@Slf4j
@Service
public class OrderServiceImpl implements OrderService {

    @Autowired
    private DiscoveryClient discoveryClient;
    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private LoadBalancerClient loadBalancerClient;

    @Override
    public Order createOrder(Long productId, Long userId) {
        Product product = getProductFromRemote3(productId);
        Order order = new Order();
        order.setId(1L);
        // 远程调用计算商品数额
        order.setTotalAmount(product.getPrice().multiply(new BigDecimal(product.getNum())));
        order.setUserId(userId);
        order.setNickName("张三");
        order.setAddress("青岛");
        // 远程调用获取商品信息
        order.setProductList(Arrays.asList(product));
        return order;
    }

    // 1 从商品服务中获取商品信息（默认第一个）
    private Product getProductFromRemote(Long productId) {
        //1 获取到商品服务所在的所有机器IP+端口
        List<ServiceInstance> instances = discoveryClient.getInstances("service-product");

        ServiceInstance instance = instances.get(0);
        //2 机器的IP+端口
        String url = "http://" + instance.getHost() + ":" + instance.getPort() + "/product/" + productId;
        log.info("url:{}", url);
        //3 通过RestTemplate远程调用

        Product product = restTemplate.getForObject(url, Product.class);
        return product;
    }

    // 2 从商品服务中获取商品信息（依赖注入的方式 负载均衡）
    private Product getProductFromRemote2(Long productId) {
        ServiceInstance instance = loadBalancerClient.choose("service-product");
        String url = "http://" + instance.getHost() + ":" + instance.getPort() + "/product/" + productId;
        log.info("url:{}", url);
        return restTemplate.getForObject(url, Product.class);
    }
    // 3 从商品服务中获取商品信息（基于注解的方式 负载均衡）
    private Product getProductFromRemote3(Long productId) {
        // 基于注解的方式，service-product会被动态替换为对应的ip地址与端口
        return restTemplate.getForObject("http://service-product/product/" + productId, Product.class);
    }