/*
    SPDX-FileCopyrightText: 2009 Benjamin K. Stuhl <bks24@cornell.edu>

    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
*/

#include "udevqtclient.h"
#include "udevqt_p.h"

#include <powerdevil_debug.h>

#include <QSocketNotifier>
#include <qplatformdefs.h>

namespace UdevQt
{
ClientPrivate::ClientPrivate(Client *q_)
    : udev(nullptr)
    , monitor(nullptr)
    , q(q_)
    , monitorNotifier(nullptr)
{
}

ClientPrivate::~ClientPrivate()
{
    udev_unref(udev);
    delete monitorNotifier;

    if (monitor)
        udev_monitor_unref(monitor);
}

void ClientPrivate::init(const QStringList &subsystemList, ListenToWhat what)
{
    udev = udev_new();

    if (what != ListenToNone) {
        setWatchedSubsystems(subsystemList);
    }
}

void ClientPrivate::setWatchedSubsystems(const QStringList &subsystemList)
{
    // create a listener
    struct udev_monitor *newM = udev_monitor_new_from_netlink(udev, "udev");

    if (!newM) {
        qCWarning(POWERDEVIL, "UdevQt: unable to create udev monitor connection");
        return;
    }

    // apply our filters; an empty list means listen to everything
    for (const QString &subsysDevtype : subsystemList) {
        int ix = subsysDevtype.indexOf(u'/');

        if (ix > 0) {
            QByteArray subsystem = QStringView(subsysDevtype).left(ix).toLatin1();
            QByteArray devType = QStringView(subsysDevtype).mid(ix + 1).toLatin1();
            udev_monitor_filter_add_match_subsystem_devtype(newM, subsystem.constData(), devType.constData());
        } else {
            udev_monitor_filter_add_match_subsystem_devtype(newM, subsysDevtype.toLatin1().constData(), nullptr);
        }
    }

    // start the new monitor receiving
    udev_monitor_enable_receiving(newM);
    QSocketNotifier *sn = new QSocketNotifier(udev_monitor_get_fd(newM), QSocketNotifier::Read);
    QObject::connect(sn, SIGNAL(activated(int)), q, SLOT(_uq_monitorReadyRead(int)));

    // kill any previous monitor
    delete monitorNotifier;
    if (monitor)
        udev_monitor_unref(monitor);

    // and save our new one
    monitor = newM;
    monitorNotifier = sn;
    watchedSubsystems = subsystemList;
}

void ClientPrivate::_uq_monitorReadyRead(int fd)
{
    Q_UNUSED(fd);
    monitorNotifier->setEnabled(false);
    struct udev_device *dev = udev_monitor_receive_device(monitor);
    monitorNotifier->setEnabled(true);

    if (!dev)
        return;

    Device device(new DevicePrivate(dev, false));

    QByteArray action(udev_device_get_action(dev));
    if (action == "add") {
        Q_EMIT q->deviceAdded(device);
    } else if (action == "remove") {
        Q_EMIT q->deviceRemoved(device);
    } else if (action == "change") {
        Q_EMIT q->deviceChanged(device);
    } else if (action == "online") {
        Q_EMIT q->deviceOnlined(device);
    } else if (action == "offline") {
        Q_EMIT q->deviceOfflined(device);
    } else {
        qCWarning(POWERDEVIL, "UdevQt: unhandled device action \"%s\"", action.constData());
    }
}

DeviceList ClientPrivate::deviceListFromEnumerate(struct udev_enumerate *en)
{
    DeviceList ret;
    struct udev_list_entry *list, *entry;

    udev_enumerate_scan_devices(en);
    list = udev_enumerate_get_list_entry(en);
    udev_list_entry_foreach(entry, list)
    {
        struct udev_device *ud = udev_device_new_from_syspath(udev_enumerate_get_udev(en), udev_list_entry_get_name(entry));

        if (!ud)
            continue;

        ret << Device(new DevicePrivate(ud, false));
    }

    udev_enumerate_unref(en);

    return ret;
}

Client::Client(QObject *parent)
    : QObject(parent)
    , d(new ClientPrivate(this))
{
    d->init(QStringList(), ClientPrivate::ListenToNone);
}

Client::Client(const QStringList &subsystemList, QObject *parent)
    : QObject(parent)
    , d(new ClientPrivate(this))
{
    d->init(subsystemList, ClientPrivate::ListenToList);
}

Client::~Client()
{
    delete d;
}

QStringList Client::watchedSubsystems() const
{
    // we're watching a specific list
    if (!d->watchedSubsystems.isEmpty())
        return d->watchedSubsystems;

    // we're not watching anything
    if (!d->monitor)
        return QStringList();

    // we're watching everything: figure out what "everything" currently is
    // we don't cache it, since it may be subject to change, depending on hotplug
    struct udev_enumerate *en = udev_enumerate_new(d->udev);
    udev_enumerate_scan_subsystems(en);
    QStringList s = listFromListEntry(udev_enumerate_get_list_entry(en));
    udev_enumerate_unref(en);
    return s;
}

void Client::setWatchedSubsystems(const QStringList &subsystemList)
{
    d->setWatchedSubsystems(subsystemList);
}

DeviceList Client::devicesByProperty(const QString &property, const QVariant &value)
{
    struct udev_enumerate *en = udev_enumerate_new(d->udev);

    if (value.isValid()) {
        udev_enumerate_add_match_property(en, property.toLatin1().constData(), value.toString().toLatin1().constData());
    } else {
        udev_enumerate_add_match_property(en, property.toLatin1().constData(), nullptr);
    }

    return d->deviceListFromEnumerate(en);
}

DeviceList Client::allDevices()
{
    struct udev_enumerate *en = udev_enumerate_new(d->udev);
    return d->deviceListFromEnumerate(en);
}

DeviceList Client::devicesBySubsystem(const QString &subsystem)
{
    struct udev_enumerate *en = udev_enumerate_new(d->udev);

    udev_enumerate_add_match_subsystem(en, subsystem.toLatin1().constData());
    return d->deviceListFromEnumerate(en);
}

Device Client::deviceByDeviceFile(const QString &deviceFile)
{
    QT_STATBUF sb;

    if (QT_STAT(deviceFile.toLatin1().constData(), &sb) != 0)
        return Device();

    struct udev_device *ud = nullptr;

    if (S_ISBLK(sb.st_mode))
        ud = udev_device_new_from_devnum(d->udev, 'b', sb.st_rdev);
    else if (S_ISCHR(sb.st_mode))
        ud = udev_device_new_from_devnum(d->udev, 'c', sb.st_rdev);

    if (!ud)
        return Device();

    return Device(new DevicePrivate(ud, false));
}

Device Client::deviceBySysfsPath(const QString &sysfsPath)
{
    struct udev_device *ud = udev_device_new_from_syspath(d->udev, sysfsPath.toLatin1().constData());

    if (!ud)
        return Device();

    return Device(new DevicePrivate(ud, false));
}

Device Client::deviceBySubsystemAndName(const QString &subsystem, const QString &name)
{
    struct udev_device *ud = udev_device_new_from_subsystem_sysname(d->udev, subsystem.toLatin1().constData(), name.toLatin1().constData());

    if (!ud)
        return Device();

    return Device(new DevicePrivate(ud, false));
}

}

#include "moc_udevqtclient.cpp"