/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.shiro.mgt;
  
  import org.apache.shiro.authc.AuthenticationException;
  import org.apache.shiro.authc.AuthenticationInfo;
  import org.apache.shiro.authc.AuthenticationToken;
  import org.apache.shiro.authc.Authenticator;
  import org.apache.shiro.authc.LogoutAware;
  import org.apache.shiro.authz.Authorizer;
  import org.apache.shiro.realm.Realm;
  import org.apache.shiro.session.InvalidSessionException;
  import org.apache.shiro.session.Session;
  import org.apache.shiro.session.mgt.DefaultSessionContext;
  import org.apache.shiro.session.mgt.DefaultSessionKey;
  import org.apache.shiro.session.mgt.SessionContext;
  import org.apache.shiro.session.mgt.SessionKey;
  import org.apache.shiro.subject.PrincipalCollection;
  import org.apache.shiro.subject.Subject;
  import org.apache.shiro.subject.SubjectContext;
  import org.apache.shiro.subject.support.DefaultSubjectContext;
  import org.apache.shiro.util.CollectionUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.Serializable;
  import java.util.Collection;
  
  /**
   * The Shiro framework's default concrete implementation of the {@link SecurityManager} interface,
   * based around a collection of {@link org.apache.shiro.realm.Realm}s.  This implementation delegates its
   * authentication, authorization, and session operations to wrapped {@link Authenticator}, {@link Authorizer}, and
   * {@link org.apache.shiro.session.mgt.SessionManager SessionManager} instances respectively via superclass
   * implementation.
   * <p/>
   * To greatly reduce and simplify configuration, this implementation (and its superclasses) will
   * create suitable defaults for all of its required dependencies, <em>except</em> the required one or more
   * {@link Realm Realm}s.  Because {@code Realm} implementations usually interact with an application's data model,
   * they are almost always application specific;  you will want to specify at least one custom
   * {@code Realm} implementation that 'knows' about your application's data/security model
   * (via {@link #setRealm} or one of the overloaded constructors).  All other attributes in this class hierarchy
   * will have suitable defaults for most enterprise applications.
   * <p/>
   * <b>RememberMe notice</b>: This class supports the ability to configure a
   * {@link #setRememberMeManager RememberMeManager}
   * for {@code RememberMe} identity services for login/logout, BUT, a default instance <em>will not</em> be created
   * for this attribute at startup.
   * <p/>
   * Because RememberMe services are inherently client tier-specific and
   * therefore aplication-dependent, if you want {@code RememberMe} services enabled, you will have to specify an
   * instance yourself via the {@link #setRememberMeManager(RememberMeManager) setRememberMeManager}
   * mutator.  However if you're reading this JavaDoc with the
   * expectation of operating in a Web environment, take a look at the
   * {@code org.apache.shiro.web.DefaultWebSecurityManager} implementation, which
   * <em>does</em> support {@code RememberMe} services by default at startup.
   *
   * @since 0.2
   */
  public class DefaultSecurityManager extends SessionsSecurityManager {
  
      private static final Logger log = LoggerFactory.getLogger(DefaultSecurityManager.class);
  
      protected RememberMeManager rememberMeManager;
      protected SubjectDAO subjectDAO;
      protected SubjectFactory subjectFactory;
  
      /**
       * Default no-arg constructor.
       */
      public DefaultSecurityManager() {
          super();
          this.subjectFactory = new DefaultSubjectFactory();
          this.subjectDAO = new DefaultSubjectDAO();
      }
  
      /**
       * Supporting constructor for a single-realm application.
       *
       * @param singleRealm the single realm used by this SecurityManager.
       */
      public DefaultSecurityManager(Realm singleRealm) {
          this();
          setRealm(singleRealm);
     }
 
     /**
      * Supporting constructor for multiple {@link #setRealms realms}.
      *
      * @param realms the realm instances backing this SecurityManager.
      */
     public DefaultSecurityManager(Collection<Realm> realms) {
         this();
         setRealms(realms);
     }
 
