validateNickname.swift

class UserInfoValidator {
    enum Validation {
        case nickname
        
        var pattern: String {
            switch self {
            case .nickname:
                return "^[a-zA-Z0-9ㄱ-ㅣ가-힣\\-\\.\\_]{1,16}$"
            default:
                return ""
            }
        }
    }
    
    static func isValid(nickname: String) -> Bool {
        isValid(target: nickname, validation: Validation.nickname)
    }
    
    static func isValid(target: String, validation: Validation) -> Bool {
        guard let regex = try? NSRegularExpression(pattern: validation.pattern, options: []) else { return false }
        let result = regex.firstMatch(in: target, options: [], range: .init(location: 0, length: target.utf16.count))
        return result != nil
    }
}


private func validateNickname() throws {
        guard let nickname = nicknameField.text, nickname.isNotEmpty else {
            nicknameField.textField.invalidText = "닉네임을 입력해주세요."
            nicknameField.textField.isInvalid = true
            throw NSError(domain: "Validation error", code: -1, userInfo: nil)
        }

        if !UserInfoValidator.isValid(nickname: nickname) {
            self.nicknameField.textField.invalidText = "[_], [-], [.] 외 특수문자 및 공백은 사용하실 수 없습니다."
            nicknameField.textField.isInvalid = true
            throw NSError(domain: "Validation error", code: -1, userInfo: nil)
        }
        nicknameField.textField.isInvalid = false
}

nicknameField.textField.rx.text.orEmpty
    .filter { [unowned self] _ in self.enableNickname }
    .filterEmpty()
    .distinctUntilChanged()
    .subscribe(onNext: { [unowned self] _ in
        try? self.validateNickname()
    })
    .disposed(by: disposeBag)