// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
// SPDX-License-Identifier: GPL-3.0-or-later

// SPDX-FileCopyrightText: 2013 Dolphin Emulator Project
// SPDX-FileCopyrightText: 2014 Citra Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#include <chrono>
#include <limits>
#include <string>
#include <thread>

#include "common/adpf.h"
#include "common/error.h"
#include "common/logging.h"
#include "common/assert.h"
#include "common/thread.h"
#ifdef __APPLE__
#include <mach/mach.h>
#elif defined(__HAIKU__)
#include <kernel/OS.h>
#elif defined(_WIN32)
#include <windows.h>
#include "common/string_util.h"
#include "common/windows/timer_resolution.h"
#else
#if defined(__FreeBSD__)
#include <sys/cpuset.h>
#include <sys/_cpuset.h>
#include <pthread_np.h>
// Compatibility with CPUset
#define cpu_set_t cpuset_t
#elif defined(__DragonFly__) || defined(__OpenBSD__) || defined(__Bitrig__)
#include <pthread_np.h>
#endif
#include <pthread.h>
#include <sched.h>
#endif

#ifndef _WIN32
#include <unistd.h>
#endif

#ifdef __linux__
#include <sys/resource.h>
#include <algorithm>

namespace {
constexpr int NICE_AUDIO = -16;
constexpr int NICE_URGENT_DISPLAY = -8;
constexpr int NICE_DISPLAY = -4;
constexpr int NICE_DEFAULT = 0;
constexpr int NICE_BACKGROUND = 10;

int LowestAllowedNice() {
    static const int lowest = [] {
        rlimit limit{};
        if (getrlimit(RLIMIT_NICE, &limit) != 0) {
            return 0;
        }
        if (limit.rlim_cur >= 40) {
            return -20;
        }
        return 20 - static_cast<int>(limit.rlim_cur);
    }();
    return lowest;
}

int NiceValueForPriority(Common::ThreadPriority priority) {
    const int wanted = [priority] {
        switch (priority) {
        case Common::ThreadPriority::Low: return NICE_BACKGROUND;
        case Common::ThreadPriority::Normal: return NICE_DEFAULT;
        case Common::ThreadPriority::High: return NICE_DISPLAY;
        case Common::ThreadPriority::VeryHigh: return NICE_URGENT_DISPLAY;
        case Common::ThreadPriority::Critical: return NICE_AUDIO;
        default: return NICE_DEFAULT;
        }
    }();
    return (std::max)(wanted, (std::min)(NICE_DEFAULT, LowestAllowedNice()));
}
} // Anonymous namespace
#endif

#ifdef __ANDROID__
#include <sys/utsname.h>
#include <atomic>
#include <cerrno>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <mutex>
#include <vector>

namespace {
constexpr size_t ANDROID_MINIMUM_PERFORMANCE_CORES = 4;

// A core counts as a performance core while it is within this much of the fastest one.
constexpr s64 ANDROID_PERFORMANCE_CAPACITY_PERCENT = 50;

constexpr std::chrono::nanoseconds ANDROID_POLICY_POLL_INTERVAL = std::chrono::milliseconds{500};

enum class CoreGroup {
    Unrestricted,
    Performance,
    Efficiency,
};

struct ThreadPolicy {
    pid_t tid;
    CoreGroup group;
    s32 nice_value;
    bool has_nice;
};

struct CoreInfo {
    s64 weight;
    u64 midr;
    s32 cpu;
};

struct CpuTopologyState {
    std::mutex topology_mutex;
    cpu_set_t allowed{};
    cpu_set_t performance{};
    cpu_set_t efficiency{};
    bool separated = false;
    bool initialized = false;

    pid_t canary_tid = 0;
    cpu_set_t canary_mask{};
    bool canary_valid = false;

    std::atomic<s64> next_poll_ns{0};

    std::mutex policy_mutex;
    std::vector<ThreadPolicy> policies;
};

