#include <psemek/ui/controller.hpp>

#include <psemek/ui/painter_impl.hpp>
#include <psemek/gfx/gl.hpp>
#include <psemek/util/recursive.hpp>
#include <psemek/geom/camera.hpp>

namespace psemek::ui
{

	struct controller::impl
	{
		async::executor * loop;
		painter_impl painter;
		std::shared_ptr<element> root;
		geom::box<float, 2> shape{{{0.f, 0.f}, {0.f, 0.f}}};

		impl(async::executor * loop);

		template <typename E>
		bool event(E const & e);
	};

	controller::impl::impl(async::executor * loop)
		: loop(loop)
	{}

	template <typename E>
	bool controller::impl::event(E const & e)
	{
		auto visitor = util::recursive([&](auto && self, element * elem) -> bool {
			for (auto c : elem->children())
				if (c && self(c)) return true;

			if (elem->enabled() && elem->on_event(e)) return true;
			return false;
		});

		if (root)
			return visitor(root.get());
		return false;
	}

	controller::controller(async::executor * loop)
		: pimpl_{make_impl(loop)}
	{}

	controller::~controller() = default;

	std::shared_ptr<element> controller::set_root(std::shared_ptr<element> r)
	{
		auto old = std::move(impl().root);
		impl().root = std::move(r);
		if (old) old->set_loop(nullptr);
		if (impl().root)
		{
			impl().root->set_loop(impl().loop);
			impl().root->reshape(impl().shape);
		}
		return old;
	}

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

	void controller::reshape(geom::box<float, 2> const & shape)
	{
		impl().shape = shape;
		if (impl().root)
			impl().root->reshape(impl().shape);
	}

	bool controller::event(mouse_move const & e)
	{
		return impl().event(e);
	}

	bool controller::event(mouse_click const & e)
	{
		return impl().event(e);
	}

	bool controller::event(mouse_wheel const & e)
	{
		return impl().event(e);
	}

	void controller::render(gfx::render_target const & rt)
	{
		rt.bind();

		gl::Enable(gl::DEPTH_TEST);
		gl::DepthFunc(gl::LEQUAL);

		gl::Enable(gl::BLEND);
		gl::BlendFunc(gl::SRC_ALPHA, gl::ONE_MINUS_SRC_ALPHA);

		auto visitor = util::recursive([&](auto && self, element * elem) -> void {
			elem->draw(impl().painter);
			for (auto c : elem->children())
				if (c) self(c);
		});

		if (impl().root)
			visitor(impl().root.get());

		impl().painter.render(geom::window_camera{rt.viewport[0].length(), rt.viewport[1].length()}.transform());
	}

}