It's 1000x considering the realtime data from smartwatch, which have no any API for that. So it includes decompiling smartwatches vendor's mobile app, or revers

It's 1000x considering the realtime data from smartwatch, which have no any API for that. So it includes decompiling smartwatches vendor's mobile app, or reverse engineering particular Bluetooth format the smartwatches use for sending the data to vendor's app.