/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** 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 http://www.qt.io/terms-conditions. For further
** information use the contact form at http://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 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qandroidcamerasession.h"

#include "androidcamera.h"
#include "androidmultimediautils.h"
#include "qandroidvideooutput.h"
#include "qandroidmediavideoprobecontrol.h"
#include "qandroidmultimediautils.h"
#include <QtConcurrent/qtconcurrentrun.h>
#include <qfile.h>
#include <qguiapplication.h>
#include <qdebug.h>
#include <qvideoframe.h>

QT_BEGIN_NAMESPACE

class DataVideoBuffer : public QAbstractVideoBuffer
{
public:
    DataVideoBuffer(const QByteArray &d, int bpl = -1)
        : QAbstractVideoBuffer(NoHandle)
        , data(d)
        , mode(NotMapped)
        , bytesPerLine(bpl)
    { }

    MapMode mapMode() const { return mode; }

    uchar *map(MapMode m, int *numBytes, int *bpl)
    {
        if (mode != NotMapped || m == NotMapped)
            return 0;

        mode = m;

        if (numBytes)
            *numBytes = data.size();

        if (bpl)
            *bpl = bytesPerLine;

        return reinterpret_cast<uchar *>(data.data());
    }

    void unmap() { mode = NotMapped; }

private:
    QByteArray data;
    MapMode mode;
    int bytesPerLine;
};

Q_GLOBAL_STATIC(QList<AndroidCameraInfo>, g_availableCameras)

QAndroidCameraSession::QAndroidCameraSession(QObject *parent)
    : QObject(parent)
    , m_selectedCamera(0)
    , m_camera(0)
    , m_nativeOrientation(0)
    , m_videoOutput(0)
    , m_captureMode(QCamera::CaptureViewfinder)
    , m_state(QCamera::UnloadedState)
    , m_savedState(-1)
    , m_status(QCamera::UnloadedStatus)
    , m_previewStarted(false)
    , m_imageSettingsDirty(true)
    , m_captureDestination(QCameraImageCapture::CaptureToFile)
    , m_captureImageDriveMode(QCameraImageCapture::SingleImageCapture)
    , m_lastImageCaptureId(0)
    , m_readyForCapture(false)
    , m_captureCanceled(false)
    , m_currentImageCaptureId(-1)
{
    m_mediaStorageLocation.addStorageLocation(
                QMediaStorageLocation::Pictures,
                AndroidMultimediaUtils::getDefaultMediaDirectory(AndroidMultimediaUtils::DCIM));

    if (qApp) {
        connect(qApp, SIGNAL(applicationStateChanged(Qt::ApplicationState)),
                this, SLOT(onApplicationStateChanged(Qt::ApplicationState)));
    }
}

QAndroidCameraSession::~QAndroidCameraSession()
{
    close();
}

void QAndroidCameraSession::setCaptureMode(QCamera::CaptureModes mode)
{
    if (m_captureMode == mode || !isCaptureModeSupported(mode))
        return;

    m_captureMode = mode;
    emit captureModeChanged(m_captureMode);

    if (m_previewStarted && m_captureMode.testFlag(QCamera::CaptureStillImage))
        adjustViewfinderSize(m_imageSettings.resolution());
}

bool QAndroidCameraSession::isCaptureModeSupported(QCamera::CaptureModes mode) const
{
    if (mode & (QCamera::CaptureStillImage & QCamera::CaptureVideo))
        return false;

    return true;
}

void QAndroidCameraSession::setState(QCamera::State state)
{
    // If the application is inactive, the camera shouldn't be started. Save the desired state
    // instead and it will be set when the application becomes active.
    if (qApp->applicationState() != Qt::ApplicationActive) {
        m_savedState = state;
        return;
    }

    if (m_state == state)
        return;

    switch (state) {
    case QCamera::UnloadedState:
        close();
        break;
    case QCamera::LoadedState:
    case QCamera::ActiveState:
        if (!m_camera && !open()) {
            emit error(QCamera::CameraError, QStringLiteral("Failed to open camera"));
            return;
        }
        if (state == QCamera::ActiveState) {
            if (!startPreview())
                return;
        } else if (state == QCamera::LoadedState) {
            stopPreview();
        }
        break;
    }

     m_state = state;
     emit stateChanged(m_state);
}

void QAndroidCameraSession::updateAvailableCameras()
{
    g_availableCameras->clear();

