/*

See LICENSE folder for this sample’s licensing information.

Abstract:

The object representing the accessibility element for the CustomLayoutAreaView.

*/

import Cocoa

class LayoutItem: NSAccessibilityElement, NSAccessibilityLayoutItem {

    var zOrder = 0

    override func accessibilityIdentifier() -> String {

        return accessibilityLabel()!

    }

   var bounds: NSRect = .zero {

        didSet {

            let minSize = CustomLayoutAreaView.LayoutInfo.LayoutItemHandleSize * 3

            if bounds.size.height < minSize {

                bounds.size.height = minSize

            }

            if bounds.size.width < minSize {

                bounds.size.width = minSize

            }

            if let parent = accessibilityParent() as? CustomLayoutAreaView {

                if !(oldValue.origin == bounds.origin) && parent.selectedLayoutItem == self {

                    // A layout item was moved (bounds changed).

                    NSAccessibilityPostNotification(accessibilityParent, NSAccessibilityNotificationName.selectedChildrenMoved)

                }

            }

        }

    }

}

// MARK: -

extension LayoutItem {

    // MARK: NSAccessibilityLayoutItem

    override func setAccessibilityFrame(_ accessibilityFrame: NSRect) {

        var newFrame = accessibilityFrame

        if let parentView = accessibilityParent() as? CustomLayoutAreaView {

            let window = parentView.window

            newFrame = (window?.convertFromScreen(newFrame))!

            newFrame = parentView.convert(newFrame, from:nil)

            bounds = newFrame

            parentView.needsDisplay = true

        }

    }

    // MARK: NSAccessibilityElement

    override func accessibilityParent() -> Any? {

        return super.accessibilityParent()

    }

    override func accessibilityFrame() -> NSRect {

        var result = NSRect.zero

        if let accessibilityParent = accessibilityParent() as? CustomLayoutAreaView {

            result = NSAccessibilityFrameInView(accessibilityParent, bounds)

        }

        return result

    }

    override func isAccessibilityFocused() -> Bool {

        var isFocused = false

        if let accessibilityParent = accessibilityParent() as? CustomLayoutAreaView {

            if accessibilityParent.selectedLayoutItem != nil {

                isFocused = accessibilityParent.selectedLayoutItem == self

            }

        }

        return isFocused

    }

    // MARK: NSAccessibility

    override func setAccessibilityFocused(_ accessibilityFocused: Bool) {

        guard let accessibilityParent = accessibilityParent() as? CustomLayoutAreaView else { return }

        if accessibilityFocused {

            accessibilityParent.selectedLayoutItem = self

        } else {

            if let layoutItem = accessibilityParent.accessibilityFocusedUIElement as? LayoutItem {

                if layoutItem == self {

                    accessibilityParent.selectedLayoutItem = self

                }

            }

        }

    }

}