#include <psemek/ui/impl/controller.hpp>

namespace psemek::ui::impl
{

	struct controller::impl
	{
		component_factory & factory;

		geom::vector<int, 2> screen_size = {0, 0};

		util::signal<>::subscription_token root_token;
		util::signal<>::subscription_token root_reshape_token;
		std::unique_ptr<ui::impl::component> root;

		impl(component_factory & factory)
			: factory(factory)
		{}

		void set_ui(react::value<std::any> ui)
		{
			root_token = ui.subscribe([this](std::any const & value)
			{
				root = factory.reconciliate(std::move(root), value);
				subscribe_reshape();
			}, true);

			on_event(resize_event{screen_size});
		}

		void subscribe_reshape()
		{
			root_reshape_token = nullptr;

			if (root)
				root_reshape_token = root->size_constraints().subscribe([this](psemek::ui::impl::size_constraints const &)
				{
					do_reshape();
				});
		}

		void do_reshape()
		{
			if (root)
				root->reshape({{{0.f, screen_size[0]}, {0.f, screen_size[1]}}});
		}

		template <typename Event>
		bool on_event(Event const & event)
		{
			return on_event_impl(event, root.get());
		}

		bool on_event(resize_event const & event)
		{
			screen_size = event.size;
			bool result = on_event_impl(event, root.get());
			do_reshape();
			return result;
		}

		template <typename Event>
		bool on_event_impl(Event const & event, component * element)
		{
			if (!element)
				return false;

			for (auto const & child : element->children())
				if (on_event_impl(event, child.get()))
					return true;

			return element->on_event(event);
		}

		void draw(renderer & renderer)
		{
			draw_impl(renderer, root.get());
		}

		void draw_impl(renderer & renderer, component * element)
		{
			if (!element)
				return;

			element->draw(renderer);

			for (auto const & child : element->children())
				draw_impl(renderer, child.get());

			element->post_draw(renderer);
		}
	};

	controller::controller(component_factory & factory)
		: pimpl_(make_impl(factory))
	{}

	controller::~controller() = default;

	void controller::set_ui(react::value<std::any> ui)
	{
		impl().set_ui(std::move(ui));
	}

	component * controller::root()
	{
		return impl().root.get();
	}

	bool controller::on_event(resize_event const & event)
	{
		return impl().on_event(event);
	}

	bool controller::on_event(mouse_move_event const & event)
	{
		return impl().on_event(event);
	}

	bool controller::on_event(mouse_wheel_event const & event)
	{
		return impl().on_event(event);
	}

	bool controller::on_event(mouse_button_event const & event)
	{
		return impl().on_event(event);
	}

	bool controller::on_event(key_event const & event)
	{
		return impl().on_event(event);
	}

	void controller::draw(renderer & renderer)
	{
		impl().draw(renderer);
	}

}