Remote control with offline functionality | Home Automation
I can't think of a smart (home automation) switch that doesn't have that "offline" capability.  I've got Insteon (Smarthome) switches in my house; they're Decora-style paddle switches with radio- and powerline connectivity. They talk to Insteon's "hub", which in turn talks to the cloud and your mobile app. You can turn the light on or off locally or remotely, and since they're bidirectional you can see on your smartphone whether a given light is on or off.  Is what you're looking to do any more complex than that?