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

    File: Event.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "AuEvent.hpp"
#include "SMTYield.hpp"

namespace Aurora::Threading::Primitives
{
    EventImpl::EventImpl(bool bTriggered, bool bAtomicRelease, bool bPermitMultipleTriggers) :
        bTriggered_(bTriggered),
        bAtomicRelease_(bAtomicRelease),
        bPermitMultipleTriggers_(bPermitMultipleTriggers),
        condition_(AuUnsafeRaiiToShared(&this->mutex_))
    {}

    EventImpl::~EventImpl() {}

    bool EventImpl::Init()
    {
        return true;
    }

    bool EventImpl::LockMS(AuUInt64 uTimeout /*=0*/)
    {
        return LockNS(AuMSToNS<AuUInt64>(uTimeout));
    }

    bool EventImpl::LockNS(AuUInt64 uTimeout /*=0*/)
    {
        AU_LOCK_GUARD(this->mutex_);

        AuInt64 uStartTime = Time::SteadyClockNS();
        AuInt64 uEndTime = uStartTime + uTimeout;

        while (!AtomicIsEventSetLogic())
        {
            AuUInt32 uTimeoutNS {};

            if (uTimeout)
            {
                uStartTime = Time::SteadyClockNS();
                if (uStartTime >= uEndTime)
                {
                    return false;
                }

                uTimeoutNS = uEndTime - uStartTime;
            }

            if (!this->condition_.WaitForSignalNS(uTimeoutNS))
            {
                continue;
            }
        }

        if (this->bAtomicRelease_)
        {
            this->bTriggered_ = false;
        }

        return true;
    }

    bool EventImpl::TryLock()
    {
        AU_LOCK_GUARD(this->mutex_);

        return AtomicIsEventSetLogic();
    }

    bool EventImpl::AtomicIsEventSetLogic()
    {
        if (!this->bTriggered_)
        {
            return false;
        }

        if (this->bAtomicRelease_)
        {
            this->bTriggered_ = false;
        }

        return true;
    }

    void EventImpl::Reset()
    {
        this->mutex_.Lock();
        this->bTriggered_ = false;
        this->mutex_.Unlock();
    }

    void EventImpl::Set()
    {
        AU_LOCK_GUARD(this->mutex_);
        SysAssertExp((this->bPermitMultipleTriggers_) || (!this->bTriggered_), "Can not trigger an awake event object");
        this->bTriggered_ = true;
        this->condition_.Broadcast();
    }

    bool EventImpl::HasOSHandle(AuMach &mach)
    {
        mach = 0;
        return false;
    }

    bool EventImpl::HasLockImplementation()
    {
        return true;
    }

    void EventImpl::Lock()
    {
        auto ok = LockNS(0);
        SysAssert(ok);
    }

    void EventImpl::Unlock()
    {
        // Unlock is always a NOP; inverse of a lock/wait is nothing
    }

    AUKN_SYM IEvent *EventNew(bool bTriggered, bool bAtomicRelease, bool bPermitMultipleTriggers)
    {
        auto event = _new EventImpl(bTriggered, bAtomicRelease, bPermitMultipleTriggers);
        if (!event)
        {
            return nullptr;
        }

        if (!event->Init())
        {
            EventRelease(event);
            return nullptr;
        }
        
        return event;
    }

    AUKN_SYM void EventRelease(IEvent *pEvent)
    {
        AuSafeDelete<EventImpl *>(pEvent);
    }

    AUROXTL_INTERFACE_SOO_SRC_EX(AURORA_SYMBOL_EXPORT, Event, EventImpl, (bool, bTriggered), (bool, bAtomicRelease), (bool, bPermitMultipleTriggers))
}