Hammerspoon Lua-script for disconnecting/connecting to a Bluetooth device when the lid is closed/opened

init.lua

require "string"

-- Make sure to install Hammerspoon (brew install --cask hammerspoon) and blueutil (brew install blueutil).
-- Ensure to give sufficient access in macOS so that the commands can be ran:
-- -- System Settings -> Privacy & Security -> Accessibility -> Allow Hammerspoon
-- -- System Settings -> Privacy & Security -> Bluetooth -> Select app "Hammerspoon"
-- Get the MAC address of your bluetooth device (use command "blueutil --paired")
-- Place this file in your home folder, then open Hammerspoon and click "Reload config"

macAddress="" -- Bluetooth Device MAC Address

function checkBluetoothResult(rc, stdout, stderr)
    -- Use for debugging
    --print(string.format("Command executed with rc=%d", rc))
    --print(string.format("stdout: '%s'", stdout or "nil"))
    --print(string.format("stderr: '%s'", stderr or "nil"))
    if rc ~= 0 then
        print(string.format("Error executing `blueutil`: rc=%d stderr=%s stdout=%s", rc, stderr, stdout))
    end
end

function disconnect(power)
    print("Disconnecting Bluetooth Device")
    local t = hs.task.new("/opt/homebrew/bin/blueutil", checkBluetoothResult, {"--disconnect", macAddress})
    t:start()
end

function connect(power)
    print("Connecting Bluetooth Device")
    local t = hs.task.new("/opt/homebrew/bin/blueutil", checkBluetoothResult, {"--connect", macAddress})
    t:start()
end

function f(event)
    if event == hs.caffeinate.watcher.systemWillSleep then
        disconnect()
    elseif event == hs.caffeinate.watcher.screensDidWake then
        connect()
    end
end

watcher = hs.caffeinate.watcher.new(f)
watcher:start()