Something like doorbell?

I have put Haven phone into metal safe and hard attached to my door. I need some software which is accessible even from locked phone (like camera or flash torch on my Android) that would call another phone on local WiFi or doing remote call to my pocket phone. Does such application exists? Given it exists or produced as mode of operation of Haven, I would get home security system.

Have as pocket client(receive calls and messages from all other Haven devices), haven doorbell, haven as surveillance camera-microphone, haven as receiving-storing device (attached to wall inside home, receive all calls and messages and alerts and video sequences via local WiFi and stores these on 64GB card, with old data replaced with new on space end; admin all other Haven devices settings). I would donate 40 USD for such solution. As of now, I will donate 10 USD in nearest future.

No source file, test, or entry point is identified. Start by determining whether Haven can operate while the phone is locked and communicate with another phone over local WiFi or remotely; define the supported doorbell, calling, messaging, storage, and administration scope before implementation.

Written by the indexing model from the issue text.