     /**
      * Returns the {@code SubjectFactory} responsible for creating {@link Subject} instances exposed to the application.
      *
      * @return the {@code SubjectFactory} responsible for creating {@link Subject} instances exposed to the application.
      */
     public SubjectFactory getSubjectFactory() {
         return subjectFactory;
     }
 
     /**
      * Sets the {@code SubjectFactory} responsible for creating {@link Subject} instances exposed to the application.
      *
      * @param subjectFactory the {@code SubjectFactory} responsible for creating {@link Subject} instances exposed to the application.
      */
     public void setSubjectFactory(SubjectFactory subjectFactory) {
         this.subjectFactory = subjectFactory;
     }
 
     /**
      * Returns the {@code SubjectDAO} responsible for persisting Subject state, typically used after login or when an
      * Subject identity is discovered (eg after RememberMe services).  Unless configured otherwise, the default
      * implementation is a {@link DefaultSubjectDAO}.
      *
      * @return the {@code SubjectDAO} responsible for persisting Subject state, typically used after login or when an
      *         Subject identity is discovered (eg after RememberMe services).
      * @see DefaultSubjectDAO
      * @since 1.2
      */
     public SubjectDAO getSubjectDAO() {
         return subjectDAO;
     }
 
     /**
      * Sets the {@code SubjectDAO} responsible for persisting Subject state, typically used after login or when an
      * Subject identity is discovered (eg after RememberMe services). Unless configured otherwise, the default
      * implementation is a {@link DefaultSubjectDAO}.
      *
      * @param subjectDAO the {@code SubjectDAO} responsible for persisting Subject state, typically used after login or when an
      *                   Subject identity is discovered (eg after RememberMe services).
      * @see DefaultSubjectDAO
      * @since 1.2
      */
     public void setSubjectDAO(SubjectDAO subjectDAO) {
         this.subjectDAO = subjectDAO;
     }
 
     public RememberMeManager getRememberMeManager() {
         return rememberMeManager;
     }
 
     public void setRememberMeManager(RememberMeManager rememberMeManager) {
         this.rememberMeManager = rememberMeManager;
     }
 
     protected SubjectContext createSubjectContext() {
         return new DefaultSubjectContext();
     }
 
     /**
      * Creates a {@code Subject} instance for the user represented by the given method arguments.
      *
      * @param token    the {@code AuthenticationToken} submitted for the successful authentication.
      * @param info     the {@code AuthenticationInfo} of a newly authenticated user.
      * @param existing the existing {@code Subject} instance that initiated the authentication attempt
      * @return the {@code Subject} instance that represents the context and session data for the newly
      *         authenticated subject.
      */
     protected Subject">Subject createSubject(AuthenticationToken token, AuthenticationInfo info, Subject existing) {
         SubjectContext context = createSubjectContext();
         context.setAuthenticated(true);
         context.setAuthenticationToken(token);
         context.setAuthenticationInfo(info);
         context.setSecurityManager(this);
         if (existing != null) {
             context.setSubject(existing);
         }
         return createSubject(context);
     }
 
     /**
      * Binds a {@code Subject} instance created after authentication to the application for later use.
      * <p/>
      * As of Shiro 1.2, this method has been deprecated in favor of {@link #save(org.apache.shiro.subject.Subject)},
      * which this implementation now calls.
      *
      * @param subject the {@code Subject} instance created after authentication to be bound to the application
      *                for later use.
      * @see #save(org.apache.shiro.subject.Subject)
      * @deprecated in favor of {@link #save(org.apache.shiro.subject.Subject) save(subject)}.
      */
     @Deprecated
     protected void bind(Subject subject) {
         save(subject);
     }
 
     protected void rememberMeSuccessfulLogin(AuthenticationToken token, AuthenticationInfo info, Subject subject) {
         RememberMeManager rmm = getRememberMeManager();
         if (rmm != null) {
             try {
                 rmm.onSuccessfulLogin(subject, token, info);
             } catch (Exception e) {
                 if (log.isWarnEnabled()) {
                     String msg = "Delegate RememberMeManager instance of type [" + rmm.getClass().getName() +
                             "] threw an exception during onSuccessfulLogin.  RememberMe services will not be " +
                             "performed for account [" + info + "].";
                     log.warn(msg, e);
                 }
             }
         } else {
             if (log.isTraceEnabled()) {
                 log.trace("This " + getClass().getName() + " instance does not have a " +
                         "[" + RememberMeManager.class.getName() + "] instance configured.  RememberMe services " +
                         "will not be performed for account [" + info + "].");
             }
         }
     }
 
