// SPDX-License-Identifier: LGPL-2.1-or-later

/***************************************************************************
 *   Copyright (c) 2006 Jürgen Riegel <juergen.riegel@web.de>              *
 *                                                                         *
 *   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                                *
 *                                                                         *
 ***************************************************************************/


#ifndef APP_FEATUREPYTHON_H
#define APP_FEATUREPYTHON_H

#include <App/GeoFeature.h>
#include <App/PropertyPythonObject.h>


namespace App
{

class Property;

// Helper class to hide implementation details
class AppExport FeaturePythonImp
{
public:
    enum ValueT
    {
        NotImplemented = 0,  // not handled
        Accepted = 1,        // handled and accepted
        Rejected = 2         // handled and rejected
    };

    explicit FeaturePythonImp(App::DocumentObject*);
    ~FeaturePythonImp();

    bool execute();
    bool mustExecute() const;
    void onBeforeChange(const Property* prop);
    bool onBeforeChangeLabel(std::string& newLabel);
    void onChanged(const Property* prop);
    void onDocumentRestored();
    void unsetupObject();
    std::string getViewProviderName();
    PyObject* getPyObject();

    bool getSubObject(App::DocumentObject*& ret,
                      const char* subname,
                      PyObject** pyObj,
                      Base::Matrix4D* mat,
                      bool transform,
                      int depth) const;

    bool getSubObjects(std::vector<std::string>& ret, int reason) const;

    bool getLinkedObject(App::DocumentObject*& ret,
                         bool recurse,
                         Base::Matrix4D* mat,
                         bool transform,
                         int depth) const;

    ValueT canLinkProperties() const;

    ValueT allowDuplicateLabel() const;

    ValueT redirectSubName(std::ostringstream& ss,
                           App::DocumentObject* topParent,
                           App::DocumentObject* child) const;

    int canLoadPartial() const;

    /// return true to activate tree view group object handling
    ValueT hasChildElement() const;
    /// Get sub-element visibility
    int isElementVisible(const char*) const;
    /// Set sub-element visibility
    int setElementVisible(const char*, bool);

    bool editProperty(const char* propName);

    ValueT isLink() const;
    ValueT isLinkGroup() const;

    bool getPlacementOf(Base::Placement& ret, const char* subname, App::DocumentObject* target) const;

private:
    App::DocumentObject* object;
    bool has__object__ {false};

#define FC_PY_FEATURE_PYTHON                                                                       \
    FC_PY_ELEMENT(execute)                                                                         \
    FC_PY_ELEMENT(mustExecute)                                                                     \
    FC_PY_ELEMENT(onBeforeChange)                                                                  \
    FC_PY_ELEMENT(onBeforeChangeLabel)                                                             \
    FC_PY_ELEMENT(onChanged)                                                                       \
    FC_PY_ELEMENT(onDocumentRestored)                                                              \
    FC_PY_ELEMENT(unsetupObject)                                                                   \
    FC_PY_ELEMENT(getViewProviderName)                                                             \
    FC_PY_ELEMENT(getSubObject)                                                                    \
    FC_PY_ELEMENT(getSubObjects)                                                                   \
    FC_PY_ELEMENT(getLinkedObject)                                                                 \
    FC_PY_ELEMENT(canLinkProperties)                                                               \
    FC_PY_ELEMENT(allowDuplicateLabel)                                                             \
    FC_PY_ELEMENT(redirectSubName)                                                                 \
    FC_PY_ELEMENT(canLoadPartial)                                                                  \
    FC_PY_ELEMENT(hasChildElement)                                                                 \
    FC_PY_ELEMENT(isElementVisible)                                                                \
    FC_PY_ELEMENT(setElementVisible)                                                               \
    FC_PY_ELEMENT(editProperty)                                                                    \
    FC_PY_ELEMENT(isLink)                                                                          \
    FC_PY_ELEMENT(isLinkGroup)                                                                     \
    FC_PY_ELEMENT(getPlacementOf)

#define FC_PY_ELEMENT_DEFINE(_name) Py::Object py_##_name;

#define FC_PY_ELEMENT_INIT(_name)                                                                  \
    FC_PY_GetCallable(pyobj, #_name, py_##_name);                                                  \
    if (!py_##_name.isNone()) {                                                                    \
        PyObject* pyRecursive = PyObject_GetAttrString(pyobj, "__allow_recursive_" #_name);        \
        if (!pyRecursive) {                                                                        \
            PyErr_Clear();                                                                         \
            _Flags.set(FlagAllowRecursive_##_name, false);                                         \
        }                                                                                          \
        else {                                                                                     \
            _Flags.set(FlagAllowRecursive_##_name, PyObject_IsTrue(pyRecursive));                  \
            Py_DECREF(pyRecursive);                                                                \
        }                                                                                          \
    }

