import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Vector;

/**
 * @author sunhao
 * @date create in 2019-12-09 14:39:52
 */
public class UserInfoRequest extends HttpServletRequestWrapper {

  private Map<String, String[]> params = new HashMap<>();

  /**
   * Constructs a request object wrapping the given request.
   *
   * @param request The request to wrap
   *
   * @throws IllegalArgumentException if the request is null
   */
  public UserInfoRequest(HttpServletRequest request) {

    super(request);
    //將參數(shù)表，賦予給當(dāng)前的Map以便于持有request中的參數(shù)
    this.params.putAll(request.getParameterMap());
  }

  /**
   * 在獲取所有的參數(shù)名,必須重寫(xiě)此方法，否則對(duì)象中參數(shù)值映射不上
   */
  @Override
  public Enumeration<String> getParameterNames() {
    return new Vector<>(params.keySet()).elements();
  }

  /**
   * 重寫(xiě)getParameter方法
   *
   * @param name 參數(shù)名
   * @return 返回參數(shù)值
   */
  @Override
  public String getParameter(String name) {
    String[] values = params.get(name);
    if (values == null || values.length == 0) {
      return null;
    }
    return values[0];
  }

  @Override
  public String[] getParameterValues(String name) {
    String[] values = params.get(name);
    if (values == null || values.length == 0) {
      return null;
    }
    return values;
  }


  /**
   * 增加參數(shù)
   *
   * @param name 參數(shù)名
   * @param value 參數(shù)值
   */
  public void addParameter(String name, Object value) {
    if (value != null) {
      if (value instanceof String[]) {
        params.put(name, (String[]) value);
      } else if (value instanceof String) {
        params.put(name, new String[]{(String) value});
      } else {
        params.put(name, new String[]{String.valueOf(value)});
      }
    }
  }
}

@Component
public class UserInfoFilter extends OncePerRequestFilter {

  @Override
  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
    filterChain.doFilter(new UserInfoRequest(request), response);
  }
}

@Component
public class UserInfoInterceptor implements HandlerInterceptor {

  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {

    Method method = ((HandlerMethod) handler).getMethod();
    AdminUserInfo adminUserInfo = method.getDeclaredAnnotation(AdminUserInfo.class);
    if (adminUserInfo != null) {
      
      // 獲取用戶信息的邏輯 自由發(fā)揮
      Long userId = ((Admin) ((OAuth3Authentication) request.getUserPrincipal()).getPrincipal()).getId();
      
      // 將用戶信息寫(xiě)入request的parameter
      ((UserInfoRequest)request).addParameter("userId", userId);
      return true;
    }

    EmployeeUserInfo employeeUserInfo = method.getDeclaredAnnotation(EmployeeUserInfo.class);
    if (employeeUserInfo != null) {
      Long userId = ((Employee) ((OAuth3Authentication) request.getUserPrincipal()).getPrincipal()).getId();
      ((UserInfoRequest)request).addParameter("userId", userId);
      return true;
    }

    return true;
  }
}

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

  private final UserInfoInterceptor userInfoInterceptor;

  public WebMvcConfig(UserInfoInterceptor userInfoInterceptor) {

    this.userInfoInterceptor = userInfoInterceptor;
  }

  @Override
  public void addInterceptors(InterceptorRegistry registry) {

    registry.addInterceptor(userInfoInterceptor);
  }
}

 @EmployeeUserInfo // 自定義注解
 @GetMapping
 public void testObtainUserInfo(Long userId) {

  System.out.println("userId = " + userId);
 }