URL?(link:).swift

extension URL {
    // https://apple.com -> https://apple.com
    // https://애플.com -> https://xn--9e5bq00a.com
    // https://apple.wow -> https://apple.wow
    // apple.com -> http://apple.com
    // 애플.com -> http://xn--9e5bq00a.com
    // apple.wow -> nil
    // apple -> nil
    init?(link: String) {
        let checkingType = NSTextCheckingResult.CheckingType.link
        guard let detector = try? NSDataDetector(types: checkingType.rawValue) else {
            preconditionFailure()
        }
        
        let range = NSRange(location: 0, length: link.utf16.count)
        guard let match = detector.firstMatch(in: link, options: [.anchored], range: range),
              let url = match.url, match.range == range
        else { return nil }
        
        self = url
    }
}