#define FC_PY_ELEMENT_FLAG(_name) FlagCalling_##_name, FlagAllowRecursive_##_name,

#define _FC_PY_CALL_CHECK(_name, _ret)                                                             \
    if ((!_Flags.test(FlagAllowRecursive_##_name) && _Flags.test(FlagCalling_##_name))             \
        || py_##_name.isNone()) {                                                                  \
        _ret;                                                                                      \
    }                                                                                              \
    Base::BitsetLocker<Flags> guard(_Flags, FlagCalling_##_name);

#undef FC_PY_ELEMENT
#define FC_PY_ELEMENT(_name) FC_PY_ELEMENT_DEFINE(_name)

    FC_PY_FEATURE_PYTHON

#undef FC_PY_ELEMENT
#define FC_PY_ELEMENT(_name) FC_PY_ELEMENT_FLAG(_name)

    enum Flag
    {
        FC_PY_FEATURE_PYTHON FlagMax,
    };

    using Flags = std::bitset<FlagMax>;
    mutable Flags _Flags;

public:
    void init(PyObject* pyobj);
};

/**
 * Generic Python feature class which allows one to behave every DocumentObject
 * derived class as Python feature -- simply by subclassing.
 * @author Werner Mayer
 */
template<class FeatureT>
class FeaturePythonT: public FeatureT
{
    PROPERTY_HEADER_WITH_OVERRIDE(App::FeaturePythonT<FeatureT>);

public:
    FeaturePythonT()
    {
        ADD_PROPERTY(Proxy, (Py::Object()));
        // cannot move this to the initializer list to avoid warning
        imp = new FeaturePythonImp(this);
    }
    ~FeaturePythonT() override
    {
        delete imp;
    }

    /** @name methods override DocumentObject */
    //@{
    short mustExecute() const override
    {
        if (this->isTouched()) {
            return 1;
        }
        auto ret = FeatureT::mustExecute();
        if (ret) {
            return ret;
        }
        return imp->mustExecute() ? 1 : 0;
    }
    /// recalculate the Feature
    DocumentObjectExecReturn* execute() override
    {
        try {
            bool handled = imp->execute();
            if (!handled) {
                return FeatureT::execute();
            }
        }
        catch (const Base::Exception& e) {
            return new App::DocumentObjectExecReturn(e.what());
        }
        return DocumentObject::StdReturn;
    }
    const char* getViewProviderNameOverride() const override
    {
        viewProviderName = imp->getViewProviderName();
        if (!viewProviderName.empty()) {
            return viewProviderName.c_str();
        }
        return FeatureT::getViewProviderNameOverride();
    }
    /// returns the type name of the ViewProvider
    const char* getViewProviderName() const override
    {
        return FeatureT::getViewProviderName();
    }

    App::DocumentObject* getSubObject(const char* subname,
                                      PyObject** pyObj,
                                      Base::Matrix4D* mat,
                                      bool transform,
                                      int depth) const override
    {
        App::DocumentObject* ret = nullptr;
        if (imp->getSubObject(ret, subname, pyObj, mat, transform, depth)) {
            return ret;
        }
        return FeatureT::getSubObject(subname, pyObj, mat, transform, depth);
    }

    std::vector<std::string> getSubObjects(int reason = 0) const override
    {
        std::vector<std::string> ret;
        if (imp->getSubObjects(ret, reason)) {
            return ret;
        }
        return FeatureT::getSubObjects(reason);
    }

    App::DocumentObject*
    getLinkedObject(bool recurse, Base::Matrix4D* mat, bool transform, int depth) const override
    {
        App::DocumentObject* ret = nullptr;
        if (imp->getLinkedObject(ret, recurse, mat, transform, depth)) {
            return ret;
        }
        return FeatureT::getLinkedObject(recurse, mat, transform, depth);
    }

