/*
    * 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.subject.support;
  
  import org.apache.shiro.SecurityUtils;
  import org.apache.shiro.UnavailableSecurityManagerException;
  import org.apache.shiro.authc.AuthenticationInfo;
  import org.apache.shiro.authc.AuthenticationToken;
  import org.apache.shiro.authc.HostAuthenticationToken;
  import org.apache.shiro.mgt.SecurityManager;
  import org.apache.shiro.session.Session;
  import org.apache.shiro.subject.PrincipalCollection;
  import org.apache.shiro.subject.Subject;
  import org.apache.shiro.subject.SubjectContext;
  import org.apache.shiro.util.MapContext;
  import org.apache.shiro.util.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.Serializable;
  
  /**
   * Default implementation of the {@link SubjectContext} interface.  Note that the getters and setters are not
   * simple pass-through methods to an underlying attribute;  the getters will employ numerous heuristics to acquire
   * their data attribute as best as possible (for example, if {@link #getPrincipals} is invoked, if the principals aren't
   * in the backing map, it might check to see if there is a subject or session in the map and attempt to acquire the
   * principals from those objects).
   *
   * @since 1.0
   */
  public class DefaultSubjectContext extends MapContext implements SubjectContext {
  
      private static final String SECURITY_MANAGER = DefaultSubjectContext.class.getName() + ".SECURITY_MANAGER";
  
      private static final String SESSION_ID = DefaultSubjectContext.class.getName() + ".SESSION_ID";
  
      private static final String AUTHENTICATION_TOKEN = DefaultSubjectContext.class.getName() + ".AUTHENTICATION_TOKEN";
  
      private static final String AUTHENTICATION_INFO = DefaultSubjectContext.class.getName() + ".AUTHENTICATION_INFO";
  
      private static final String SUBJECT = DefaultSubjectContext.class.getName() + ".SUBJECT";
  
      private static final String PRINCIPALS = DefaultSubjectContext.class.getName() + ".PRINCIPALS";
  
      private static final String SESSION = DefaultSubjectContext.class.getName() + ".SESSION";
  
      private static final String AUTHENTICATED = DefaultSubjectContext.class.getName() + ".AUTHENTICATED";
  
      private static final String HOST = DefaultSubjectContext.class.getName() + ".HOST";
  
      public static final String SESSION_CREATION_ENABLED = DefaultSubjectContext.class.getName() + ".SESSION_CREATION_ENABLED";
  
      /**
       * The session key that is used to store subject principals.
       */
      public static final String PRINCIPALS_SESSION_KEY = DefaultSubjectContext.class.getName() + "_PRINCIPALS_SESSION_KEY";
  
      /**
       * The session key that is used to store whether or not the user is authenticated.
       */
      public static final String AUTHENTICATED_SESSION_KEY = DefaultSubjectContext.class.getName() + "_AUTHENTICATED_SESSION_KEY";
  
      private static final transient Logger log = LoggerFactory.getLogger(DefaultSubjectContext.class);
  
      public DefaultSubjectContext() {
          super();
      }
  
      public DefaultSubjectContext(SubjectContext ctx) {
          super(ctx);
      }
  
      public SecurityManager getSecurityManager() {
          return getTypedValue(SECURITY_MANAGER, SecurityManager.class);
      }
  
      public void setSecurityManager(SecurityManager securityManager) {
          nullSafePut(SECURITY_MANAGER, securityManager);
      }
  
      public SecurityManager resolveSecurityManager() {
          SecurityManager securityManager = getSecurityManager();
          if (securityManager == null) {
             if (log.isDebugEnabled()) {
                 log.debug("No SecurityManager available in subject context map.  " +
                         "Falling back to SecurityUtils.getSecurityManager() lookup.");
             }
             try {
                 securityManager = SecurityUtils.getSecurityManager();
             } catch (UnavailableSecurityManagerException e) {
                 if (log.isDebugEnabled()) {
                     log.debug("No SecurityManager available via SecurityUtils.  Heuristics exhausted.", e);
                 }
             }
         }
         return securityManager;
     }
 
     public Serializable getSessionId() {
         return getTypedValue(SESSION_ID, Serializable.class);
     }
 
     public void setSessionId(Serializable sessionId) {
         nullSafePut(SESSION_ID, sessionId);
     }
 
