Hello sir,
I stronglly recommend that you use the same app, and not to create a new one. For this, I can help you to install a local web server(on your computer), and you will be able to run exactlly the same application without an internet connection. The requirments are not high at all(1G of RAM).
Developing this kind of app as new desktop app, is a lot of work, a lot of bugs to be fixed on the way and so on. Alos, the app version might not work on a version of windows, for example...while installing a web server(thing that can be done on linux and windows also) assures you of full capability(LINUX,WINDOWS,MAC OS).
Installing and running this app locally won't take more than 2 days.
Thank you