/*

     File: SKTGraphicView+Accessibility.m

 Abstract: Adds accessibility support to SKTGraphicView.

  Version: 1.1

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 */

#import "SKTGraphicView.h"

#import "SKTGraphicAccessibilityProxy.h"

@interface SKTGraphicView (Private)

- (NSArray *)graphics;

- (SKTGraphic *)graphicUnderPoint:(NSPoint)point index:(NSUInteger *)outIndex isSelected:(BOOL *)outIsSelected handle:(NSInteger *)outHandle;

@end

@implementation SKTGraphicView (Accessibility)

- (BOOL)isGraphicSelected:(SKTGraphic *)graphic {

    return [[self selectedGraphics] containsObject:graphic];

}

- (BOOL)accessibilityIsIgnored {

    return NO;

}

#pragma mark -

#pragma mark Attributes

- (NSArray *)accessibilityAttributeNames {

    static NSArray *attributes;

    if (!attributes) {

        NSMutableArray *temp = [[super accessibilityAttributeNames] mutableCopy];

        [temp addObject:NSAccessibilityEnabledAttribute];

        [temp addObject:NSAccessibilityVerticalUnitsAttribute];

        [temp addObject:NSAccessibilityHorizontalUnitsAttribute];

        [temp addObject:NSAccessibilityVerticalUnitDescriptionAttribute];

        [temp addObject:NSAccessibilityHorizontalUnitDescriptionAttribute];

        attributes = [temp copy];

        [temp release];

    }

    return attributes;

}

- (id)accessibilityAttributeValue:(NSString *)attribute {

    if ([attribute isEqualToString:NSAccessibilityRoleAttribute]) {

        return NSAccessibilityLayoutAreaRole;

    } else if ([attribute isEqualToString:NSAccessibilityChildrenAttribute]) {

        // Get all the graphics

        NSArray *allGraphics = [self graphics];

        // Create an autoreleased mutable array to hold the graphic proxy elements

        NSMutableArray *children = [NSMutableArray arrayWithCapacity:[allGraphics count]];

        // Iterate through the graphics.  We go backwards so they are returned in z-order.

        SKTGraphic *graphic = nil;

        NSEnumerator *reverseEnumerator = [allGraphics reverseObjectEnumerator];

        while (graphic = [reverseEnumerator nextObject]) {

            // For each graphic, create an autoreleased proxy element and add it to the array

            id child = [SKTGraphicAccessibilityProxy graphicProxyWithGraphic:graphic parent:self];

            [children addObject:child];

        }

        // Send back the array.

        return children;

    } else if ([attribute isEqualToString:NSAccessibilityEnabledAttribute]) {

        return [NSNumber numberWithBool:YES];

    } else if ([attribute isEqualToString:NSAccessibilityVerticalUnitsAttribute] || [attribute isEqualToString:NSAccessibilityHorizontalUnitsAttribute]) {

        return NSAccessibilityPointsUnitValue;

    } else if ([attribute isEqualToString:NSAccessibilityVerticalUnitDescriptionAttribute] || [attribute isEqualToString:NSAccessibilityHorizontalUnitDescriptionAttribute]) {

        return NSLocalizedStringFromTable(@"points", @"Accessibility", @"accessibility description for unit measurement");

    } else {

        return [super accessibilityAttributeValue:attribute];

    }

}

/* Our superclass NSView will report NO for any attribute it does not explicitly allow.  Since all of the attributes we have added are read-only, we do not need to override -accessibilityIsAttributeSettable:, however, this template is here to be uncommented and used if a settable attribute is ever added by this subclass.  Change the NSSet init method to -initWithObjects: and list the settable attributes.

*/

/*- (BOOL)accessibilityIsAttributeSettable:(NSString *)attribute {

    static NSSet *settableAttributes;

    if (!settableAttributes) {

    settableAttributes = [[NSSet alloc] init];

    }

    if ([settableAttributes containsObject:attribute]) {

    return YES;

    }

    else {

    return [super accessibilityIsAttributeSettable:attribute];

    }

}*/

#pragma mark -

#pragma mark Parameterized Attributes

/* The parameterized attributes of a layout area allow an accessibility client to take usual information about sub-elements, such as the AXSize and AXPosition and translate into the units used by the user interface, so they can be reported by the user.  Similarly, the accessibility client can let its user work with units in this application's user interface, and then use these parameterized methods to convert to the correct screen units.