     public Subject getSubject() {
         return getTypedValue(SUBJECT, Subject.class);
     }
 
     public void setSubject(Subject subject) {
         nullSafePut(SUBJECT, subject);
     }
 
     public PrincipalCollection getPrincipals() {
         return getTypedValue(PRINCIPALS, PrincipalCollection.class);
     }
 
     private static boolean isEmpty(PrincipalCollection pc) {
         return pc == null || pc.isEmpty();
     }
 
     public void setPrincipals(PrincipalCollection principals) {
         if (!isEmpty(principals)) {
             put(PRINCIPALS, principals);
         }
     }
 
     public PrincipalCollection resolvePrincipals() {
         PrincipalCollection principals = getPrincipals();
 
         if (isEmpty(principals)) {
             //check to see if they were just authenticated:
             AuthenticationInfo info = getAuthenticationInfo();
             if (info != null) {
                 principals = info.getPrincipals();
             }
         }
 
         if (isEmpty(principals)) {
             Subject subject = getSubject();
             if (subject != null) {
                 principals = subject.getPrincipals();
             }
         }
 
         if (isEmpty(principals)) {
             //try the session:
             Session session = resolveSession();
             if (session != null) {
                 principals = (PrincipalCollection) session.getAttribute(PRINCIPALS_SESSION_KEY);
             }
         }
 
         return principals;
     }
 
 
     public Session getSession() {
         return getTypedValue(SESSION, Session.class);
     }
 
     public void setSession(Session session) {
         nullSafePut(SESSION, session);
     }
 
     public Session resolveSession() {
         Session session = getSession();
         if (session == null) {
             //try the Subject if it exists:
             Subject existingSubject = getSubject();
             if (existingSubject != null) {
                 session = existingSubject.getSession(false);
             }
         }
         return session;
     }
 
     public boolean isSessionCreationEnabled() {
         Boolean val = getTypedValue(SESSION_CREATION_ENABLED, Boolean.class);
         return val == null || val;
     }
 
     public void setSessionCreationEnabled(boolean enabled) {
         nullSafePut(SESSION_CREATION_ENABLED, enabled);
     }
 
     public boolean isAuthenticated() {
         Boolean authc = getTypedValue(AUTHENTICATED, Boolean.class);
         return authc != null && authc;
     }
 
     public void setAuthenticated(boolean authc) {
         put(AUTHENTICATED, authc);
     }
 
     public boolean resolveAuthenticated() {
         Boolean authc = getTypedValue(AUTHENTICATED, Boolean.class);
         if (authc == null) {
             //see if there is an AuthenticationInfo object.  If so, the very presence of one indicates a successful
             //authentication attempt:
             AuthenticationInfo info = getAuthenticationInfo();
             authc = info != null;
         }
         if (!authc) {
             //fall back to a session check:
             Session session = resolveSession();
             if (session != null) {
                 Boolean sessionAuthc = (Boolean) session.getAttribute(AUTHENTICATED_SESSION_KEY);
                 authc = sessionAuthc != null && sessionAuthc;
             }
         }
 
         return authc;
     }
 
     public AuthenticationInfo getAuthenticationInfo() {
         return getTypedValue(AUTHENTICATION_INFO, AuthenticationInfo.class);
     }
 
     public void setAuthenticationInfo(AuthenticationInfo info) {
         nullSafePut(AUTHENTICATION_INFO, info);
     }
 
     public AuthenticationToken getAuthenticationToken() {
         return getTypedValue(AUTHENTICATION_TOKEN, AuthenticationToken.class);
     }
 
     public void setAuthenticationToken(AuthenticationToken token) {
         nullSafePut(AUTHENTICATION_TOKEN, token);
     }
 
     public String getHost() {
         return getTypedValue(HOST, String.class);
     }
 
     public void setHost(String host) {
         if (StringUtils.hasText(host)) {
             put(HOST, host);
         }
     }
 
     public String resolveHost() {
         String host = getHost();
 
         if (host == null) {
             //check to see if there is an AuthenticationToken from which to retrieve it:
             AuthenticationToken token = getAuthenticationToken();
             if (token instanceof HostAuthenticationToken) {
                 host = ((HostAuthenticationToken) token).getHost();
             }
         }
 
         if (host == null) {
             Session session = resolveSession();
             if (session != null) {
                 host = session.getHost();
             }
         }
 
         return host;
     }
 }