/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Copyright (C) 2016 Pelagicore AG
** Copyright (C) 2015 Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>
** Contact: https://www.qt.io/licensing/
**
** This file is part of the plugins of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qkmsdevice_p.h"

#include <QtCore/QJsonDocument>
#include <QtCore/QJsonObject>
#include <QtCore/QJsonArray>
#include <QtCore/QFile>
#include <QtCore/QLoggingCategory>

#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])

QT_BEGIN_NAMESPACE

Q_LOGGING_CATEGORY(qLcKmsDebug, "qt.qpa.eglfs.kms")

enum OutputConfiguration {
    OutputConfigOff,
    OutputConfigPreferred,
    OutputConfigCurrent,
    OutputConfigMode,
    OutputConfigModeline
};

int QKmsDevice::crtcForConnector(drmModeResPtr resources, drmModeConnectorPtr connector)
{
    for (int i = 0; i < connector->count_encoders; i++) {
        drmModeEncoderPtr encoder = drmModeGetEncoder(m_dri_fd, connector->encoders[i]);
        if (!encoder) {
            qWarning("Failed to get encoder");
            continue;
        }

        quint32 possibleCrtcs = encoder->possible_crtcs;
        drmModeFreeEncoder(encoder);

        for (int j = 0; j < resources->count_crtcs; j++) {
            bool isPossible = possibleCrtcs & (1 << j);
            bool isAvailable = !(m_crtc_allocator & 1 << resources->crtcs[j]);

            if (isPossible && isAvailable)
                return j;
        }
    }

    return -1;
}

static const char * const connector_type_names[] = { // must match DRM_MODE_CONNECTOR_*
    "None",
    "VGA",
    "DVI",
    "DVI",
    "DVI",
    "Composite",
    "TV",
    "LVDS",
    "CTV",
    "DIN",
    "DP",
    "HDMI",
    "HDMI",
    "TV",
    "eDP",
    "Virtual",
    "DSI"
};

static QByteArray nameForConnector(const drmModeConnectorPtr connector)
{
    QByteArray connectorName("UNKNOWN");

    if (connector->connector_type < ARRAY_LENGTH(connector_type_names))
        connectorName = connector_type_names[connector->connector_type];

    connectorName += QByteArray::number(connector->connector_type_id);

    return connectorName;
}

static bool parseModeline(const QByteArray &text, drmModeModeInfoPtr mode)
{
    char hsync[16];
    char vsync[16];
    float fclock;

    mode->type = DRM_MODE_TYPE_USERDEF;
    mode->hskew = 0;
    mode->vscan = 0;
    mode->vrefresh = 0;
    mode->flags = 0;

    if (sscanf(text.constData(), "%f %hd %hd %hd %hd %hd %hd %hd %hd %15s %15s",
               &fclock,
               &mode->hdisplay,
               &mode->hsync_start,
               &mode->hsync_end,
               &mode->htotal,
               &mode->vdisplay,
               &mode->vsync_start,
               &mode->vsync_end,
               &mode->vtotal, hsync, vsync) != 11)
        return false;

    mode->clock = fclock * 1000;

    if (strcmp(hsync, "+hsync") == 0)
        mode->flags |= DRM_MODE_FLAG_PHSYNC;
    else if (strcmp(hsync, "-hsync") == 0)
        mode->flags |= DRM_MODE_FLAG_NHSYNC;
    else
        return false;

    if (strcmp(vsync, "+vsync") == 0)
        mode->flags |= DRM_MODE_FLAG_PVSYNC;
    else if (strcmp(vsync, "-vsync") == 0)
        mode->flags |= DRM_MODE_FLAG_NVSYNC;
    else
        return false;

    return true;
}

QPlatformScreen *QKmsDevice::createScreenForConnector(drmModeResPtr resources,
                                                      drmModeConnectorPtr connector,
                                                      VirtualDesktopInfo *vinfo)
{
    const QByteArray connectorName = nameForConnector(connector);

    const int crtc = crtcForConnector(resources, connector);
    if (crtc < 0) {
        qWarning() << "No usable crtc/encoder pair for connector" << connectorName;
        return Q_NULLPTR;
    }

