#include <psemek/ui/impl/stack_layout_base.hpp>
#include <psemek/ui/impl/size_polygon_utils.hpp>
#include <psemek/react/join.hpp>
#include <psemek/react/map.hpp>

namespace psemek::ui::impl
{

	namespace
	{

		size_polygon compute_size_constraints(std::vector<size_polygon const *> const & children_size_constraints)
		{
			if (children_size_constraints.empty())
				return component::default_size_polygon();

			auto result = *children_size_constraints.front();
			for (std::size_t i = 1; i < children_size_constraints.size(); ++i)
				result = intersect(result, *children_size_constraints[i]);
			return result;
		}

	}

	stack_layout_base::stack_layout_base()
		: size_constraints_(react::map([](auto const & children_size_constraints){
			return compute_size_constraints(children_size_constraints);
		}, react::join(react::map(react::unpack_with_transform([](react::value<size_polygon> const & arg){ return &(*arg); }), children_size_constraints_))))
	{}

	void stack_layout_base::reshape(geom::box<float, 2> const & new_shape)
	{
		for (auto const & child : children())
			if (child)
				child->reshape(new_shape);
	}

	react::value<size_polygon> stack_layout_base::size_constraints() const
	{
		return size_constraints_;
	}

	void stack_layout_base::set_children(std::vector<std::unique_ptr<component>> children)
	{
		container::set_children(std::move(children));
		std::vector<react::value<size_polygon>> children_size_constraints;
		for (auto const & child : this->children())
		{
			if (child)
				children_size_constraints.push_back(child->size_constraints());
			else
				children_size_constraints.push_back(default_size_constraints());
		}
		children_size_constraints_.set(std::move(children_size_constraints));
	}

	std::vector<std::unique_ptr<component>> stack_layout_base::release_children()
	{
		auto result = container::release_children();
		children_size_constraints_.set({});
		return result;
	}


}