CpuTopologyState& State() {
    static CpuTopologyState* const state = new CpuTopologyState();
    return *state;
}

struct PolicyRegistration {
    ~PolicyRegistration() {
        const pid_t tid = gettid();
        ::Common::ADPF::RemoveCurrentThread();
        CpuTopologyState& state = State();
        std::scoped_lock lock{state.policy_mutex};
        std::erase_if(state.policies,
                      [tid](const ThreadPolicy& policy) { return policy.tid == tid; });
    }
};

thread_local PolicyRegistration t_policy_registration;

s32 PossibleCpuCount() {
    std::ifstream file("/sys/devices/system/cpu/possible");
    std::string list;
    if (file && std::getline(file, list) && !list.empty()) {
        s64 highest = -1;
        const char* cursor = list.c_str();
        while (*cursor != '\0') {
            char* end = nullptr;
            const s64 value = std::strtol(cursor, &end, 10);
            if (end == cursor) {
                break;
            }
            highest = (std::max)(highest, value);
            cursor = end;
            while (*cursor == '-' || *cursor == ',') {
                ++cursor;
            }
        }
        if (highest >= 0) {
            return static_cast<s32>((std::min<s64>)(highest + 1, CPU_SETSIZE));
        }
    }
    const s64 configured = sysconf(_SC_NPROCESSORS_CONF);
    if (configured > 0) {
        return static_cast<s32>((std::min<s64>)(configured, CPU_SETSIZE));
    }
    return static_cast<s32>((std::min<s64>)(std::thread::hardware_concurrency(), CPU_SETSIZE));
}

s64 ReadCpuScalar(s32 cpu, const char* node) {
    s64 value = 0;
    std::ifstream file("/sys/devices/system/cpu/cpu" + std::to_string(cpu) + "/" + node);
    if (!file || !(file >> value) || value <= 0) {
        return 0;
    }
    return value;
}

u64 ReadCpuMidr(s32 cpu) {
    u64 midr = 0;
    std::ifstream file("/sys/devices/system/cpu/cpu" + std::to_string(cpu) +
                       "/regs/identification/midr_el1");
    if (!file || !(file >> std::hex >> midr)) {
        return 0;
    }
    return midr;
}

std::vector<CoreInfo> CollectCores(const cpu_set_t& allowed, s32 total, const char* node,
                                   bool require_all) {
    std::vector<CoreInfo> cores;
    for (s32 cpu = 0; cpu < total; ++cpu) {
        if (!CPU_ISSET(cpu, &allowed)) {
            continue;
        }
        const s64 weight = ReadCpuScalar(cpu, node);
        if (weight <= 0) {
            if (require_all) {
                return {};
            }
            LOG_WARNING(Common, "Could not read {} for CPU {}, treating it as an efficiency core",
                        node, cpu);
            continue;
        }
        cores.push_back(CoreInfo{weight, ReadCpuMidr(cpu), cpu});
    }
    return cores;
}

bool WeightsAreUniform(const std::vector<CoreInfo>& cores) {
    return std::all_of(cores.begin(), cores.end(),
                       [&](const CoreInfo& core) { return core.weight == cores.front().weight; });
}

bool MidrsAreDistinct(const std::vector<CoreInfo>& cores) {
    return std::none_of(cores.begin(), cores.end(),
                        [](const CoreInfo& core) { return core.midr == 0; }) &&
           std::any_of(cores.begin(), cores.end(),
                       [&](const CoreInfo& core) { return core.midr != cores.front().midr; });
}

void ComputeTopologyLocked(CpuTopologyState& state) {
    state.initialized = true;
    state.separated = false;
    CPU_ZERO(&state.allowed);
    CPU_ZERO(&state.performance);
    CPU_ZERO(&state.efficiency);

    if (sched_getaffinity(getpid(), sizeof(state.allowed), &state.allowed) != 0) {
        LOG_WARNING(Common, "Could not query process CPU affinity: {}",
                    ::Common::GetLastErrorMsg());
        return;
    }

    const s32 total = PossibleCpuCount();
    auto cores = CollectCores(state.allowed, total, "cpu_capacity", true);
    if (cores.empty() || (WeightsAreUniform(cores) && MidrsAreDistinct(cores))) {
        auto by_frequency = CollectCores(state.allowed, total, "cpufreq/cpuinfo_max_freq", false);
        if (!by_frequency.empty()) {
            cores = std::move(by_frequency);
        }
    }
    if (cores.empty()) {
        LOG_WARNING(Common, "Could not determine CPU topology, thread placement is disabled");
        return;
    }

    if (WeightsAreUniform(cores)) {
        if (MidrsAreDistinct(cores)) {
            LOG_WARNING(Common, "CPU clusters differ but rank identically, thread placement is "
                                "disabled");
        } else {
            LOG_INFO(Common, "CPU cores are symmetric, thread placement is disabled");
        }
        return;
    }

