My stunning adventures in Swift

shuttle.swift

import Foundation
import IOKit
import IOKit.hid
import Quartz

let ioman = IOHIDManagerCreate(kCFAllocatorDefault,
    IOOptionBits(kIOHIDOptionsTypeNone))
let runloop : CFRunLoop = CFRunLoopGetCurrent()
let devices = [
    kIOHIDVendorIDKey: 0x0b33,
    kIOHIDProductIDKey: 0x0020
] as CFDictionary

let vendorKey = kIOHIDVendorIDKey as CFString
let productKey = kIOHIDProductIDKey as CFString

func generateMediaKeyEvent(key: Int32, down: Bool) -> CGEvent {
    let state : Int32 = down ? 0xa00 : 0xb00
    let data1 : Int32 = key << 16 | state

    let event = NSEvent.otherEvent(
        with: NSSystemDefined,
        location: NSPoint(x: 0, y: 0),
        modifierFlags: NSEventModifierFlags(rawValue: UInt(state)),
        timestamp: 0,
        windowNumber: 0,
        context: nil,
        subtype: 8,
        data1: Int(data1),
        data2: -1
    )

    return event!.cgEvent!
}

var valueCallback : IOHIDValueCallback = {
    (context, result, sender, value) in

    let element = IOHIDValueGetElement(value)
    let cookie = IOHIDElementGetCookie(element)
    let code = IOHIDValueGetIntegerValue(value)

    var event : CGEvent?

    switch cookie {
        case 7:     /* Button 1 */
            print("Button 1: ", code)
            event = generateMediaKeyEvent(key: NX_KEYTYPE_SOUND_DOWN, down: code == 1)
        case 8:     /* Button 2 */
            print("Button 2: ", code)
            event = generateMediaKeyEvent(key: NX_KEYTYPE_PREVIOUS, down: code == 1)
        case 9:     /* Button 3 */
            print("Button 3: ", code)
            event = generateMediaKeyEvent(key: NX_KEYTYPE_PLAY, down: code == 1)
        case 10:     /* Button 4 */
            print("Button 4: ", code)
            event = generateMediaKeyEvent(key: NX_KEYTYPE_NEXT, down: code == 1)
        case 11:     /* Button 5 */
            print("Button 5: ", code)
            event = generateMediaKeyEvent(key: NX_KEYTYPE_SOUND_UP, down: code == 1)
        case 16:    /* Jog Dial */
            print("Jog Dial: ", code)
            event = nil
        case 17:    /* Wheel */
            print("Wheel   : ", code)
            event = nil
        default:
            print("Unknown element")
            event = nil
    }

    if (event != nil) {
        event!.post(tap:.cgSessionEventTap)
    }
}

var attachCallback : IOHIDDeviceCallback = {
    (context, result, sender, device) in

    let v = IOHIDDeviceGetProperty(device, vendorKey) as! CFNumber as Int
    let p = IOHIDDeviceGetProperty(device, productKey) as! CFNumber as Int

    IOHIDDeviceOpen(device, IOOptionBits(kIOHIDOptionsTypeSeizeDevice))
    IOHIDDeviceRegisterInputValueCallback(device, valueCallback, nil)

    print(String(format: "attached: vendor %04x device %04x", v, p))
}

var detachCallback : IOHIDDeviceCallback = {
    (context, result, sender, device) in

    let v = IOHIDDeviceGetProperty(device, vendorKey) as! CFNumber as Int
    let p = IOHIDDeviceGetProperty(device, productKey) as! CFNumber as Int

    print(String(format: "detached: vendor %04x device %04x", v, p))
}

IOHIDManagerSetDeviceMatching(ioman, devices)
IOHIDManagerRegisterDeviceMatchingCallback(ioman, attachCallback, nil)
IOHIDManagerRegisterDeviceRemovalCallback(ioman, detachCallback, nil)

IOHIDManagerScheduleWithRunLoop(ioman, runloop,
    CFRunLoopMode.defaultMode.rawValue)
IOHIDManagerOpen(ioman, IOOptionBits(kIOHIDOptionsTypeNone))

CFRunLoopRun()