Authentication.swift

// Decoding User Info
 func decodeUserInfo(from data: Data) -> Result<User, Failure> {
        
        let decoder = JSONDecoder()
        let decodedData = try? decoder.decode(DecodedUserInfo.self, from: data)
        guard let userData = decodedData?.person else { print("Errors while decoding UserData: \(Failure.failedDecodingFile.errorDescription)"); return .failure(.failedDecodingFile)}
        let user = User(userID: userData.id, userName: userData.username.content, iconServer: userData.iconserver, iconFarm: userData.iconfarm)
        _ = user.iconURL
        
        return .success(user)
    }
    
    // Saving User Info with FileManager
    
    func saveUserInfo(_ userData: Result<User, Failure>) {
        
        let plistEncoder = PropertyListEncoder()
        plistEncoder.outputFormat = .xml
        
        let userDirectoryPath = FileManager.documentsDirectory
        let fileToSaveInto = URL(fileURLWithPath: "SavedUserData", relativeTo: userDirectoryPath).appendingPathExtension("plist")
        print("File location: \(fileToSaveInto.path)")
        
        switch userData {
            
        case .failure(let error ):
            print("Error: \(error.localizedDescription)")
            
        case .success(let user):
            do {
                let dataToBeSaved = try plistEncoder.encode(user)
                try dataToBeSaved.write(to: fileToSaveInto, options: .atomic)

            } catch {
                print("Errors while writing user to Documents Directory: \(error.localizedDescription)")
            }
        }
    }
    
    // Retrieving User Info with FileManager
    
        func retrieveUserInfo() throws -> User {
        
        let plistDecoder = PropertyListDecoder()
        let filePath = FileManager.documentsDirectory
        let file = filePath.appendingPathComponent("SavedUserData").appendingPathExtension("plist")
        guard let retrievedData = try? Data(contentsOf: file) else { print("Errors: \(Failure.missingFile.errorDescription)"); throw Failure.missingFile }
        guard let decodedUserData = try? plistDecoder.decode(User.self, from: retrievedData) else { print("Error: \(Failure.failedDecodingFile.errorDescription)"); throw Failure.failedDecodingFile}

        return decodedUserData
    }