// SPDX-License-Identifier: LGPL-2.1-or-later
/***************************************************************************
 *   Copyright (c) 2009 Werner Mayer <wmayer[at]users.sourceforge.net>     *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Library General Public           *
 *   License as published by the Free Software Foundation; either          *
 *   version 2 of the License, or (at your option) any later version.      *
 *                                                                         *
 *   This library  is distributed in the hope that it will be useful,      *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file COPYING.LIB. If not,    *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/

#include <FCConfig.h>

#if HAVE_CONFIG_H
# include <config.h>
#endif  // HAVE_CONFIG_H

#ifdef _MSC_VER
# pragma warning(disable : 4005)
#endif

#include <QApplication>
#include <QIcon>
#if defined(Q_OS_WIN)
# include <windows.h>
#elif defined(Q_WS_X11)
# include <QX11EmbedWidget>
#endif
#include <thread>

// FreeCAD Base header
#include <App/Application.h>
#include <Base/Exception.h>
#include <Base/Factory.h>
#include <Base/Interpreter.h>
#include <Base/PyObjectBase.h>
#include <Gui/Application.h>
#include <Gui/BitmapFactory.h>
#include <Gui/MainWindow.h>
#include <Gui/StartupProcess.h>
#include <Gui/SoFCDB.h>
#include <Gui/Quarter/Quarter.h>
#include <Inventor/SoDB.h>
#include <Inventor/SoInteraction.h>
#include <Inventor/nodekits/SoNodeKit.h>


static bool _isSetupWithoutGui = false;

static QWidget* setupMainWindow();

class QtApplication: public QApplication
{
public:
    QtApplication(int& argc, char** argv)
        : QApplication(argc, argv)
    {}
    bool notify(QObject* receiver, QEvent* event) override
    {
        try {
            return QApplication::notify(receiver, event);
        }
        catch (const Base::SystemExitException& e) {
            exit(e.getExitCode());
            return true;
        }
    }
};

#if defined(Q_OS_WIN)
HHOOK hhook;

LRESULT CALLBACK FilterProc(int nCode, WPARAM wParam, LPARAM lParam)
{
    if (qApp) {
        qApp->sendPostedEvents(0, -1);  // special DeferredDelete
    }
    return CallNextHookEx(hhook, nCode, wParam, lParam);
}
#endif

static PyObject* FreeCADGui_showMainWindow(PyObject* /*self*/, PyObject* args)
{
    if (_isSetupWithoutGui) {
        PyErr_SetString(
            PyExc_RuntimeError,
            "Cannot call showMainWindow() after calling setupWithoutGUI()\n"
        );
        return nullptr;
    }

    PyObject* inThread = Py_False;
    if (!PyArg_ParseTuple(args, "|O!", &PyBool_Type, &inThread)) {
        return nullptr;
    }

    static bool thr = false;
    if (!qApp) {
        if (Base::asBoolean(inThread) && !thr) {
            thr = true;
            std::thread t([]() {
                static int argc = 0;
                static char** argv = {nullptr};
                QApplication::setAttribute(Qt::AA_ShareOpenGLContexts);
                // This only works well if the QApplication is the very first created instance
                // of a QObject. Otherwise the application lives in a different thread than the
                // main thread which will cause hazardous behaviour.
                QtApplication app(argc, argv);
                if (setupMainWindow()) {
                    app.exec();
                }
            });
            t.detach();
        }
        else {
            // In order to get Jupiter notebook integration working we must create a direct instance
            // of QApplication. Not even a sub-class can be used because otherwise PySide2 wraps it
            // with a QtCore.QCoreApplication which will raise an exception in ipykernel
#if defined(Q_OS_WIN)
            static int argc = 0;
            static char** argv = {0};
            (void)new QApplication(argc, argv);
            // When QApplication is constructed
            hhook = SetWindowsHookEx(WH_GETMESSAGE, FilterProc, 0, GetCurrentThreadId());
#elif !defined(QT_NO_GLIB)
            static int argc = 0;
            static char** argv = {nullptr};
            (void)new QApplication(argc, argv);
#else
            PyErr_SetString(PyExc_RuntimeError, "Must construct a QApplication before a QPaintDevice\n");
            return nullptr;
#endif
        }
    }
    else if (!qobject_cast<QApplication*>(qApp)) {
        PyErr_SetString(PyExc_RuntimeError, "Cannot create widget when no GUI is being used\n");
        return nullptr;
    }

