Build Laptop Shutdown Script for CentOS 7+ (XCP-NG)

Easy one but I dont have a lot of time at the moment. At the moment I have a VM Server running XCP-NG on a laptop. I need the server (laptop) to detect when power is lost and run the attached script which will begin the shutdown of all VMs the server is running before it shuts itself down. I require a script to be built for CentOs7+. The script will: Check AC power is applied every X minutes. When AC power is removed from lapotp and battery reaches X percent, run the attached VM shutdown script. Script must be tested and working properly for milestone to be realeased. Install/config instructions to be provided also.