ha_extension.swift

private struct AssociatedKeys {
    static var highlightAnimation = "VIV_highlightAnimation"
}

extension HighlightAnimatable where Self: UIView {

    private var animationAvailable: Bool {
        get { return (objc_getAssociatedObject(self, &AssociatedKeys.highlightAnimation) as? Bool) ?? true }
        set { objc_setAssociatedObject(self, &AssociatedKeys.highlightAnimation, newValue, .OBJC_ASSOCIATION_ASSIGN) }
    }

    var settings: HighlightAnimatableSettings { return HighlightAnimatableSettings() }

    func lockAnimation() {
        animationAvailable = false
        layer.removeAllAnimations()
    }

    func unlockAnimation() {
        animationAvailable = true
    }

    func highlight(_ touched: Bool) {
        highlight(touched, completion: nil)
    }

    func highlight(_ touched: Bool, completion: ((Bool) -> Void)?) {
        guard animationAvailable else { return }

        UIView.animate(withDuration: settings.duration,
                       delay: settings.delay,
                       usingSpringWithDamping: settings.springDamping,
                       initialSpringVelocity: settings.springVelocity,
                       options: settings.options,
                       animations: {
                        self.transform = touched ? self.settings.transform : .identity
        }, completion: completion)
    }

}