/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
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**
** This file is part of the QtPositioning module of the Qt Toolkit.
**
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** 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
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** 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
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** $QT_END_LICENSE$
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****************************************************************************/

#include <QTimerEvent>
#include <QDebug>
#include <QtCore/qglobal.h>
#include <QtCore/private/qglobal_p.h>

#include "qgeopositioninfosource_cl_p.h"

#define MINIMUM_UPDATE_INTERVAL 1000

@interface PositionLocationDelegate : NSObject <CLLocationManagerDelegate>
@end

@implementation PositionLocationDelegate
{
    QGeoPositionInfoSourceCL *m_positionInfoSource;
}

- (instancetype)initWithInfoSource:(QGeoPositionInfoSourceCL*) positionInfoSource
{
    if ((self = [self init])) {
        m_positionInfoSource = positionInfoSource;
    }
    return self;
}
- (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    Q_UNUSED(manager)
    if (status == kCLAuthorizationStatusNotDetermined)
        m_positionInfoSource->requestUpdate(MINIMUM_UPDATE_INTERVAL);
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    Q_UNUSED(manager);
    Q_UNUSED(oldLocation);

    // Convert location timestamp to QDateTime
    NSTimeInterval locationTimeStamp = [newLocation.timestamp timeIntervalSince1970];
    const QDateTime timeStamp = QDateTime::fromMSecsSinceEpoch(qRound64(locationTimeStamp * 1000), Qt::UTC);

    // Construct position info from location data
    QGeoPositionInfo location(QGeoCoordinate(newLocation.coordinate.latitude,
                                             newLocation.coordinate.longitude,
                                             newLocation.altitude),
                                             timeStamp);
    if (newLocation.horizontalAccuracy >= 0)
        location.setAttribute(QGeoPositionInfo::HorizontalAccuracy, newLocation.horizontalAccuracy);
    if (newLocation.verticalAccuracy >= 0)
        location.setAttribute(QGeoPositionInfo::VerticalAccuracy, newLocation.verticalAccuracy);
#ifndef Q_OS_TVOS
    if (newLocation.course >= 0)
        location.setAttribute(QGeoPositionInfo::Direction, newLocation.course);
    if (newLocation.speed >= 0)
        location.setAttribute(QGeoPositionInfo::GroundSpeed, newLocation.speed);
#endif

    m_positionInfoSource->locationDataAvailable(location);
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    Q_UNUSED(manager);
    m_positionInfoSource->setError(QGeoPositionInfoSource::AccessError);

    qWarning() << QString::fromNSString([error localizedDescription]);

    if ([error code] == 0
        && QString::fromNSString([error domain]) == QStringLiteral("kCLErrorDomain"))
      qWarning() << "(is Wi-Fi turned on?)";
}
@end

QT_BEGIN_NAMESPACE

QGeoPositionInfoSourceCL::QGeoPositionInfoSourceCL(QObject *parent)
    : QGeoPositionInfoSource(parent)
    , m_locationManager(0)
    , m_started(false)
    , m_updateTimer(0)
    , m_updateTimeout(0)
    , m_positionError(QGeoPositionInfoSource::NoError)
{
}

QGeoPositionInfoSourceCL::~QGeoPositionInfoSourceCL()
{
    stopUpdates();
    [m_locationManager release];
}

void QGeoPositionInfoSourceCL::setUpdateInterval(int msec)
{
    // If msec is 0 we send updates as data becomes available, otherwise we force msec to be equal
    // to or larger than the minimum update interval.
    if (msec != 0 && msec < minimumUpdateInterval())
        msec = minimumUpdateInterval();

    QGeoPositionInfoSource::setUpdateInterval(msec);

    // Must timeout if update takes longer than specified interval
    m_updateTimeout = msec;
    if (m_started) setTimeoutInterval(m_updateTimeout);
}

bool QGeoPositionInfoSourceCL::enableLocationManager()
{
    if (!m_locationManager) {
        if ([CLLocationManager locationServicesEnabled]) {
            // Location Services Are Enabled
            switch ([CLLocationManager authorizationStatus]) {
                case kCLAuthorizationStatusNotDetermined:
                    // User has not yet made a choice with regards to this application
                    break;
                case kCLAuthorizationStatusRestricted:
                    // This application is not authorized to use location services.  Due
                    // to active restrictions on location services, the user cannot change
                    // this status, and may not have personally denied authorization
                    return false;
                case kCLAuthorizationStatusDenied:
                    // User has explicitly denied authorization for this application, or
                    // location services are disabled in Settings
                    return false;
                case kCLAuthorizationStatusAuthorizedAlways:
                    // This app is authorized to start location services at any time.
                    break;
#ifndef Q_OS_MACOS
                case kCLAuthorizationStatusAuthorizedWhenInUse:
                    // This app is authorized to start most location services while running in the foreground.
                    break;
#endif
                default:
                    // By default, try to enable it
                    break;
            }
        } else {
            // Location Services Disabled
            return false;
        }

    m_locationManager = [[CLLocationManager alloc] init];

