import { Injectable } from '@nestjs/common';
import { EncryptionAlgorithm } from '../core/domain/username.types';
import * as bcrypt from 'bcrypt';
import * as argon2 from 'argon2';
import { PasswordVerifierPort } from '../core/application/ports/password-verifier.port';

@Injectable()
export class PasswordVerifier implements PasswordVerifierPort {
  verify = async (
    passwordToVerify: string,
    encryptedPassword: string,
  ): Promise<boolean> => {
    const encryptionAlgorithm: EncryptionAlgorithm =
      this.guessEncryptionAlgorithm(encryptedPassword);
    switch (encryptionAlgorithm) {
      case EncryptionAlgorithm.BCRYPT:
        return await bcrypt.compare(passwordToVerify, encryptedPassword);
      case EncryptionAlgorithm.ARGON2D:
      case EncryptionAlgorithm.ARGON2I:
      case EncryptionAlgorithm.ARGON2ID:
        return await argon2.verify(encryptedPassword, passwordToVerify, {
          type: this.argonType(encryptionAlgorithm),
        });
    }
  };

  private guessEncryptionAlgorithm = (
    password: string,
  ): EncryptionAlgorithm => {
    if (password.substring(1, 9) === 'argon2id')
      return EncryptionAlgorithm.ARGON2ID;
    if (password.substring(1, 8) === 'argon2i')
      return EncryptionAlgorithm.ARGON2I;
    if (password.substring(1, 8) === 'argon2d')
      return EncryptionAlgorithm.ARGON2D;
    return EncryptionAlgorithm.BCRYPT;
  };

  private argonType = (
    encryptionAlgorithm: EncryptionAlgorithm,
  ): typeof argon2.argon2d | typeof argon2.argon2i | typeof argon2.argon2id => {
    switch (encryptionAlgorithm) {
      case EncryptionAlgorithm.ARGON2D:
        return argon2.argon2d;
      case EncryptionAlgorithm.ARGON2I:
        return argon2.argon2i;
      default:
        return argon2.argon2id;
    }
  };
}