import crypto from "crypto";

/**
 * Utility class for the AES-128/256 encryption.
 *
 *   - AES-128/256
 *   - CBC mode
 *   - PKCS#5 Padding
 *   - Base64 Encoding
 *
 * @author Jeongho Nam - https://github.com/samchon
 */
export namespace AesPkcs5 {
  /**
   * Encrypt data
   *
   * @param data Target data
   * @param key Key value of the encryption.
   * @param iv Initializer Vector for the encryption
   * @return Encrypted data
   */
  export function encrypt(data: string, key: string, iv: string): string {
    const bytes: number = key.length * 8;
    const cipher: crypto.Cipher = crypto.createCipheriv(
      `AES-${bytes}-CBC`,
      key,
      iv,
    );
    return cipher.update(data, "utf8", "base64") + cipher.final("base64");
  }

  /**
   * Decrypt data.
   *
   * @param data Target data
   * @param key Key value of the decryption.
   * @param iv Initializer Vector for the decryption
   * @return Decrypted data.
   */
  export function decrypt(data: string, key: string, iv: string): string {
    const bytes: number = key.length * 8;
    const decipher: crypto.Decipher = crypto.createDecipheriv(
      `AES-${bytes}-CBC`,
      key,
      iv,
    );

    return decipher.update(data, "base64", "utf8") + decipher.final("utf8");
  }
}