/*
    SPDX-FileCopyrightText: 2010 Michael Zanetti <mzanetti@kde.org>
    SPDX-FileCopyrightText: 2010-2012 Lukáš Tinkl <ltinkl@redhat.com>

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

#include "udisksopticaldisc.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include <QMap>
#include <QSharedMemory>
#include <QSystemSemaphore>
#include <QThreadStorage>

#include "soliddefs_p.h"
#include "udisks2.h"
#include "udisks_debug.h"

// inspired by http://cgit.freedesktop.org/hal/tree/hald/linux/probing/probe-volume.c
static Solid::OpticalDisc::ContentType advancedDiscDetect(const QByteArray &device_file)
{
    /* the discs block size */
    unsigned short bs;
    /* the path table size */
    unsigned short ts;
    /* the path table location (in blocks) */
    unsigned int tl;
    /* length of the directory name in current path table entry */
    unsigned char len_di = 0;
    /* the number of the parent directory's path table entry */
    unsigned int parent = 0;
    /* filename for the current path table entry */
    char dirname[256];
    /* our position into the path table */
    int pos = 0;
    /* the path table record we're on */
    int curr_record = 1;
    /* import debug category */
    using Solid::Backends::UDisks2::UDISKS2;

    Solid::OpticalDisc::ContentType result = Solid::OpticalDisc::NoContent;

    int fd = open(device_file.constData(), O_RDONLY);

    /* read the block size */
    lseek(fd, 0x8080, SEEK_CUR);
    if (read(fd, &bs, 2) != 2) {
        qCDebug(UDISKS2, "Advanced probing on %s failed while reading block size", qPrintable(device_file));
        goto out;
    }

    /* read in size of path table */
    lseek(fd, 2, SEEK_CUR);
    if (read(fd, &ts, 2) != 2) {
        qCDebug(UDISKS2, "Advanced probing on %s failed while reading path table size", qPrintable(device_file));
        goto out;
    }

    /* read in which block path table is in */
    lseek(fd, 6, SEEK_CUR);
    if (read(fd, &tl, 4) != 4) {
        qCDebug(UDISKS2, "Advanced probing on %s failed while reading path table block", qPrintable(device_file));
        goto out;
    }

    /* seek to the path table */
    lseek(fd, bs * tl, SEEK_SET);

    /* loop through the path table entries */
    while (pos < ts) {
        /* get the length of the filename of the current entry */
        if (read(fd, &len_di, 1) != 1) {
            qCDebug(UDISKS2, "Advanced probing on %s failed, cannot read more entries", qPrintable(device_file));
            break;
        }

        /* get the record number of this entry's parent
           i'm pretty sure that the 1st entry is always the top directory */
        lseek(fd, 5, SEEK_CUR);
        if (read(fd, &parent, 2) != 2) {
            qCDebug(UDISKS2, "Advanced probing on %s failed, couldn't read parent entry", qPrintable(device_file));
            break;
        }

        /* read the name */
        if (read(fd, dirname, len_di) != len_di) {
            qCDebug(UDISKS2, "Advanced probing on %s failed, couldn't read the entry name", qPrintable(device_file));
            break;
        }
        dirname[len_di] = 0;

        /* if we found a folder that has the root as a parent, and the directory name matches
           one of the special directories then set the properties accordingly */
        if (parent == 1) {
            if (!strcasecmp(dirname, "VIDEO_TS")) {
                qCDebug(UDISKS2, "Disc in %s is a Video DVD", qPrintable(device_file));
                result = Solid::OpticalDisc::VideoDvd;
                break;
            } else if (!strcasecmp(dirname, "BDMV")) {
                qCDebug(UDISKS2, "Disc in %s is a Blu-ray video disc", qPrintable(device_file));
                result = Solid::OpticalDisc::VideoBluRay;
                break;
            } else if (!strcasecmp(dirname, "VCD")) {
                qCDebug(UDISKS2, "Disc in %s is a Video CD", qPrintable(device_file));
                result = Solid::OpticalDisc::VideoCd;
                break;
            } else if (!strcasecmp(dirname, "SVCD")) {
                qCDebug(UDISKS2, "Disc in %s is a Super Video CD", qPrintable(device_file));
                result = Solid::OpticalDisc::SuperVideoCd;
                break;
            }
        }

        /* all path table entries are padded to be even,
           so if this is an odd-length table, seek a byte to fix it */
        if (len_di % 2 == 1) {
            lseek(fd, 1, SEEK_CUR);
            pos++;
        }

