contacts.swift

import Contacts

func update()
{
    func makeNickname(name: String) -> String
    {
        let transform: UnicodeScalar -> String = { u in
            let c = Int(u.value)
            guard case 0xac00...0xd7a3 = c else { return "" }
            return String(UnicodeScalar((c - 0xac00) / 28 / 21 + 0x1100))
        }

        let result = name.unicodeScalars.map(transform).joinWithSeparator("")
        return result
    }

    let store = CNContactStore()
    let fetchRequest = CNContactFetchRequest(keysToFetch:[CNContactGivenNameKey,
                                                CNContactNicknameKey])
    let saveRequest = CNSaveRequest()

    do {
        try store.enumerateContactsWithFetchRequest(fetchRequest){ contact, stop in
            let name = contact.givenName
            let nickname = makeNickname(name)
            guard nickname.utf8.count > 0 && nickname != contact.nickname else { return }
            let mutableContact = contact.mutableCopy() as! CNMutableContact
            mutableContact.nickname = nickname
            saveRequest.updateContact(mutableContact)
        }
    } catch {
        print("An error occurred during fetching contact information.")
    }

    do {
        try store.executeSaveRequest(saveRequest)
    } catch {
        print("An error occurred during saving contacts.")
    }
}