    std::sort(cores.begin(), cores.end(), [](const CoreInfo& lhs, const CoreInfo& rhs) {
        if (lhs.weight != rhs.weight) {
            return lhs.weight > rhs.weight;
        }
        return lhs.cpu < rhs.cpu;
    });

    const s64 fastest = cores.front().weight;
    size_t taken = 0;
    for (const auto& core : cores) {
        const bool fast_enough =
            core.weight * 100 >= fastest * ANDROID_PERFORMANCE_CAPACITY_PERCENT;
        if (!fast_enough && taken >= ANDROID_MINIMUM_PERFORMANCE_CORES) {
            break;
        }
        CPU_SET(core.cpu, &state.performance);
        ++taken;
    }
    if (taken == 0) {
        return;
    }

    for (s32 cpu = 0; cpu < total; ++cpu) {
        if (CPU_ISSET(cpu, &state.allowed) && !CPU_ISSET(cpu, &state.performance)) {
            CPU_SET(cpu, &state.efficiency);
        }
    }

    state.separated = CPU_COUNT(&state.efficiency) > 0;
    LOG_INFO(Common, "CPU topology: {} performance cores, {} efficiency cores, separation {}",
             CPU_COUNT(&state.performance), CPU_COUNT(&state.efficiency),
             state.separated ? "enabled" : "unavailable");
}

void EnsureTopologyLocked(CpuTopologyState& state) {
    if (!state.initialized) {
        ComputeTopologyLocked(state);
    }
}

void RefreshTopologyLocked(CpuTopologyState& state) {
    if (!state.initialized) {
        ComputeTopologyLocked(state);
        return;
    }
    cpu_set_t current;
    CPU_ZERO(&current);
    if (sched_getaffinity(getpid(), sizeof(current), &current) != 0) {
        return;
    }
    if (std::memcmp(&current, &state.allowed, sizeof(current)) != 0) {
        ComputeTopologyLocked(state);
    }
}

bool ApplyCoreGroupLocked(CpuTopologyState& state, pid_t tid, CoreGroup group,
                          bool* gone = nullptr) {
    const bool restrict_group = group != CoreGroup::Unrestricted && state.separated;
    const cpu_set_t* mask = &state.allowed;
    if (restrict_group) {
        mask = group == CoreGroup::Performance ? &state.performance : &state.efficiency;
    }
    if (CPU_COUNT(mask) == 0) {
        return false;
    }
    if (sched_setaffinity(tid, sizeof(*mask), mask) != 0) {
        if (gone != nullptr && errno == ESRCH) {
            *gone = true;
            return false;
        }
        LOG_WARNING(Common, "Could not restrict thread {} to its core group: {}", tid,
                    ::Common::GetLastErrorMsg());
        return false;
    }
    return true;
}

bool KernelPreservesRequestedAffinity() {
    utsname info{};
    if (uname(&info) != 0) {
        return false;
    }
    s32 major = 0;
    s32 minor = 0;
    if (std::sscanf(info.release, "%d.%d", &major, &minor) != 2) {
        return false;
    }
    return major > 6 || (major == 6 && minor >= 2);
}

void SnapshotCanaryLocked(CpuTopologyState& state) {
    state.canary_valid = false;
    if (!state.separated) {
        return;
    }
    for (const auto& policy : state.policies) {
        if (policy.group == CoreGroup::Unrestricted) {
            continue;
        }
        cpu_set_t mask;
        CPU_ZERO(&mask);
        if (sched_getaffinity(policy.tid, sizeof(mask), &mask) != 0) {
            continue;
        }
        state.canary_tid = policy.tid;
        state.canary_mask = mask;
        state.canary_valid = true;
        return;
    }
}

bool DueForPoll(CpuTopologyState& state) {
    const auto now = std::chrono::steady_clock::now().time_since_epoch();
    const s64 now_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(now).count();
    s64 next = state.next_poll_ns.load(std::memory_order_relaxed);
    if (now_ns < next) {
        return false;
    }
    return state.next_poll_ns.compare_exchange_strong(
        next, now_ns + ANDROID_POLICY_POLL_INTERVAL.count(), std::memory_order_relaxed);
}

