Pretty sure someone just made some Angel Wing stickers when they started putting motors on bikes. The motor (like stated earlier) are China made units that sell on eBay for around $100 for the kit (motor, tank, chain, sprocket, mounts, clutch handle) they are a 68.5cc engine, they vibrate like crazy at high RPMS (I've got one) they are fun, but you will be working on it constantly if you want it to last and you care about your safety.
The bike, can't tell from the photo, maybe someone else can, as of now I'd just say it's your run of the mill cantilever cruiser frame, and there's nothing wrong with that, but I'd be weary about riding it on engine power with that springer fork, I doubt it's heavy duty.
The bike was probably put together from the motor kit in the past 2 years or so.