Cross platform file system browser using Dear ImGui and std::filesystem

filebrowser.cpp

template<typename T> struct complete
{
    bool good = true, done = false;
    T value;
    complete() {}
    complete(const T& t, bool g = true, bool d = false) : value(t), good(g), done(d) {}
    complete(T&& t, bool g = true, bool d = false) : value(t), good(g), done(d) {}
};
void windowOpenPath(complete<fs::path>& dir, bool file = true)
{
    if (ImGui::Begin("Open File", &dir.good))
    {
        bool hasParent = dir.value.has_parent_path();
        bool isDir = fs::is_directory(dir.value);
        fs::path p = (isDir ? dir.value : (hasParent ? dir.value.parent_path() : fs::current_path()));
        const float footer = ImGui::GetStyle().ItemSpacing.y + (ImGui::GetFrameHeightWithSpacing() * 2);
        ImGui::BeginChild("Viewer", ImVec2(0, -footer));
        if ((hasParent && isDir) || (hasParent && dir.value.parent_path().has_parent_path()))
        {
            if (ImGui::Button("<- Back"))
                dir.value = isDir ? dir.value.parent_path() : dir.value.parent_path().parent_path();
            ImGui::Separator();
        }
        for(auto& d : fs::directory_iterator(p))
        {
            bool selected = dir.value == d.path();
            if (ImGui::Selectable(d.path().filename().u8string().c_str(), &selected))
                dir.value = d.path();
        }
        ImGui::EndChild();
        ImGui::Separator();
        ImGui::Text(dir.value.u8string().c_str());
        if (file ? fs::is_regular_file(dir.value) : fs::is_directory(dir.value))
        {
            dir.done |= ImGui::Button("Open");
            ImGui::SameLine();
        }
        else if (!file && hasParent) 
        {
            if (ImGui::Button("Open"))
            {
                dir.value = dir.value.parent_path();
                dir.done = true;
            }
            ImGui::SameLine();
        }
        dir.good ^= ImGui::Button("Cancel");
    }
    ImGui::End();
}