package com.atlassian.sal.core.net;
   
   import org.apache.commons.lang3.StringUtils;
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
   import javax.annotation.Nonnull;
   import javax.annotation.Nullable;
   import java.net.URI;
  import java.net.URISyntaxException;
  import java.util.Arrays;
  
  public class ProxyUtil {
      private static final Logger log = LoggerFactory.getLogger(ProxyUtil.class);
  
      /**
       * Check if proxy configuration requires authentication before sending request to requestUrl
       * @param proxyConfig proxy configuration
       * @param requestUrl url
       * @return true if proxy authentication should be requested before fetching requestUrl
       */
      static boolean requiresAuthentication(final ProxyConfig proxyConfig, final String requestUrl) {
          if (proxyConfig.getNonProxyHosts().length != 0
                  && proxyConfig.requiresAuthentication()) {
              try {
                  final String host = new URI(requestUrl).getHost();
                  if (!shouldBeProxied(host, proxyConfig.getNonProxyHosts())) {
                      return false;
                  }
              }
              catch (URISyntaxException e) {
                  log.debug("Can't get host value from {}", requestUrl);
              }
          }
          return proxyConfig.requiresAuthentication();
      }
  
      /**
       * Check if host should be proxied.
       * @param host to be checked
       * @param nonProxyHosts array of nonProxyHosts, wildcards supported
       * @return true if proxy server should be used to access host
       */
      static boolean shouldBeProxied(@Nullable String host, @Nonnull String[] nonProxyHosts) {
          if (StringUtils.isBlank(host)) {
              return false;
          }
          try {
              for (String nonProxyHost : nonProxyHosts) {
                  String pattern = nonProxyHost.replace(".", "\\.")
                          .replace("*", ".*")
                          .replace("[", "\\[")
                          .replace("]", "\\]");
                  if (host.matches(pattern)) {
                      return false;
                  }
              }
          } catch (Exception e) {
              log.debug("Failed to match host {} against non proxy hosts {}, will assume host should be proxied: {}",
                      host, Arrays.toString(nonProxyHosts), e.getMessage());
          }
          return true;
      }
  }