/**
 * @file lluictrlfactory.h
 * @brief Factory class for creating UI controls
 *
 * $LicenseInfo:firstyear=2003&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LLUICTRLFACTORY_H
#define LLUICTRLFACTORY_H

#include "llfasttimer.h"
#include "llinitparam.h"
#include "llregistry.h"
#include "llxuiparser.h"
#include "llstl.h"
#include "lldir.h"
#include "llsingleton.h"
#include "llheteromap.h"

class LLView;
void deleteView(LLView*); // Inside LLView.cpp, avoid having to potentially delete an incomplete type here.

// lookup widget constructor funcs by widget name
template <typename DERIVED_TYPE>
class LLChildRegistry : public LLRegistrySingleton<std::string, LLWidgetCreatorFunc, DERIVED_TYPE>
{
public:
    typedef LLRegistrySingleton<std::string, LLWidgetCreatorFunc, DERIVED_TYPE> super_t;
    // local static instance for registering a particular widget
    template<typename T>
    class Register : public super_t::StaticRegistrar
    {
    public:
        // register with either the provided builder, or the generic templated builder
        Register(const char* tag, LLWidgetCreatorFunc func = NULL);
    };

protected:
    LLChildRegistry() {}
};

class LLDefaultChildRegistry : public LLChildRegistry<LLDefaultChildRegistry>
{
    LLSINGLETON_EMPTY_CTOR(LLDefaultChildRegistry);
};

// lookup widget name by type
class LLWidgetNameRegistry
:   public LLRegistrySingleton<const std::type_info*, std::string, LLWidgetNameRegistry>
{
    LLSINGLETON_EMPTY_CTOR(LLWidgetNameRegistry);
};

// lookup function for generating empty param block by widget type
// this is used for schema generation
//typedef const LLInitParam::BaseBlock& (*empty_param_block_func_t)();
//class LLDefaultParamBlockRegistry
//: public LLRegistrySingleton<const std::type_info*, empty_param_block_func_t, LLDefaultParamBlockRegistry>
//{
//  LLSINGLETON(LLDefaultParamBlockRegistry);
//};

// Build time optimization, generate this once in .cpp file
#ifndef LLUICTRLFACTORY_CPP
extern template class LLUICtrlFactory* LLSingleton<class LLUICtrlFactory>::getInstance();
#endif

class LLUICtrlFactory : public LLSingleton<LLUICtrlFactory>
{
    LLSINGLETON(LLUICtrlFactory);
    ~LLUICtrlFactory();

    // only partial specialization allowed in inner classes, so use extra dummy parameter
    template <typename PARAM_BLOCK, int DUMMY>
    class ParamDefaults
    {
    public:
        ParamDefaults();
        const PARAM_BLOCK& get() { return mPrototype; }

    private:
        PARAM_BLOCK mPrototype;
    };

    // base case for recursion, there are NO base classes of LLInitParam::BaseBlock
    template<int DUMMY>
    class ParamDefaults<LLInitParam::BaseBlock, DUMMY>
    {
    public:
        ParamDefaults();
        const LLInitParam::BaseBlock& get() { return mBaseBlock; }
    private:
        LLInitParam::BaseBlock mBaseBlock;
    };

public:

    // get default parameter block for widget of a specific type
    template<typename T>
    static const typename T::Params& getDefaultParams()
    {
        return instance().mParamDefaultsMap.obtain< ParamDefaults<typename T::Params, 0> >().get();
    }

    // Does what you want for LLFloaters and LLPanels
    // Returns 0 on success
    S32 saveToXML(LLView* viewp, const std::string& filename);

    // filename tracking for debugging info
    std::string getCurFileName();
    void pushFileName(const std::string& name);
    void popFileName();

    template<typename T>
    static T* create(typename T::Params& params, LLView* parent = NULL)
    {
        params.fillFrom(instance().mParamDefaultsMap.obtain<
                        ParamDefaults<typename T::Params, 0> >().get());

        T* widget = createWidgetImpl<T>(params, parent);
        if (widget)
        {
            widget->postBuild();
        }

        return widget;
    }

    LLView* createFromXML(LLXMLNodePtr node, LLView* parent, const std::string& filename, const widget_registry_t&, LLXMLNodePtr output_node );

    template<typename T>
    static T* createFromFile(const std::string &filename, LLView *parent, const widget_registry_t& registry)
    {
        T* widget = NULL;

        instance().pushFileName(filename);
        {
            LLXMLNodePtr root_node;

            if (!LLUICtrlFactory::getLayeredXMLNode(filename, root_node))
            {
                LL_WARNS() << "Couldn't parse XUI from path: " << instance().getCurFileName() << ", from filename: " << filename << LL_ENDL;
                goto fail;
            }

            LLView* view = getInstance()->createFromXML(root_node, parent, filename, registry, NULL);
            if (view)
            {
                widget = dynamic_cast<T*>(view);
                // not of right type, so delete it
                if (!widget)
                {
                    LL_WARNS() << "Widget in " << filename << " was of type " << typeid(view).name() << " instead of expected type " << typeid(T).name() << LL_ENDL;

                    deleteView(view);
                    view = NULL;
                }
            }
        }
fail:
        instance().popFileName();
        return widget;
    }

    template<class T>
    static T* getDefaultWidget(std::string_view name)
    {
        typename T::Params widget_params;
        widget_params.name = std::string(name);
        return create<T>(widget_params);
    }

    static void createChildren(LLView* viewp, LLXMLNodePtr node, const widget_registry_t&, LLXMLNodePtr output_node = NULL);

    static bool getLayeredXMLNode(const std::string &filename, LLXMLNodePtr& root,
                                  LLDir::ESkinConstraint constraint=LLDir::CURRENT_SKIN);

private:
    //NOTE: both friend declarations are necessary to keep both gcc and msvc happy
    template <typename T> friend class LLChildRegistry;
    template <typename T> template <typename U> friend class LLChildRegistry<T>::Register;

    static void copyName(LLXMLNodePtr src, LLXMLNodePtr dest);

