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#include "quiview.h"

#include "qiosglobal.h"
#include "qiosintegration.h"
#include "qioswindow.h"

#include <QtGui/private/qguiapplication_p.h>
#include <QtGui/private/qwindow_p.h>

@implementation QUIView

+ (Class)layerClass
{
    return [CAEAGLLayer class];
}

-(id)initWithQIOSWindow:(QIOSWindow *)window
{
    if (self = [self initWithFrame:toCGRect(window->geometry())])
        m_qioswindow = window;

    m_accessibleElements = [[NSMutableArray alloc] init];
    return self;
}

- (id)initWithFrame:(CGRect)frame
{
    if ((self = [super initWithFrame:frame])) {
        // Set up EAGL layer
        CAEAGLLayer *eaglLayer = static_cast<CAEAGLLayer *>(self.layer);
        eaglLayer.opaque = TRUE;
        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
            [NSNumber numberWithBool:YES], kEAGLDrawablePropertyRetainedBacking,
            kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];

        if (isQtApplication())
            self.hidden = YES;

        self.multipleTouchEnabled = YES;
    }

    return self;
}

- (void)willMoveToWindow:(UIWindow *)newWindow
{
    // UIKIt will normally set the scale factor of a view to match the corresponding
    // screen scale factor, but views backed by CAEAGLLayers need to do this manually.
    self.contentScaleFactor = newWindow && newWindow.screen ?
        newWindow.screen.scale : [[UIScreen mainScreen] scale];

    // FIXME: Allow the scale factor to be customized through QSurfaceFormat.
}

- (void)didAddSubview:(UIView *)subview
{
    if ([subview isKindOfClass:[QUIView class]])
        self.clipsToBounds = YES;
}

- (void)willRemoveSubview:(UIView *)subview
{
    for (UIView *view in self.subviews) {
        if (view != subview && [view isKindOfClass:[QUIView class]])
            return;
    }

    self.clipsToBounds = NO;
}

- (void)setNeedsDisplay
{
    [super setNeedsDisplay];

    // We didn't implement drawRect: so we have to manually
    // mark the layer as needing display.
    [self.layer setNeedsDisplay];
}

- (void)layoutSubviews
{
    // This method is the de facto way to know that view has been resized,
    // or otherwise needs invalidation of its buffers. Note though that we
    // do not get this callback when the view just changes its position, so
    // the position of our QWindow (and platform window) will only get updated
    // when the size is also changed.

    if (!CGAffineTransformIsIdentity(self.transform))
        qWarning() << m_qioswindow->window()
            << "is backed by a UIView that has a transform set. This is not supported.";

    // The original geometry requested by setGeometry() might be different
    // from what we end up with after applying window constraints.
    QRect requestedGeometry = m_qioswindow->geometry();

    QRect actualGeometry;
    if (m_qioswindow->window()->isTopLevel()) {
        UIWindow *uiWindow = self.window;
        UIView *rootView = uiWindow.rootViewController.view;
        CGRect rootViewPositionInRelationToRootViewController =
            [rootView convertRect:uiWindow.bounds fromView:uiWindow];

        actualGeometry = fromCGRect(CGRectOffset([self.superview convertRect:self.frame toView:rootView],
                                    -rootViewPositionInRelationToRootViewController.origin.x,
                                    -rootViewPositionInRelationToRootViewController.origin.y
                                    + rootView.bounds.origin.y)).toRect();
    } else {
        actualGeometry = fromCGRect(self.frame).toRect();
    }

    // Persist the actual/new geometry so that QWindow::geometry() can
    // be queried on the resize event.
    m_qioswindow->QPlatformWindow::setGeometry(actualGeometry);

    QRect previousGeometry = requestedGeometry != actualGeometry ?
            requestedGeometry : qt_window_private(m_qioswindow->window())->geometry;

    QWindowSystemInterface::handleGeometryChange(m_qioswindow->window(), actualGeometry, previousGeometry);
    QWindowSystemInterface::flushWindowSystemEvents();

    if (actualGeometry.size() != previousGeometry.size()) {
        // Trigger expose event on resize
        [self setNeedsDisplay];

        // A new size means we also need to resize the FBO's corresponding buffers,
        // but we defer that to when the application calls makeCurrent.
    }
}

- (void)displayLayer:(CALayer *)layer
{
    Q_UNUSED(layer);
    Q_ASSERT(layer == self.layer);

    [self sendUpdatedExposeEvent];
}

- (void)sendUpdatedExposeEvent
{
    QRegion region;

    if (m_qioswindow->isExposed()) {
        QSize bounds = fromCGRect(self.layer.bounds).toRect().size();

        Q_ASSERT(m_qioswindow->geometry().size() == bounds);
        Q_ASSERT(self.hidden == !m_qioswindow->window()->isVisible());

        region = QRect(QPoint(), bounds);
    }

    QWindowSystemInterface::handleExposeEvent(m_qioswindow->window(), region);
    QWindowSystemInterface::flushWindowSystemEvents();
}

