/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.userdirectory.sakai;
  
  import org.opencastproject.security.api.Organization;
  import org.opencastproject.security.api.OrganizationDirectoryService;
  import org.opencastproject.security.api.RoleProvider;
  import org.opencastproject.security.api.UserProvider;
  import org.opencastproject.util.NotFoundException;
  
  import org.apache.commons.lang3.StringUtils;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.ServiceRegistration;
  import org.osgi.service.cm.ConfigurationException;
  import org.osgi.service.cm.ManagedServiceFactory;
  import org.osgi.service.component.ComponentContext;
  import org.osgi.service.component.annotations.Activate;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Reference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.lang.management.ManagementFactory;
  import java.util.Arrays;
  import java.util.Dictionary;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  
  import javax.management.MalformedObjectNameException;
  import javax.management.ObjectName;
  
  /**
   * Sakai implementation of the spring UserDetailsService, taking configuration information from the component context.
   */
  @Component(
      immediate = true,
      service = ManagedServiceFactory.class,
      property = {
          "service.pid=org.opencastproject.userdirectory.sakai",
          "service.description=Provides Sakai user directory instances"
      }
  )
  public class SakaiUserProviderFactory implements ManagedServiceFactory {
  
    /** The logger */
    protected static final Logger logger = LoggerFactory.getLogger(SakaiUserProviderFactory.class);
  
    /** This service factory's PID */
    public static final String PID = "org.opencastproject.userdirectory.sakai";
  
    /** The key to look up the organization identifer in the service configuration properties */
    private static final String ORGANIZATION_KEY = "org.opencastproject.userdirectory.sakai.org";
  
    /** The key to look up the user DN to use for performing searches. */
    private static final String SAKAI_SEARCH_USER = "org.opencastproject.userdirectory.sakai.user";
  
    /** The key to look up the password to use for performing searches */
    private static final String SEARCH_PASSWORD = "org.opencastproject.userdirectory.sakai.password";
  
    /** The key to look up the regular expression used to validate sites */
    private static final String SITE_PATTERN_KEY = "org.opencastproject.userdirectory.sakai.site.pattern";
  
    /** The key to look up the regular expression used to validate users */
    private static final String USER_PATTERN_KEY = "org.opencastproject.userdirectory.sakai.user.pattern";
  
    /** The key to look up the number of user records to cache */
    private static final String CACHE_SIZE = "org.opencastproject.userdirectory.sakai.cache.size";
  
    /** The key to look up the URL of the Sakai instance */
    private static final String SAKAI_URL_KEY = "org.opencastproject.userdirectory.sakai.url";
  
    /** The key to look up the list of Instructor roles on the Sakai instance */
    private static final String SAKAI_INSTRUCTOR_ROLES_KEY = "org.opencastproject.userdirectory.sakai.instructor.roles";
  
    /** The key to look up the number of minutes to cache users */
    private static final String CACHE_EXPIRATION = "org.opencastproject.userdirectory.sakai.cache.expiration";
  
    /** A map of pid to sakai user provider instance */
   private Map<String, ServiceRegistration> providerRegistrations = new ConcurrentHashMap<String, ServiceRegistration>();
 
   /** The OSGI bundle context */
   protected BundleContext bundleContext = null;
 
   /** The organization directory service */
   private OrganizationDirectoryService orgDirectory;
 
   /** OSGi callback for setting the organization directory service. */
   @Reference
   public void setOrgDirectory(OrganizationDirectoryService orgDirectory) {
     this.orgDirectory = orgDirectory;
   }
 
   /**
    * Callback for the activation of this component
    *
    * @param cc
    *          the component context
    */
   @Activate
   public void activate(ComponentContext cc) {
     logger.debug("Activate SakaiUserProviderFactory");
     this.bundleContext = cc.getBundleContext();
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.osgi.service.cm.ManagedServiceFactory#getName()
    */
   @Override
   public String getName() {
     return PID;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.osgi.service.cm.ManagedServiceFactory#updated(java.lang.String, java.util.Dictionary)
    */
   @Override
   public void updated(String pid, Dictionary properties) throws ConfigurationException {
 
     logger.debug("updated SakaiUserProviderFactory");
 
     String organization = (String) properties.get(ORGANIZATION_KEY);
     if (StringUtils.isBlank(organization)) {
       throw new ConfigurationException(ORGANIZATION_KEY, "is not set");
     }
 