    /// return true to activate tree view group object handling
    bool hasChildElement() const override
    {
        switch (imp->hasChildElement()) {
            case FeaturePythonImp::Accepted:
                return true;
            case FeaturePythonImp::Rejected:
                return false;
            default:
                return FeatureT::hasChildElement();
        }
    }
    /// Get sub-element visibility
    int isElementVisible(const char* element) const override
    {
        int ret = imp->isElementVisible(element);
        if (ret == -2) {
            return FeatureT::isElementVisible(element);
        }
        return ret;
    }
    /// Set sub-element visibility
    int setElementVisible(const char* element, bool visible) override
    {
        int ret = imp->setElementVisible(element, visible);
        if (ret == -2) {
            return FeatureT::setElementVisible(element, visible);
        }
        return ret;
    }

    bool canLinkProperties() const override
    {
        switch (imp->canLinkProperties()) {
            case FeaturePythonImp::Accepted:
                return true;
            case FeaturePythonImp::Rejected:
                return false;
            default:
                return FeatureT::canLinkProperties();
        }
    }

    bool allowDuplicateLabel() const override
    {
        switch (imp->allowDuplicateLabel()) {
            case FeaturePythonImp::Accepted:
                return true;
            case FeaturePythonImp::Rejected:
                return false;
            default:
                return FeatureT::allowDuplicateLabel();
        }
    }

    bool redirectSubName(std::ostringstream& ss,
                         App::DocumentObject* topParent,
                         App::DocumentObject* child) const override
    {
        switch (imp->redirectSubName(ss, topParent, child)) {
            case FeaturePythonImp::Accepted:
                return true;
            case FeaturePythonImp::Rejected:
                return false;
            default:
                return FeatureT::redirectSubName(ss, topParent, child);
        }
    }

    int canLoadPartial() const override
    {
        int ret = imp->canLoadPartial();
        if (ret >= 0) {
            return ret;
        }
        return FeatureT::canLoadPartial();
    }

    /**
     * @brief Called when a property is edited by the user.
     *
     * This override first attempts to handle the property edit in the
     * associated Python object.
     *
     * @param[in] propName The name of the property to be edited.
     */
    void editProperty(const char* propName) override
    {
        if (!imp->editProperty(propName)) {
            FeatureT::editProperty(propName);
        }
    }

    bool isLink() const override
    {
        switch (imp->isLink()) {
            case FeaturePythonImp::Accepted:
                return true;
            case FeaturePythonImp::Rejected:
                return false;
            default:
                return FeatureT::isLink();
        }
    }

    bool isLinkGroup() const override
    {
        switch (imp->isLinkGroup()) {
            case FeaturePythonImp::Accepted:
                return true;
            case FeaturePythonImp::Rejected:
                return false;
            default:
                return FeatureT::isLinkGroup();
        }
    }

    Base::Placement getPlacementOf(const std::string& sub, DocumentObject* targetObj = nullptr) override
    {
        Base::Placement ret;
        // Try to call the python implementation first
        if (imp->getPlacementOf(ret, sub.c_str(), targetObj)) {
            return ret;
        }
        // Fallback to C++ implementation
        return FeatureT::getPlacementOf(sub, targetObj);
    }

    PyObject* getPyObject() override
    {
        if (FeatureT::PythonObject.is(Py::_None())) {
            // ref counter is set to 1
            FeatureT::PythonObject = Py::Object(imp->getPyObject(), true);
        }
        return Py::new_reference_to(FeatureT::PythonObject);
    }
    void setPyObject(PyObject* obj) override
    {
        if (obj) {
            FeatureT::PythonObject = obj;
        }
        else {
            FeatureT::PythonObject = Py::None();
        }
    }

protected:
    void onBeforeChange(const Property* prop) override
    {
        FeatureT::onBeforeChange(prop);
        imp->onBeforeChange(prop);
    }
    void onBeforeChangeLabel(std::string& newLabel) override
    {
        if (!imp->onBeforeChangeLabel(newLabel)) {
            FeatureT::onBeforeChangeLabel(newLabel);
        }
    }
    void onChanged(const Property* prop) override
    {
        if (prop == &Proxy) {
            imp->init(Proxy.getValue().ptr());
        }
        imp->onChanged(prop);
        FeatureT::onChanged(prop);
    }
    void onDocumentRestored() override
    {
        imp->onDocumentRestored();
        FeatureT::onDocumentRestored();
    }
    void unsetupObject() override
    {
        imp->unsetupObject();
        FeatureT::unsetupObject();
    }

public:
    FeaturePythonT(const FeaturePythonT&) = delete;
    FeaturePythonT(FeaturePythonT&&) = delete;
    FeaturePythonT& operator=(const FeaturePythonT&) = delete;
    FeaturePythonT& operator=(FeaturePythonT&&) = delete;

private:
    FeaturePythonImp* imp;
    PropertyPythonObject Proxy;
    mutable std::string viewProviderName;
};

// Special Feature-Python classes
using FeaturePython = FeaturePythonT<DocumentObject>;
using GeometryPython = FeaturePythonT<GeoFeature>;

}  // namespace App

#endif  // APP_FEATUREPYTHON_H