#include "pixmap.hpp"

#include <windows.h>

namespace t5de {

namespace {

using Getter = unsigned(__thiscall*)(const imvu::Pixmap*);
using PixelsGetter = std::uint32_t*(__thiscall*)(const imvu::Pixmap*);
using SizeConstructor = imvu::Pixmap*(__thiscall*)(void*, int, int);
using DefaultConstructor = imvu::Pixmap*(__thiscall*)(void*);
using CopyConstructor = imvu::Pixmap*(__thiscall*)(void*, const imvu::Pixmap*);
using Destructor = void(__thiscall*)(imvu::Pixmap*);

struct Methods {
    Getter width = nullptr;
    Getter height = nullptr;
    Getter rowBytes = nullptr;
    PixelsGetter pixels = nullptr;
    SizeConstructor construct = nullptr;
    DefaultConstructor constructEmpty = nullptr;
    CopyConstructor copy = nullptr;
    Destructor destroy = nullptr;
};

const Methods& methods()
{
    static const Methods methods = [] {
        Methods found;
        if (HMODULE module = GetModuleHandleW(L"pixmap.dll")) {
            found.width = reinterpret_cast<Getter>(GetProcAddress(module, "?width@Pixmap@@QBEIXZ"));
            found.height = reinterpret_cast<Getter>(GetProcAddress(module, "?height@Pixmap@@QBEIXZ"));
            found.rowBytes = reinterpret_cast<Getter>(GetProcAddress(module, "?rowBytes@Pixmap@@QBEIXZ"));
            found.pixels = reinterpret_cast<PixelsGetter>(GetProcAddress(module, "?pixels@Pixmap@@QBEPAIXZ"));
            found.construct = reinterpret_cast<SizeConstructor>(GetProcAddress(module, "??0Pixmap@@QAE@HH@Z"));
            found.constructEmpty = reinterpret_cast<DefaultConstructor>(GetProcAddress(module, "??0Pixmap@@QAE@XZ"));
            found.copy = reinterpret_cast<CopyConstructor>(GetProcAddress(module, "??0Pixmap@@QAE@ABV0@@Z"));
            found.destroy = reinterpret_cast<Destructor>(GetProcAddress(module, "??1Pixmap@@QAE@XZ"));
        }
        return found;
    }();
    return methods;
}

} // namespace

std::optional<PixmapPixels> pixmap_pixels(const imvu::Pixmap& pixmap)
{
    const Methods& m = methods();
    if (m.width == nullptr || m.height == nullptr || m.rowBytes == nullptr || m.pixels == nullptr) {
        return std::nullopt;
    }
    return PixmapPixels{m.width(&pixmap), m.height(&pixmap), m.rowBytes(&pixmap), m.pixels(&pixmap)};
}

OwnedPixmap::OwnedPixmap(int width, int height)
{
    const Methods& m = methods();
    if (m.construct != nullptr && m.constructEmpty != nullptr && m.copy != nullptr && m.destroy != nullptr) {
        m.construct(storage_, width, height);
        valid_ = true;
    }
}

OwnedPixmap::~OwnedPixmap()
{
    if (valid_) {
        methods().destroy(reinterpret_cast<imvu::Pixmap*>(storage_));
    }
}

imvu::Pixmap* OwnedPixmap::copyTo(imvu::Pixmap* result) const
{
    const Methods& m = methods();
    if (valid_) {
        return m.copy(result, &get());
    }
    // Without pixmap.dll's methods there's nothing to construct one with (IMVU's own code would have failed already).
    return m.constructEmpty != nullptr ? m.constructEmpty(result) : result;
}

} // namespace t5de