bwidgets/inc/basic_widgets/w/aligned_layout.hpp

#ifndef BWIDGETS_ALIGNED_LAYOUT_HPP
#define BWIDGETS_ALIGNED_LAYOUT_HPP

#include <basic_widgets/core/math.hpp>
#include <basic_widgets/w/base/layout.hpp>

namespace bwidgets
{
    enum struct LayoutAlignment
    {
        HORIZONTAL,
        VERTICAL
    };

    template<LayoutAlignment alignment>
    class AlignedLayout final : public Layout
    {
    private:
        void _update_layout(const SDL_Rect& vp) override
        {
            if constexpr (alignment == LayoutAlignment::HORIZONTAL) {
                int widget_width =
                  (vp.w - ((int)_widgets.size() + 1) * margins.w) / (int)_widgets.size();

                for (std::vector<Widget*>::size_type i = 0; i < _widgets.size(); i++) {
                    const auto& w {_widgets[i]};
                    w->viewport({vp.x + margins.w + (int)i * (widget_width + margins.w),
                                 vp.y + center_line(vp.h, w->size().h), widget_width,
                                 w->size().h});
                }
            }
            else {
                int offset = 0;
                for (std::vector<Widget*>::size_type i = 0; i < _widgets.size(); i++) {
                    const auto& w {_widgets[i]};
                    w->viewport({
                      vp.x,
                      vp.y + ((int)i + 1) * margins.h + offset,
                      vp.w,
                      w->size().h,
                    });
                    offset += w->size().h;
                }
            }
        }

    public:
        AlignedLayout(Widget* p = nullptr) noexcept : Layout(p) {}

        AlignedLayout(const AlignedLayout&) = delete;
        AlignedLayout(AlignedLayout&&)      = delete;
        ~AlignedLayout() override           = default;
        auto operator=(const AlignedLayout&) = delete;
        auto operator=(AlignedLayout&&) = delete;

        [[nodiscard]] auto size() const noexcept -> Size override
        {
            Size min_size {0, 0};

            if constexpr (alignment == LayoutAlignment::HORIZONTAL) {
                for (const auto& w : _widgets) {
                    if (w->size().w > min_size.w) min_size.w = w->size().w;
                    if (w->size().h > min_size.h) min_size.h = w->size().h;
                }

                return {(int)_widgets.size() * min_size.w
                          + ((int)_widgets.size() + 1) * margins.w,
                        min_size.h + 2 * margins.h};
            }

            for (const auto& w : _widgets) {
                if (w->size().w > min_size.w) min_size.w = w->size().w;

                min_size.h += w->size().h;
            }

            return {min_size.w + 2 * margins.w,
                    min_size.h + ((int)_widgets.size() + 1) * margins.h};
        }
    };
}

#endif