/*
    * 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.security.util;
  
  import static org.apache.commons.lang3.StringUtils.isBlank;
  import static org.opencastproject.security.api.SecurityConstants.EPISODE_ROLE_ID_PREFIX;
  import static org.opencastproject.security.api.SecurityConstants.GLOBAL_ADMIN_ROLE;
  import static org.opencastproject.security.api.SecurityConstants.GLOBAL_ANONYMOUS_USERNAME;
  import static org.opencastproject.security.api.SecurityConstants.GLOBAL_CAPTURE_AGENT_ROLE;
  import static org.opencastproject.util.data.Tuple.tuple;
  
  import org.opencastproject.security.api.JaxbOrganization;
  import org.opencastproject.security.api.JaxbRole;
  import org.opencastproject.security.api.JaxbUser;
  import org.opencastproject.security.api.Organization;
  import org.opencastproject.security.api.OrganizationDirectoryService;
  import org.opencastproject.security.api.SecurityConstants;
  import org.opencastproject.security.api.SecurityService;
  import org.opencastproject.security.api.UnauthorizedException;
  import org.opencastproject.security.api.User;
  import org.opencastproject.security.api.UserDirectoryService;
  import org.opencastproject.util.ConfigurationException;
  import org.opencastproject.util.NotFoundException;
  import org.opencastproject.util.data.Tuple;
  
  import org.apache.commons.lang3.StringUtils;
  import org.osgi.service.component.ComponentContext;
  
  import java.net.URL;
  import java.util.Optional;
  import java.util.regex.Pattern;
  
  /** Opencast security helpers. */
  public final class SecurityUtil {
    private static final Pattern SANITIZING_PATTERN = Pattern.compile("[^a-zA-Z0-9_]");
  
    private SecurityUtil() {
    }
  
    /** The name of the key used to store the name of the system user in the global config. */
    public static final String PROPERTY_KEY_SYS_USER = "org.opencastproject.security.digest.user";
  
    /**
     * Run function <code>f</code> in the context described by the given organization and user.
     *
     * @param sec
     *          Security service to use for getting data
     * @param org
     *          Organization to switch to
     * @param user
     *          User to switch to
     * @param fn
     *          Function to execute
     */
    public static void runAs(SecurityService sec, Organization org, User user, Runnable fn) {
      final Organization prevOrg = sec.getOrganization();
      final User prevUser = prevOrg != null ? sec.getUser() : null;
      sec.setOrganization(org);
      sec.setUser(user);
      try {
        fn.run();
      } finally {
        sec.setOrganization(prevOrg);
        sec.setUser(prevUser);
      }
    }
  
    /**
     * Create a system user for the given organization with global and organization local admin role. Get the
     * <code>systemUserName</code> from the global config where it is stored under {@link #PROPERTY_KEY_SYS_USER}. In an
     * OSGi environment this is typically done calling
     * <code>componentContext.getBundleContext().getProperty(PROPERTY_KEY_SYS_USER)</code>.
     *
     * @see #createSystemUser(org.osgi.service.component.ComponentContext, org.opencastproject.security.api.Organization)
     */
    public static User createSystemUser(String systemUserName, Organization org) {
      JaxbOrganization jaxbOrganization = JaxbOrganization.fromOrganization(org);
      return new JaxbUser(systemUserName, null, jaxbOrganization, new JaxbRole(GLOBAL_ADMIN_ROLE, jaxbOrganization),
              new JaxbRole(org.getAdminRole(), jaxbOrganization));
    }
 
   /**
    * Create the global anonymous user with the given organization.
    *
    * @param org
    *          the organization
    * @return the global anonymous user
    */
   public static User createAnonymousUser(Organization org) {
     JaxbOrganization jaxbOrganization = JaxbOrganization.fromOrganization(org);
     return new JaxbUser(GLOBAL_ANONYMOUS_USERNAME, null, jaxbOrganization, new JaxbRole(
             jaxbOrganization.getAnonymousRole(), jaxbOrganization));
   }
 
   /**
    * Create a system user for the given organization with global admin role. The system user name is fetched from the
    * global OSGi config.
    *
    * @see #createSystemUser(String, org.opencastproject.security.api.Organization)
    */
   public static User createSystemUser(ComponentContext cc, Organization org) {
     final String systemUserName = cc.getBundleContext().getProperty(PROPERTY_KEY_SYS_USER);
     return createSystemUser(systemUserName, org);
   }
 
   /**
    * Fetch the system user name from the configuration.
    *
    * @see #PROPERTY_KEY_SYS_USER
    */
   public static String getSystemUserName(ComponentContext cc) {
     final String systemUserName = cc.getBundleContext().getProperty(PROPERTY_KEY_SYS_USER);
     if (systemUserName != null) {
       return systemUserName;
     } else {
       throw new ConfigurationException(
               "An Opencast installation always needs a system user name. Please configure one under the key "
                       + PROPERTY_KEY_SYS_USER);
     }
   }
 
   /**
    * Get a user and an organization. Only returns something if both elements can be determined.
    */
   public static Optional<Tuple<User, Organization>> getUserAndOrganization(SecurityService sec,
           OrganizationDirectoryService orgDir, String orgId, UserDirectoryService userDir, String userId) {
     final Organization prevOrg = sec.getOrganization();
     try {
       final Organization org = orgDir.getOrganization(orgId);
       sec.setOrganization(org);
       return Optional.ofNullable(userDir.loadUser(userId))
               .map(user -> tuple(user, org));
     } catch (NotFoundException e) {
       return Optional.empty();
     } finally {
       sec.setOrganization(prevOrg);
     }
   }
 
   /** Extract hostname and port number from a URL. */
   public static Tuple<String, Integer> hostAndPort(URL url) {
     int port = url.getPort();
     if (port < 0) {
       port = url.getDefaultPort();
     }
     return tuple(StringUtils.strip(url.getHost(), "/"), port);
   }
 
   /**
    * Check if the current user has access to the capture agent with the given id.
    * @param agentId
    *           The agent id to check.
    * @throws UnauthorizedException
    *           If the user doesn't have access.
    */
   public static void checkAgentAccess(final SecurityService securityService, final String agentId)
       throws UnauthorizedException {
     if (isBlank(agentId)) {
       return;
     }
     final User user = securityService.getUser();
     if (user.hasRole(SecurityConstants.GLOBAL_ADMIN_ROLE) || user.hasRole(user.getOrganization().getAdminRole())) {
       return;
     }
     if (!user.hasRole(SecurityUtil.getCaptureAgentRole(agentId))) {
       throw new UnauthorizedException(user, "schedule");
     }
   }
 
   private static String sanitizeCaName(final String ca) {
     return SANITIZING_PATTERN.matcher(ca).replaceAll("").toUpperCase();
   }
 
   /**
    * Get the role name of the role required to access the capture agent with the given agent id.
    *
    * @param
    *     agentId The id of the agent to get the role for.
    * @return
    *     The role name.
    */
   public static String getCaptureAgentRole(final String agentId) {
     return GLOBAL_CAPTURE_AGENT_ROLE + "_" + sanitizeCaName(agentId);
   }
 
   /**
    * Get the episode role id for a mediapackage and an action
    *
    * @param mediaPackageId the id of the mediapackage
    * @param action the action as a string
    * @return the role
    */
   public static String getEpisodeRoleId(final String mediaPackageId, final String action) {
     return EPISODE_ROLE_ID_PREFIX + "_" + mediaPackageId + "_" + action.toUpperCase();
   }
 }