#ifndef MEMGRAPH_THREADING_SYNC_TIMED_SPINLOCK_HPP
#define MEMGRAPH_THREADING_SYNC_TIMED_SPINLOCK_HPP

#include <atomic>
#include <chrono>
#include <stdexcept>

#include <unistd.h>

class LockExpiredError : public std::runtime_error
{
    using runtime_error::runtime_error;
};

class TimedSpinLock
{
public:
    TimedSpinLock(std::chrono::seconds expiration)
        : expiration(expiration) {}

    TimedSpinLock(std::chrono::milliseconds expiration)
        : expiration(expiration) {}

    void lock()
    {
        using clock = std::chrono::high_resolution_clock;

        auto start = clock::now();

        while(lock_flag.test_and_set(std::memory_order_acquire))
        {
            // how long have we been locked? if we exceeded the expiration
            // time, throw an exception and stop being blocked because this
            // might be a deadlock!

            if(clock::now() - start > expiration)
                throw LockExpiredError("This lock has expired");

            usleep(250);
        }
    }

    void unlock()
    {
        lock_flag.clear(std::memory_order_release);
    }

private:
    std::chrono::milliseconds expiration;

    // guaranteed by standard to be lock free!
    std::atomic_flag lock_flag = ATOMIC_FLAG_INIT;
};

#endif