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#include <AppKit/AppKit.h>

#include "qcocoaaccessibilityelement.h"
#include "qcocoaaccessibility.h"
#include "qcocoahelpers.h"
#include "qcocoawindow.h"
#include "qcocoascreen.h"

#include <QtGui/private/qaccessiblecache_p.h>
#include <QtGui/private/qaccessiblebridgeutils_p.h>
#include <QtGui/qaccessible.h>

QT_USE_NAMESPACE

#ifndef QT_NO_ACCESSIBILITY

/**
 * Converts between absolute character offsets and line numbers of a
 * QAccessibleTextInterface. Works in exactly one of two modes:
 *
 *  - Pass *line == -1 in order to get a line containing character at the given
 *    *offset
 *  - Pass *offset == -1 in order to get the offset of first character of the
 *    given *line
 *
 * You can optionally also pass non-NULL `start` and `end`, which will in both
 * modes be filled with the offset of the first and last characters of the
 * relevant line.
 */
static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *offset, NSUInteger *start = 0, NSUInteger *end = 0)
{
    Q_ASSERT(*line == -1 || *offset == -1);
    Q_ASSERT(*line != -1 || *offset != -1);
    Q_ASSERT(*offset <= text->characterCount());

    int curLine = -1;
    int curStart = 0, curEnd = 0;

    do {
        curStart = curEnd;
        text->textAtOffset(curStart, QAccessible::LineBoundary, &curStart, &curEnd);
        // If the text is empty then we just return
        if (curStart == -1 || curEnd == -1) {
            if (start)
                *start = 0;
            if (end)
                *end = 0;
            return;
        }
        ++curLine;
        {
            // check for a case where a single word longer than the text edit's width and gets wrapped
            // in the middle of the word; in this case curEnd will be an offset belonging to the next line
            // and therefore nextEnd will not be equal to curEnd
            int nextStart;
            int nextEnd;
            text->textAtOffset(curEnd, QAccessible::LineBoundary, &nextStart, &nextEnd);
            if (nextEnd == curEnd)
                ++curEnd;
        }
    } while ((*line == -1 || curLine < *line) && (*offset == -1 || (curEnd <= *offset)) && curEnd <= text->characterCount());

    curEnd = qMin(curEnd, text->characterCount());

    if (*line == -1)
        *line = curLine;
    if (*offset == -1)
        *offset = curStart;

    Q_ASSERT(curStart >= 0);
    Q_ASSERT(curEnd >= 0);
    if (start)
        *start = curStart;
    if (end)
        *end = curEnd;
}

@implementation QMacAccessibilityElement {
    QAccessible::Id axid;
}

- (instancetype)initWithId:(QAccessible::Id)anId
{
    Q_ASSERT((int)anId < 0);
    self = [super init];
    if (self) {
        axid = anId;
    }

    return self;
}

+ (instancetype)elementWithId:(QAccessible::Id)anId
{
    Q_ASSERT(anId);
    if (!anId)
        return nil;

    QAccessibleCache *cache = QAccessibleCache::instance();

    QMacAccessibilityElement *element = cache->elementForId(anId);
    if (!element) {
        QAccessibleInterface *iface = QAccessible::accessibleInterface(anId);
        Q_ASSERT(iface);
        if (!iface || !iface->isValid())
            return nil;
        element = [[self alloc] initWithId:anId];
        cache->insertElement(anId, element);
    }
    return element;
}

- (void)invalidate {
    axid = 0;
    NSAccessibilityPostNotification(self, NSAccessibilityUIElementDestroyedNotification);
    [self release];
}

- (void)dealloc {
    [super dealloc];
}

- (BOOL)isEqual:(id)object {
    if ([object isKindOfClass:[QMacAccessibilityElement class]]) {
        QMacAccessibilityElement *other = object;
        return other->axid == axid;
    } else {
        return NO;
    }
}

- (NSUInteger)hash {
    return axid;
}

//
// accessibility protocol
//

- (BOOL)isAccessibilityFocused
{
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid()) {
        return false;
    }
    // Just check if the app thinks we're focused.
    id focusedElement = NSApp.accessibilityApplicationFocusedUIElement;
    return [focusedElement isEqual:self];
}

// attributes

+ (id) lineNumberForIndex: (int)index forText:(const QString &)text
{
    auto textBefore = QStringView(text).left(index);
    int newlines = textBefore.count(QLatin1Char('\n'));
    return @(newlines);
}

- (BOOL) accessibilityNotifiesWhenDestroyed {
    return YES;
}

- (NSString *) accessibilityRole {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return NSAccessibilityUnknownRole;
    return QCocoaAccessible::macRole(iface);
}

- (NSString *) accessibilitySubRole {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return NSAccessibilityUnknownRole;
    return QCocoaAccessible::macSubrole(iface);
}

