package com.atlassian.asap.core.keys.privatekey;
   
   import com.atlassian.asap.core.keys.DataUriKeyReader;
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
   import java.net.URI;
   import java.net.URISyntaxException;
   import java.util.Optional;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  /**
   * Reads private keys specified as data uri from system properties.
   */
  public final class SystemPropertyKeyProvider extends DataUriKeyProvider {
      static final String URL_SCHEME = "sysprop";
      private static final Logger logger = LoggerFactory.getLogger(SystemPropertyKeyProvider.class);
  
      private SystemPropertyKeyProvider(String propertyName, DataUriKeyReader keyReader) {
          super(getDataUriFromSystemProperty(propertyName), keyReader);
      }
  
      private static URI getDataUriFromSystemProperty(String propertyName) {
          logger.debug("Reading private key from system property {}", propertyName);
          String systemPropertyValue = Optional.ofNullable(System.getProperty(propertyName))
                  .orElseThrow(() -> new IllegalArgumentException("Undefined system property: " + propertyName));
          try {
              return new URI(systemPropertyValue);
          } catch (URISyntaxException e) {
              throw new IllegalArgumentException("Value of system property " + propertyName +
                      " cannot be parsed as a URI");
          }
      }
  
      /**
       * Instantiates the class by parsing a URL with the following syntax:
       * <code>sysprop:///[BASE_SYSTEM_PROPERTY_NAME]</code>.
       *
       * @param uri       URI with the syntax described above
       * @param keyReader reader of PEM documents
       * @return a new instance of the class
       */
      public static SystemPropertyKeyProvider fromUri(URI uri, DataUriKeyReader keyReader) {
          checkArgument(uri.isAbsolute(), "URL must be absolute"); // implies that scheme != null
          checkArgument(URL_SCHEME.equals(uri.getScheme()), "URL must have " + URL_SCHEME + " scheme");
          checkArgument(uri.getPath() != null && uri.getPath().startsWith("/"), "URL must have a path component");
          checkArgument(uri.getQuery() == null, "URL must not have a query component");
          checkArgument(uri.getAuthority() == null, "URL must not have an authority component");
  
          String basePropertyName = uri.getPath().substring(1); // remove the trailing slash
          return new SystemPropertyKeyProvider(basePropertyName, keyReader);
      }
  }