    OutputConfiguration configuration;
    QSize configurationSize;
    drmModeModeInfo configurationModeline;

    auto userConfig = m_screenConfig->outputSettings();
    auto userConnectorConfig = userConfig.value(QString::fromUtf8(connectorName));
    // default to the preferred mode unless overridden in the config
    const QByteArray mode = userConnectorConfig.value(QStringLiteral("mode"), QStringLiteral("preferred"))
        .toByteArray().toLower();
    if (mode == "off") {
        configuration = OutputConfigOff;
    } else if (mode == "preferred") {
        configuration = OutputConfigPreferred;
    } else if (mode == "current") {
        configuration = OutputConfigCurrent;
    } else if (sscanf(mode.constData(), "%dx%d", &configurationSize.rwidth(), &configurationSize.rheight()) == 2) {
        configuration = OutputConfigMode;
    } else if (parseModeline(mode, &configurationModeline)) {
        configuration = OutputConfigModeline;
    } else {
        qWarning("Invalid mode \"%s\" for output %s", mode.constData(), connectorName.constData());
        configuration = OutputConfigPreferred;
    }
    if (vinfo) {
        *vinfo = VirtualDesktopInfo();
        vinfo->virtualIndex = userConnectorConfig.value(QStringLiteral("virtualIndex"), INT_MAX).toInt();
        if (userConnectorConfig.contains(QStringLiteral("virtualPos"))) {
            const QByteArray vpos = userConnectorConfig.value(QStringLiteral("virtualPos")).toByteArray();
            const QByteArrayList vposComp = vpos.split(',');
            if (vposComp.count() == 2)
                vinfo->virtualPos = QPoint(vposComp[0].trimmed().toInt(), vposComp[1].trimmed().toInt());
        }
        if (userConnectorConfig.value(QStringLiteral("primary")).toBool())
            vinfo->isPrimary = true;
    }

    const uint32_t crtc_id = resources->crtcs[crtc];

    if (configuration == OutputConfigOff) {
        qCDebug(qLcKmsDebug) << "Turning off output" << connectorName;
        drmModeSetCrtc(m_dri_fd, crtc_id, 0, 0, 0, 0, 0, Q_NULLPTR);
        return Q_NULLPTR;
    }

    // Skip disconnected output
    if (configuration == OutputConfigPreferred && connector->connection == DRM_MODE_DISCONNECTED) {
        qCDebug(qLcKmsDebug) << "Skipping disconnected output" << connectorName;
        return Q_NULLPTR;
    }

    // Get the current mode on the current crtc
    drmModeModeInfo crtc_mode;
    memset(&crtc_mode, 0, sizeof crtc_mode);
    if (drmModeEncoderPtr encoder = drmModeGetEncoder(m_dri_fd, connector->connector_id)) {
        drmModeCrtcPtr crtc = drmModeGetCrtc(m_dri_fd, encoder->crtc_id);
        drmModeFreeEncoder(encoder);

        if (!crtc)
            return Q_NULLPTR;

        if (crtc->mode_valid)
            crtc_mode = crtc->mode;

        drmModeFreeCrtc(crtc);
    }

    QList<drmModeModeInfo> modes;
    modes.reserve(connector->count_modes);
    qCDebug(qLcKmsDebug) << connectorName << "mode count:" << connector->count_modes;
    for (int i = 0; i < connector->count_modes; i++) {
        const drmModeModeInfo &mode = connector->modes[i];
        qCDebug(qLcKmsDebug) << "mode" << i << mode.hdisplay << "x" << mode.vdisplay
                                  << '@' << mode.vrefresh << "hz";
        modes << connector->modes[i];
    }

    int preferred = -1;
    int current = -1;
    int configured = -1;
    int best = -1;

    for (int i = modes.size() - 1; i >= 0; i--) {
        const drmModeModeInfo &m = modes.at(i);

        if (configuration == OutputConfigMode &&
                m.hdisplay == configurationSize.width() &&
                m.vdisplay == configurationSize.height()) {
            configured = i;
        }

        if (!memcmp(&crtc_mode, &m, sizeof m))
            current = i;

        if (m.type & DRM_MODE_TYPE_PREFERRED)
            preferred = i;

        best = i;
    }

    if (configuration == OutputConfigModeline) {
        modes << configurationModeline;
        configured = modes.size() - 1;
    }

    if (current < 0 && crtc_mode.clock != 0) {
        modes << crtc_mode;
        current = mode.size() - 1;
    }

    if (configuration == OutputConfigCurrent)
        configured = current;

    int selected_mode = -1;

    if (configured >= 0)
        selected_mode = configured;
    else if (preferred >= 0)
        selected_mode = preferred;
    else if (current >= 0)
        selected_mode = current;
    else if (best >= 0)
        selected_mode = best;

    if (selected_mode < 0) {
        qWarning() << "No modes available for output" << connectorName;
        return Q_NULLPTR;
    } else {
        int width = modes[selected_mode].hdisplay;
        int height = modes[selected_mode].vdisplay;
        int refresh = modes[selected_mode].vrefresh;
        qCDebug(qLcKmsDebug) << "Selected mode" << selected_mode << ":" << width << "x" << height
                                  << '@' << refresh << "hz for output" << connectorName;
    }

