/*

See LICENSE folder for this sample’s licensing information.

Abstract:

An example demonstrating the preferred method of making an accessible,

 custom button by subclassing NSButton and implementing the NSAccessibilityButton protocol.

*/

import Cocoa

// Note that NSButton already conforms to protocol "NSAccessibilityButton".

class CustomButton: NSButton {

    // MARK: - View Lifecycle

    required override init(frame frameRect: NSRect) {

        super.init(frame: frameRect)

        commonInit()

    }

    required init?(coder aDecoder: NSCoder) {

        super.init(coder: aDecoder)

        commonInit()

    }

    fileprivate func commonInit() {

        image = NSImage(named: NSImage.Name(rawValue: ButtonImages.buttonUp))

        alternateImage = NSImage(named: NSImage.Name(rawValue: ButtonImages.buttonDown))

        // Track the mouse for enter and exit for proper highlighting.

        let trackingArea = NSTrackingArea(rect: bounds,

                                          options: [NSTrackingArea.Options.activeAlways, NSTrackingArea.Options.mouseEnteredAndExited],

                                          owner: self,

                                          userInfo: nil)

        addTrackingArea(trackingArea)

    }

    // MARK: - Mouse events

    override func mouseEntered(with event: NSEvent) {

        super.mouseEntered(with: event)

        image = NSImage(named: NSImage.Name(rawValue: ButtonImages.buttonHighlight))

    }

    override func mouseExited(with event: NSEvent) {

        super.mouseExited(with: event)

        image = NSImage(named: NSImage.Name(rawValue: ButtonImages.buttonUp))

    }

}

// MARK: - NSAccessibilityButton

extension CustomButton {

    /// - Tag: accessibilityLabel

    override func accessibilityLabel() -> String? {

        return NSLocalizedString("Play", comment: "accessibility label of the Play button")

    }

    override func accessibilityHelp() -> String {

        return NSLocalizedString("Increase press count.", comment: "accessibility help of the Play button")

    }

    // MARK: NSAccessibility

    override func accessibilityPerformPress() -> Bool {

        // User did control-option-space keyboard shortcut.

        performClick(nil)

        return true

    }

}