- (NSString *) accessibilityRoleDescription {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return NSAccessibilityUnknownRole;
    return NSAccessibilityRoleDescription(self.accessibilityRole, self.accessibilitySubRole);
}

- (NSArray *) accessibilityChildren {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return nil;
    return QCocoaAccessible::unignoredChildren(iface);
}

- (id) accessibilityWindow {
    // We're in the same window as our parent.
    return [self.accessibilityParent accessibilityWindow];
}

- (id) accessibilityTopLevelUIElementAttribute {
    // We're in the same top level element as our parent.
    return [self.accessibilityParent accessibilityTopLevelUIElementAttribute];
}

- (NSString *) accessibilityTitle {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return nil;
    if (iface->role() == QAccessible::StaticText)
        return nil;
    return iface->text(QAccessible::Name).toNSString();
}

- (BOOL) isAccessibilityEnabled {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return false;
    return !iface->state().disabled;
}

- (id)accessibilityParent {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return nil;

    // macOS expects that the hierarchy is:
    // App -> Window -> Children
    // We don't actually have the window reflected properly in QAccessibility.
    // Check if the parent is the application and then instead return the native window.

    if (QAccessibleInterface *parent = iface->parent()) {
        if (parent->role() != QAccessible::Application) {
            QAccessible::Id parentId = QAccessible::uniqueId(parent);
            return NSAccessibilityUnignoredAncestor([QMacAccessibilityElement elementWithId: parentId]);
        }
    }

    if (QWindow *window = iface->window()) {
        QPlatformWindow *platformWindow = window->handle();
        if (platformWindow) {
            QCocoaWindow *win = static_cast<QCocoaWindow*>(platformWindow);
            return NSAccessibilityUnignoredAncestor(qnsview_cast(win->view()));
        }
    }
    return nil;
}

- (NSRect)accessibilityFrame {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return NSZeroRect;
    return QCocoaScreen::mapToNative(iface->rect());
}

- (NSString*)accessibilityLabel {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid()) {
        qWarning() << "Called accessibilityLabel on invalid object: " << axid;
        return nil;
    }
    return iface->text(QAccessible::Description).toNSString();
}

- (void)setAccessibilityLabel:(NSString*)label{
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return;
    iface->setText(QAccessible::Description, QString::fromNSString(label));
}

- (id) accessibilityMinValue:(QAccessibleInterface*)iface {
    if (QAccessibleValueInterface *val = iface->valueInterface())
        return @(val->minimumValue().toDouble());
    return nil;
}

- (id) accessibilityMaxValue:(QAccessibleInterface*)iface {
    if (QAccessibleValueInterface *val = iface->valueInterface())
        return @(val->maximumValue().toDouble());
    return nil;
}

- (id) accessibilityValue {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return nil;

    // VoiceOver asks for the value attribute for all elements. Return nil
    // if we don't want the element to have a value attribute.
    if (!QCocoaAccessible::hasValueAttribute(iface))
        return nil;

    return QCocoaAccessible::getValueAttribute(iface);
}

- (NSInteger) accessibilityNumberOfCharacters {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return 0;
    if (QAccessibleTextInterface *text = iface->textInterface())
        return text->characterCount();
    return 0;
}

- (NSString *) accessibilitySelectedText {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return nil;
    if (QAccessibleTextInterface *text = iface->textInterface()) {
        int start = 0;
        int end = 0;
        text->selection(0, &start, &end);
        return text->text(start, end).toNSString();
    }
    return nil;
}

- (NSRange) accessibilitySelectedTextRange {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return NSRange();
    if (QAccessibleTextInterface *text = iface->textInterface()) {
        int start = 0;
        int end = 0;
        if (text->selectionCount() > 0) {
            text->selection(0, &start, &end);
        } else {
            start = text->cursorPosition();
            end = start;
        }
        return NSMakeRange(quint32(start), quint32(end - start));
    }
    return NSMakeRange(0, 0);
}

- (NSInteger)accessibilityLineForIndex:(NSInteger)index {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return 0;
    if (QAccessibleTextInterface *text = iface->textInterface()) {
        QString textToPos = text->text(0, index);
        return textToPos.count('\n');
    }
    return 0;
}

- (NSRange)accessibilityVisibleCharacterRange {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return NSRange();
    // FIXME This is not correct and may impact performance for big texts
    if (QAccessibleTextInterface *text = iface->textInterface())
        return NSMakeRange(0, static_cast<uint>(text->characterCount()));
    return NSMakeRange(0, static_cast<uint>(iface->text(QAccessible::Name).length()));
}

- (NSInteger) accessibilityInsertionPointLineNumber {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return 0;
    if (QAccessibleTextInterface *text = iface->textInterface()) {
        int position = text->cursorPosition();
        return [self accessibilityLineForIndex:position];
    }
    return 0;
}