    // physical size from connector < config values < env vars
    int pwidth = qEnvironmentVariableIntValue("QT_QPA_EGLFS_PHYSICAL_WIDTH");
    if (!pwidth)
        pwidth = qEnvironmentVariableIntValue("QT_QPA_PHYSICAL_WIDTH");
    int pheight = qEnvironmentVariableIntValue("QT_QPA_EGLFS_PHYSICAL_HEIGHT");
    if (!pheight)
        pheight = qEnvironmentVariableIntValue("QT_QPA_PHYSICAL_HEIGHT");
    QSizeF physSize(pwidth, pheight);
    if (physSize.isEmpty()) {
        physSize = QSize(userConnectorConfig.value(QStringLiteral("physicalWidth")).toInt(),
                         userConnectorConfig.value(QStringLiteral("physicalHeight")).toInt());
        if (physSize.isEmpty()) {
            physSize.setWidth(connector->mmWidth);
            physSize.setHeight(connector->mmHeight);
        }
    }
    qCDebug(qLcKmsDebug) << "Physical size is" << physSize << "mm" << "for output" << connectorName;

    QKmsOutput output = {
        QString::fromUtf8(connectorName),
        connector->connector_id,
        crtc_id,
        physSize,
        selected_mode,
        false,
        drmModeGetCrtc(m_dri_fd, crtc_id),
        modes,
        connector->subpixel,
        connectorProperty(connector, QByteArrayLiteral("DPMS")),
        false,
        0,
        false
    };

    bool ok;
    int idx = qEnvironmentVariableIntValue("QT_QPA_EGLFS_KMS_PLANE_INDEX", &ok);
    if (ok) {
        drmModePlaneRes *planeResources = drmModeGetPlaneResources(m_dri_fd);
        if (planeResources) {
            if (idx >= 0 && idx < int(planeResources->count_planes)) {
                drmModePlane *plane = drmModeGetPlane(m_dri_fd, planeResources->planes[idx]);
                if (plane) {
                    output.wants_plane = true;
                    output.plane_id = plane->plane_id;
                    qCDebug(qLcKmsDebug, "Forcing plane index %d, plane id %u (belongs to crtc id %u)",
                            idx, plane->plane_id, plane->crtc_id);
                    drmModeFreePlane(plane);
                }
            } else {
                qWarning("Invalid plane index %d, must be between 0 and %u", idx, planeResources->count_planes - 1);
            }
        }
    }

    m_crtc_allocator |= (1 << output.crtc_id);
    m_connector_allocator |= (1 << output.connector_id);

    return createScreen(output);
}

drmModePropertyPtr QKmsDevice::connectorProperty(drmModeConnectorPtr connector, const QByteArray &name)
{
    drmModePropertyPtr prop;

    for (int i = 0; i < connector->count_props; i++) {
        prop = drmModeGetProperty(m_dri_fd, connector->props[i]);
        if (!prop)
            continue;
        if (strcmp(prop->name, name.constData()) == 0)
            return prop;
        drmModeFreeProperty(prop);
    }

    return Q_NULLPTR;
}

QKmsDevice::QKmsDevice(QKmsScreenConfig *screenConfig, const QString &path)
    : m_screenConfig(screenConfig)
    , m_path(path)
    , m_dri_fd(-1)
    , m_crtc_allocator(0)
    , m_connector_allocator(0)
{
    if (m_path.isEmpty()) {
        m_path = m_screenConfig->devicePath();
        qCDebug(qLcKmsDebug, "Using DRM device %s specified in config file", qPrintable(m_path));
        if (m_path.isEmpty())
            qFatal("No DRM device given");
    } else {
        qCDebug(qLcKmsDebug, "Using backend-provided DRM device %s", qPrintable(m_path));
    }
}

QKmsDevice::~QKmsDevice()
{
}

struct OrderedScreen
{
    OrderedScreen() : screen(nullptr) { }
    OrderedScreen(QPlatformScreen *screen, const QKmsDevice::VirtualDesktopInfo &vinfo)
        : screen(screen), vinfo(vinfo) { }
    QPlatformScreen *screen;
    QKmsDevice::VirtualDesktopInfo vinfo;
};