    if (!thr) {
        if (!setupMainWindow()) {
            PyErr_SetString(PyExc_RuntimeError, "Cannot create main window\n");
            return nullptr;
        }
    }

    // if successful then enable Console logger
    Base::ILogger* console = Base::Console().get("Console");
    if (console) {
        console->bMsg = true;
        console->bWrn = true;
        console->bErr = true;
    }

    Py_INCREF(Py_None);
    return Py_None;
}

static PyObject* FreeCADGui_exec_loop(PyObject* /*self*/, PyObject* args)
{
    if (!PyArg_ParseTuple(args, "")) {
        return nullptr;
    }

    if (!qApp) {
        PyErr_SetString(PyExc_RuntimeError, "Must construct a QApplication before a QPaintDevice\n");
        return nullptr;
    }
    else if (!qobject_cast<QApplication*>(qApp)) {
        PyErr_SetString(PyExc_RuntimeError, "Cannot create widget when no GUI is being used\n");
        return nullptr;
    }

    qApp->exec();

    Py_INCREF(Py_None);
    return Py_None;
}

static PyObject* FreeCADGui_setupWithoutGUI(PyObject* /*self*/, PyObject* args)
{
    if (!PyArg_ParseTuple(args, "")) {
        return nullptr;
    }

    if (!Gui::Application::Instance) {
        static Gui::Application* app = new Gui::Application(false);
        _isSetupWithoutGui = true;
        Q_UNUSED(app);
    }
    if (!SoDB::isInitialized()) {
        // init the Inventor subsystem
        SoDB::init();
        SoNodeKit::init();
        SoInteraction::init();
    }
    if (!Gui::SoFCDB::isInitialized()) {
        Gui::SoFCDB::init();
    }

    Py_INCREF(Py_None);
    return Py_None;
}

static PyObject* FreeCADGui_embedToWindow(PyObject* /*self*/, PyObject* args)
{
    char* pointer;
    if (!PyArg_ParseTuple(args, "s", &pointer)) {
        return nullptr;
    }

    QWidget* widget = Gui::getMainWindow();
    if (!widget) {
        PyErr_SetString(Base::PyExc_FC_GeneralError, "No main window");
        return nullptr;
    }

    std::string pointer_str = pointer;
    std::stringstream str(pointer_str);

#if defined(Q_OS_WIN)
    void* window = 0;
    str >> window;
    HWND winid = (HWND)window;

    LONG oldLong = GetWindowLong(winid, GWL_STYLE);
    SetWindowLong(winid, GWL_STYLE, oldLong | WS_CLIPCHILDREN | WS_CLIPSIBLINGS);
    // SetWindowLong(widget->winId(), GWL_STYLE,
    //     WS_CHILD | WS_CLIPCHILDREN | WS_CLIPSIBLINGS);
    SetParent((HWND)widget->winId(), winid);

    QEvent embeddingEvent(QEvent::EmbeddingControl);
    QApplication::sendEvent(widget, &embeddingEvent);
#elif defined(Q_WS_X11)
    WId winid;
    str >> winid;

    QX11EmbedWidget* x11 = new QX11EmbedWidget();
    widget->setParent(x11);
    x11->embedInto(winid);
    x11->show();
#else
    PyErr_SetString(PyExc_NotImplementedError, "Not implemented for this platform");
    return nullptr;
#endif

