public class ServerConnectionImpl implements ServerConnection {

    private RestTemplate restTemplate;
    private String serverURL = "http://localhost:8080/rest/api";
    private HttpHeaders headers;

    public ServerConnectionImpl() {
        restTemplate = new RestTemplate();
        restTemplate.setMessageConverters(Collections.<HttpMessageConverter<?>>singletonList(new MappingJacksonHttpMessageConverter()));
    }

    @Override
    public UserClient getUser(String login, String password) throws IOException {

        String url = serverURL + "/" + login;
        System.out.println(login + " " + password);

//        UserClient user = restTemplate.getForObject(url, UserClient.class);
//        ObjectMapper mapper = new ObjectMapper();
//        byte[] json = mapper.writeValueAsBytes(user);
//        UserClient userClient = mapper.readValue(json, new TypeReference<UserClient>(){});
//
//        if (userClient != null && userClient.getPassword().equals(password)) {
//            return userClient;
//        } else {
//            return null;
//        }

        byte[] bytes = (login + ":" + password).getBytes();
        String loginPass = "Basic " + Base64.getEncoder().encodeToString(bytes);
        headers = new HttpHeaders();
        headers.add("Authorization", loginPass); //Login and password like login:password
        HttpEntity<String> request = new HttpEntity<String>(headers);
        try {
            UserClient user = restTemplate.exchange(url, HttpMethod.GET, request, UserClient.class).getBody();
            return user;
        }
        catch (Exception e) {
            return null;
        }

    }

    @Override
    public List<ClassClient> getClasses() throws IOException {
        String url = serverURL + "/classes";
        List<ClassClient> classClientList = restTemplate.getForObject(url, List.class);
        ObjectMapper mapper = new ObjectMapper();
        byte[] json = mapper.writeValueAsBytes(classClientList);

        return mapper.readValue(json, new TypeReference<List<ClassClient>>(){});
    }

    @Override
    public Boolean addClass(String name, String description) {
        String url = serverURL + "/add_class?name=" + name + "&description=" + description;

        headers = new HttpHeaders();
        HttpEntity<String> request = new HttpEntity<String>(headers);

        return restTemplate.exchange(url, HttpMethod.POST, request, Boolean.class).getBody();
    }

    @Override
    public void deleteClass(int id) {
        String url = serverURL + "/classes/delete?id=" + id;
        headers = new HttpHeaders();
        HttpEntity<String> request = new HttpEntity<String>(headers);

        restTemplate.exchange(url, HttpMethod.POST, request, ClassClient.class);
    }

    @Override
    public void editClass(String name, String new_description) {
        String url = serverURL + "/classes/edit?name=" + name + "&description=" + new_description;
        headers = new HttpHeaders();
        HttpEntity<String> request = new HttpEntity<String>(headers);

        restTemplate.exchange(url, HttpMethod.POST, request, ClassClient.class);
    }

}