QDebug operator<<(QDebug dbg, const OrderedScreen &s)
{
    QDebugStateSaver saver(dbg);
    dbg.nospace() << "OrderedScreen(QPlatformScreen=" << s.screen << " (" << s.screen->name() << ") : "
                  << s.vinfo.virtualIndex
                  << " / " << s.vinfo.virtualPos
                  << " / primary: " << s.vinfo.isPrimary
                  << ")";
    return dbg;
}

static bool orderedScreenLessThan(const OrderedScreen &a, const OrderedScreen &b)
{
    return a.vinfo.virtualIndex < b.vinfo.virtualIndex;
}

void QKmsDevice::createScreens()
{
    drmModeResPtr resources = drmModeGetResources(m_dri_fd);
    if (!resources) {
        qWarning("drmModeGetResources failed");
        return;
    }

    QVector<OrderedScreen> screens;

    int wantedConnectorIndex = -1;
    bool ok;
    int idx = qEnvironmentVariableIntValue("QT_QPA_EGLFS_KMS_CONNECTOR_INDEX", &ok);
    if (ok) {
        if (idx >= 0 && idx < resources->count_connectors)
            wantedConnectorIndex = idx;
        else
            qWarning("Invalid connector index %d, must be between 0 and %u", idx, resources->count_connectors - 1);
    }

    for (int i = 0; i < resources->count_connectors; i++) {
        if (wantedConnectorIndex >= 0 && i != wantedConnectorIndex)
            continue;

        drmModeConnectorPtr connector = drmModeGetConnector(m_dri_fd, resources->connectors[i]);
        if (!connector)
            continue;

        VirtualDesktopInfo vinfo;
        QPlatformScreen *screen = createScreenForConnector(resources, connector, &vinfo);
        if (screen)
            screens.append(OrderedScreen(screen, vinfo));

        drmModeFreeConnector(connector);
    }

    drmModeFreeResources(resources);

    // Use stable sort to preserve the original (DRM connector) order
    // for outputs with unspecified indices.
    std::stable_sort(screens.begin(), screens.end(), orderedScreenLessThan);
    qCDebug(qLcKmsDebug) << "Sorted screen list:" << screens;

    QPoint pos(0, 0);
    QList<QPlatformScreen *> siblings;
    QVector<QPoint> virtualPositions;
    int primarySiblingIdx = -1;

    for (const OrderedScreen &orderedScreen : screens) {
        QPlatformScreen *s = orderedScreen.screen;
        QPoint virtualPos(0, 0);
        // set up a horizontal or vertical virtual desktop
        if (orderedScreen.vinfo.virtualPos.isNull()) {
            virtualPos = pos;
            if (m_screenConfig->virtualDesktopLayout() == QKmsScreenConfig::VirtualDesktopLayoutVertical)
                pos.ry() += s->geometry().height();
            else
                pos.rx() += s->geometry().width();
        } else {
            virtualPos = orderedScreen.vinfo.virtualPos;
        }
        qCDebug(qLcKmsDebug) << "Adding QPlatformScreen" << s << "(" << s->name() << ")"
                             << "to QPA with geometry" << s->geometry()
                             << "and isPrimary=" << orderedScreen.vinfo.isPrimary;
        // The order in qguiapp's screens list will match the order set by
        // virtualIndex. This is not only handy but also required since for instance
        // evdevtouch relies on it when performing touch device - screen mapping.
        if (!m_screenConfig->separateScreens()) {
            siblings.append(s);
            virtualPositions.append(virtualPos);
            if (orderedScreen.vinfo.isPrimary)
                primarySiblingIdx = siblings.count() - 1;
        } else {
            registerScreen(s, orderedScreen.vinfo.isPrimary, virtualPos, QList<QPlatformScreen *>() << s);
        }
    }

    if (!m_screenConfig->separateScreens()) {
        // enable the virtual desktop
        for (int i = 0; i < siblings.count(); ++i)
            registerScreen(siblings[i], i == primarySiblingIdx, virtualPositions[i], siblings);
    }
}

int QKmsDevice::fd() const
{
    return m_dri_fd;
}

QString QKmsDevice::devicePath() const
{
    return m_path;
}

void QKmsDevice::setFd(int fd)
{
    m_dri_fd = fd;
}

QKmsScreenConfig *QKmsDevice::screenConfig() const
{
    return m_screenConfig;
}

QKmsScreenConfig::QKmsScreenConfig()
    : m_hwCursor(true)
    , m_separateScreens(false)
    , m_pbuffers(false)
    , m_virtualDesktopLayout(VirtualDesktopLayoutHorizontal)
{
    loadConfig();
}

void QKmsScreenConfig::loadConfig()
{
    QByteArray json = qgetenv("QT_QPA_EGLFS_KMS_CONFIG");
    if (json.isEmpty()) {
        json = qgetenv("QT_QPA_KMS_CONFIG");
        if (json.isEmpty())
            return;
    }

    qCDebug(qLcKmsDebug) << "Loading KMS setup from" << json;