     String url = (String) properties.get(SAKAI_URL_KEY);
     if (StringUtils.isBlank(url)) {
       throw new ConfigurationException(SAKAI_URL_KEY, "is not set");
     }
 
     String userDn = (String) properties.get(SAKAI_SEARCH_USER);
     String password = (String) properties.get(SEARCH_PASSWORD);
 
     String sitePattern = (String) properties.get(SITE_PATTERN_KEY);
     String userPattern = (String) properties.get(USER_PATTERN_KEY);
 
     int cacheSize = 1000;
     try {
       if (properties.get(CACHE_SIZE) != null) {
         Integer configuredCacheSize = Integer.parseInt(properties.get(CACHE_SIZE).toString());
         if (configuredCacheSize != null) {
           cacheSize = configuredCacheSize.intValue();
         }
       }
     } catch (Exception e) {
       logger.warn("{} could not be loaded, default value is used: {}", CACHE_SIZE, cacheSize);
     }
 
 
     int cacheExpiration = 60;
     try {
       if (properties.get(CACHE_EXPIRATION) != null) {
         Integer configuredCacheExpiration = Integer.parseInt(properties.get(CACHE_EXPIRATION).toString());
         if (configuredCacheExpiration != null) {
           cacheExpiration = configuredCacheExpiration.intValue();
         }
       }
     } catch (Exception e) {
       logger.warn("{} could not be loaded, default value is used: {}", CACHE_EXPIRATION, cacheExpiration);
     }
 
     // Instructor roles
     Set<String> instructorRoles;
     String instructorRoleList = (String) properties.get(SAKAI_INSTRUCTOR_ROLES_KEY);
 
     if (!StringUtils.isEmpty(instructorRoleList)) {
       String trimmedRoles = StringUtils.trim(instructorRoleList);
       String[] roles = trimmedRoles.split(",");
       instructorRoles = new HashSet<String>(Arrays.asList(roles));
       logger.info("Sakai instructor roles: {}", Arrays.toString(roles));
     } else {
       // Default instructor roles
       instructorRoles = new HashSet<String>();
       instructorRoles.add("Site owner");
       instructorRoles.add("Instructor");
       instructorRoles.add("maintain");
     }
 
     // Now that we have everything we need, go ahead and activate a new provider, removing an old one if necessary
     ServiceRegistration existingRegistration = providerRegistrations.remove(pid);
     if (existingRegistration != null) {
       existingRegistration.unregister();
     }
 
     Organization org;
     try {
       org = orgDirectory.getOrganization(organization);
     } catch (NotFoundException e) {
       logger.warn("Organization {} not found!", organization);
       throw new ConfigurationException(ORGANIZATION_KEY, "not found");
     }
 
     logger.debug("creating new SakaiUserProviderInstance for pid=" + pid);
     SakaiUserProviderInstance provider = new SakaiUserProviderInstance(pid,
             org, url, userDn, password, sitePattern, userPattern, instructorRoles, cacheSize, cacheExpiration);
 
     providerRegistrations.put(pid, bundleContext.registerService(UserProvider.class.getName(), provider, null));
     providerRegistrations.put(pid, bundleContext.registerService(RoleProvider.class.getName(), provider, null));
 
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.osgi.service.cm.ManagedServiceFactory#deleted(java.lang.String)
    */
   @Override
   public void deleted(String pid) {
     logger.debug("delete SakaiUserProviderInstance for pid=" + pid);
     ServiceRegistration registration = providerRegistrations.remove(pid);
     if (registration != null) {
       registration.unregister();
       try {
         ManagementFactory.getPlatformMBeanServer().unregisterMBean(SakaiUserProviderFactory.getObjectName(pid));
       } catch (Exception e) {
         logger.warn("Unable to unregister mbean for pid='{}': {}", pid, e.getMessage());
       }
     }
   }
 
   /**
    * Builds a JMX object name for a given PID
    *
    * @param pid
    *          the PID
    * @return the object name
    * @throws NullPointerException
    * @throws MalformedObjectNameException
    */
   public static final ObjectName getObjectName(String pid) throws MalformedObjectNameException, NullPointerException {
     return new ObjectName(pid + ":type=SakaiRequests");
   }
 
 }