     protected void rememberMeFailedLogin(AuthenticationToken token, AuthenticationException ex, Subject subject) {
         RememberMeManager rmm = getRememberMeManager();
         if (rmm != null) {
             try {
                 rmm.onFailedLogin(subject, token, ex);
             } catch (Exception e) {
                 if (log.isWarnEnabled()) {
                     String msg = "Delegate RememberMeManager instance of type [" + rmm.getClass().getName() +
                             "] threw an exception during onFailedLogin for AuthenticationToken [" +
                             token + "].";
                     log.warn(msg, e);
                 }
             }
         }
     }
 
     protected void rememberMeLogout(Subject subject) {
         RememberMeManager rmm = getRememberMeManager();
         if (rmm != null) {
             try {
                 rmm.onLogout(subject);
             } catch (Exception e) {
                 if (log.isWarnEnabled()) {
                     String msg = "Delegate RememberMeManager instance of type [" + rmm.getClass().getName() +
                             "] threw an exception during onLogout for subject with principals [" +
                             (subject != null ? subject.getPrincipals() : null) + "]";
                     log.warn(msg, e);
                 }
             }
         }
     }
 
     /**
      * First authenticates the {@code AuthenticationToken} argument, and if successful, constructs a
      * {@code Subject} instance representing the authenticated account's identity.
      * <p/>
      * Once constructed, the {@code Subject} instance is then {@link #bind bound} to the application for
      * subsequent access before being returned to the caller.
      *
      * @param token the authenticationToken to process for the login attempt.
      * @return a Subject representing the authenticated user.
      * @throws AuthenticationException if there is a problem authenticating the specified {@code token}.
      */
     public Subjectf="../../../../org/apache/shiro/subject/Subject.html#Subject">Subject login(Subject subject, AuthenticationToken token) throws AuthenticationException {
         AuthenticationInfo info;
         try {
             info = authenticate(token);
         } catch (AuthenticationException ae) {
             try {
                 onFailedLogin(token, ae, subject);
             } catch (Exception e) {
                 if (log.isInfoEnabled()) {
                     log.info("onFailedLogin method threw an " +
                             "exception.  Logging and propagating original AuthenticationException.", e);
                 }
             }
             throw ae; //propagate
         }
 
         Subject loggedIn = createSubject(token, info, subject);
 
         onSuccessfulLogin(token, info, loggedIn);
 
         return loggedIn;
     }
 
     protected void onSuccessfulLogin(AuthenticationToken token, AuthenticationInfo info, Subject subject) {
         rememberMeSuccessfulLogin(token, info, subject);
     }
 
     protected void onFailedLogin(AuthenticationToken token, AuthenticationException ae, Subject subject) {
         rememberMeFailedLogin(token, ae, subject);
     }
 
     protected void beforeLogout(Subject subject) {
         rememberMeLogout(subject);
     }
 
     protected SubjectContext../../../org/apache/shiro/subject/SubjectContext.html#SubjectContext">SubjectContext copy(SubjectContext subjectContext) {
         return new DefaultSubjectContext(subjectContext);
     }
 
