#include <psemek/ui/impl/extend_base.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> shape, float left, float right, float top, float bottom)
		{
			shape[0].min -= left;
			shape[0].max += right;
			shape[1].min -= top;
			shape[1].max += bottom;
			return shape;
		}

	}

	extend_base::extend_base()
		: left_(0.f)
		, right_(0.f)
		, top_(0.f)
		, bottom_(0.f)
		, child_size_constraints_(size_constraints::max())
		, size_constraints_(react::join(child_size_constraints_))
	{}

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

		if (auto child = this->child())
			child->reshape(compute_child_shape(new_shape, **left_, **right_, **top_, **bottom_));
	}

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

	void extend_base::set_child(std::unique_ptr<component> child)
	{
		if (child)
			child_size_constraints_.set(child->size_constraints());
		else
			child_size_constraints_.set(size_constraints::max());
		single_container::set_child(std::move(child));
	}

	std::unique_ptr<component> extend_base::release_child()
	{
		child_size_constraints_.set(size_constraints::max());
		return single_container::release_child();
	}

	void extend_base::update(extend const & value)
	{
		left_.set(value.left);
		right_.set(value.right);
		top_.set(value.top);
		bottom_.set(value.bottom);
	}

}