/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: LSSemaphore.Linux.cpp
    Date: 2022-4-5
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "LSSemaphore.hpp"
#include "LSFromFdNonblocking.hpp"

namespace Aurora::Loop
{
    LSSemaphore::LSSemaphore(AuUInt32 initialCount)
    {
        Init(initialCount);
    }

    void LSSemaphore::Init(AuUInt32 initialCount)
    {
        handle = eventfd(initialCount, EFD_SEMAPHORE | EFD_NONBLOCK);
    }

    bool LSSemaphore::IsSignaledNonblocking()
    {
        AuUInt64 oldSemaphoreValue {};
        return read(this->handle, &oldSemaphoreValue, sizeof(oldSemaphoreValue)) == 8;
    }

    bool LSSemaphore::AddOne()
    {
        AuUInt64 plsNoOverflow {1};

        if (write(this->handle, &plsNoOverflow, sizeof(plsNoOverflow)) != 8)
        {
            // todo push error
            return false;
        }

        return true;
    }

    bool LSSemaphore::OnTrigger(AuUInt handle)
    {
        return IsSignaledNonblocking();
    }

    bool LSSemaphore::IsSignaled()
    {
        return IsSignaledFromNonblockingImpl(this, this, &LSSemaphore::IsSignaledNonblocking);
    }

    ELoopSource LSSemaphore::GetType()
    {
        return ELoopSource::eSourceSemaphore;
    }

    AUKN_SYM AuSPtr<ILSSemaphore> NewLSSemaphore(AuUInt32 initialCount)
    {
        auto semaphore = AuMakeShared<LSSemaphore>(initialCount);
        if (!semaphore)
        {
            return {};
        }

        if (!semaphore->HasValidHandle())
        {
            return {};
        }

        return semaphore;
    }
}