//SPDX-FileCopyrightText: 2023 Yury Gubich <blue@macaw.me>
//SPDX-License-Identifier: GPL-3.0-or-later

#include "manager.h"

TM::Manager::Manager ():
    terminating(false),
    threads(),
    queue(),
    mtx(),
    cond()
{}

TM::Manager::~Manager () {
    std::unique_lock lock(mtx);
    if (threads.empty())
        return;

    lock.unlock();
    stop();
}

void TM::Manager::start () {
    std::lock_guard lock(mtx);

    std::size_t amount = std::thread::hardware_concurrency();
    for (std::size_t i = 0; i < amount; ++i)
        threads.emplace_back(std::thread(&Manager::loop, this));
}

void TM::Manager::stop () {
    std::unique_lock lock(mtx);

    terminating = true;

    lock.unlock();
    cond.notify_all();
    for (std::thread& thread : threads)
        thread.join();

    lock.lock();
    threads.clear();
    terminating = false;
}

void TM::Manager::loop () {
    while (true) {
        std::unique_lock lock(mtx);
        while (!terminating && queue.empty())
            cond.wait(lock);

        if (terminating)
            return;

        std::unique_ptr<Job> job = std::move(queue.front());
        queue.pop();
        lock.unlock();

        job->execute();
    }
}

void TM::Manager::schedule (std::unique_ptr<Job> job) {
    std::unique_lock lock(mtx);
    queue.emplace(std::move(job));

    lock.unlock();
    cond.notify_one();
}