// -------------------------------------------------------------------------

- (BOOL)canBecomeFirstResponder
{
    return YES;
}

- (BOOL)becomeFirstResponder
{
    if ([super becomeFirstResponder]) {
        QWindowSystemInterface::handleWindowActivated(m_qioswindow->window());
        QWindowSystemInterface::flushWindowSystemEvents();

        return YES;
    }

    return NO;
}

- (BOOL)resignFirstResponder
{
    if ([super resignFirstResponder]) {
        // We don't want to send window deactivation in case we're in the process
        // of activating another window. The handleWindowActivated of the activation
        // will take care of both.
        dispatch_async(dispatch_get_main_queue (), ^{
            if (![[UIResponder currentFirstResponder] isKindOfClass:[QUIView class]])
                QWindowSystemInterface::handleWindowActivated(0);
                QWindowSystemInterface::flushWindowSystemEvents();
        });

        return YES;
    }

    return NO;
}

// -------------------------------------------------------------------------


- (void)updateTouchList:(NSSet *)touches withState:(Qt::TouchPointState)state
{
    // We deliver touch events in global coordinates. But global in this respect
    // means the same coordinate system that we use for describing the geometry
    // of the top level QWindow we're inside. And that would be the coordinate
    // system of the superview of the UIView that backs that window:
    QPlatformWindow *topLevel = m_qioswindow;
    while (QPlatformWindow *topLevelParent = topLevel->parent())
        topLevel = topLevelParent;
    UIView *rootView = reinterpret_cast<UIView *>(topLevel->winId()).superview;
    CGSize rootViewSize = rootView.frame.size;

    foreach (UITouch *uiTouch, m_activeTouches.keys()) {
        QWindowSystemInterface::TouchPoint &touchPoint = m_activeTouches[uiTouch];
        if (![touches containsObject:uiTouch]) {
            touchPoint.state = Qt::TouchPointStationary;
        } else {
            touchPoint.state = state;
            touchPoint.pressure = (state == Qt::TouchPointReleased) ? 0.0 : 1.0;
            QPoint touchPos = fromCGPoint([uiTouch locationInView:rootView]).toPoint();
            touchPoint.area = QRectF(touchPos, QSize(0, 0));
            touchPoint.normalPosition = QPointF(touchPos.x() / rootViewSize.width, touchPos.y() / rootViewSize.height);
        }
    }
}

- (void) sendTouchEventWithTimestamp:(ulong)timeStamp
{
    // Send touch event synchronously
    QIOSIntegration *iosIntegration = QIOSIntegration::instance();
    QWindowSystemInterface::handleTouchEvent(m_qioswindow->window(), timeStamp, iosIntegration->touchDevice(), m_activeTouches.values());
    QWindowSystemInterface::flushWindowSystemEvents();
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    // UIKit generates [Began -> Moved -> Ended] event sequences for
    // each touch point. Internally we keep a hashmap of active UITouch
    // points to QWindowSystemInterface::TouchPoints, and assigns each TouchPoint
    // an id for use by Qt.
    for (UITouch *touch in touches) {
        Q_ASSERT(!m_activeTouches.contains(touch));
        m_activeTouches[touch].id = m_nextTouchId++;
    }

    if (m_activeTouches.size() == 1) {
        QPlatformWindow *topLevel = m_qioswindow;
        while (QPlatformWindow *p = topLevel->parent())
            topLevel = p;
        if (topLevel->window() != QGuiApplication::focusWindow())
            topLevel->requestActivateWindow();
    }

    [self updateTouchList:touches withState:Qt::TouchPointPressed];
    [self sendTouchEventWithTimestamp:ulong(event.timestamp * 1000)];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self updateTouchList:touches withState:Qt::TouchPointMoved];
    [self sendTouchEventWithTimestamp:ulong(event.timestamp * 1000)];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self updateTouchList:touches withState:Qt::TouchPointReleased];
    [self sendTouchEventWithTimestamp:ulong(event.timestamp * 1000)];

    // Remove ended touch points from the active set:
    for (UITouch *touch in touches)
        m_activeTouches.remove(touch);
    if (m_activeTouches.isEmpty())
        m_nextTouchId = 0;
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    if (m_activeTouches.isEmpty())
        return;

    // When four-finger swiping, we get a touchesCancelled callback
    // which includes all four touch points. The swipe gesture is
    // then active until all four touches have been released, and
    // we start getting touchesBegan events again.

    // When five-finger pinching, we also get a touchesCancelled
    // callback with all five touch points, but the pinch gesture
    // ends when the second to last finger is released from the
    // screen. The last finger will not emit any more touch
    // events, _but_, will contribute to starting another pinch
    // gesture. That second pinch gesture will _not_ trigger a
    // touchesCancelled event when starting, but as each finger
    // is released, and we may get touchesMoved events for the
    // remaining fingers. [event allTouches] also contains one
    // less touch point than it should, so this behavior is
    // likely a bug in the iOS system gesture recognizer, but we
    // have to take it into account when maintaining the Qt state.
    // We do this by assuming that there are no cases where a
    // sub-set of the active touch events are intentionally cancelled.

    if (touches && (static_cast<NSInteger>([touches count]) != m_activeTouches.count()))
        qWarning("Subset of active touches cancelled by UIKit");

    m_activeTouches.clear();
    m_nextTouchId = 0;

    NSTimeInterval timestamp = event ? event.timestamp : [[NSProcessInfo processInfo] systemUptime];

    // Send cancel touch event synchronously
    QIOSIntegration *iosIntegration = static_cast<QIOSIntegration *>(QGuiApplicationPrivate::platformIntegration());
    QWindowSystemInterface::handleTouchCancelEvent(m_qioswindow->window(), ulong(timestamp * 1000), iosIntegration->touchDevice());
    QWindowSystemInterface::flushWindowSystemEvents();
}

@end

@implementation UIView (QtHelpers)

- (QWindow *)qwindow
{
    if ([self isKindOfClass:[QUIView class]]) {
        if (QIOSWindow *w = static_cast<QUIView *>(self)->m_qioswindow)
            return w->window();
    }
    return nil;
}

- (UIViewController *)viewController
{
    id responder = self;
    while ((responder = [responder nextResponder])) {
        if ([responder isKindOfClass:UIViewController.class])
            return responder;
    }
    return nil;
}

@end

// Include category as an alternative to using -ObjC (Apple QA1490)
#include "quiview_accessibility.mm"