/**
    * Waffle (https://github.com/dblock/waffle)
    *
    * Copyright (c) 2010 - 2015 Application Security, Inc.
    *
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of the Eclipse Public License v1.0
    * which accompanies this distribution, and is available at
    * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *     Application Security, Inc.
   */
  package waffle.servlet.spi;
  
  import java.io.IOException;
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.sun.jna.platform.win32.Win32Exception;
  
  import waffle.util.AuthorizationHeader;
  import waffle.windows.auth.IWindowsAuthProvider;
  import waffle.windows.auth.IWindowsIdentity;
  
  /**
   * A collection of security filter providers.
   * 
   * @author dblock[at]dblock[dot]org
   */
  public class SecurityFilterProviderCollection {
  
      /** The Constant LOGGER. */
      private static final Logger          LOGGER    = LoggerFactory.getLogger(SecurityFilterProviderCollection.class);
      
      /** The providers. */
      private final List<SecurityFilterProvider> providers = new ArrayList<SecurityFilterProvider>();
  
      /**
       * Instantiates a new security filter provider collection.
       *
       * @param providerArray
       *            the provider array
       */
      public SecurityFilterProviderCollection(final SecurityFilterProvider[] providerArray) {
          for (final SecurityFilterProvider provider : providerArray) {
              SecurityFilterProviderCollection.LOGGER.info("using '{}'", provider.getClass().getName());
              this.providers.add(provider);
          }
      }
  
      /**
       * Instantiates a new security filter provider collection.
       *
       * @param providerNames
       *            the provider names
       * @param auth
       *            the auth
       */
      @SuppressWarnings("unchecked")
      public SecurityFilterProviderCollection(final String[] providerNames, final IWindowsAuthProvider auth) {
          Class<SecurityFilterProvider> providerClass;
          Constructor<SecurityFilterProvider> providerConstructor;
          for (String providerName : providerNames) {
              providerName = providerName.trim();
              SecurityFilterProviderCollection.LOGGER.info("loading '{}'", providerName);
              try {
                  providerClass = (Class<SecurityFilterProvider>) Class.forName(providerName);
                  providerConstructor = providerClass.getConstructor(IWindowsAuthProvider.class);
                  final SecurityFilterProvider provider = providerConstructor.newInstance(auth);
                  this.providers.add(provider);
              } catch (final ClassNotFoundException e) {
                  SecurityFilterProviderCollection.LOGGER.error("error loading '{}': {}", providerName, e.getMessage());
                  SecurityFilterProviderCollection.LOGGER.trace("{}", e);
                  throw new RuntimeException(e);
              } catch (final SecurityException e) {
                  SecurityFilterProviderCollection.LOGGER.error("error loading '{}': {}", providerName, e.getMessage());
                  SecurityFilterProviderCollection.LOGGER.trace("{}", e);
              } catch (final NoSuchMethodException e) {
                  SecurityFilterProviderCollection.LOGGER.error("error loading '{}': {}", providerName, e.getMessage());
                  SecurityFilterProviderCollection.LOGGER.trace("{}", e);
              } catch (final IllegalArgumentException e) {
                  SecurityFilterProviderCollection.LOGGER.error("error loading '{}': {}", providerName, e.getMessage());
                  SecurityFilterProviderCollection.LOGGER.trace("{}", e);
              } catch (final InstantiationException e) {
                  SecurityFilterProviderCollection.LOGGER.error("error loading '{}': {}", providerName, e.getMessage());
                  SecurityFilterProviderCollection.LOGGER.trace("{}", e);
              } catch (final IllegalAccessException e) {
                  SecurityFilterProviderCollection.LOGGER.error("error loading '{}': {}", providerName, e.getMessage());
                  SecurityFilterProviderCollection.LOGGER.trace("{}", e);
              } catch (final InvocationTargetException e) {
                 SecurityFilterProviderCollection.LOGGER.error("error loading '{}': {}", providerName, e.getMessage());
                 SecurityFilterProviderCollection.LOGGER.trace("{}", e);
             }
         }
     }
 
     /**
      * Instantiates a new security filter provider collection.
      *
      * @param auth
      *            the auth
      */
     public SecurityFilterProviderCollection(final IWindowsAuthProvider auth) {
         this.providers.add(new NegotiateSecurityFilterProvider(auth));
         this.providers.add(new BasicSecurityFilterProvider(auth));
     }
 
     /**
      * Tests whether a specific security package is supported by any of the underlying providers.
      * 
      * @param securityPackage
      *            Security package.
      * @return True if the security package is supported, false otherwise.
      */
     public boolean isSecurityPackageSupported(final String securityPackage) {
         return this.get(securityPackage) != null;
     }
 
     /**
      * Gets the.
      *
      * @param securityPackage
      *            the security package
      * @return the security filter provider
      */
     private SecurityFilterProvider get(final String securityPackage) {
         for (final SecurityFilterProvider provider : this.providers) {
             if (provider.isSecurityPackageSupported(securityPackage)) {
                 return provider;
             }
         }
         return null;
     }
 
     /**
      * Filter.
      * 
      * @param request
      *            Http Request
      * @param response
      *            Http Response
      * @return Windows Identity or NULL.
      * @throws IOException
      *             on doFilter.
      */
     public IWindowsIdentity doFilter(final HttpServletRequest request, final HttpServletResponse response)
             throws IOException {
         final AuthorizationHeader authorizationHeader = new AuthorizationHeader(request);
         final SecurityFilterProvider provider = this.get(authorizationHeader.getSecurityPackage());
         if (provider == null) {
             throw new RuntimeException("Unsupported security package: " + authorizationHeader.getSecurityPackage());
         }
         try {
             return provider.doFilter(request, response);
         } catch (final Win32Exception e) {
             throw new IOException(e);
         }
     }
 
     /**
      * Returns true if authentication still needs to happen despite an existing principal.
      * 
      * @param request
      *            Http Request
      * @return True if authentication is required.
      */
     public boolean isPrincipalException(final HttpServletRequest request) {
         for (final SecurityFilterProvider provider : this.providers) {
             if (provider.isPrincipalException(request)) {
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Send authorization headers.
      * 
      * @param response
      *            Http Response
      */
     public void sendUnauthorized(final HttpServletResponse response) {
         for (final SecurityFilterProvider provider : this.providers) {
             provider.sendUnauthorized(response);
         }
     }
 
     /**
      * Number of providers.
      * 
      * @return Number of providers.
      */
     public int size() {
         return this.providers.size();
     }
 
     /**
      * Get a security provider by class name.
      * 
      * @param name
      *            Class name.
      * @return A security provider instance.
      * @throws ClassNotFoundException
      *             when class not found.
      */
     public SecurityFilterProvider getByClassName(final String name) throws ClassNotFoundException {
         for (final SecurityFilterProvider provider : this.providers) {
             if (provider.getClass().getName().equals(name)) {
                 return provider;
             }
         }
         throw new ClassNotFoundException(name);
     }
 }