CLI for bluetooth on OSX: power, discoverable state, list, etc.
blueutil is a command-line utility for managing Bluetooth on macOS. It provides control over Bluetooth connections, device pairing, and power state from the terminal.
The Kiwi-User-Interface-Framework supports the implementation of graphical user interface for Mac OS X. You can implement GUI based on multi threading software architecture. For more details see http://kiwi-ui-frmk.sourceforge.net/