    const int numCameras = AndroidCamera::getNumberOfCameras();
    for (int i = 0; i < numCameras; ++i) {
        AndroidCameraInfo info;
        AndroidCamera::getCameraInfo(i, &info);

        if (!info.name.isNull())
            g_availableCameras->append(info);
    }
}

const QList<AndroidCameraInfo> &QAndroidCameraSession::availableCameras()
{
    if (g_availableCameras->isEmpty())
        updateAvailableCameras();

    return *g_availableCameras;
}

bool QAndroidCameraSession::open()
{
    close();

    m_status = QCamera::LoadingStatus;
    emit statusChanged(m_status);

    m_camera = AndroidCamera::open(m_selectedCamera);

    if (m_camera) {
        connect(m_camera, SIGNAL(pictureExposed()), this, SLOT(onCameraPictureExposed()));
        connect(m_camera, SIGNAL(previewFetched(QByteArray)), this, SLOT(onCameraPreviewFetched(QByteArray)));
        connect(m_camera, SIGNAL(frameFetched(QByteArray)),
                this, SLOT(onCameraFrameFetched(QByteArray)),
                Qt::DirectConnection);
        connect(m_camera, SIGNAL(pictureCaptured(QByteArray)), this, SLOT(onCameraPictureCaptured(QByteArray)));
        connect(m_camera, SIGNAL(previewStarted()), this, SLOT(onCameraPreviewStarted()));
        connect(m_camera, SIGNAL(previewStopped()), this, SLOT(onCameraPreviewStopped()));

        m_nativeOrientation = m_camera->getNativeOrientation();

        m_status = QCamera::LoadedStatus;

        if (m_camera->getPreviewFormat() != AndroidCamera::NV21)
            m_camera->setPreviewFormat(AndroidCamera::NV21);

        m_camera->fetchEachFrame(m_videoProbes.count());

        emit opened();
    } else {
        m_status = QCamera::UnavailableStatus;
    }

    emit statusChanged(m_status);

    return m_camera != 0;
}

void QAndroidCameraSession::close()
{
    if (!m_camera)
        return;

    stopPreview();

    m_status = QCamera::UnloadingStatus;
    emit statusChanged(m_status);

    m_readyForCapture = false;
    m_currentImageCaptureId = -1;
    m_currentImageCaptureFileName.clear();
    m_imageSettingsDirty = true;

    m_camera->release();
    delete m_camera;
    m_camera = 0;

    m_status = QCamera::UnloadedStatus;
    emit statusChanged(m_status);
}

void QAndroidCameraSession::setVideoPreview(QObject *videoOutput)
{
    if (m_videoOutput) {
        m_videoOutput->stop();
        m_videoOutput->reset();
    }

    if (videoOutput) {
        connect(videoOutput, SIGNAL(readyChanged(bool)), this, SLOT(onVideoOutputReady(bool)));
        m_videoOutput = qobject_cast<QAndroidVideoOutput *>(videoOutput);
    } else {
        m_videoOutput = 0;
    }
}

void QAndroidCameraSession::adjustViewfinderSize(const QSize &captureSize, bool restartPreview)
{
    if (!m_camera)
        return;

    QSize currentViewfinderResolution = m_camera->previewSize();
    const qreal aspectRatio = qreal(captureSize.width()) / qreal(captureSize.height());
    if (currentViewfinderResolution.isValid() &&
            qAbs(aspectRatio - (qreal(currentViewfinderResolution.width()) / currentViewfinderResolution.height())) < 0.01) {
        return;
    }

    QSize adjustedViewfinderResolution;
    QList<QSize> previewSizes = m_camera->getSupportedPreviewSizes();
    for (int i = previewSizes.count() - 1; i >= 0; --i) {
        const QSize &size = previewSizes.at(i);
        // search for viewfinder resolution with the same aspect ratio
        if (qAbs(aspectRatio - (qreal(size.width()) / size.height())) < 0.01) {
            adjustedViewfinderResolution = size;
            break;
        }
    }

    if (!adjustedViewfinderResolution.isValid()) {
        qWarning("Cannot find a viewfinder resolution matching the capture aspect ratio.");
        return;
    }

    if (currentViewfinderResolution != adjustedViewfinderResolution) {
        if (m_videoOutput)
            m_videoOutput->setVideoSize(adjustedViewfinderResolution);

