Xaml animation for button with click if completed

Intention: MouseEnter-triggered animation for app-wide each button.

Details:

• Animation should not happen if a button is pushed by spacebar.
• If animation is finished, button should be clicked.
• If button is clicked or pushed by user while animation is running, animation should stop at once (disappear).
• Xaml-only code, if possible, otherwise C#

Basic code for App.xaml:

<Style TargetType="{x:Type Button}">
    <Style.Triggers>
        <EventTrigger RoutedEvent="MouseEnter">
            <EventTrigger.Actions>
                <BeginStoryboard Name="buttonStoryboard">
                    <Storyboard>
                        <DoubleAnimation From="0" To="1" Duration="0:0:2.5" Storyboard.TargetProperty="(Opacity)" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger.Actions>
        </EventTrigger>
    </Style.Triggers>
</Style>

Any help would be appreciated.