyObject *>(result));

    return reinterpret_cast<QWidget *>(Shiboken::Object::cppPointer(result, Py_TYPE(result)));
}

void PyDesignerCustomWidget::initialize(QDesignerFormEditorInterface *core)
{
    m_core = core;
}

// QPyDesignerCustomWidgetCollection: A QDesignerCustomWidgetCollectionInterface
// implementation that is instantiated as a singleton and stored as a dynamic
// property of QCoreApplication. The PySide Designer plugin retrieves it from
// there. Provides static convenience functions for registering types
// or adding QDesignerCustomWidgetInterface instances.

static QPyDesignerCustomWidgetCollection *collectionInstance = nullptr;

static const char propertyName[] =  "__qt_PySideCustomWidgetCollection";

static void cleanup()
{
    delete collectionInstance;
    collectionInstance = nullptr;
}

QPyDesignerCustomWidgetCollection::QPyDesignerCustomWidgetCollection() = default;

QPyDesignerCustomWidgetCollection::~QPyDesignerCustomWidgetCollection()
{
    qDeleteAll(m_customWidgets);
}

QList<QDesignerCustomWidgetInterface *> QPyDesignerCustomWidgetCollection::customWidgets() const
{
    return m_customWidgets;
}

QPyDesignerCustomWidgetCollection *QPyDesignerCustomWidgetCollection::instance()
{
    if (collectionInstance == nullptr) {
        collectionInstance = new QPyDesignerCustomWidgetCollection();
        if (auto coreApp = QCoreApplication::instance()) {
            QDesignerCustomWidgetCollectionInterface *c = collectionInstance;
            coreApp->setProperty(propertyName, QVariant::fromValue<void *>(c));
            qAddPostRoutine(cleanup);
        } else {
            qWarning("%s: Cannot find QCoreApplication instance.", Q_FUNC_INFO);
        }
    }
    return collectionInstance;
}

// Register a custom widget by type and optional keyword arguments providing
// the parameters of QDesignerCustomWidgetInterface.
bool QPyDesignerCustomWidgetCollection::_registerCustomWidgetHelper(PyObject *typeArg, PyObject *kwds)
{
    if (!PyType_Check(typeArg)) {
        PyErr_SetString(PyExc_TypeError, "registerCustomWidget() requires a type argument.");
        return false;
    }

    auto pyCustomWidget = new PyDesignerCustomWidget(typeArg);

    static PyObject *xmlKey = Shiboken::String::createStaticString("xml");
    pyCustomWidget->setDomXml(kwdString(kwds, xmlKey));
    static PyObject *toolTipKey = Shiboken::String::createStaticString("tool_tip");
    pyCustomWidget->setToolTip(kwdString(kwds, toolTipKey));
    static PyObject *groupKey = Shiboken::String::createStaticString("group");
    pyCustomWidget->setGroup(kwdString(kwds, groupKey));
    static PyObject *moduleKey = Shiboken::String::createStaticString("module");
    pyCustomWidget->setIncludeFile(kwdString(kwds, moduleKey));
    static PyObject *containerKey = Shiboken::String::createStaticString("container");
    pyCustomWidget->setContainer(kwdBool(kwds, containerKey));
    static PyObject *iconKey = Shiboken::String::createStaticString("icon");
    const QString iconPath = kwdString(kwds, iconKey);
    if (!iconPath.isEmpty()) {
        QIcon icon(iconPath);
        if (icon.availableSizes().isEmpty())
            qWarning("%s: Cannot load icon from '%s'.", __FUNCTION__, qPrintable(iconPath));
        else
            pyCustomWidget->setIcon(icon);
    }

    addCustomWidget(pyCustomWidget);
    return true;
}

void QPyDesignerCustomWidgetCollection::addCustomWidget(QDesignerCustomWidgetInterface *c)
{
    instance()->m_customWidgets.append(c);
}