backend/src/door-lock/services/encryption.services.ts

import { HttpException, HttpStatus, Injectable } from '@nestjs/common';
import * as CryptoJS from 'crypto-js';
import { ConfigService } from '@nestjs/config';
import { EnableDisableStatusEnum } from '@app/common/constants/days.enum';

@Injectable()
export class PasswordEncryptionService {
  constructor(private readonly configService: ConfigService) {}

  encrypt(plainText: string, secretKey: string): string {
    const keyBytes = CryptoJS.enc.Utf8.parse(secretKey);

    const encrypted = CryptoJS.AES.encrypt(plainText, keyBytes, {
      mode: CryptoJS.mode.ECB,
      padding: CryptoJS.pad.Pkcs7,
    });

    return encrypted.ciphertext.toString(CryptoJS.enc.Hex);
  }

  decrypt(encryptedText: string, secretKey: string): string {
    const keyBytes = CryptoJS.enc.Utf8.parse(secretKey);

    const decrypted = CryptoJS.AES.decrypt(
      {
        ciphertext: CryptoJS.enc.Hex.parse(encryptedText),
      } as any,
      keyBytes,
      {
        mode: CryptoJS.mode.ECB,
        padding: CryptoJS.pad.Pkcs7,
      },
    );

    return decrypted.toString(CryptoJS.enc.Utf8);
  }

  generateEncryptedPassword(
    plainTextPassword: string,
    ticketKey: string,
  ): string {
    try {
      const accessSecret = this.configService.get<string>(
        'auth-config.SECRET_KEY',
      );
      // The accessSecret must be 32 bytes, ensure it is properly padded or truncated
      const paddedAccessSecret = accessSecret
        .padEnd(32, EnableDisableStatusEnum.DISABLED)
        .slice(0, 32);
      const plainTextTicketKey = this.decrypt(ticketKey, paddedAccessSecret);

      return this.encrypt(plainTextPassword, plainTextTicketKey);
    } catch (error) {
      throw new HttpException(
        `Error encrypting password: ${error.message}`,
        HttpStatus.INTERNAL_SERVER_ERROR,
      );
    }
  }
}