import CryptoJS from 'crypto-js';

class AesUtil {
  keySize: number;
  iterationCount: number;

  constructor(keySize: number, iterationCount: number) {
    this.keySize = keySize / 32;
    this.iterationCount = iterationCount;
  }

  generateKey(salt: string, passPhrase: string): CryptoJS.lib.WordArray {
    // Use SHA1 as hasher to match Java's PBKDF2WithHmacSHA1 default
    const key = CryptoJS.PBKDF2(passPhrase, CryptoJS.enc.Hex.parse(salt), {
      keySize: this.keySize,
      iterations: this.iterationCount,
      hasher: CryptoJS.algo.SHA1
    });
    return key;
  }

  encrypt(salt: string, iv: string, passPhrase: string, plainText: string): string {
    const key = this.generateKey(salt, passPhrase);
    const encrypted = CryptoJS.AES.encrypt(plainText, key, {
      iv: CryptoJS.enc.Hex.parse(iv),
      mode: CryptoJS.mode.CBC,
      padding: CryptoJS.pad.Pkcs7
    });
    return encrypted.ciphertext.toString(CryptoJS.enc.Base64);
  }

  decrypt(salt: string, iv: string, passPhrase: string, cipherText: string): string {
    const key = this.generateKey(salt, passPhrase);
    const cipherParams = CryptoJS.lib.CipherParams.create({
      ciphertext: CryptoJS.enc.Base64.parse(cipherText)
    });
    const decrypted = CryptoJS.AES.decrypt(cipherParams, key, {
      iv: CryptoJS.enc.Hex.parse(iv),
      mode: CryptoJS.mode.CBC,
      padding: CryptoJS.pad.Pkcs7
    });
    return decrypted.toString(CryptoJS.enc.Utf8);
  }
}

export { AesUtil };