/*
    * MIT License
    *
    * Copyright (c) 2010-2024 The Waffle Project Contributors: https://github.com/Waffle/waffle/graphs/contributors
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy
    * of this software and associated documentation files (the "Software"), to deal
    * in the Software without restriction, including without limitation the rights
    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  package waffle.jaas;
  
  import java.io.IOException;
  import java.security.Principal;
  import java.util.ArrayList;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Set;
  
  import javax.security.auth.Subject;
  import javax.security.auth.callback.Callback;
  import javax.security.auth.callback.CallbackHandler;
  import javax.security.auth.callback.NameCallback;
  import javax.security.auth.callback.PasswordCallback;
  import javax.security.auth.callback.UnsupportedCallbackException;
  import javax.security.auth.login.LoginException;
  import javax.security.auth.spi.LoginModule;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import waffle.windows.auth.IWindowsAccount;
  import waffle.windows.auth.IWindowsAuthProvider;
  import waffle.windows.auth.IWindowsIdentity;
  import waffle.windows.auth.PrincipalFormat;
  import waffle.windows.auth.impl.WindowsAuthProviderImpl;
  
  /**
   * A Java Security login module for Windows authentication.
   *
   * @see javax.security.auth.spi.LoginModule
   */
  public class WindowsLoginModule implements LoginModule {
  
      /** The Constant LOGGER. */
      private static final Logger LOGGER = LoggerFactory.getLogger(WindowsLoginModule.class);
  
      /** The username. */
      private String username;
  
      /** The debug. */
      private boolean debug;
  
      /** The subject. */
      private Subject subject;
  
      /** The callback handler. */
      private CallbackHandler callbackHandler;
  
      /** The auth. */
      private IWindowsAuthProvider auth = new WindowsAuthProviderImpl();
  
      /** The principals. */
      private Set<Principal> principals;
  
      /** The principal format. */
      private PrincipalFormat principalFormat = PrincipalFormat.FQN;
  
      /** The role format. */
      private PrincipalFormat roleFormat = PrincipalFormat.FQN;
  
      /** The allow guest login. */
      private boolean allowGuestLogin = true;
  
      @Override
      public void initialize(final Subject initSubject, final CallbackHandler initCallbackHandler,
              final Map<String, ?> initSharedState, final Map<String, ?> initOptions) {
  
          this.subject = initSubject;
          this.callbackHandler = initCallbackHandler;
  
          for (final Map.Entry<String, ?> option : initOptions.entrySet()) {
              if ("debug".equalsIgnoreCase(option.getKey())) {
                  this.debug = Boolean.parseBoolean((String) option.getValue());
             } else if ("principalFormat".equalsIgnoreCase(option.getKey())) {
                 this.principalFormat = PrincipalFormat
                         .valueOf(((String) option.getValue()).toUpperCase(Locale.ENGLISH));
             } else if ("roleFormat".equalsIgnoreCase(option.getKey())) {
                 this.roleFormat = PrincipalFormat.valueOf(((String) option.getValue()).toUpperCase(Locale.ENGLISH));
             }
         }
     }
 
     /**
      * Use Windows SSPI to authenticate a username with a password.
      *
      * @return true, if successful
      *
      * @throws LoginException
      *             the login exception
      */
     @Override
     public boolean login() throws LoginException {
         if (this.callbackHandler == null) {
             throw new LoginException("Missing callback to gather information from the user.");
         }
 
         final NameCallback usernameCallback = new NameCallback("user name: ");
         final PasswordCallback passwordCallback = new PasswordCallback("password: ", false);
 
         final Callback[] callbacks = new Callback[2];
         callbacks[0] = usernameCallback;
         callbacks[1] = passwordCallback;
 
         final String userName;
         final String password;
 
         try {
             this.callbackHandler.handle(callbacks);
             userName = usernameCallback.getName();
             password = passwordCallback.getPassword() == null ? "" : new String(passwordCallback.getPassword());
             passwordCallback.clearPassword();
         } catch (final IOException e) {
             WindowsLoginModule.LOGGER.trace("", e);
             throw new LoginException(e.toString());
         } catch (final UnsupportedCallbackException e) {
             WindowsLoginModule.LOGGER.trace("", e);
             throw new LoginException("Callback {} not available to gather authentication information from the user."
                     .replace("{}", e.getCallback().getClass().getName()));
         }
 