        // if preview is started, we have to stop it first before changing its size
        if (m_previewStarted && restartPreview)
            m_camera->stopPreview();

        m_camera->setPreviewSize(adjustedViewfinderResolution);

        // restart preview
        if (m_previewStarted && restartPreview)
            m_camera->startPreview();
    }
}

bool QAndroidCameraSession::startPreview()
{
    if (!m_camera)
        return false;

    if (!m_videoOutput) {
        Q_EMIT error(QCamera::InvalidRequestError, tr("Camera cannot be started without a viewfinder."));
        return false;
    }

    if (m_previewStarted)
        return true;

    if (!m_videoOutput->isReady())
        return true; // delay starting until the video output is ready

    if (!m_camera->setPreviewTexture(m_videoOutput->surfaceTexture()))
        return false;

    m_status = QCamera::StartingStatus;
    emit statusChanged(m_status);

    applyImageSettings();
    adjustViewfinderSize(m_imageSettings.resolution());

    AndroidMultimediaUtils::enableOrientationListener(true);

    m_camera->startPreview();
    m_previewStarted = true;

    return true;
}

void QAndroidCameraSession::stopPreview()
{
    if (!m_camera || !m_previewStarted)
        return;

    m_status = QCamera::StoppingStatus;
    emit statusChanged(m_status);

    AndroidMultimediaUtils::enableOrientationListener(false);

    m_camera->stopPreview();
    m_camera->setPreviewSize(QSize());
    m_camera->setPreviewTexture(0);

    if (m_videoOutput) {
        m_videoOutput->stop();
        m_videoOutput->reset();
    }
    m_previewStarted = false;
}

void QAndroidCameraSession::setImageSettings(const QImageEncoderSettings &settings)
{
    if (m_imageSettings == settings)
        return;

    m_imageSettings = settings;
    if (m_imageSettings.codec().isEmpty())
        m_imageSettings.setCodec(QLatin1String("jpeg"));

    m_imageSettingsDirty = true;

    applyImageSettings();

    if (m_readyForCapture && m_captureMode.testFlag(QCamera::CaptureStillImage))
        adjustViewfinderSize(m_imageSettings.resolution());
}

int QAndroidCameraSession::currentCameraRotation() const
{
    if (!m_camera)
        return 0;

    // subtract natural camera orientation and physical device orientation
    int rotation = 0;
    int deviceOrientation = (AndroidMultimediaUtils::getDeviceOrientation() + 45) / 90 * 90;
    if (m_camera->getFacing() == AndroidCamera::CameraFacingFront)
        rotation = (m_nativeOrientation - deviceOrientation + 360) % 360;
    else // back-facing camera
        rotation = (m_nativeOrientation + deviceOrientation) % 360;

    return rotation;
}

void QAndroidCameraSession::addProbe(QAndroidMediaVideoProbeControl *probe)
{
    m_videoProbesMutex.lock();
    if (probe)
        m_videoProbes << probe;
    if (m_camera)
        m_camera->fetchEachFrame(m_videoProbes.count());
    m_videoProbesMutex.unlock();
}

void QAndroidCameraSession::removeProbe(QAndroidMediaVideoProbeControl *probe)
{
    m_videoProbesMutex.lock();
    m_videoProbes.remove(probe);
    if (m_camera)
        m_camera->fetchEachFrame(m_videoProbes.count());
    m_videoProbesMutex.unlock();
}

void QAndroidCameraSession::applyImageSettings()
{
    if (!m_camera || !m_imageSettingsDirty)
        return;

    const QSize requestedResolution = m_imageSettings.resolution();
    const QList<QSize> supportedResolutions = m_camera->getSupportedPictureSizes();

    if (!requestedResolution.isValid()) {
        // if no resolution is set, use the highest supported one
        m_imageSettings.setResolution(supportedResolutions.last());
    } else if (!supportedResolutions.contains(requestedResolution)) {
        // if the requested resolution is not supported, find the closest one
        int reqPixelCount = requestedResolution.width() * requestedResolution.height();
        QList<int> supportedPixelCounts;
        for (int i = 0; i < supportedResolutions.size(); ++i) {
            const QSize &s = supportedResolutions.at(i);
            supportedPixelCounts.append(s.width() * s.height());
        }
        int closestIndex = qt_findClosestValue(supportedPixelCounts, reqPixelCount);
        m_imageSettings.setResolution(supportedResolutions.at(closestIndex));
    }

