// yabridge: a Wine plugin bridge
// Copyright (C) 2020-2022 Robbert van der Helm
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

#include "utils.h"

#include <stdlib.h>

#include <sched.h>
#include <xmmintrin.h>

namespace fs = ghc::filesystem;

using namespace std::literals::string_view_literals;

/**
 * If this environment variable is set to `1`, then we won't enable the watchdog
 * timer. This is only necessary when running the Wine process under a different
 * namespace than the host.
 */
constexpr char disable_watchdog_timer_env_var[] = "YABRIDGE_NO_WATCHDOG";

/**
 * If this environment variable is set, yabridge will store its sockets and
 * other temporary files here instead of in `$XDG_RUNTIME_DIR` or `/tmp`. This
 * is only relevant when using some namespacing setup for sandboxing.
 */
constexpr char temp_dir_override_env_var[] = "YABRIDGE_TEMP_DIR";

fs::path get_temporary_directory() {
    // NOLINTNEXTLINE(concurrency-mt-unsafe)
    if (const auto directory = getenv(temp_dir_override_env_var)) {
        return fs::path(directory);
        // NOLINTNEXTLINE(concurrency-mt-unsafe)
    } else if (const auto directory = getenv("XDG_RUNTIME_DIR")) {
        return fs::path(directory);
    } else {
        return fs::temp_directory_path();
    }
}

std::optional<int> get_realtime_priority() noexcept {
    sched_param current_params{};
    if (sched_getparam(0, &current_params) == 0 &&
        current_params.sched_priority > 0) {
        return current_params.sched_priority;
    } else {
        return std::nullopt;
    }
}

bool set_realtime_priority(bool sched_fifo, int priority) noexcept {
    sched_param params{.sched_priority = (sched_fifo ? priority : 0)};
    return sched_setscheduler(0, sched_fifo ? SCHED_FIFO : SCHED_OTHER,
                              &params) == 0;
}

std::optional<rlim_t> get_memlock_limit() noexcept {
    rlimit limits{};
    if (getrlimit(RLIMIT_MEMLOCK, &limits) == 0) {
        return limits.rlim_cur;
    } else {
        return std::nullopt;
    }
}

std::optional<rlim_t> get_rttime_limit() noexcept {
    rlimit limits{};
    if (getrlimit(RLIMIT_RTTIME, &limits) == 0) {
        return limits.rlim_cur;
    } else {
        return std::nullopt;
    }
}

bool is_watchdog_timer_disabled() {
    // This is safe because we're not storing the pointer anywhere and the
    // environment doesn't get modified anywhere
    // NOLINTNEXTLINE(concurrency-mt-unsafe)
    const char* disable_watchdog_env = getenv(disable_watchdog_timer_env_var);

    return disable_watchdog_env && disable_watchdog_env == "1"sv;
}

ScopedFlushToZero::ScopedFlushToZero() noexcept {
    old_ftz_mode_ = _MM_GET_FLUSH_ZERO_MODE();
    _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
}

ScopedFlushToZero::~ScopedFlushToZero() noexcept {
    if (old_ftz_mode_) {
        _MM_SET_FLUSH_ZERO_MODE(*old_ftz_mode_);
    }
}

ScopedFlushToZero::ScopedFlushToZero(ScopedFlushToZero&& o) noexcept
    : old_ftz_mode_(std::move(o.old_ftz_mode_)) {
    o.old_ftz_mode_.reset();
}

ScopedFlushToZero& ScopedFlushToZero::operator=(
    ScopedFlushToZero&& o) noexcept {
    old_ftz_mode_ = std::move(o.old_ftz_mode_);
    o.old_ftz_mode_.reset();

    return *this;
}