let permission: Permission = .contacts

print(permission.status) // .notDetermined

permission.request { status in
    switch status {
    case .authorized:    print("authorized")
    case .denied:        print("denied")
    case .disabled:      print("disabled")
    case .notDetermined: print("not determined")
    }
}

let alert = permission.deniedAlert // or permission.disabledAlert

alert.title    = "Please allow access to your contacts"
alert.message  = nil
alert.cancel   = "Cancel"
alert.settings = "Settings"

permission.presentPrePermissionAlert = true

let alert = permission.prePermissionAlert

alert.title   = "Let Foo Access Photos?"
alert.message = "This lets you choose which photos you want to add to your Foo profile"
alert.cancel  = "Not now"
alert.confirm = "Give Access"

let permissionSet = PermissionSet(.contacts, .camera, .microphone, .photos)
permissionSet.delegate = self

print(permissionSet.status) // .notDetermined

// ...

func permissionSet(permissionSet: PermissionSet, willRequestPermission permission: Permission) {
    print("Will request \(permission)")
}

func permissionSet(permissionSet: PermissionSet, didRequestPermission permission: Permission) {
    switch permissionSet.status {
    case .authorized:    print("all the permissions are granted")
    case .denied:        print("at least one permission is denied")
    case .disabled:      print("at least one permission is disabled")
    case .notDetermined: print("at least one permission is not determined")
    }
}

let button = PermissionButton(.photos)

button.setTitles([
    .authorized:    "Authorized",
    .denied:        "Denied",
    .disabled:      "Disabled",
    .notDetermined: "Not determined"
])

// button.setAttributedTitles
// button.setTitleColors
// button.setTitleShadowColors
// button.setImages
// button.setBackgroundImages
// etc.

class PermissionsViewController: UIViewController, PermissionSetDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        let label = UILabel()

        let contacts   = PermissionButton(.contacts)
        let camera     = PermissionButton(.camera)
        let microphone = PermissionButton(.microphone)
        let photos     = PermissionButton(.photos)

        contacts.setTitles([
            .notDetermined: "Contacts - NotDetermined"
            .authorized:    "Contacts - Authorized",
            .denied:        "Contacts - Denied"
        ])

        contacts.setTitleColors([
            .notDetermined: .black,
            .authorized:    .green,
            .denied:        .red
        ])

        // ...

        let permissionSet = PermissionSet(contacts, camera, microphone, photos)

        permissionSet.delegate = self

        label.text = String(describing: permissionSet.status)

        for subview in [label, contacts, camera, microphone, photos] {
            view.addSubview(subview)
        }
    }

    func permissionSet(permissionSet: PermissionSet, didRequestPermission permission: Permission) {
        label.text = String(permissionSet.status)
    }
}