     /**
      * This implementation functions as follows:
      * <p/>
      * <ol>
      * <li>Ensures the {@code SubjectContext} is as populated as it can be, using heuristics to acquire
      * data that may not have already been available to it (such as a referenced session or remembered principals).</li>
      * <li>Calls {@link #doCreateSubject(org.apache.shiro.subject.SubjectContext)} to actually perform the
      * {@code Subject} instance creation.</li>
      * <li>calls {@link #save(org.apache.shiro.subject.Subject) save(subject)} to ensure the constructed
      * {@code Subject}'s state is accessible for future requests/invocations if necessary.</li>
      * <li>returns the constructed {@code Subject} instance.</li>
      * </ol>
      *
      * @param subjectContext any data needed to direct how the Subject should be constructed.
      * @return the {@code Subject} instance reflecting the specified contextual data.
      * @see #ensureSecurityManager(org.apache.shiro.subject.SubjectContext)
      * @see #resolveSession(org.apache.shiro.subject.SubjectContext)
      * @see #resolvePrincipals(org.apache.shiro.subject.SubjectContext)
      * @see #doCreateSubject(org.apache.shiro.subject.SubjectContext)
      * @see #save(org.apache.shiro.subject.Subject)
      * @since 1.0
      */
     public Subject createSubject(SubjectContext subjectContext) {
         //create a copy so we don't modify the argument's backing map:
         SubjectContext context = copy(subjectContext);
 
         //ensure that the context has a SecurityManager instance, and if not, add one:
         context = ensureSecurityManager(context);
 
         //Resolve an associated Session (usually based on a referenced session ID), and place it in the context before
         //sending to the SubjectFactory.  The SubjectFactory should not need to know how to acquire sessions as the
         //process is often environment specific - better to shield the SF from these details:
         context = resolveSession(context);
 
         //Similarly, the SubjectFactory should not require any concept of RememberMe - translate that here first
         //if possible before handing off to the SubjectFactory:
         context = resolvePrincipals(context);
 
         Subject subject = doCreateSubject(context);
 
         //save this subject for future reference if necessary:
         //(this is needed here in case rememberMe principals were resolved and they need to be stored in the
         //session, so we don't constantly rehydrate the rememberMe PrincipalCollection on every operation).
         //Added in 1.2:
         save(subject);
 
         return subject;
     }
 
     /**
      * Actually creates a {@code Subject} instance by delegating to the internal
      * {@link #getSubjectFactory() subjectFactory}.  By the time this method is invoked, all possible
      * {@code SubjectContext} data (session, principals, et. al.) has been made accessible using all known heuristics
      * and will be accessible to the {@code subjectFactory} via the {@code subjectContext.resolve*} methods.
      *
      * @param context the populated context (data map) to be used by the {@code SubjectFactory} when creating a
      *                {@code Subject} instance.
      * @return a {@code Subject} instance reflecting the data in the specified {@code SubjectContext} data map.
      * @see #getSubjectFactory()
      * @see SubjectFactory#createSubject(org.apache.shiro.subject.SubjectContext)
      * @since 1.2
      */
     protected Subject doCreateSubject(SubjectContext context) {
         return getSubjectFactory().createSubject(context);
     }
 
     /**
      * Saves the subject's state to a persistent location for future reference if necessary.
      * <p/>
      * This implementation merely delegates to the internal {@link #setSubjectDAO(SubjectDAO) subjectDAO} and calls
      * {@link SubjectDAO#save(org.apache.shiro.subject.Subject) subjectDAO.save(subject)}.
      *
      * @param subject the subject for which state will potentially be persisted
      * @see SubjectDAO#save(org.apache.shiro.subject.Subject)
      * @since 1.2
      */
     protected void save(Subject subject) {
         this.subjectDAO.save(subject);
     }
 
     /**
      * Removes (or 'unbinds') the Subject's state from the application, typically called during {@link #logout}..
      * <p/>
      * This implementation merely delegates to the internal {@link #setSubjectDAO(SubjectDAO) subjectDAO} and calls
      * {@link SubjectDAO#delete(org.apache.shiro.subject.Subject) delete(subject)}.
      *
      * @param subject the subject for which state will be removed
      * @see SubjectDAO#delete(org.apache.shiro.subject.Subject)
      * @since 1.2
      */
     protected void delete(Subject subject) {
         this.subjectDAO.delete(subject);
     }
 