    QFile file(QString::fromUtf8(json));
    if (!file.open(QFile::ReadOnly)) {
        qCWarning(qLcKmsDebug) << "Could not open config file"
                               << json << "for reading";
        return;
    }

    const QJsonDocument doc = QJsonDocument::fromJson(file.readAll());
    if (!doc.isObject()) {
        qCWarning(qLcKmsDebug) << "Invalid config file" << json
                              << "- no top-level JSON object";
        return;
    }

    const QJsonObject object = doc.object();

    m_hwCursor = object.value(QLatin1String("hwcursor")).toBool(m_hwCursor);
    m_pbuffers = object.value(QLatin1String("pbuffers")).toBool(m_pbuffers);
    m_devicePath = object.value(QLatin1String("device")).toString();
    m_separateScreens = object.value(QLatin1String("separateScreens")).toBool(m_separateScreens);

    const QString vdOriString = object.value(QLatin1String("virtualDesktopLayout")).toString();
    if (!vdOriString.isEmpty()) {
        if (vdOriString == QLatin1String("horizontal"))
            m_virtualDesktopLayout = VirtualDesktopLayoutHorizontal;
        else if (vdOriString == QLatin1String("vertical"))
            m_virtualDesktopLayout = VirtualDesktopLayoutVertical;
        else
            qCWarning(qLcKmsDebug) << "Unknown virtualDesktopOrientation value" << vdOriString;
    }

    const QJsonArray outputs = object.value(QLatin1String("outputs")).toArray();
    for (int i = 0; i < outputs.size(); i++) {
        const QVariantMap outputSettings = outputs.at(i).toObject().toVariantMap();

        if (outputSettings.contains(QStringLiteral("name"))) {
            const QString name = outputSettings.value(QStringLiteral("name")).toString();

            if (m_outputSettings.contains(name)) {
                qCDebug(qLcKmsDebug) << "Output" << name << "configured multiple times!";
            }

            m_outputSettings.insert(name, outputSettings);
        }
    }

    qCDebug(qLcKmsDebug) << "Requested configuration (some settings may be ignored):\n"
                         << "\thwcursor:" << m_hwCursor << "\n"
                         << "\tpbuffers:" << m_pbuffers << "\n"
                         << "\tseparateScreens:" << m_separateScreens << "\n"
                         << "\tvirtualDesktopLayout:" << m_virtualDesktopLayout << "\n"
                         << "\toutputs:" << m_outputSettings;
}

void QKmsOutput::restoreMode(QKmsDevice *device)
{
    if (mode_set && saved_crtc) {
        drmModeSetCrtc(device->fd(),
                       saved_crtc->crtc_id,
                       saved_crtc->buffer_id,
                       0, 0,
                       &connector_id, 1,
                       &saved_crtc->mode);
        mode_set = false;
    }
}

void QKmsOutput::cleanup(QKmsDevice *device)
{
    if (dpms_prop) {
        drmModeFreeProperty(dpms_prop);
        dpms_prop = nullptr;
    }

    restoreMode(device);

    if (saved_crtc) {
        drmModeFreeCrtc(saved_crtc);
        saved_crtc = nullptr;
    }
}

QPlatformScreen::SubpixelAntialiasingType QKmsOutput::subpixelAntialiasingTypeHint() const
{
    switch (subpixel) {
    default:
    case DRM_MODE_SUBPIXEL_UNKNOWN:
    case DRM_MODE_SUBPIXEL_NONE:
        return QPlatformScreen::Subpixel_None;
    case DRM_MODE_SUBPIXEL_HORIZONTAL_RGB:
        return QPlatformScreen::Subpixel_RGB;
    case DRM_MODE_SUBPIXEL_HORIZONTAL_BGR:
        return QPlatformScreen::Subpixel_BGR;
    case DRM_MODE_SUBPIXEL_VERTICAL_RGB:
        return QPlatformScreen::Subpixel_VRGB;
    case DRM_MODE_SUBPIXEL_VERTICAL_BGR:
        return QPlatformScreen::Subpixel_VBGR;
    }
}

void QKmsOutput::setPowerState(QKmsDevice *device, QPlatformScreen::PowerState state)
{
    if (dpms_prop)
        drmModeConnectorSetProperty(device->fd(), connector_id,
                                    dpms_prop->prop_id, (int) state);
}

QT_END_NAMESPACE