ThreadPolicy& AcquirePolicyLocked(CpuTopologyState& state, pid_t tid) {
    for (auto& policy : state.policies) {
        if (policy.tid == tid) {
            return policy;
        }
    }
    return state.policies.emplace_back(ThreadPolicy{tid, CoreGroup::Unrestricted, 0, false});
}

void SetCurrentThreadCoreGroup(CoreGroup group) {
    const pid_t tid = gettid();
    (void)&t_policy_registration;

    CoreGroup effective = group;
    if (tid == getpid() && group != CoreGroup::Unrestricted) {
        LOG_WARNING(Common, "Refusing to place the main thread: the CPU topology is read from it");
        effective = CoreGroup::Unrestricted;
    }

    CpuTopologyState& state = State();
    std::scoped_lock topology_lock{state.topology_mutex};
    EnsureTopologyLocked(state);
    ApplyCoreGroupLocked(state, tid, effective);

    std::scoped_lock policy_lock{state.policy_mutex};
    AcquirePolicyLocked(state, tid).group = effective;
    if (!state.canary_valid) {
        SnapshotCanaryLocked(state);
    }
}

void RememberCurrentThreadNice(pid_t tid, s32 nice_value) {
    (void)&t_policy_registration;
    CpuTopologyState& state = State();
    std::scoped_lock lock{state.policy_mutex};
    ThreadPolicy& policy = AcquirePolicyLocked(state, tid);
    policy.nice_value = nice_value;
    policy.has_nice = true;
}
} // Anonymous namespace
#endif

#include "common/cpu_features.h"
#ifdef ARCHITECTURE_x86_64
#ifdef _MSC_VER
#include <intrin.h>
#else
#include <x86intrin.h>
#endif
#include "common/x64/rdtsc.h"
#endif

namespace Common {

void SetCurrentThreadPriority(ThreadPriority new_priority) {
#ifdef _WIN32
    int windows_priority = [&]() {
        switch (new_priority) {
        case ThreadPriority::Low: return THREAD_PRIORITY_BELOW_NORMAL;
        case ThreadPriority::Normal: return THREAD_PRIORITY_NORMAL;
        case ThreadPriority::High: return THREAD_PRIORITY_ABOVE_NORMAL;
        case ThreadPriority::VeryHigh: return THREAD_PRIORITY_HIGHEST;
        case ThreadPriority::Critical: return THREAD_PRIORITY_TIME_CRITICAL;
        default: return THREAD_PRIORITY_NORMAL;
        }
    }();
    SetThreadPriority(GetCurrentThread(), windows_priority);
#elif defined(__HAIKU__)
    // TODO: We have priorities for 3D rendering applications - may help lavapipe?
    int priority = [&]() {
        switch (new_priority) {
        case ThreadPriority::Low: return B_LOW_PRIORITY;
        case ThreadPriority::Normal: return B_NORMAL_PRIORITY;
        case ThreadPriority::High: return B_DISPLAY_PRIORITY;
        case ThreadPriority::VeryHigh: return B_URGENT_DISPLAY_PRIORITY;
        case ThreadPriority::Critical: return B_URGENT_PRIORITY;
        default: return B_NORMAL_PRIORITY;
        }
    }();
    set_thread_priority(find_thread(NULL), priority);
#elif defined(__ANDROID__)
    const int nice_value = NiceValueForPriority(new_priority);
    const pid_t tid = gettid();
    if (setpriority(PRIO_PROCESS, static_cast<id_t>(tid), nice_value) != 0) {
        LOG_WARNING(Common, "Could not set thread nice value to {}: {}", nice_value,
                    GetLastErrorMsg());
        return;
    }
    RememberCurrentThreadNice(tid, nice_value);
#elif defined(__linux__)
    const int nice_value = NiceValueForPriority(new_priority);
    if (setpriority(PRIO_PROCESS, 0, nice_value) != 0) {
        LOG_DEBUG(Common, "Could not set thread nice value to {}: {}", nice_value,
                  GetLastErrorMsg());
    }
#else
    const s32 max_prio = sched_get_priority_max(SCHED_OTHER);
    const s32 min_prio = sched_get_priority_min(SCHED_OTHER);
    if (max_prio > min_prio) {
        const u32 level = (std::min)(static_cast<u32>(new_priority), 4U);
        sched_param params{};
        params.sched_priority =
            min_prio + static_cast<s32>(static_cast<u32>(max_prio - min_prio) * level) / 4;
        pthread_setschedparam(pthread_self(), SCHED_OTHER, &params);
    }
#endif
}