- (NSArray *)accessibilityParameterizedAttributeNames {

    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid()) {
        qWarning() << "Called attribute on invalid object: " << axid;
        return nil;
    }

    if (iface->textInterface()) {
        return @[
            NSAccessibilityStringForRangeParameterizedAttribute,
            NSAccessibilityLineForIndexParameterizedAttribute,
            NSAccessibilityRangeForLineParameterizedAttribute,
            NSAccessibilityRangeForPositionParameterizedAttribute,
//          NSAccessibilityRangeForIndexParameterizedAttribute,
            NSAccessibilityBoundsForRangeParameterizedAttribute,
//          NSAccessibilityRTFForRangeParameterizedAttribute,
            NSAccessibilityStyleRangeForIndexParameterizedAttribute,
            NSAccessibilityAttributedStringForRangeParameterizedAttribute
        ];
    }

    return nil;
}

- (id)accessibilityAttributeValue:(NSString *)attribute forParameter:(id)parameter {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid()) {
        qWarning() << "Called attribute on invalid object: " << axid;
        return nil;
    }

    if (!iface->textInterface())
        return nil;

    if ([attribute isEqualToString: NSAccessibilityStringForRangeParameterizedAttribute]) {
        NSRange range = [parameter rangeValue];
        QString text = iface->textInterface()->text(range.location, range.location + range.length);
        return text.toNSString();
    }
    if ([attribute isEqualToString: NSAccessibilityLineForIndexParameterizedAttribute]) {
        int index = [parameter intValue];
        if (index < 0 || index > iface->textInterface()->characterCount())
            return nil;
        int line = 0; // true for all single line edits
        if (iface->state().multiLine) {
            line = -1;
            convertLineOffset(iface->textInterface(), &line, &index);
        }
        return @(line);
    }
    if ([attribute isEqualToString: NSAccessibilityRangeForLineParameterizedAttribute]) {
        int line = [parameter intValue];
        if (line < 0)
            return nil;
        int lineOffset = -1;
        NSUInteger startOffset = 0;
        NSUInteger endOffset = 0;
        convertLineOffset(iface->textInterface(), &line, &lineOffset, &startOffset, &endOffset);
        return [NSValue valueWithRange:NSMakeRange(startOffset, endOffset - startOffset)];
    }
    if ([attribute isEqualToString: NSAccessibilityBoundsForRangeParameterizedAttribute]) {
        NSRange range = [parameter rangeValue];
        QRect firstRect = iface->textInterface()->characterRect(range.location);
        QRectF rect;
        if (range.length > 0) {
            NSUInteger position = range.location + range.length - 1;
            if (position > range.location && iface->textInterface()->text(position, position + 1) == QStringLiteral("\n"))
                --position;
            QRect lastRect = iface->textInterface()->characterRect(position);
            rect = firstRect.united(lastRect);
        } else {
            rect = firstRect;
            rect.setWidth(1);
        }
        return [NSValue valueWithRect:QCocoaScreen::mapToNative(rect)];
    }
    if ([attribute isEqualToString: NSAccessibilityAttributedStringForRangeParameterizedAttribute]) {
        NSRange range = [parameter rangeValue];
        QString text = iface->textInterface()->text(range.location, range.location + range.length);
        return [[NSAttributedString alloc] initWithString:text.toNSString()];
    } else if ([attribute isEqualToString: NSAccessibilityRangeForPositionParameterizedAttribute]) {
        QPoint point = QCocoaScreen::mapFromNative([parameter pointValue]).toPoint();
        int offset = iface->textInterface()->offsetAtPoint(point);
        return [NSValue valueWithRange:NSMakeRange(static_cast<NSUInteger>(offset), 1)];
    } else if ([attribute isEqualToString: NSAccessibilityStyleRangeForIndexParameterizedAttribute]) {
        int start = 0;
        int end = 0;
        iface->textInterface()->attributes([parameter intValue], &start, &end);
        return [NSValue valueWithRange:NSMakeRange(static_cast<NSUInteger>(start), static_cast<NSUInteger>(end - start))];
    }
    return nil;
}

- (BOOL)accessibilityIsAttributeSettable:(NSString *)attribute {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return NO;

    if ([attribute isEqualToString:NSAccessibilityFocusedAttribute]) {
        return iface->state().focusable ? YES : NO;
    } else if ([attribute isEqualToString:NSAccessibilityValueAttribute]) {
        if (iface->textInterface() && iface->state().editable)
            return YES;
        if (iface->valueInterface())
            return YES;
        return NO;
    } else if ([attribute isEqualToString:NSAccessibilitySelectedTextRangeAttribute]) {
        return iface->textInterface() ? YES : NO;
    }
    return NO;
}

