/**
 * @file EventLoop.cpp
 * @author apio (cloudapio.eu)
 * @brief Base class for event-driven applications.
 *
 * @copyright Copyright (c) 2023, the Luna authors.
 *
 */

#include <errno.h>
#include <os/EventLoop.h>
#include <os/File.h>
#include <string.h>

static os::EventLoop* s_the = nullptr;

namespace os
{
    EventLoop::EventLoop()
    {
        s_the = this;
    }

    EventLoop::~EventLoop()
    {
        s_the = nullptr;
    }

    EventLoop& EventLoop::the()
    {
        check(s_the);
        return *s_the;
    }

    Result<void> EventLoop::register_fd_listener(int fd, void (*listener)(int, int))
    {
        TRY(m_fd_listeners.try_set(fd, listener));
        TRY(m_pollfds.try_append({ .fd = fd, .events = POLLIN, .revents = 0 }));
        return {};
    }

    int EventLoop::run()
    {
        while (!m_should_quit)
        {
            for (auto& pfd : m_pollfds) { pfd.revents = 0; }

            int rc = poll(m_pollfds.data(), m_pollfds.size(), 1000);
            if (!rc) continue;
            if (rc < 0 && errno != EINTR)
            {
                os::println("poll: error: %s", strerror(errno));
                return 1;
            }

            for (usize i = 0; i < m_fd_listeners.size(); i++)
            {
                if (m_pollfds[i].revents)
                    m_fd_listeners.try_get(m_pollfds[i].fd)
                        .value()(m_pollfds[i].fd, m_pollfds[i].revents); // Invoke the callback
            }
        }

        return m_quit_status;
    }

    void EventLoop::quit(int status)
    {
        m_quit_status = status;
        m_should_quit = true;
    }
}