void SetCurrentThreadName(const char* name) {
#ifdef _MSC_VER
    // Sets the debugger-visible name of the current thread.
    if (auto pf = (decltype(&SetThreadDescription))(void*)GetProcAddress(GetModuleHandle(TEXT("KernelBase.dll")), "SetThreadDescription"); pf)
        pf(GetCurrentThread(), UTF8ToUTF16W(name).data()); // Windows 10+
    else
        ; // No-op
#elif  defined(__APPLE__)
    pthread_setname_np(name);
#elif defined(__HAIKU__)
    rename_thread(find_thread(NULL), name);
#elif defined(__Bitrig__) || defined(__DragonFly__) || defined(__FreeBSD__) || defined(__OpenBSD__)
    pthread_set_name_np(pthread_self(), name);
#elif defined(__NetBSD__)
    pthread_setname_np(pthread_self(), "%s", (void*)name);
#elif defined(__linux__) || defined(__CYGWIN__) || defined(__sun__) || defined(__glibc__) || defined(__managarm__)
    int ret = pthread_setname_np(pthread_self(), name);
    if (ret == ERANGE) {
        // Linux limits thread names to 15 characters and will outright reject any
        // attempt to set a longer name with ERANGE.
        char buf[16];
        size_t const len = std::min<size_t>(std::strlen(name), sizeof(buf) - 1);
        std::memcpy(buf, name, len);
        buf[len] = '\0';
        pthread_setname_np(pthread_self(), buf);
    }
#elif defined(_WIN32)
    // MinGW with the POSIX threading model does not support pthread_setname_np
    // See for reference
    // https://gitlab.freedesktop.org/mesa/mesa/-/blame/main/src/util/u_thread.c?ref_type=heads#L75
    (void)name;
#else
    pthread_setname_np(pthread_self(), name);
#endif
}

void SetCurrentThreadToPerformanceCores() {
#if defined(__ANDROID__)
    if (ADPF::AddCurrentThread(ADPF::Session::Render)) {
        SetCurrentThreadCoreGroup(CoreGroup::Unrestricted);
        return;
    }
    SetCurrentThreadCoreGroup(CoreGroup::Performance);
#endif
}

void SetCurrentThreadToEfficiencyCores() {
#if defined(__ANDROID__)
    if (ADPF::AddCurrentThread(ADPF::Session::Background)) {
        SetCurrentThreadCoreGroup(CoreGroup::Unrestricted);
        return;
    }
    SetCurrentThreadCoreGroup(CoreGroup::Efficiency);
#endif
}

void SetCurrentThreadToBackgroundWork() {
#if defined(__ANDROID__)
    ADPF::AddCurrentThread(ADPF::Session::Background);
    SetCurrentThreadCoreGroup(CoreGroup::Unrestricted);
#endif
}

void SetCurrentThreadToAllCores() {
#if defined(__ANDROID__)
    ADPF::RemoveCurrentThread();
    SetCurrentThreadCoreGroup(CoreGroup::Unrestricted);
#endif
}

void RefreshThreadPolicies() {
#if defined(__ANDROID__)
    CpuTopologyState& state = State();
    std::scoped_lock topology_lock{state.topology_mutex};
    RefreshTopologyLocked(state);

    std::scoped_lock policy_lock{state.policy_mutex};
    std::erase_if(state.policies, [&state](const ThreadPolicy& policy) {
        bool gone = false;
        if (policy.has_nice &&
            setpriority(PRIO_PROCESS, static_cast<id_t>(policy.tid), policy.nice_value) != 0 &&
            errno == ESRCH) {
            gone = true;
        }
        if (!gone) {
            ApplyCoreGroupLocked(state, policy.tid, policy.group, &gone);
        }
        return gone;
    });
    SnapshotCanaryLocked(state);
#endif
}

void PollThreadPolicies() {
#if defined(__ANDROID__)
    static const bool needed = !KernelPreservesRequestedAffinity();
    if (!needed) {
        return;
    }

    CpuTopologyState& state = State();
    if (!DueForPoll(state)) {
        return;
    }

    pid_t tid;
    cpu_set_t expected;
    {
        std::scoped_lock lock{state.topology_mutex};
        if (!state.canary_valid) {
            return;
        }
        tid = state.canary_tid;
        expected = state.canary_mask;
    }

    cpu_set_t current;
    CPU_ZERO(&current);
    if (sched_getaffinity(tid, sizeof(current), &current) == 0 &&
        std::memcmp(&current, &expected, sizeof(current)) == 0) {
        return;
    }
    RefreshThreadPolicies();
#endif
}