- (void)accessibilitySetValue:(id)value forAttribute:(NSString *)attribute {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return;
    if ([attribute isEqualToString:NSAccessibilityFocusedAttribute]) {
        if (QAccessibleActionInterface *action = iface->actionInterface())
            action->doAction(QAccessibleActionInterface::setFocusAction());
    } else if ([attribute isEqualToString:NSAccessibilityValueAttribute]) {
        if (iface->textInterface()) {
            QString text = QString::fromNSString((NSString *)value);
            iface->setText(QAccessible::Value, text);
        } else if (QAccessibleValueInterface *valueIface = iface->valueInterface()) {
            double val = [value doubleValue];
            valueIface->setCurrentValue(val);
        }
    } else if ([attribute isEqualToString:NSAccessibilitySelectedTextRangeAttribute]) {
        if (QAccessibleTextInterface *text = iface->textInterface()) {
            NSRange range = [value rangeValue];
            if (range.length > 0)
                text->setSelection(0, range.location, range.location + range.length);
            else
                text->setCursorPosition(range.location);
        }
    }
}

// actions

- (NSArray *)accessibilityActionNames {
    NSMutableArray *nsActions = [[NSMutableArray new] autorelease];
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return nsActions;

    const QStringList &supportedActionNames = QAccessibleBridgeUtils::effectiveActionNames(iface);
    for (const QString &qtAction : supportedActionNames) {
        NSString *nsAction = QCocoaAccessible::getTranslatedAction(qtAction);
        if (nsAction)
            [nsActions addObject : nsAction];
    }

    return nsActions;
}

- (NSString *)accessibilityActionDescription:(NSString *)action {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return nil; // FIXME is that the right return type??
    QString qtAction = QCocoaAccessible::translateAction(action, iface);
    QString description;
    // Return a description from the action interface if this action is not known to the OS.
    if (qtAction.isEmpty()) {
        if (QAccessibleActionInterface *actionInterface = iface->actionInterface()) {
            qtAction = QString::fromNSString((NSString *)action);
            description = actionInterface->localizedActionDescription(qtAction);
        }
    } else {
        description = qAccessibleLocalizedActionDescription(qtAction);
    }
    return description.toNSString();
}

- (void)accessibilityPerformAction:(NSString *)action {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (iface && iface->isValid()) {
        const QString qtAction = QCocoaAccessible::translateAction(action, iface);
        QAccessibleBridgeUtils::performEffectiveAction(iface, qtAction);
    }
}

// misc

- (BOOL)accessibilityIsIgnored {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid())
        return true;
    return QCocoaAccessible::shouldBeIgnored(iface);
}

- (id)accessibilityHitTest:(NSPoint)point {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (!iface || !iface->isValid()) {
//        qDebug("Hit test: INVALID");
        return NSAccessibilityUnignoredAncestor(self);
    }

    QPointF screenPoint = QCocoaScreen::mapFromNative(point);
    QAccessibleInterface *childInterface = iface->childAt(screenPoint.x(), screenPoint.y());
    // No child found, meaning we hit this element.
    if (!childInterface || !childInterface->isValid())
        return NSAccessibilityUnignoredAncestor(self);

    // find the deepest child at the point
    QAccessibleInterface *childOfChildInterface = nullptr;
    do {
        childOfChildInterface = childInterface->childAt(screenPoint.x(), screenPoint.y());
        if (childOfChildInterface && childOfChildInterface->isValid())
            childInterface = childOfChildInterface;
    } while (childOfChildInterface && childOfChildInterface->isValid());

    QAccessible::Id childId = QAccessible::uniqueId(childInterface);
    // hit a child, forward to child accessible interface.
    QMacAccessibilityElement *accessibleElement = [QMacAccessibilityElement elementWithId:childId];
    if (accessibleElement)
        return NSAccessibilityUnignoredAncestor(accessibleElement);
    return NSAccessibilityUnignoredAncestor(self);
}

- (id)accessibilityFocusedUIElement {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);

    if (!iface || !iface->isValid()) {
        qWarning("FocusedUIElement for INVALID");
        return nil;
    }

    QAccessibleInterface *childInterface = iface->focusChild();
    if (childInterface && childInterface->isValid()) {
        QAccessible::Id childAxid = QAccessible::uniqueId(childInterface);
        QMacAccessibilityElement *accessibleElement = [QMacAccessibilityElement elementWithId:childAxid];
        return NSAccessibilityUnignoredAncestor(accessibleElement);
    }

    return NSAccessibilityUnignoredAncestor(self);
}

- (NSString *) accessibilityHelp {
    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
    if (iface && iface->isValid()) {
        const QString helpText = iface->text(QAccessible::Help);
        if (!helpText.isEmpty())
            return helpText.toNSString();
    }
    return nil;
}

@end

#endif // QT_NO_ACCESSIBILITY
