#include <psemek/ui/impl/floating_base.hpp>
#include <psemek/ui/alignment.hpp>
#include <psemek/react/join.hpp>
#include <psemek/react/map.hpp>

namespace psemek::ui::impl
{

	namespace
	{

		geom::box<float, 2> compute_child_shape(geom::box<float, 2> const & size_constraints, geom::point<float, 2> const & anchor, halignment halign, valignment valign)
		{
			geom::vector size{size_constraints[0].min, size_constraints[1].min};

			geom::box<float, 2> result;
			result[0] = geom::interval{- size[0], 0.f} + (1.f - lerp_factor(halign)) * size[0] + anchor[0];
			result[1] = geom::interval{- size[1], 0.f} + (1.f - lerp_factor(valign)) * size[1] + anchor[1];

			return result;
		}

	}

	floating_base::floating_base()
		: size_constraints_(impl::size_constraints::max())
	{}

	void floating_base::reshape(geom::box<float, 2> const & new_shape)
	{
		single_container::reshape(new_shape);

		if (auto child = this->child())
			child->reshape(compute_child_shape((*(child->size_constraints())).box, *anchor_, *halign_, *valign_));
	}

	react::value<struct size_constraints> floating_base::size_constraints() const
	{
		return size_constraints_;
	}

	void floating_base::update(floating const & value)
	{
		anchor_ = value.anchor;
		halign_ = value.halign;
		valign_ = value.valign;
	}

}