@PutMapping
    public ResponseEntity sendMessage(@RequestHeader("Token") String givenToken, @Validated @RequestBody Message message) {

        message.setSenderId(sessionController.checkToken(givenToken).getUserId());
        message.setTimestamp(System.currentTimeMillis());

        return new ResponseEntity<>(messageRepository.save(message), HttpStatus.OK);
    }

    @GetMapping
    public ResponseEntity getMessages(@RequestHeader("Token") String givenToken) {
        List<Message> messages = messageRepository.findAllByReceiverId(sessionController.checkToken(givenToken).getUserId());
        messages.addAll(messageRepository.findAllBySenderId(sessionController.checkToken(givenToken).getUserId()));
        return new ResponseEntity<>(messages, HttpStatus.OK);
    }

@PostMapping
    public ResponseEntity tryToLogin(@RequestBody User user) {
        String email = user.getEmail();
        String password = user.getPassword();

        if (StringUtils.isEmpty(email)) {
            return new ResponseEntity<>("No email field or value", HttpStatus.BAD_REQUEST);
        }

        if (StringUtils.isEmpty(password)) {
            return new ResponseEntity<>("No password field or value", HttpStatus.BAD_REQUEST);
        }

        User dbUser = userRepository.findByEmail(email);

        if (dbUser == null) {
            return new ResponseEntity(HttpStatus.NOT_FOUND);
        }

        if (!dbUser.getPassword().equals(password)) {
            return new ResponseEntity(HttpStatus.CONFLICT);
        }

        Token token = new Token();
        token.setUserId(dbUser.getId());
        token.setValue(SessionController.generateTokenValue());

        return new ResponseEntity<>(tokenRepository.save(token), HttpStatus.OK);
    }