MLEncoderTool.swift

public struct MLEncoderTool {
  // The first argument is the file name
  // The second argument is key
  private let arguments: [String]
  
  private let cryptor: MLCryptor
  
  public init(
    arguments: [String] = CommandLine.arguments,
    cryptor: MLCryptor = MLCryptor.cryptoKit
  ) {
    self.arguments = arguments
    self.cryptor = cryptor
  }
  
  public func run() throws {
    if arguments.count == 1 {
      throw Error.missingAllArguments
    }
    
    if arguments.count == 2 {
      throw Error.missingKey
    }
    
    try encryptFile()
  }
  
  func encryptFile() throws {
    let fileName = arguments[1]
    let key = arguments[2]
    
    let currentPath = FileManager.default.currentDirectoryPath
    let fullPath = currentPath + "/" + fileName
    
    guard let data = FileManager.default.contents(atPath: fullPath) else {
      throw Error.noFile
    }
    
    guard let encryptedData = try cryptor.encrypt(data: data, withPassword: key) else {
      throw Error.undefinedError
    }
    
    let destinationPath = currentPath + "/" + fileName + ".enc"
    let destinationURL = URL(fileURLWithPath: destinationPath)
    
    try encryptedData.write(to: destinationURL)
    
    print("The file was encrypted successfully.")
  }
  
  func decryptFile() throws {
    let fileName = arguments[1]
    let key = arguments[2]
    
    let currentPath = FileManager.default.currentDirectoryPath
    let fullPath = currentPath + "/" + fileName
    
    guard let data = FileManager.default.contents(atPath: fullPath) else {
      throw Error.noFile
    }
    
    guard let encryptedData = try cryptor.decrypt(data: data, withPassword: key) else {
      throw Error.undefinedError
    }
    
    let destinationPath = currentPath + "/" + (fileName as NSString).deletingPathExtension
    let destionationURL = URL(fileURLWithPath: destinationPath)
    
    try encryptedData.write(to: destionationURL)
    
    print("The file was decrypted successfully.")
  }
}
 
public extension MLEncoderTool {
  enum Error: Swift.Error {
    case missingAllArguments
    case missingKey
    case noFile
    case undefinedError
  }
}