 */

- (NSArray *)accessibilityParameterizedAttributeNames {

    static NSArray *attributes;

    if (!attributes) {

        NSMutableArray *temp = [[super accessibilityParameterizedAttributeNames] mutableCopy];

        [temp addObject:NSAccessibilityLayoutPointForScreenPointParameterizedAttribute];

        [temp addObject:NSAccessibilityLayoutSizeForScreenSizeParameterizedAttribute];

        [temp addObject:NSAccessibilityScreenPointForLayoutPointParameterizedAttribute];

        [temp addObject:NSAccessibilityScreenSizeForLayoutSizeParameterizedAttribute];

        attributes = [temp copy];

        [temp release];

    }

    return attributes;

}

/* Sketch uses points as the unit of measure - the coordinate system reported to the user is the same as the SKTGraphicView's native coordinate system.  So for these methods, convert between view coordinates and screen coordinates and vice versa.  If Sketch reported inches to the user, for instance, we would need to add an additional conversion from view coordinates to the reported measurement system and vice versa.

 */

- (id)accessibilityAttributeValue:(NSString *)attribute forParameter:(id)parameter {

    if (![parameter isKindOfClass:[NSValue class]]) NSAccessibilityRaiseBadArgumentException(self, attribute, parameter);

    if ([attribute isEqualToString:NSAccessibilityLayoutPointForScreenPointParameterizedAttribute]) {

        NSPoint point = [parameter pointValue];

        NSPoint windowPoint = [[self window] convertScreenToBase:point];

        NSPoint localPoint = [self convertPointFromBase:windowPoint];

        return [NSValue valueWithPoint:localPoint];

    }

    else if ([attribute isEqualToString:NSAccessibilityLayoutSizeForScreenSizeParameterizedAttribute]) {

        NSSize size = [parameter sizeValue];

        NSSize localSize = [self convertSizeFromBase:size];

        return [NSValue valueWithSize:localSize];

    }

    else if ([attribute isEqualToString:NSAccessibilityScreenPointForLayoutPointParameterizedAttribute]) {

        NSPoint point = [parameter pointValue];

        NSPoint windowPoint = [self convertPointToBase:point];

        NSPoint screenPoint = [[self window] convertBaseToScreen:windowPoint];

        return [NSValue valueWithPoint:screenPoint];

    }

    else if ([attribute isEqualToString:NSAccessibilityScreenSizeForLayoutSizeParameterizedAttribute]) {

        NSSize size = [parameter sizeValue];

        NSSize screenSize = [self convertSizeToBase:size];

        return [NSValue valueWithSize:screenSize];

    }

    else {

        return [super accessibilityAttributeValue:attribute forParameter:parameter];

    }

}

#pragma mark -

#pragma mark Hit Testing

/* If accessibilityHitTest: is called, it has already been determined that the point is either contained in this element, or one of its descendants.  We figure out whether one of our graphics is hit, if so we create a graphic proxy element and ask it to perform an accessibility hit test.  If not, we return our first unignored anscestor (which in this case is us).

 */

- (id)accessibilityHitTest:(NSPoint)point {

    // Convert screen point to window point

    NSPoint windowPoint = [[self window] convertScreenToBase:point];

    // Convert window point to local point

    NSPoint localPoint = [self convertPointFromBase:windowPoint];

    // Use existing method to hit test graphics

    SKTGraphic *hitGraphic = [self graphicUnderPoint:localPoint index:0 isSelected:0 handle:0];

    if (hitGraphic) {

        // If we hit a graphic, make a graphic proxy object

        SKTGraphicAccessibilityProxy *graphicProxy = [SKTGraphicAccessibilityProxy graphicProxyWithGraphic:hitGraphic parent:self];

        // And ask it to do an accessibility hit test, return the result

        return [graphicProxy accessibilityHitTest:point];

    } else {

        // Otherwise, just return our unignored anscestor.  In this case, ourself.

        return NSAccessibilityUnignoredAncestor(self);

    }

}

@end