/** Path restart hook.
 *
 * @author Steffen Vogel <post@steffenvogel.de>
 * @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
 * @license Apache 2.0
 *********************************************************************************/

#include <cinttypes>

#include <villas/hook.hpp>
#include <villas/node.hpp>
#include <villas/sample.hpp>

namespace villas {
namespace node {

class RestartHook : public Hook {

protected:
	struct Sample *prev;

public:
	using Hook::Hook;

	virtual void start()
	{
		assert(state == State::PREPARED);

		prev = nullptr;

		state = State::STARTED;
	}

	virtual void stop()
	{
		assert(state == State::STARTED);

		if (prev)
			sample_decref(prev);

		state = State::STOPPED;
	}

	virtual Hook::Reason process(struct Sample *smp)
	{
		assert(state == State::STARTED);

		if (prev) {
			/* A wrap around of the sequence no should not be treated as a simulation restart */
			if (smp->sequence == 0 && prev->sequence != 0 && prev->sequence < UINT64_MAX - 16) {
				logger->warn("Simulation from node {} restarted (previous->sequence={}, current->sequence={})",
					node->getName(), prev->sequence, smp->sequence);

				smp->flags |= (int) SampleFlags::IS_FIRST;

				/* Restart hooks */
				for (auto k : node->in.hooks)
					k->restart();

				for (auto k : node->out.hooks)
					k->restart();
			}
		}

		sample_incref(smp);
		if (prev)
			sample_decref(prev);

		prev = smp;

		return Reason::OK;
	}
};

/* Register hook */
static char n[] = "restart";
static char d[] = "Call restart hooks for current node";
static HookPlugin<RestartHook, n, d, (int) Hook::Flags::BUILTIN | (int) Hook::Flags::NODE_READ, 1> p;

} /* namespace node */
} /* namespace villas */