        /* update our position */
        pos += 8 + len_di;
        curr_record++;
    }

    close(fd);
    return result;

out:
    /* go back to the start of the file */
    lseek(fd, 0, SEEK_SET);
    close(fd);
    return result;
}

using namespace Solid::Backends::UDisks2;

class ContentTypesCache
{
public:
    ContentTypesCache()
        : m_n(0)
    {
    }

    void add(const OpticalDisc::Identity &key, Solid::OpticalDisc::ContentTypes content)
    {
        if (!find(key)) {
            m_n = qMin(m_n + 1, sizeof(m_info) / sizeof(*m_info));
            moveToFront(m_n - 1);
            front().first = key;
        }
        front().second = content;
    }

    bool find(const OpticalDisc::Identity &key)
    {
        for (size_t i = 0; i < m_n; i++) {
            if (m_info[i].first == key) {
                moveToFront(i);
                return true;
            }
        }
        return false;
    }

    QPair<OpticalDisc::Identity, Solid::OpticalDisc::ContentTypes> &front()
    {
        return *m_info;
    }

private:
    void moveToFront(size_t i)
    {
        while (i) {
            qSwap(m_info[i - 1], m_info[i]);
            --i;
        }
    }

    size_t m_n;
    QPair<OpticalDisc::Identity, Solid::OpticalDisc::ContentTypes> m_info[100];
};

class SharedContentTypesCache
{
private:
    ContentTypesCache *m_pointer;
    QSystemSemaphore m_semaphore;
    QSharedMemory m_shmem;

    struct Unlocker {
    public:
        Unlocker(QSharedMemory *mem)
            : m_mem(mem)
        {
        }
        ~Unlocker()
        {
            m_mem->unlock();
        }
        Unlocker(const Unlocker &) = delete;
        Unlocker &operator=(const Unlocker &) = delete;

    private:
        QSharedMemory *m_mem;
    };

    struct Releaser {
    public:
        Releaser(QSystemSemaphore *sem)
            : m_sem(sem)
        {
        }
        ~Releaser()
        {
            m_sem->release();
        }
        Releaser(const Releaser &) = delete;
        Releaser &operator=(const Releaser &) = delete;

    private:
        QSystemSemaphore *m_sem;
    };

    static QString getKey()
    {
        static const QString keyTemplate("solid-disk-info-1-%1-%2");
        static const QString tableSize(QString::number(sizeof(ContentTypesCache)));

        return keyTemplate.arg(tableSize, QString::number(geteuid()));
    }

public:
    SharedContentTypesCache()
        : m_pointer(nullptr)
        , m_semaphore(getKey() + "sem", 1)
        , m_shmem(getKey() + "mem")
    {
        if (!m_semaphore.acquire()) {
            return;
        }
        Releaser releaser(&m_semaphore);

        if (m_shmem.attach()) {
            m_pointer = reinterpret_cast<ContentTypesCache *>(m_shmem.data());
            return;
        }

        if (!m_shmem.create(sizeof(ContentTypesCache))) {
            return;
        }

        if (!m_shmem.lock()) {
            m_shmem.detach();
            return;
        }
        Unlocker unlocker(&m_shmem);

        m_pointer = new (m_shmem.data()) ContentTypesCache;
    }

    Solid::OpticalDisc::ContentTypes getContent(const OpticalDisc::Identity &info, const QByteArray &file)
    {
        if (!m_pointer) {
            return advancedDiscDetect(file);
        }

        if (!m_semaphore.acquire()) {
            return advancedDiscDetect(file);
        }
        Releaser releaser(&m_semaphore);

        if (!m_shmem.lock()) {
            return advancedDiscDetect(file);
        }
        Unlocker unlocker(&m_shmem);

        if (!m_pointer->find(info)) {
            m_pointer->add(info, advancedDiscDetect(file));
        }

        Solid::OpticalDisc::ContentTypes content = m_pointer->front().second;
        return content;
    }

    ~SharedContentTypesCache()
    {
        m_semaphore.acquire();
        Releaser releaser(&m_semaphore);
        m_shmem.detach();
    }
};

Q_GLOBAL_STATIC(QThreadStorage<SharedContentTypesCache>, sharedContentTypesCache)

OpticalDisc::Identity::Identity()
    : m_detectTime(0)
    , m_size(0)
    , m_labelHash(0)
{
}

OpticalDisc::Identity::Identity(const Device &device, const Device &drive)
    : m_detectTime(drive.prop("TimeMediaDetected").toLongLong())
    , m_size(device.prop("Size").toLongLong())
    , m_labelHash(qHash(device.prop("IdLabel").toString()))
{
}

bool OpticalDisc::Identity::operator==(const OpticalDisc::Identity &b) const
{
    /* clang-format off */
    return m_detectTime == b.m_detectTime
        && m_size == b.m_size
        && m_labelHash == b.m_labelHash;
    /* clang-format on */
}