     /**
      * Determines if there is a {@code SecurityManager} instance in the context, and if not, adds 'this' to the
      * context.  This ensures the SubjectFactory instance will have access to a SecurityManager during Subject
      * construction if necessary.
      *
      * @param context the subject context data that may contain a SecurityManager instance.
      * @return The SubjectContext to use to pass to a {@link SubjectFactory} for subject creation.
      * @since 1.0
      */
     @SuppressWarnings({"unchecked"})
     protected SubjectContexthe/shiro/subject/SubjectContext.html#SubjectContext">SubjectContext ensureSecurityManager(SubjectContext context) {
         if (context.resolveSecurityManager() != null) {
             log.trace("Context already contains a SecurityManager instance.  Returning.");
             return context;
         }
         log.trace("No SecurityManager found in context.  Adding self reference.");
         context.setSecurityManager(this);
         return context;
     }
 
     /**
      * Attempts to resolve any associated session based on the context and returns a
      * context that represents this resolved {@code Session} to ensure it may be referenced if necessary by the
      * invoked {@link SubjectFactory} that performs actual {@link Subject} construction.
      * <p/>
      * If there is a {@code Session} already in the context because that is what the caller wants to be used for
      * {@code Subject} construction, or if no session is resolved, this method effectively does nothing
      * returns the context method argument unaltered.
      *
      * @param context the subject context data that may resolve a Session instance.
      * @return The context to use to pass to a {@link SubjectFactory} for subject creation.
      * @since 1.0
      */
     @SuppressWarnings({"unchecked"})
     protected SubjectContextrg/apache/shiro/subject/SubjectContext.html#SubjectContext">SubjectContext resolveSession(SubjectContext context) {
         if (context.resolveSession() != null) {
             log.debug("Context already contains a session.  Returning.");
             return context;
         }
         try {
             //Context couldn't resolve it directly, let's see if we can since we have direct access to 
             //the session manager:
             Session session = resolveContextSession(context);
             if (session != null) {
                 context.setSession(session);
             }
         } catch (InvalidSessionException e) {
             log.debug("Resolved SubjectContext context session is invalid.  Ignoring and creating an anonymous " +
                     "(session-less) Subject instance.", e);
         }
         return context;
     }
 
     protected Session resolveContextSession(SubjectContext context) throws InvalidSessionException {
         SessionKey key = getSessionKey(context);
         if (key != null) {
             return getSession(key);
         }
         return null;
     }
 
     protected SessionKey getSessionKey(SubjectContext context) {
         Serializable sessionId = context.getSessionId();
         if (sessionId != null) {
             return new DefaultSessionKey(sessionId);
         }
         return null;
     }
 
     private static boolean isEmpty(PrincipalCollection pc) {
         return pc == null || pc.isEmpty();
     }
 
     /**
      * Attempts to resolve an identity (a {@link PrincipalCollection}) for the context using heuristics.  This
      * implementation functions as follows:
      * <ol>
      * <li>Check the context to see if it can already {@link SubjectContext#resolvePrincipals resolve an identity}.  If
      * so, this method does nothing and returns the method argument unaltered.</li>
      * <li>Check for a RememberMe identity by calling {@link #getRememberedIdentity}.  If that method returns a
      * non-null value, place the remembered {@link PrincipalCollection} in the context.</li>
      * </ol>
      *
      * @param context the subject context data that may provide (directly or indirectly through one of its values) a
      *                {@link PrincipalCollection} identity.
      * @return The Subject context to use to pass to a {@link SubjectFactory} for subject creation.
      * @since 1.0
      */
     @SuppressWarnings({"unchecked"})
     protected SubjectContextapache/shiro/subject/SubjectContext.html#SubjectContext">SubjectContext resolvePrincipals(SubjectContext context) {
 
         PrincipalCollection principals = context.resolvePrincipals();
 
         if (isEmpty(principals)) {
             log.trace("No identity (PrincipalCollection) found in the context.  Looking for a remembered identity.");
 
             principals = getRememberedIdentity(context);
 
             if (!isEmpty(principals)) {
                 log.debug("Found remembered PrincipalCollection.  Adding to the context to be used " +
                         "for subject construction by the SubjectFactory.");
 
                 context.setPrincipals(principals);
 
                 // The following call was removed (commented out) in Shiro 1.2 because it uses the session as an
                 // implementation strategy.  Session use for Shiro's own needs should be controlled in a single place
                 // to be more manageable for end-users: there are a number of stateless (e.g. REST) applications that
                 // use Shiro that need to ensure that sessions are only used when desirable.  If Shiro's internal
                 // implementations used Subject sessions (setting attributes) whenever we wanted, it would be much
                 // harder for end-users to control when/where that occurs.
                 //
                 // Because of this, the SubjectDAO was created as the single point of control, and session state logic
                 // has been moved to the DefaultSubjectDAO implementation.
 