#if defined(Q_OS_IOS) || defined(Q_OS_WATCHOS)
        if (__builtin_available(watchOS 4.0, *)) {
            NSDictionary<NSString *, id> *infoDict = [[NSBundle mainBundle] infoDictionary];
            if (id value = [infoDict objectForKey:@"UIBackgroundModes"]) {
                if ([value isKindOfClass:[NSArray class]]) {
                    NSArray *modes = static_cast<NSArray *>(value);
                    for (id mode in modes) {
                        if ([@"location" isEqualToString:mode]) {
                            m_locationManager.allowsBackgroundLocationUpdates = YES;
                            break;
                        }
                    }
                }
            }
        }
#endif

        m_locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        m_locationManager.delegate = [[PositionLocationDelegate alloc] initWithInfoSource:this];

        // -requestAlwaysAuthorization is available on iOS (>= 8.0) and watchOS (>= 2.0).
        // This method requires both NSLocationAlwaysAndWhenInUseUsageDescription and
        // NSLocationWhenInUseUsageDescription entries present in Info.plist (otherwise,
        // while probably a noop, the call generates a warning).
        // -requestWhenInUseAuthorization only requires NSLocationWhenInUseUsageDescription
        // entry in Info.plist (available on iOS (>= 8.0), tvOS (>= 9.0) and watchOS (>= 2.0).
    }

#ifndef Q_OS_MACOS
    NSDictionary<NSString *, id> *infoDict = NSBundle.mainBundle.infoDictionary;
    const bool hasAlwaysUseUsage = !![infoDict objectForKey:@"NSLocationAlwaysAndWhenInUseUsageDescription"];
    const bool hasWhenInUseUsage = !![infoDict objectForKey:@"NSLocationWhenInUseUsageDescription"];
#ifndef Q_OS_TVOS
    if (hasAlwaysUseUsage && hasWhenInUseUsage)
        [m_locationManager requestAlwaysAuthorization];
    else
#endif // !Q_OS_TVOS
    if (hasWhenInUseUsage)
        [m_locationManager requestWhenInUseAuthorization];
#endif // !Q_OS_MACOS

    return (m_locationManager != nullptr);
}

void QGeoPositionInfoSourceCL::setTimeoutInterval(int msec)
{
    // Start timeout timer
    if (m_updateTimer) killTimer(m_updateTimer);
    if (msec > 0) m_updateTimer = startTimer(msec);
    else m_updateTimer = 0;
}

void QGeoPositionInfoSourceCL::startUpdates()
{
    if (enableLocationManager()) {
#ifdef Q_OS_TVOS
        [m_locationManager requestLocation];    // service will run long enough for one location update
#else
        [m_locationManager startUpdatingLocation];
#endif
        m_started = true;

        setTimeoutInterval(m_updateTimeout);
    } else setError(QGeoPositionInfoSource::AccessError);
}

void QGeoPositionInfoSourceCL::stopUpdates()
{
    if (m_locationManager) {
        [m_locationManager stopUpdatingLocation];
        m_started = false;

        // Stop timeout timer
        setTimeoutInterval(0);
    } else setError(QGeoPositionInfoSource::AccessError);
}

void QGeoPositionInfoSourceCL::requestUpdate(int timeout)
{
    // Get a single update within timeframe
    if (timeout < minimumUpdateInterval() && timeout != 0)
        emit updateTimeout();
    else if (enableLocationManager()) {
        // This will force LM to generate a new update
        [m_locationManager stopUpdatingLocation];
#ifdef Q_OS_TVOS
        [m_locationManager requestLocation];    // service will run long enough for one location update
#else
        [m_locationManager startUpdatingLocation];
#endif

        setTimeoutInterval(timeout);
    } else setError(QGeoPositionInfoSource::AccessError);
}

void QGeoPositionInfoSourceCL::timerEvent( QTimerEvent * event )
{
    // Update timed out?
    if (event->timerId() == m_updateTimer) {
        emit updateTimeout();

        // Only timeout once since last data
        setTimeoutInterval(0);

        // Started for single update?
        if (!m_started) stopUpdates();
    }
}

QGeoPositionInfoSource::PositioningMethods QGeoPositionInfoSourceCL::supportedPositioningMethods() const
{
    // CoreLocation doesn't say which positioning method(s) it used
    return QGeoPositionInfoSource::AllPositioningMethods;
}

int QGeoPositionInfoSourceCL::minimumUpdateInterval() const
{
    return MINIMUM_UPDATE_INTERVAL;
}

void QGeoPositionInfoSourceCL::locationDataAvailable(QGeoPositionInfo location)
{
    // Signal position data available
    m_lastUpdate = location;
    emit positionUpdated(location);

    // Started for single update?
    if (!m_started) stopUpdates();
    // ...otherwise restart timeout timer
    else setTimeoutInterval(m_updateTimeout);
}

QGeoPositionInfo QGeoPositionInfoSourceCL::lastKnownPosition(bool fromSatellitePositioningMethodsOnly) const
{
    Q_UNUSED(fromSatellitePositioningMethodsOnly);

    return m_lastUpdate;
}

QGeoPositionInfoSource::Error QGeoPositionInfoSourceCL::error() const
{
    return m_positionError;
}

void QGeoPositionInfoSourceCL::setError(QGeoPositionInfoSource::Error positionError)
{
    m_positionError = positionError;
    emit QGeoPositionInfoSource::error(positionError);
}

QT_END_NAMESPACE

#include "moc_qgeopositioninfosource_cl_p.cpp"