/*
    * 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.search.impl;
  
  import static org.opencastproject.security.api.SecurityConstants.GLOBAL_ADMIN_ROLE;
  import static org.opencastproject.util.data.functions.Functions.chuck;
  
  import org.opencastproject.job.api.AbstractJobProducer;
  import org.opencastproject.job.api.Job;
  import org.opencastproject.mediapackage.MediaPackage;
  import org.opencastproject.mediapackage.MediaPackageParser;
  import org.opencastproject.search.api.SearchException;
  import org.opencastproject.search.api.SearchResultList;
  import org.opencastproject.search.api.SearchService;
  import org.opencastproject.search.impl.persistence.SearchServiceDatabase;
  import org.opencastproject.search.impl.persistence.SearchServiceDatabaseException;
  import org.opencastproject.security.api.Organization;
  import org.opencastproject.security.api.OrganizationDirectoryService;
  import org.opencastproject.security.api.SecurityService;
  import org.opencastproject.security.api.StaticFileAuthorization;
  import org.opencastproject.security.api.UnauthorizedException;
  import org.opencastproject.security.api.User;
  import org.opencastproject.security.api.UserDirectoryService;
  import org.opencastproject.security.util.SecurityUtil;
  import org.opencastproject.serviceregistry.api.ServiceRegistry;
  import org.opencastproject.serviceregistry.api.ServiceRegistryException;
  import org.opencastproject.util.LoadUtil;
  import org.opencastproject.util.NotFoundException;
  import org.opencastproject.util.data.Tuple;
  
  import com.google.common.cache.CacheBuilder;
  import com.google.common.cache.CacheLoader;
  import com.google.common.cache.LoadingCache;
  
  import org.apache.commons.lang3.tuple.Pair;
  import org.elasticsearch.action.search.SearchResponse;
  import org.elasticsearch.search.builder.SearchSourceBuilder;
  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.Modified;
  import org.osgi.service.component.annotations.Reference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * An Opensearch-based {@link SearchService} implementation.
   */
  @Component(
      immediate = true,
      service = { SearchService.class, SearchServiceImpl.class, StaticFileAuthorization.class },
      property = {
          "service.description=Search Service",
          "service.pid=org.opencastproject.search.impl.SearchServiceImpl"
      }
  )
  public final class SearchServiceImpl extends AbstractJobProducer implements SearchService, StaticFileAuthorization {
  
    /** Log facility */
    private static final Logger logger = LoggerFactory.getLogger(SearchServiceImpl.class);
  
    /** The job type */
    public static final String JOB_TYPE = "org.opencastproject.search";
  
    /** The load introduced on the system by creating an add job */
    public static final float DEFAULT_ADD_JOB_LOAD = 0.1f;
  
    /** The load introduced on the system by creating a delete job */
    public static final float DEFAULT_DELETE_JOB_LOAD = 0.1f;
  
    /** The key to look for in the service configuration file to override the {@link #DEFAULT_ADD_JOB_LOAD} */
    public static final String ADD_JOB_LOAD_KEY = "job.load.add";
 
   /** The key to look for in the service configuration file to override the {@link #DEFAULT_DELETE_JOB_LOAD} */
   public static final String DELETE_JOB_LOAD_KEY = "job.load.delete";
 
   /** The load introduced on the system by creating an add job */
   private float addJobLoad = DEFAULT_ADD_JOB_LOAD;
 
   /** The load introduced on the system by creating a delete job */
   private float deleteJobLoad = DEFAULT_DELETE_JOB_LOAD;
 
   /** List of available operations on jobs */
   private enum Operation {
     Add, Delete, DeleteSeries
   }
 
   private SearchServiceIndex index;
 
   /** The security service */
   private SecurityService securityService;
 
   /** The service registry */
   private ServiceRegistry serviceRegistry;
 
   /** Persistent storage */
   private SearchServiceDatabase persistence;
 
   /** The user directory service */
   protected UserDirectoryService userDirectoryService = null;
 
   /** The organization directory service */
   protected OrganizationDirectoryService organizationDirectory = null;
 
   private final LoadingCache<Tuple<User, String>, Boolean> cache;
 
   private static final Pattern staticFilePattern =
       Pattern.compile("^/([^/]+)/(?:engage-player|engage-live)/([^/]+)/.*$");
 
   /**
    * Creates a new instance of the search service.
    */
   public SearchServiceImpl() {
     super(JOB_TYPE);
 
     cache = CacheBuilder.newBuilder()
         .maximumSize(2048)
         .expireAfterWrite(1, TimeUnit.MINUTES)
         .build(new CacheLoader<>() {
           @Override
           public Boolean load(Tuple<User, String> key) {
             return loadUrlAccess(key.getB());
           }
         });
   }
 
