#ifndef RTSCHEDULER_HH
#define RTSCHEDULER_HH

#include "SchedulerQueue.hh"
#include "Timer.hh"

#include <cstdint>
#include <optional>

namespace openmsx {

class RTSchedulable;

struct RTSyncPoint
{
	uint64_t time;
	RTSchedulable* schedulable;
};

class RTScheduler
{
public:
	/** Execute all expired RTSchedulables. */
	void execute() {
		if (!queue.empty()) {
			auto limit = Timer::getTime();
			if (limit >= queue.front().time) [[unlikely]] {
				scheduleHelper(limit); // slow path not inlined
			}
		}
	}

	/** Get the next scheduled time point (absolute, in microseconds).
	  * @return The earliest scheduled time, or nullopt if queue is empty.
	  */
	[[nodiscard]] std::optional<uint64_t> getNextTime() const {
		return queue.empty() ? std::nullopt
		                     : std::optional(queue.front().time);
	}

private:
	// These are called by RTSchedulable
	friend class RTSchedulable;
	void add(uint64_t delta, RTSchedulable& schedulable);
	bool remove(RTSchedulable& schedulable);
	[[nodiscard]] bool isPending(const RTSchedulable& schedulable) const;

	void scheduleHelper(uint64_t limit);

private:
	SchedulerQueue<RTSyncPoint> queue;
};

} // namespace openmsx

#endif