/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuSemaphore.Unix.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "AuSemaphore.Generic.hpp"
#include "AuSemaphore.Unix.hpp"

#if !defined(_AURUNTIME_GENERIC_SEMAPHORE) && !defined(AURORA_IS_XNU_DERIVED)
#include <Source/Time/Time.hpp>
        
namespace Aurora::Threading::Primitives
{
    Semaphore::Semaphore(long intialValue)
    {
        auto status = sem_init(&this->value_, 0, intialValue) == 0;
        SysAssert(status, "Semaphore init failed");
    }
    
    Semaphore::~Semaphore()
    {
        int status = sem_destroy(&this->value_);
        RUNTIME_ASSERT_SHUTDOWN_SAFE(status == 0, "Semaphore destroy failed: {} {}", status, errno);
    }

    bool Semaphore::HasOSHandle(AuMach &mach)
    {
        mach = reinterpret_cast<AuMach>(&this->value_);
        return true;
    }
    
    bool Semaphore::HasLockImplementation()
    {
        return true;
    }
    
    bool Semaphore::TryLock()
    {
        return sem_trywait(&this->value_) == 0;
    }
    
    bool Semaphore::Lock(AuUInt64 timeout)
    {
        if (timeout == 0)
        {
            int ret {};

            do
            {
                if ((ret = sem_wait(&this->value_)) == 0)
                {
                    return true;
                }

            } while (errno == EINTR);

            SysPanic("semaphore lock failed {}", errno);
            return true;
        }
        else
        {
            struct timespec tspec;
            Time::ms2tsabs(&tspec, timeout);
   
            int ret {};

            do
            {
                ret = sem_timedwait(&this->value_, &tspec);

                if (ret == 0)
                {
                    return true;
                }

                if (errno == ETIMEDOUT)
                {
                    return false;
                }

            } while (errno == EINTR);
            
            SysPanic("semaphore timed lock failed");
            return true;
        }
    }
    
    void Semaphore::Lock()
    {
        auto status = Lock(0);
        SysAssert(status, "Couldn't lock semaphore");
    }
    
    void Semaphore::Unlock(long count)
    {
        for (int i = 0; i < count; i++)
        {
            Unlock();
        }
    }
    
    void Semaphore::Unlock()
    {
        auto status = sem_post(&this->value_) == 0;
        SysAssert(status, "Semaphore release error");
    }
    
    AUKN_SYM ISemaphore *SemaphoreNew(int initialCount)
    {
        return _new Semaphore(initialCount);
    }

    AUKN_SYM void SemaphoreRelease(ISemaphore *waitable)
    {
        AuSafeDelete<Semaphore *>(waitable);
    }
}
#endif