#ifdef ARCHITECTURE_x86_64
// On Linux and UNIX systems, a futex would nominally be used to cover the costs
// the idea is that it's intuitivelly cheaper to use a direct instruction as opposed to a full futex call
// the underlying libc++ implementation uses pthread_cond_timedwait which MAY invoke a futex
// Let's pretend the OS is too expensive to jump into, and avoid ANY context switches
// this should *IN THEORY* lower CPU usage while just waiting for stuff effectively
// For windows the minimal quanta resolution is about 500us, and normal CRT cond var is 1.5ms(?)
// so may as well avoid that too
// Let's just give ALL platforms the same mechanisms (almost) for when they have umonitor OR waitpkg
#ifdef __clang__
__attribute__((target("waitpkg,mwaitx")))
#elif defined(__GNUC__)
#pragma GCC target("waitpkg")
#pragma GCC target("mwaitx")
#endif
bool Event::WaitFor(const std::chrono::nanoseconds time) {
#ifdef _WIN32
    auto const start = Common::X64::FencedRDTSC();
    auto const& caps = Common::g_cpu_caps;
    [[maybe_unused]] auto const end = start + Common::g_wall_clock.NsToTicks(time);
    if (caps.monitorx) {
        while (true) {
            // Armed monitor, as per manual, MWAITX must be conditional if the condition isn't satisfied
            // to prevent a race condition.
            _mm_monitorx(reinterpret_cast<u64*>(std::addressof(is_set)), 0, 0);
            if (!is_set.load()) {
                // RDTSC may be fenced here due to atomic load
#ifdef _MSC_VER
                auto const now = __rdtsc();
#else
                auto const now = _rdtsc();
#endif
                if (end > now) {
                    u32 const cycles = std::min<u32>((std::numeric_limits<u32>::max)(), s64(end) - s64(now));
                    // See here: https://github.com/torvalds/linux/blob/948a64995aca6820abefd17f1a4258f5835c5ad9/arch/x86/lib/delay.c#L93
                    // MWAITX accepts a 32-bit input timer which determines the total number of cycles to wait for
                    // NOT THE TOTAL ABSOLUTE TSC VALUE, it's just a delta
                    // BIT[1] = use a timer
                    // Hint = 0: Use C1 state when sleepy (means slower wakeup but better savings)
                    _mm_mwaitx(1 << 1, 0u, cycles);
                    if (!is_set.load())
                        return false;
                } else
                    return false; //timeout
            }
            bool expected = true;
            if (is_set.compare_exchange_weak(expected, false, std::memory_order_release))
                return true;
        }
    } else if (caps.waitpkg) {
        // #UD If CPUID.7.0:ECX.WAITPKG[bit 5]=0.
        while (true) {
            _umonitor(std::addressof(is_set));
            if (!is_set.load() && !_umwait(0, end)) //umwait is absolute time!!!
                return false;
            bool expected = true;
            if (is_set.compare_exchange_weak(expected, false, std::memory_order_release))
                return true;
        }
    } else {
#ifdef _MSC_VER
        while (!is_set.load() && end > __rdtsc())
            Common::Windows::SleepForOneTick();
#else
        while (!is_set.load() && end > _rdtsc())
            Common::Windows::SleepForOneTick();
#endif
        if (is_set.load())
            Reset();
        return true;
    }
#else
    std::unique_lock lk{mutex};
    if (!condvar.wait_for(lk, time, [this] { return is_set.load(); }))
        return false;
    is_set = false;
    return true;
#endif
}
#else
bool Event::WaitFor(const std::chrono::nanoseconds time) {
#ifdef _WIN32
    auto const end = Common::g_wall_clock.GetTimeNS() + time;
    while (!is_set.load() && end > Common::g_wall_clock.GetTimeNS())
        Common::Windows::SleepForOneTick();
    if (is_set.load())
        Reset();
    return true;
#else
    std::unique_lock lk{mutex};
    if (!condvar.wait_for(lk, time, [this] { return is_set.load(); }))
        return false;
    is_set = false;
    return true;
#endif
}
#endif

} // namespace Common