                 // Removed in Shiro 1.2.  SHIRO-157 is still satisfied by the new DefaultSubjectDAO implementation
                 // introduced in 1.2
                 // Satisfies SHIRO-157:
                 // bindPrincipalsToSession(principals, context);
 
             } else {
                 log.trace("No remembered identity found.  Returning original context.");
             }
         }
 
         return context;
     }
 
     protected SessionContext createSessionContext(SubjectContext subjectContext) {
         DefaultSessionContexthtml#DefaultSessionContext">DefaultSessionContext sessionContext = new DefaultSessionContext();
         if (!CollectionUtils.isEmpty(subjectContext)) {
             sessionContext.putAll(subjectContext);
         }
         Serializable sessionId = subjectContext.getSessionId();
         if (sessionId != null) {
             sessionContext.setSessionId(sessionId);
         }
         String host = subjectContext.resolveHost();
         if (host != null) {
             sessionContext.setHost(host);
         }
         return sessionContext;
     }
 
     public void logout(Subject subject) {
 
         if (subject == null) {
             throw new IllegalArgumentException("Subject method argument cannot be null.");
         }
 
         beforeLogout(subject);
 
         PrincipalCollection principals = subject.getPrincipals();
         if (principals != null && !principals.isEmpty()) {
             if (log.isDebugEnabled()) {
                 log.debug("Logging out subject with primary principal {}", principals.getPrimaryPrincipal());
             }
             Authenticator authc = getAuthenticator();
             if (authc instanceof LogoutAware) {
                 ((LogoutAware) authc).onLogout(principals);
             }
         }
 
         try {
             delete(subject);
         } catch (Exception e) {
             if (log.isDebugEnabled()) {
                 String msg = "Unable to cleanly unbind Subject.  Ignoring (logging out).";
                 log.debug(msg, e);
             }
         } finally {
             try {
                 stopSession(subject);
             } catch (Exception e) {
                 if (log.isDebugEnabled()) {
                     String msg = "Unable to cleanly stop Session for Subject [" + subject.getPrincipal() + "] " +
                             "Ignoring (logging out).";
                     log.debug(msg, e);
                 }
             }
         }
     }
 
     protected void stopSession(Subject subject) {
         Session s = subject.getSession(false);
         if (s != null) {
             s.stop();
         }
     }
 
     /**
      * Unbinds or removes the Subject's state from the application, typically called during {@link #logout}.
      * <p/>
      * This has been deprecated in Shiro 1.2 in favor of the {@link #delete(org.apache.shiro.subject.Subject) delete}
      * method.  The implementation has been updated to invoke that method.
      *
      * @param subject the subject to unbind from the application as it will no longer be used.
      * @deprecated in Shiro 1.2 in favor of {@link #delete(org.apache.shiro.subject.Subject)}
      */
     @Deprecated
     @SuppressWarnings({"UnusedDeclaration"})
     protected void unbind(Subject subject) {
         delete(subject);
     }
 
     protected PrincipalCollection getRememberedIdentity(SubjectContext subjectContext) {
         RememberMeManager rmm = getRememberMeManager();
         if (rmm != null) {
             try {
                 return rmm.getRememberedPrincipals(subjectContext);
             } catch (Exception e) {
                 if (log.isWarnEnabled()) {
                     String msg = "Delegate RememberMeManager instance of type [" + rmm.getClass().getName() +
                             "] threw an exception during getRememberedPrincipals().";
                     log.warn(msg, e);
                 }
             }
         }
         return null;
     }
 }