#include <psemek/ui/screen.hpp>

namespace psemek::ui
{

	screen::screen()
		: container_(this)
	{}

	element::children_range screen::children() const
	{
		return container_.children();
	}

	bool screen::add_child(std::shared_ptr<element> c, x_policy x, y_policy y)
	{
		auto i = container_.add(std::move(c));
		if (i >= policies_.size())
			policies_.resize(i + 1);
		policies_[i] = {x, y};
		return true;
	}

	bool screen::add_child(std::shared_ptr<element> c)
	{
		return add_child(std::move(c), x_policy::floating, y_policy::floating);
	}

	bool screen::has_child(element *c) const
	{
		return static_cast<bool>(container_.find(c));
	}

	std::shared_ptr<element> screen::remove_child(element * c)
	{
		return container_.remove(c);
	}

	void screen::reshape(geom::box<float, 2> const & bbox)
	{
		shape_.box = bbox;
		auto cs = children();
		for (std::size_t i = 0; i < cs.size(); ++i)
		{
			auto c = cs[i];
			if (!c) continue;
			auto sc = c->size_constraints();
			auto size = bbox.dimensions();
			size[0] = std::min(size[0], sc[0].min);
			size[1] = std::min(size[1], sc[1].min);

			auto m = bbox.center();

			geom::box<float, 2> cbox = c->shape().bbox();

			switch (policies_[i].x)
			{
			case x_policy::left:
				cbox[0] = {bbox[0].min, bbox[0].min + size[0]};
				break;
			case x_policy::center:
				cbox[0] = {m[0] - size[0] / 2.f, m[0] + size[0] / 2.f};
				break;
			case x_policy::right:
				cbox[0] = {bbox[0].max - size[0], bbox[0].max};
				break;
			case x_policy::fill:
				cbox[0] = bbox[0];
				break;
			case x_policy::floating:
				cbox[0] = geom::expand(cbox[0], (size[0] - cbox[0].length()) / 2.f);

				if (cbox[0].min < bbox[0].min)
					cbox[0] += (bbox[0].min - cbox[0].min);
				else if (cbox[0].max > bbox[0].max)
					cbox[0] -= (cbox[0].max - bbox[0].max);
				break;
			}

			switch (policies_[i].y)
			{
			case y_policy::top:
				cbox[1] = {bbox[1].min, bbox[1].min + size[1]};
				break;
			case y_policy::center:
				cbox[1] = {m[1] - size[1] / 2.f, m[1] + size[1] / 2.f};
				break;
			case y_policy::bottom:
				cbox[1] = {bbox[1].max - size[1], bbox[1].max};
				break;
			case y_policy::fill:
				cbox[1] = bbox[1];
				break;
			case y_policy::floating:
				cbox[1] = geom::expand(cbox[1], (size[1] - cbox[1].length()) / 2.f);

				if (cbox[1].min < bbox[1].min)
					cbox[1] += (bbox[1].min - cbox[1].min);
				else if (cbox[1].max > bbox[1].max)
					cbox[1] -= (cbox[1].max - bbox[1].max);
				break;
			}

			c->reshape(cbox);
		}
	}

	geom::box<float, 2> screen::size_constraints() const
	{
		geom::box<float, 2> result = element::size_constraints();
		for (auto c : children())
			if (c) result &= c->size_constraints();
		return result;
	}

}