    Py_INCREF(Py_None);
    return Py_None;
}

struct PyMethodDef FreeCADGui_methods[] = {
    {"showMainWindow",
     FreeCADGui_showMainWindow,
     METH_VARARGS,
     "showMainWindow() -- Show the main window\n"
     "If no main window does exist one gets created"},
    {"exec_loop",
     FreeCADGui_exec_loop,
     METH_VARARGS,
     "exec_loop() -- Starts the event loop\n"
     "Note: this will block the call until the event loop has terminated"},
    {"setupWithoutGUI",
     FreeCADGui_setupWithoutGUI,
     METH_VARARGS,
     "setupWithoutGUI() -- Uses this module without starting\n"
     "an event loop or showing up any GUI\n"},
    {"embedToWindow",
     FreeCADGui_embedToWindow,
     METH_VARARGS,
     "embedToWindow() -- Embeds the main window into another window\n"},
    {nullptr, nullptr, 0, nullptr} /* sentinel */
};

static QWidget* setupMainWindow()
{
    if (!Gui::Application::Instance) {
        static Gui::Application* app = new Gui::Application(true);
        Q_UNUSED(app);
    }

    if (!Gui::MainWindow::getInstance()) {
        static bool hasMainWindow = false;
        if (hasMainWindow) {
            // if a main window existed and has been deleted it's not supported
            // to re-create it
            return nullptr;
        }

        Gui::StartupProcess process;
        process.execute();

        Base::PyGILStateLocker lock;
        // It's sufficient to create the config key
        App::Application::Config()["DontOverrideStdIn"] = "";
        Gui::MainWindow* mw = new Gui::MainWindow();
        hasMainWindow = true;

        QIcon icon = qApp->windowIcon();
        if (icon.isNull()) {
            qApp->setWindowIcon(
                Gui::BitmapFactory().pixmap(App::Application::Config()["AppIcon"].c_str())
            );
        }
        mw->setWindowIcon(qApp->windowIcon());

        try {
            Gui::StartupPostProcess postProcess(mw, *Gui::Application::Instance, qApp);
            postProcess.setLoadFromPythonModule(true);
            postProcess.execute();
        }
        catch (const Base::Exception&) {
            return nullptr;
        }
    }
    else {
        Gui::getMainWindow()->show();
    }

    return Gui::getMainWindow();
}

PyMOD_INIT_FUNC(FreeCADGui)
{
    try {
        // clang-format off
        Base::Interpreter().loadModule("FreeCAD");
        App::Application::Config()["AppIcon"] = "freecad";
        App::Application::Config()["SplashScreen"] = "freecadsplash";
        App::Application::Config()["CopyrightInfo"] = "\xc2\xa9 Juergen Riegel, Werner Mayer, Yorik van Havre and others 2001-2025\n";
        App::Application::Config()["LicenseInfo"] = "FreeCAD is free and open-source software licensed under the terms of LGPL2+ license.\n";
        App::Application::Config()["CreditsInfo"] = "FreeCAD would not be possible without the FreeCAD community.\n";
        // clang-format on

        // it's possible that the GUI is already initialized when the Gui version of the executable
        // is started in command mode
        if (Base::Type::fromName("Gui::BaseView").isBad()) {
            Gui::Application::initApplication();
        }
        static struct PyModuleDef FreeCADGuiModuleDef = {
            PyModuleDef_HEAD_INIT,
            "FreeCADGui",
            "FreeCAD GUI module\n",
            -1,
            FreeCADGui_methods,
            nullptr,
            nullptr,
            nullptr,
            nullptr
        };
        PyObject* module = PyModule_Create(&FreeCADGuiModuleDef);
        return module;
    }
    catch (const Base::Exception& e) {
        PyErr_Format(PyExc_ImportError, "%s\n", e.what());
    }
    catch (...) {
        PyErr_SetString(PyExc_ImportError, "Unknown runtime error occurred");
    }
    return nullptr;
}