OpticalDisc::OpticalDisc(Device *dev)
    : StorageVolume(dev)
{
#if UDEV_FOUND
    UdevQt::Client client(this);
    m_udevDevice = client.deviceByDeviceFile(device());
    // qDebug() << "udev device:" << m_udevDevice.name() << "valid:" << m_udevDevice.isValid();
    /*qDebug() << "\tProperties:" << */ m_udevDevice.deviceProperties(); // initialize the properties DB so that it doesn't crash further down, #298416
#endif

    m_drive = new Device(m_device->drivePath());
}

OpticalDisc::~OpticalDisc()
{
    delete m_drive;
}

qulonglong OpticalDisc::capacity() const
{
    return m_device->prop("Size").toULongLong();
}

bool OpticalDisc::isRewritable() const
{
    // the hard way, udisks has no notion of a disc "rewritability"
    const QString mediaType = media();
    /* clang-format off */
    return mediaType == "optical_cd_rw"
        || mediaType == "optical_dvd_rw"
        || mediaType == "optical_dvd_ram"
        || mediaType == "optical_dvd_plus_rw"
        || mediaType == "optical_dvd_plus_rw_dl"
        || mediaType == "optical_bd_re"
        || mediaType == "optical_hddvd_rw";
    /* clang-format on */
}

bool OpticalDisc::isBlank() const
{
    return m_drive->prop("OpticalBlank").toBool();
}

bool OpticalDisc::isAppendable() const
{
    // qDebug() << "appendable prop" << m_udevDevice.deviceProperty("ID_CDROM_MEDIA_STATE");
#if UDEV_FOUND
    return m_udevDevice.deviceProperty("ID_CDROM_MEDIA_STATE").toString() == QLatin1String("appendable");
#elif defined(Q_OS_FREEBSD) || defined(Q_OS_OPENBSD)
    return m_device->prop("bsdisks_IsAppendable").toBool();
#else
#error Implement this or stub this out for your platform
#endif
}

Solid::OpticalDisc::DiscType OpticalDisc::discType() const
{
    QMap<Solid::OpticalDisc::DiscType, QString> map;
    map[Solid::OpticalDisc::CdRom] = "optical_cd";
    map[Solid::OpticalDisc::CdRecordable] = "optical_cd_r";
    map[Solid::OpticalDisc::CdRewritable] = "optical_cd_rw";
    map[Solid::OpticalDisc::DvdRom] = "optical_dvd";
    map[Solid::OpticalDisc::DvdRecordable] = "optical_dvd_r";
    map[Solid::OpticalDisc::DvdRewritable] = "optical_dvd_rw";
    map[Solid::OpticalDisc::DvdRam] = "optical_dvd_ram";
    map[Solid::OpticalDisc::DvdPlusRecordable] = "optical_dvd_plus_r";
    map[Solid::OpticalDisc::DvdPlusRewritable] = "optical_dvd_plus_rw";
    map[Solid::OpticalDisc::DvdPlusRecordableDuallayer] = "optical_dvd_plus_r_dl";
    map[Solid::OpticalDisc::DvdPlusRewritableDuallayer] = "optical_dvd_plus_rw_dl";
    map[Solid::OpticalDisc::BluRayRom] = "optical_bd";
    map[Solid::OpticalDisc::BluRayRecordable] = "optical_bd_r";
    map[Solid::OpticalDisc::BluRayRewritable] = "optical_bd_re";
    map[Solid::OpticalDisc::HdDvdRom] = "optical_hddvd";
    map[Solid::OpticalDisc::HdDvdRecordable] = "optical_hddvd_r";
    map[Solid::OpticalDisc::HdDvdRewritable] = "optical_hddvd_rw";
    // TODO add these to Solid
    // map[Solid::OpticalDisc::MagnetoOptical] ="optical_mo";
    // map[Solid::OpticalDisc::MountRainer] ="optical_mrw";
    // map[Solid::OpticalDisc::MountRainerWritable] ="optical_mrw_w";

    return map.key(media(), Solid::OpticalDisc::UnknownDiscType); // FIXME optimize, lookup by value, not key
}

Solid::OpticalDisc::ContentTypes OpticalDisc::availableContent() const
{
    if (isBlank()) {
        return Solid::OpticalDisc::NoContent;
    }

    Solid::OpticalDisc::ContentTypes content = Solid::OpticalDisc::NoContent;
    const bool hasData = m_drive->prop("OpticalNumDataTracks").toUInt() > 0;
    const bool hasAudio = m_drive->prop("OpticalNumAudioTracks").toUInt() > 0;

    if (hasData) {
        content |= Solid::OpticalDisc::Data;

        Identity newIdentity(*m_device, *m_drive);
        if (!(m_identity == newIdentity)) {
            QByteArray deviceFile(m_device->prop("Device").toByteArray());
            m_cachedContent = sharedContentTypesCache->localData().getContent(newIdentity, deviceFile);
            m_identity = newIdentity;
        }

        content |= m_cachedContent;
    }
    if (hasAudio) {
        content |= Solid::OpticalDisc::Audio;
    }

    return content;
}

QString OpticalDisc::media() const
{
    return m_drive->prop("Media").toString();
}