// *****************************************************************************
// * This file is part of the FreeFileSync project. It is distributed under    *
// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
// *****************************************************************************

#include "image_resources.h"
#include <memory>
#include <map>
#include <zen/utf.h>
#include <zen/globals.h>
#include <zen/thread.h>
#include <wx/wfstream.h>
#include <wx/zipstrm.h>
#include <wx/image.h>
#include <wx/mstream.h>
#include "image_tools.h"

using namespace zen;


namespace
{
#ifndef NDEBUG
    const std::thread::id mainThreadId = std::this_thread::get_id();
#endif

void loadAnimFromZip(wxZipInputStream& zipInput, wxAnimation& anim)
{
    //work around wxWidgets bug:
    //construct seekable input stream (zip-input stream is not seekable) for wxAnimation::Load()
    //luckily this method call is very fast: below measurement precision!
    std::vector<char> data;
    data.reserve(10000);

    int newValue = 0;
    while ((newValue = zipInput.GetC()) != wxEOF)
        data.push_back(newValue);

    wxMemoryInputStream seekAbleStream(&data.front(), data.size()); //stream does not take ownership of data

    anim.Load(seekAbleStream, wxANIMATION_TYPE_GIF);
}


class GlobalBitmaps
{
public:
    static std::shared_ptr<GlobalBitmaps> instance()
    {
        static Global<GlobalBitmaps> inst(std::make_unique<GlobalBitmaps>());
        assert(std::this_thread::get_id() == mainThreadId); //wxWidgets is not thread-safe!
        return inst.get();
    }

    GlobalBitmaps() {}
    ~GlobalBitmaps() { assert(bitmaps.empty() && anims.empty()); } //don't leave wxWidgets objects for static destruction!

    void init(const Zstring& filepath);
    void cleanup()
    {
        bitmaps.clear();
        anims.clear();
    }

    const wxBitmap&    getImage    (const wxString& name) const;
    const wxAnimation& getAnimation(const wxString& name) const;

private:
    GlobalBitmaps           (const GlobalBitmaps&) = delete;
    GlobalBitmaps& operator=(const GlobalBitmaps&) = delete;

    std::map<wxString, wxBitmap> bitmaps;
    std::map<wxString, wxAnimation> anims;
};


void GlobalBitmaps::init(const Zstring& filepath)
{
    assert(bitmaps.empty() && anims.empty());

    wxFFileInputStream input(utfCvrtTo<wxString>(filepath));
    if (input.IsOk()) //if not... we don't want to react too harsh here
    {
        //activate support for .png files
        wxImage::AddHandler(new wxPNGHandler); //ownership passed

        wxZipInputStream streamIn(input, wxConvUTF8);
        //do NOT rely on wxConvLocal! On failure shows unhelpful popup "Cannot convert from the charset 'Unknown encoding (-1)'!"

        for (;;)
        {
            std::unique_ptr<wxZipEntry> entry(streamIn.GetNextEntry()); //take ownership!
            if (!entry)
                break;

            const wxString name = entry->GetName();

            //generic image loading
            if (endsWith(name, L".png"))
            {
                wxImage img(streamIn, wxBITMAP_TYPE_PNG);

                //end this alpha/no-alpha/mask/wxDC::DrawBitmap/RTL/high-contrast-scheme interoperability nightmare here and now!!!!
                //=> there's only one type of png image: with alpha channel, no mask!!!
                convertToVanillaImage(img);

                bitmaps.emplace(name, img);
            }
            else if (endsWith(name, L".gif"))
                loadAnimFromZip(streamIn, anims[name]);
        }
    }
}


const wxBitmap& GlobalBitmaps::getImage(const wxString& name) const
{
    auto it = bitmaps.find(contains(name, L'.') ? name : name + L".png"); //assume .png ending if nothing else specified
    if (it != bitmaps.end())
        return it->second;
    assert(false);
    return wxNullBitmap;
}


const wxAnimation& GlobalBitmaps::getAnimation(const wxString& name) const
{
    auto it = anims.find(contains(name, L'.') ? name : name + L".gif");
    if (it != anims.end())
        return it->second;
    assert(false);
    return wxNullAnimation;
}
}


void zen::initResourceImages(const Zstring& filepath)
{
    if (std::shared_ptr<GlobalBitmaps> inst = GlobalBitmaps::instance())
        inst->init(filepath);
    else
        assert(false);
}


void zen::cleanupResourceImages()
{
    if (std::shared_ptr<GlobalBitmaps> inst = GlobalBitmaps::instance())
        inst->cleanup();
    else
        assert(false);
}


const wxBitmap& zen::getResourceImage(const wxString& name)
{
    if (std::shared_ptr<GlobalBitmaps> inst = GlobalBitmaps::instance())
        return inst->getImage(name);
    assert(false);
    return wxNullBitmap;
}


const wxAnimation& zen::getResourceAnimation(const wxString& name)
{
    if (std::shared_ptr<GlobalBitmaps> inst = GlobalBitmaps::instance())
        return inst->getAnimation(name);
    assert(false);
    return wxNullAnimation;
}