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

    File: ConditionVariable.Win32.hpp
    Date: 2021-6-12
    Author: Reece
***/
#pragma once

#if !defined(_AURUNTIME_GENERICCV)
#include "AuConditionMutex.NT.hpp"

namespace Aurora::Threading::Primitives
{
    struct ConditionVariableImpl final : IConditionVariable
    {
        ConditionVariableImpl(const AuSPtr<IConditionMutex> &mutex);
        
        auline AuSPtr<IConditionMutex> GetMutex() override;
        auline bool WaitForSignal(AuUInt32 timeout) override;
        auline bool WaitForSignalNsEx(const AuSPtr<IConditionMutex> &pMutex, AuUInt64 timeout);
        auline bool WaitForSignalNS(AuUInt64 qwTimeout);
        auline void Signal() override;
        auline void Broadcast() override;

        auline bool CheckOut(bool &bRet);

    private:
    #if defined(AURORA_FORCE_SRW_LOCKS)
        CONDITION_VARIABLE winCond_;
    #else
        AuUInt32 wlist {};
        AuUInt32 signalCount {};
    #endif

        std::shared_ptr<Win32ConditionMutex> mutex_;
    };

    struct CondVarDummy : IConditionVariable
    {
    private:
    #if defined(AURORA_FORCE_SRW_LOCKS)
        CONDITION_VARIABLE winCond_;
    #else
        AuUInt32 wlist {};
        AuUInt32 signalCount {};
    #endif
    };

    static const auto kSizeOfDummyCondVar = sizeof(CondVarDummy);

    static const auto kBoolRequiredLateSet = true;

    // Future (Reece): I got future plans
    static const auto kShiftCountByBits = 8u;
    // ...otherwise
    // assume undefined behaviour past:
    //  * bit zero is used for atomic bit test and yield loops 
    //    ( keyed events are an optimization mechanism for Windows XPs spinloop i had accidentally recreated in xenus. )
    //    ( originally, nt yielding sucked with the most barebones spinlock being dumb a hypervisor-unaware, smt-aware, spinner. )
    //    ( keyed events would then go in these spinners to serve as an early futex as early back as the year 2000 (?). )
    //    ( that does, in fact, mean the free-toddlers crying about how 'windows stole muh kernels totally originally idea' is entirely wrong at each sub-point. )
    //    ( though, keyed didn't see much use until Windows Vistas synch primitives were built on top of them. )
    //    ( infamously missing 100ths scale nanosecond yimeouts and an inablity to lock with a timeout. )
    //    ( raymond chen once claimed they didnt make it to xp because they werent fast enough )
    //    ( raymond chen once claimed a "con" of keyedevents were that they were linear )
    //    ( problem is, as far as i can tell, they didnt really change. whats worse, WakeOnAddress (windows 8+)
    //    ( ...inherits the issue of not having relative/abs nanosecond scale timeouts AND the issue the primitives sucking. )
    //    ( WakeOnAddress is nothing more than keyed events 2.0 - but with userland list keeping. )
    //    ( scratch the concept of how i implement WakeOnAddress with lists, how older nts waited with lists under lock, )
    //    ( they use hashmaps with "le meme lockless" interactions which are surly less expensive than reusing tls allocations ?! )
    //    ( whether or not its even faster is still up for debate. its just easier to use. )
    //  * bit one might be used under some niche versions of windows
    //    (hearsay paranoia)
    // i actually have zero reason to believe windows ever implemented lock-awareness into the kernel
    // i think it might be fine to skip the whole bit zero thing, but still, im going to say keep the min=2
    // worst case scenario, we end up using these bits.
    // ....
    // =8 is future proof
    // =2 is recommended
    // =0 would require a bit of a require. i think this is how other people use keyed events nowadays

}
#endif