For https://medium.com/@maxchuquimia/create-a-punchable-tag-build-button-f5264cf50d7a

KeyMonitorMain.swift

import Foundation
import AppKit
import IOKit
import IOKit.hid

let manager = IOHIDManagerCreate(
    kCFAllocatorDefault,
    IOOptionBits(kIOHIDOptionsTypeNone)
)

var locked = false

@discardableResult
func shell(_ args: String...) -> Int32 {
    let task = Process()
    task.launchPath = "/usr/bin/env"
    task.arguments = args
    task.launch()
    task.waitUntilExit()
    return task.terminationStatus
}

func runScript() {

    shell("bash", "/Users/max.chuquimia/xcode/KeyMonitor/run.sh")
    print("unlocking soon")

    // Don't allow multiple presses quickly
    DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
        locked = false
        print("unlocked")
    }
}

let matchDict: [CFString: NSNumber] = [
    kIOHIDVendorIDKey as CFString: NSNumber(value: 5050),
    kIOHIDProductIDKey as CFString: NSNumber(value: 1),
]

IOHIDManagerSetDeviceMatching(manager, matchDict as CFDictionary)

// IOHIDManagerRegisterDeviceMatchingCallback(manager, { (_, _, _, inIOHIDDeviceRef) in
//     print(inIOHIDDeviceRef)
// }, nil)

IOHIDManagerScheduleWithRunLoop( manager, CFRunLoopGetMain(), CFRunLoopMode.defaultMode!.rawValue);

IOHIDManagerRegisterInputValueCallback(manager, { (context, inResult, inSent, value) in
    guard !locked else { return }
    locked = true
    print("INPUT DETECTED")
    print(IOHIDValueGetIntegerValue(value))
    runScript()
}, nil)


let result = IOHIDManagerOpen(manager, IOOptionBits(kIOHIDOptionsTypeNone))

assert(result == kIOReturnSuccess)

CFRunLoopRun()