import Gtk

extension WidgetView {
    /// Adds `name` to the mounted widget when `enabled` is true; a false value
    /// appends no configuration step at all.
    func styleClass(_ name: String, _ enabled: Bool) -> Self {
        guard enabled else { return self }
        return appending { w, _ in w.addCssClass(cssClass: name) }
    }

    /// Adds `name` at mount when the binding is true, then adds/removes it on the
    /// live widget on every change. The subscription is registered with the mount
    /// context's registry, so unmount cancels it.
    func styleClass(_ name: String, _ enabled: Binding<Bool>) -> Self {
        appending { w, ctx in
            if enabled.untrackedValue { w.addCssClass(cssClass: name) }
            ctx.registry.add(enabled.subscribe { [w] on in
                if on { w.addCssClass(cssClass: name) } else { w.removeCssClass(cssClass: name) }
            })
        }
    }
}

extension View {
    /// `AnyView`-returning counterpart for views that are not ``WidgetView``
    /// (`HStack`, `VStack`, `AnyView`, raw `Gtk.Widget`).
    func styleClass(_ name: String, _ enabled: Bool) -> AnyView {
        guard enabled else { return AnyView(self) }
        return AnyView(makeWidget: { ctx in
            let w = AnyView(self).makeWidget(ctx)
            w.addCssClass(cssClass: name)
            return w
        })
    }

    /// `AnyView`-returning counterpart for views that are not ``WidgetView``
    /// (`HStack`, `VStack`, `AnyView`, raw `Gtk.Widget`). The subscription is
    /// registered with the mount context's registry, so unmount cancels it.
    func styleClass(_ name: String, _ enabled: Binding<Bool>) -> AnyView {
        AnyView(makeWidget: { ctx in
            let w = AnyView(self).makeWidget(ctx)
            if enabled.untrackedValue { w.addCssClass(cssClass: name) }
            ctx.registry.add(enabled.subscribe { [w] on in
                if on { w.addCssClass(cssClass: name) } else { w.removeCssClass(cssClass: name) }
            })
            return w
        })
    }
}