source: phonelux-backend/src/main/java/finki/it/phoneluxbackend/services/RegistrationService.java

package finki.it.phoneluxbackend.services;

import finki.it.phoneluxbackend.data.RegistrationRequest;
import finki.it.phoneluxbackend.data.UserRole;
import finki.it.phoneluxbackend.entities.ConfirmationToken;
import finki.it.phoneluxbackend.entities.User;
import finki.it.phoneluxbackend.security.email.EmailSender;
import finki.it.phoneluxbackend.security.email.EmailValidator;
import lombok.AllArgsConstructor;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;

@Service
@AllArgsConstructor
public class RegistrationService {
    private final UserService userService;
    private final EmailValidator emailValidator;
    private final ConfirmationTokenService confirmationTokenService;
    private final EmailSender emailSender;


    public ResponseEntity<Object> register(RegistrationRequest request) {
        boolean isValidEmail = emailValidator.test(request.getEmail());

        // mail is validated on frontend already
        if (!isValidEmail)
            throw new IllegalStateException("Email"+request.getEmail()+" not valid!");

        ResponseEntity response = userService.signUpUser(
                new User(request.getFirstName(),
                        request.getLastName(),
                        request.getEmail(),
                        request.getPassword(),
                        UserRole.USER));

        if (response.getStatusCode() == HttpStatus.BAD_REQUEST)
        {
            return response;
        }

        String link = "http://localhost:8080/registration/confirm?token="+response.getBody()
                .toString().split(":")[1];
        emailSender.send(request.getEmail(), buildEmail(request.getFirstName(),link));

        return response;
    }

    private String buildEmail(String name, String link) {
        return "<div style=\"font-family:Helvetica,Arial,sans-serif;font-size:16px;margin:0;color:#0b0c0c\">\n" +
                "\n" +
                "<span style=\"display:none;font-size:1px;color:#fff;max-height:0\"></span>\n" +
                "\n" +
                "  <table role=\"presentation\" width=\"100%\" style=\"border-collapse:collapse;min-width:100%;width:100%!important\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\">\n" +
                "    <tbody><tr>\n" +
                "      <td width=\"100%\" height=\"53\" bgcolor=\"#0b0c0c\">\n" +
                "        \n" +
                "        <table role=\"presentation\" width=\"100%\" style=\"border-collapse:collapse;max-width:580px\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" align=\"center\">\n" +
                "          <tbody><tr>\n" +
                "            <td width=\"70\" bgcolor=\"#0b0c0c\" valign=\"middle\">\n" +
                "                <table role=\"presentation\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"border-collapse:collapse\">\n" +
                "                  <tbody><tr>\n" +
                "                    <td style=\"padding-left:10px\">\n" +
                "                  \n" +
                "                    </td>\n" +
                "                    <td style=\"font-size:28px;line-height:1.315789474;Margin-top:4px;padding-left:10px\">\n" +
                "                      <span style=\"font-family:Helvetica,Arial,sans-serif;font-weight:700;color:#ffffff;text-decoration:none;vertical-align:top;display:inline-block\">Confirm your email</span>\n" +
                "                    </td>\n" +
                "                  </tr>\n" +
                "                </tbody></table>\n" +
                "              </a>\n" +
                "            </td>\n" +
                "          </tr>\n" +
                "        </tbody></table>\n" +
                "        \n" +
                "      </td>\n" +
                "    </tr>\n" +
                "  </tbody></table>\n" +
                "  <table role=\"presentation\" class=\"m_-6186904992287805515content\" align=\"center\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"border-collapse:collapse;max-width:580px;width:100%!important\" width=\"100%\">\n" +
                "    <tbody><tr>\n" +
                "      <td width=\"10\" height=\"10\" valign=\"middle\"></td>\n" +
                "      <td>\n" +
                "        \n" +
                "                <table role=\"presentation\" width=\"100%\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"border-collapse:collapse\">\n" +
                "                  <tbody><tr>\n" +
                "                    <td bgcolor=\"#1D70B8\" width=\"100%\" height=\"10\"></td>\n" +
                "                  </tr>\n" +
                "                </tbody></table>\n" +
                "        \n" +
                "      </td>\n" +
                "      <td width=\"10\" valign=\"middle\" height=\"10\"></td>\n" +
                "    </tr>\n" +
                "  </tbody></table>\n" +
                "\n" +
                "\n" +
                "\n" +
                "  <table role=\"presentation\" class=\"m_-6186904992287805515content\" align=\"center\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"border-collapse:collapse;max-width:580px;width:100%!important\" width=\"100%\">\n" +
                "    <tbody><tr>\n" +
                "      <td height=\"30\"><br></td>\n" +
                "    </tr>\n" +
                "    <tr>\n" +
                "      <td width=\"10\" valign=\"middle\"><br></td>\n" +
                "      <td style=\"font-family:Helvetica,Arial,sans-serif;font-size:19px;line-height:1.315789474;max-width:560px\">\n" +
                "        \n" +
                "            <p style=\"Margin:0 0 20px 0;font-size:19px;line-height:25px;color:#0b0c0c\">Hi " + name + ",</p><p style=\"Margin:0 0 20px 0;font-size:19px;line-height:25px;color:#0b0c0c\"> Thank you for registering. Please click on the below link to activate your account: </p><blockquote style=\"Margin:0 0 20px 0;border-left:10px solid #b1b4b6;padding:15px 0 0.1px 15px;font-size:19px;line-height:25px\"><p style=\"Margin:0 0 20px 0;font-size:19px;line-height:25px;color:#0b0c0c\"> <a href=\"" + link + "\">Activate Now</a> </p></blockquote>\n Link will expire in 15 minutes. <p>See you soon</p>" +
                "        \n" +
                "      </td>\n" +
                "      <td width=\"10\" valign=\"middle\"><br></td>\n" +
                "    </tr>\n" +
                "    <tr>\n" +
                "      <td height=\"30\"><br></td>\n" +
                "    </tr>\n" +
                "  </tbody></table><div class=\"yj6qo\"></div><div class=\"adL\">\n" +
                "\n" +
                "</div></div>";
    }


    @Transactional
    public String confirmToken(String token) {
        boolean confirmationTokenExists = confirmationTokenService.getToken(token).isPresent();

        ConfirmationToken confirmationToken;

        if(confirmationTokenExists)
            confirmationToken = confirmationTokenService.getToken(token).get();
        else
            return "Token not found!";

        if(confirmationToken.getConfirmedAt() != null)
            return "Email already confirmed!";

        LocalDateTime expiresAt = confirmationToken.getExpiresAt();

        if (expiresAt.isBefore(LocalDateTime.now())){
            return "Token expired";
        }

        confirmationTokenService.setConfirmedAt(token);
        userService.enableUser(confirmationToken.getUser().getEmail());

        return "Email confirmed";
    }


}