    int jpegQuality = 100;
    switch (m_imageSettings.quality()) {
    case QMultimedia::VeryLowQuality:
        jpegQuality = 20;
        break;
    case QMultimedia::LowQuality:
        jpegQuality = 40;
        break;
    case QMultimedia::NormalQuality:
        jpegQuality = 60;
        break;
    case QMultimedia::HighQuality:
        jpegQuality = 80;
        break;
    case QMultimedia::VeryHighQuality:
        jpegQuality = 100;
        break;
    }

    m_camera->setPictureSize(m_imageSettings.resolution());
    m_camera->setJpegQuality(jpegQuality);

    m_imageSettingsDirty = false;
}

bool QAndroidCameraSession::isCaptureDestinationSupported(QCameraImageCapture::CaptureDestinations destination) const
{
    return destination & (QCameraImageCapture::CaptureToFile | QCameraImageCapture::CaptureToBuffer);
}

QCameraImageCapture::CaptureDestinations QAndroidCameraSession::captureDestination() const
{
    return m_captureDestination;
}

void QAndroidCameraSession::setCaptureDestination(QCameraImageCapture::CaptureDestinations destination)
{
    if (m_captureDestination != destination) {
        m_captureDestination = destination;
        emit captureDestinationChanged(m_captureDestination);
    }
}

bool QAndroidCameraSession::isReadyForCapture() const
{
    return m_status == QCamera::ActiveStatus && m_readyForCapture;
}

void QAndroidCameraSession::setReadyForCapture(bool ready)
{
    if (m_readyForCapture == ready)
        return;

    m_readyForCapture = ready;
    emit readyForCaptureChanged(ready);
}

QCameraImageCapture::DriveMode QAndroidCameraSession::driveMode() const
{
    return m_captureImageDriveMode;
}

void QAndroidCameraSession::setDriveMode(QCameraImageCapture::DriveMode mode)
{
    m_captureImageDriveMode = mode;
}

int QAndroidCameraSession::capture(const QString &fileName)
{
    ++m_lastImageCaptureId;

    if (!isReadyForCapture()) {
        emit imageCaptureError(m_lastImageCaptureId, QCameraImageCapture::NotReadyError,
                               tr("Camera not ready"));
        return m_lastImageCaptureId;
    }

    if (m_captureImageDriveMode == QCameraImageCapture::SingleImageCapture) {
        setReadyForCapture(false);

        m_currentImageCaptureId = m_lastImageCaptureId;
        m_currentImageCaptureFileName = fileName;

        applyImageSettings();
        adjustViewfinderSize(m_imageSettings.resolution());

        // adjust picture rotation depending on the device orientation
        m_camera->setRotation(currentCameraRotation());

        m_camera->takePicture();
    } else {
        //: Drive mode is the camera's shutter mode, for example single shot, continuos exposure, etc.
        emit imageCaptureError(m_lastImageCaptureId, QCameraImageCapture::NotSupportedFeatureError,
                               tr("Drive mode not supported"));
    }

    return m_lastImageCaptureId;
}

void QAndroidCameraSession::cancelCapture()
{
    if (m_readyForCapture)
        return;

    m_captureCanceled = true;
}

void QAndroidCameraSession::onCameraPictureExposed()
{
    if (m_captureCanceled)
        return;

    emit imageExposed(m_currentImageCaptureId);
    m_camera->fetchLastPreviewFrame();
}

void QAndroidCameraSession::onCameraPreviewFetched(const QByteArray &preview)
{
    if (preview.size()) {
        QtConcurrent::run(this, &QAndroidCameraSession::processPreviewImage,
                          m_currentImageCaptureId,
                          preview,
                          m_camera->getRotation());
    }
}

void QAndroidCameraSession::onCameraFrameFetched(const QByteArray &frame)
{
    m_videoProbesMutex.lock();
    if (frame.size() && m_videoProbes.count()) {
        const QSize frameSize = m_camera->previewSize();
        // Bytes per line should be only for the first plane. For NV21, the Y plane has 8 bits
        // per sample, so bpl == width
        QVideoFrame videoFrame(new DataVideoBuffer(frame, frameSize.width()),
                               frameSize,
                               QVideoFrame::Format_NV21);
        foreach (QAndroidMediaVideoProbeControl *probe, m_videoProbes)
            probe->newFrameProbed(videoFrame);
    }
    m_videoProbesMutex.unlock();
}

void QAndroidCameraSession::onCameraPictureCaptured(const QByteArray &data)
{
    if (!m_captureCanceled) {
        // Loading and saving the captured image can be slow, do it in a separate thread
        QtConcurrent::run(this, &QAndroidCameraSession::processCapturedImage,
                          m_currentImageCaptureId,
                          data,
                          m_imageSettings.resolution(),
                          m_captureDestination,
                          m_currentImageCaptureFileName);
    }

    m_captureCanceled = false;