    // helper function for adding widget type info to various registries
    static void registerWidget(const std::type_info* widget_type, const std::type_info* param_block_type, const std::string& tag);

    static void loadWidgetTemplate(const std::string& widget_tag, LLInitParam::BaseBlock& block);

    template<typename T>
    static T* createWidgetImpl(const typename T::Params& params, LLView* parent = NULL)
    {
        LL_PROFILE_ZONE_SCOPED_CATEGORY_UI;
        T* widget = NULL;

        if (!params.validateBlock())
        {
            LL_WARNS() << getInstance()->getCurFileName() << ": Invalid parameter block for " << typeid(T).name() << LL_ENDL;
            //return NULL;
        }

        widget = new T(params);

        widget->initFromParams(params);

        if (parent)
        {
            S32 tab_group = params.tab_group.isProvided() ? params.tab_group() : S32_MAX;
            setCtrlParent(widget, parent, tab_group);
        }
        return widget;
    }

    template<typename T>
    static T* defaultBuilder(LLXMLNodePtr node, LLView *parent, LLXMLNodePtr output_node)
    {
        LL_PROFILE_ZONE_SCOPED_CATEGORY_UI;

        typename T::Params params(getDefaultParams<T>());

        LLXUIParser parser;
        parser.readXUI(node, params, LLUICtrlFactory::getInstance()->getCurFileName());

        if (output_node)
        {
            // We always want to output top-left coordinates
            typename T::Params output_params(params);
            T::setupParamsForExport(output_params, parent);
            copyName(node, output_node);
            parser.writeXUI(output_node, output_params, LLInitParam::default_parse_rules(), &getDefaultParams<T>());
        }

        // Apply layout transformations, usually munging rect
        params.from_xui = true;
        T::applyXUILayout(params, parent);
        T* widget = createWidgetImpl<T>(params, parent);

        typedef typename T::child_registry_t registry_t;

        createChildren(widget, node, registry_t::instance(), output_node);

        if (widget && !widget->postBuild())
        {
            delete widget;
            widget = NULL;
        }

        return widget;
    }


    // this exists to get around dependency on llview
    static void setCtrlParent(LLView* view, LLView* parent, S32 tab_group);

    class LLPanel*      mDummyPanel;
    std::vector<std::string>    mFileNames;

    // store ParamDefaults specializations
    // Each ParamDefaults specialization used to be an LLSingleton in its own
    // right. But the 2016 changes to the LLSingleton mechanism, making
    // LLSingleton instances polymorphic, are incompatible with current
    // LLInitParam::BaseBlock functionality. (Thanks NickyD for spotting
    // that!) Moreover, instances of the private nested ParamDefaults template
    // aren't global resources -- which is what LLSingleton is designed for.
    // This is simply a cache looked up by type. Its lifespan is tied to
    // LLUICtrlFactory. Use LLHeteroMap for this cache.
    LLHeteroMap mParamDefaultsMap;
};

template <typename PARAM_BLOCK, int DUMMY>
LLUICtrlFactory::ParamDefaults<PARAM_BLOCK, DUMMY>::ParamDefaults()
{
    // look up template file for this param block...
    const std::string* param_block_tag = LLWidgetNameRegistry::instance().getValue(&typeid(PARAM_BLOCK));
    if (param_block_tag)
    {   // ...and if it exists, back fill values using the most specific template first
        PARAM_BLOCK params;
        LLUICtrlFactory::loadWidgetTemplate(*param_block_tag, params);
        mPrototype.fillFrom(params);
    }
    // recursively fill from base class param block
    ((typename PARAM_BLOCK::base_block_t&)mPrototype).fillFrom(
        LLUICtrlFactory::instance().mParamDefaultsMap.obtain<
        ParamDefaults<typename PARAM_BLOCK::base_block_t, DUMMY> >().get());

}

template <int DUMMY>
LLUICtrlFactory::ParamDefaults<LLInitParam::BaseBlock, DUMMY>::ParamDefaults() {}

// this is here to make gcc happy with reference to LLUICtrlFactory
template<typename DERIVED>
template<typename T>
LLChildRegistry<DERIVED>::Register<T>::Register(const char* tag, LLWidgetCreatorFunc func)
:   LLChildRegistry<DERIVED>::StaticRegistrar(tag, func.empty() ? (LLWidgetCreatorFunc)&LLUICtrlFactory::defaultBuilder<T> : func)
{
    // add this widget to various registries
    LLUICtrlFactory::instance().registerWidget(&typeid(T), &typeid(typename T::Params), tag);

    // since registry_t depends on T, do this in line here
    // TODO: uncomment this for schema generation
    //typedef typename T::child_registry_t registry_t;
    //LLChildRegistryRegistry::instance().defaultRegistrar().add(&typeid(T), registry_t::instance());
}

#endif //LLUICTRLFACTORY_H