         IWindowsIdentity windowsIdentity;
         try {
             windowsIdentity = this.auth.logonUser(userName, password);
         } catch (final Exception e) {
             WindowsLoginModule.LOGGER.trace("", e);
             throw new LoginException(e.getMessage());
         }
 
         try {
             // disable guest login
             if (!this.allowGuestLogin && windowsIdentity.isGuest()) {
                 WindowsLoginModule.LOGGER.debug("guest login disabled: {}", windowsIdentity.getFqn());
                 throw new LoginException("Guest login disabled");
             }
 
             this.principals = new LinkedHashSet<>();
             // add the main user principal to the subject principals
             this.principals.addAll(WindowsLoginModule.getUserPrincipals(windowsIdentity, this.principalFormat));
             if (this.roleFormat != PrincipalFormat.NONE) {
                 // add Windows Groups as role principles
                 for (final IWindowsAccount group : windowsIdentity.getGroups()) {
                     this.principals.addAll(getRolePrincipals(group, this.roleFormat));
                 }
             }
 
             this.username = windowsIdentity.getFqn();
             WindowsLoginModule.LOGGER.debug("successfully logged in {} ({})", this.username,
                     windowsIdentity.getSidString());
         } finally {
             windowsIdentity.dispose();
         }
 
         return true;
     }
 
     /**
      * Abort a login process.
      *
      * @return true, if successful
      *
      * @throws LoginException
      *             the login exception
      */
     @Override
     public boolean abort() throws LoginException {
         return this.logout();
     }
 
     /**
      * Commit principals to the subject.
      *
      * @return true, if successful
      *
      * @throws LoginException
      *             the login exception
      */
     @Override
     public boolean commit() throws LoginException {
         if (this.principals == null) {
             return false;
         }
 
         if (this.subject.isReadOnly()) {
             throw new LoginException("Subject cannot be read-only.");
         }
 
         final Set<Principal> principalsSet = this.subject.getPrincipals();
         principalsSet.addAll(this.principals);
 
         WindowsLoginModule.LOGGER.debug("committing {} principals",
                 Integer.valueOf(this.subject.getPrincipals().size()));
         if (this.debug) {
             for (final Principal principal : principalsSet) {
                 WindowsLoginModule.LOGGER.debug(" principal: {}", principal.getName());
             }
         }
 
         return true;
     }
 
     /**
      * Logout a user.
      *
      * @return true, if successful
      *
      * @throws LoginException
      *             the login exception
      */
     @Override
     public boolean logout() throws LoginException {
         if (this.subject.isReadOnly()) {
             throw new LoginException("Subject cannot be read-only.");
         }
 
         this.subject.getPrincipals().clear();
 
         if (this.username != null) {
             WindowsLoginModule.LOGGER.debug("logging out {}", this.username);
         }
 
         return true;
     }
 
     /**
      * True if Debug is enabled.
      *
      * @return True or false.
      */
     public boolean isDebug() {
         return this.debug;
     }
 
     /**
      * Windows auth provider.
      *
      * @return IWindowsAuthProvider.
      */
     public IWindowsAuthProvider getAuth() {
         return this.auth;
     }
 
     /**
      * Set Windows auth provider.
      *
      * @param provider
      *            Class implements IWindowsAuthProvider.
      */
     public void setAuth(final IWindowsAuthProvider provider) {
         this.auth = provider;
     }
 
     /**
      * Returns a list of user principal objects.
      *
      * @param windowsIdentity
      *            Windows identity.
      * @param principalFormat
      *            Principal format.
      *
      * @return A list of user principal objects.
      */
     private static List<Principal> getUserPrincipals(final IWindowsIdentity windowsIdentity,
             final PrincipalFormat principalFormat) {
 
         final List<Principal> principalsList = new ArrayList<>();
         switch (principalFormat) {
             case FQN:
                 principalsList.add(new UserPrincipal(windowsIdentity.getFqn()));
                 break;
             case SID:
                 principalsList.add(new UserPrincipal(windowsIdentity.getSidString()));
                 break;
             case BOTH:
                 principalsList.add(new UserPrincipal(windowsIdentity.getFqn()));
                 principalsList.add(new UserPrincipal(windowsIdentity.getSidString()));
                 break;
             case NONE:
             default:
                 break;
         }
         return principalsList;
     }
 
     /**
      * Returns a list of role principal objects.
      *
      * @param group
      *            Windows group.
      * @param principalFormat
      *            Principal format.
      *
      * @return List of role principal objects.
      */
     private static List<Principal> getRolePrincipals(final IWindowsAccount group,
             final PrincipalFormat principalFormat) {
 
         final List<Principal> principalsList = new ArrayList<>();
         switch (principalFormat) {
             case FQN:
                 principalsList.add(new RolePrincipal(group.getFqn()));
                 break;
             case SID:
                 principalsList.add(new RolePrincipal(group.getSidString()));
                 break;
             case BOTH:
                 principalsList.add(new RolePrincipal(group.getFqn()));
                 principalsList.add(new RolePrincipal(group.getSidString()));
                 break;
             case NONE:
                 break;
             default:
                 break;
         }
         return principalsList;
     }
 
     /**
      * True if Guest login permitted.
      *
      * @return True if Guest login permitted, false otherwise.
      */
     public boolean isAllowGuestLogin() {
         return this.allowGuestLogin;
     }
 
     /**
      * Set whether Guest login is permitted. Default is true, if the Guest account is enabled, an invalid
      * username/password results in a Guest login.
      *
      * @param value
      *            True or false.
      */
     public void setAllowGuestLogin(final boolean value) {
         this.allowGuestLogin = value;
     }
 }