/*
 * pm-inhibit - Power Management Inhibition Tool
 * Copyright (C) 2022 Damien Goutte-Gattat
 *
 * 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 <http://www.gnu.org/licenses/>.
 */

#include "inhibitor.h"

#include <QDBusConnection>
#include <QDBusInterface>
#include <QDBusReply>

#define LOGIN1_NAME "org.freedesktop.login1"
#define LOGIN1_PATH "/org/freekdesktop/login1"

#define INHIBIT_NAME "org.freedesktop.PowerManagement.Inhibit"
#define INHIBIT_PATH "/org/freedesktop/PowerManagement/Inhibit"

Inhibitor::Inhibitor(const QString& program, const QString& reason)
{
    m_cookie = nullptr;
    m_fallbackCookie = 0;

    /* First try the modern login1 interface. */
    QDBusInterface manager(LOGIN1_NAME, LOGIN1_PATH,
            LOGIN1_NAME ".Manager", QDBusConnection::systemBus());
    QDBusReply<QDBusUnixFileDescriptor> reply = manager.call("Inhibit",
            "idle", program, reason, "block");
    if ( reply.isValid() ) {
        /* We need a copy of the file descriptor to prevent the lock from
         * being automatically released at the end of the current scope. */
        m_cookie = new QDBusUnixFileDescriptor(reply.value());
    }
    else {
        /* Fallback to the old PowerManagement interface. */
        QDBusInterface inhibit(INHIBIT_NAME, INHIBIT_PATH, INHIBIT_NAME,
                QDBusConnection::sessionBus());
        QDBusReply<unsigned> reply = inhibit.call("Inhibit", program, reason);
        if ( reply.isValid() ) {
            m_fallbackCookie = reply.value();
        }
    }
}

Inhibitor::~Inhibitor()
{
    if ( m_cookie != nullptr ) {
        /* Deleting this object will close the associated file
         * descriptor, which will in turn release the lock. */
        delete m_cookie;
    }
    else if ( m_fallbackCookie != 0 ) {
        /* If we had to use the old interface to acquire the lock, it
         * has to be explicitly released. */
        QDBusInterface inhibit(INHIBIT_NAME, INHIBIT_PATH, INHIBIT_NAME,
                QDBusConnection::sessionBus());
        inhibit.call("UnInhibit", m_fallbackCookie);
    }
}

bool
Inhibitor::isInhibited()
{
    return m_cookie != nullptr || m_fallbackCookie != 0;
}