@PostMapping("/login")

@PostMapping("/login")
    public ResponseEntity<String> login(@RequestParam(name = "username", required = true) String username, @RequestParam(name = "password", required = true) String password) {
        try {
            if (userRepository.findByUsername(username) == null) {
                User user = new User(username, passwordEncoder.encode(password));
                userRepository.save(user);
            }
            UsernamePasswordAuthenticationToken authReq = new UsernamePasswordAuthenticationToken(username,password);
            Authentication auth = authenticationManager.authenticate(authReq);
            SecurityContext sc = SecurityContextHolder.getContext();
            sc.setAuthentication(auth);
            HttpHeaders headers = new HttpHeaders();
            headers.add("Location","/main");
            return new ResponseEntity<>(headers, HttpStatus.FOUND);
            }

            catch (AuthenticationException e) {
            return new ResponseEntity<>(("Wrong password"), HttpStatus.UNAUTHORIZED);
        }
    }