    // Preview needs to be restarted after taking a picture
    m_camera->startPreview();
}

void QAndroidCameraSession::onCameraPreviewStarted()
{
    if (m_status == QCamera::StartingStatus) {
        m_status = QCamera::ActiveStatus;
        emit statusChanged(m_status);
    }

    setReadyForCapture(true);
}

void QAndroidCameraSession::onCameraPreviewStopped()
{
    if (m_status == QCamera::StoppingStatus) {
        m_status = QCamera::LoadedStatus;
        emit statusChanged(m_status);
    }

    setReadyForCapture(false);
}

void QAndroidCameraSession::processCapturedImage(int id,
                                                 const QByteArray &data,
                                                 const QSize &resolution,
                                                 QCameraImageCapture::CaptureDestinations dest,
                                                 const QString &fileName)
{


    if (dest & QCameraImageCapture::CaptureToFile) {
        const QString actualFileName = m_mediaStorageLocation.generateFileName(fileName,
                                                                               QMediaStorageLocation::Pictures,
                                                                               QLatin1String("IMG_"),
                                                                               QLatin1String("jpg"));

        QFile file(actualFileName);
        if (file.open(QFile::WriteOnly)) {
            if (file.write(data) == data.size()) {
                // if the picture is saved into the standard picture location, register it
                // with the Android media scanner so it appears immediately in apps
                // such as the gallery.
                QString standardLoc = AndroidMultimediaUtils::getDefaultMediaDirectory(AndroidMultimediaUtils::DCIM);
                if (actualFileName.startsWith(standardLoc))
                    AndroidMultimediaUtils::registerMediaFile(actualFileName);

                emit imageSaved(id, actualFileName);
            } else {
                emit imageCaptureError(id, QCameraImageCapture::OutOfSpaceError, file.errorString());
            }
        } else {
            const QString errorMessage = tr("Could not open destination file: %1").arg(actualFileName);
            emit imageCaptureError(id, QCameraImageCapture::ResourceError, errorMessage);
        }
    }

    if (dest & QCameraImageCapture::CaptureToBuffer) {
        QVideoFrame frame(new DataVideoBuffer(data), resolution, QVideoFrame::Format_Jpeg);
        emit imageAvailable(id, frame);
    }
}

void QAndroidCameraSession::processPreviewImage(int id, const QByteArray &data, int rotation)
{
    emit imageCaptured(id, prepareImageFromPreviewData(data, rotation));
}

QImage QAndroidCameraSession::prepareImageFromPreviewData(const QByteArray &data, int rotation)
{
    QSize frameSize = m_camera->previewSize();
    QImage result(frameSize, QImage::Format_ARGB32);
    qt_convert_NV21_to_ARGB32((const uchar *)data.constData(),
                              (quint32 *)result.bits(),
                              frameSize.width(),
                              frameSize.height());

    QTransform transform;

    // Preview display of front-facing cameras is flipped horizontally, but the frame data
    // we get here is not. Flip it ourselves if the camera is front-facing to match what the user
    // sees on the viewfinder.
    if (m_camera->getFacing() == AndroidCamera::CameraFacingFront)
        transform.scale(-1, 1);

    transform.rotate(rotation);

    result = result.transformed(transform);

    return result;
}

void QAndroidCameraSession::onVideoOutputReady(bool ready)
{
    if (ready && m_state == QCamera::ActiveState)
        startPreview();
}

void QAndroidCameraSession::onApplicationStateChanged(Qt::ApplicationState state)
{
    switch (state) {
    case Qt::ApplicationInactive:
        if (m_state != QCamera::UnloadedState) {
            m_savedState = m_state;
            close();
            m_state = QCamera::UnloadedState;
            emit stateChanged(m_state);
        }
        break;
    case Qt::ApplicationActive:
        if (m_savedState != -1) {
            setState(QCamera::State(m_savedState));
            m_savedState = -1;
        }
        break;
    default:
        break;
    }
}

QT_END_NAMESPACE