   /**
    * Service activator, called via declarative services configuration.
    *
    * @param cc
    *          the component context
    */
   @Override
   @Activate
   public void activate(final ComponentContext cc) throws IllegalStateException {
     super.activate(cc);
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.search.api.SearchService#add(org.opencastproject.mediapackage.MediaPackage)
    */
   public Job add(MediaPackage mediaPackage) throws SearchException, IllegalArgumentException {
     try {
       return serviceRegistry.createJob(JOB_TYPE, Operation.Add.toString(),
           Collections.singletonList(MediaPackageParser.getAsXml(mediaPackage)), addJobLoad);
     } catch (ServiceRegistryException e) {
       throw new SearchException(e);
     }
   }
 
   @Override
   public void addSynchronously(MediaPackage mediaPackage)
           throws SearchException, IllegalArgumentException, UnauthorizedException {
     try {
       index.addSynchronously(mediaPackage);
     } catch (SearchServiceDatabaseException e) {
       throw new SearchException(e);
     }
   }
 
   @Override
   public Collection<Pair<Organization, MediaPackage>> getSeries(String seriesId) {
     try {
       return persistence.getSeries(seriesId);
     } catch (SearchServiceDatabaseException e) {
       throw new SearchException(e);
     }
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.search.api.SearchService#delete(java.lang.String)
    */
   public Job delete(String mediaPackageId) throws SearchException {
     try {
       return serviceRegistry.createJob(
         JOB_TYPE, Operation.Delete.toString(), Collections.singletonList(mediaPackageId), deleteJobLoad);
     } catch (ServiceRegistryException e) {
       throw new SearchException(e);
     }
   }
 
   public boolean deleteSynchronously(String mediaPackageId) throws SearchException {
     return index.deleteSynchronously(mediaPackageId);
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.search.api.SearchService#deleteSeries(java.lang.String)
    */
   public Job deleteSeries(String seriesId) throws SearchException {
     try {
       return serviceRegistry.createJob(
           JOB_TYPE, Operation.DeleteSeries.toString(), Collections.singletonList(seriesId), deleteJobLoad);
     } catch (ServiceRegistryException e) {
       throw new SearchException(e);
     }
   }
 
   @Override
   public MediaPackage get(String mediaPackageId) throws NotFoundException, UnauthorizedException {
     try {
       return persistence.getMediaPackage(mediaPackageId);
     } catch (SearchServiceDatabaseException e) {
       throw new SearchException(e);
     }
   }
 
   public SearchResultList search(SearchSourceBuilder searchSource) throws SearchException {
     SearchResponse idxResp = this.index.search(searchSource);
     return new SearchResultList(idxResp.getHits());
   }
 
 
   /**
    * @see org.opencastproject.job.api.AbstractJobProducer#process(org.opencastproject.job.api.Job)
    */
   @Override
   protected String process(Job job) throws Exception {
     Operation op = null;
     String operation = job.getOperation();
     List<String> arguments = job.getArguments();
     try {
       op = Operation.valueOf(operation);
       Organization org = organizationDirectory.getOrganization(job.getOrganization());
       User user = userDirectoryService.loadUser(job.getCreator());
       boolean[] deleted = new boolean[1];
       switch (op) {
         case Add:
           MediaPackage mediaPackage = MediaPackageParser.getFromXml(arguments.get(0));
           SecurityUtil.runAs(securityService, org, user, () -> {
             try {
               index.addSynchronously(mediaPackage);
             } catch (UnauthorizedException | SearchServiceDatabaseException e) {
               chuck(e);
             }
           });
           return null;
         case Delete:
           String mediapackageId = arguments.get(0);
           SecurityUtil.runAs(securityService, org, user, () -> {
             deleted[0] = index.deleteSynchronously(mediapackageId);
           });
           return Boolean.toString(deleted[0]);
         case DeleteSeries:
           String seriesId = arguments.get(0);
           SecurityUtil.runAs(securityService, org, user, () -> {
             deleted[0] = index.deleteSeriesSynchronously(seriesId);
           });
           return Boolean.toString(deleted[0]);
         default:
           throw new IllegalStateException("Don't know how to handle operation '" + operation + "'");
       }
     } catch (IllegalArgumentException e) {
       throw new ServiceRegistryException("This service can't handle operations of type '" + op + "'", e);
     } catch (IndexOutOfBoundsException e) {
       throw new ServiceRegistryException("This argument list for operation '" + op + "' does not meet expectations", e);
     } catch (Exception e) {
       throw new ServiceRegistryException("Error handling operation '" + op + "'", e);
     }
   }
 
   @Reference
   public void setSearchIndex(SearchServiceIndex ssi) {
     this.index = ssi;
   }
 
   @Reference
   public void setPersistence(SearchServiceDatabase persistence) {
     this.persistence = persistence;
   }
 
 
   @Reference
   public void setServiceRegistry(ServiceRegistry serviceRegistry) {
     this.serviceRegistry = serviceRegistry;
   }
 
   /**
    * Callback for setting the security service.
    *
    * @param securityService
    *          the securityService to set
    */
   @Reference
   public void setSecurityService(SecurityService securityService) {
     this.securityService = securityService;
   }
 
   /**
    * Callback for setting the user directory service.
    *
    * @param userDirectoryService
    *          the userDirectoryService to set
    */
   @Reference
   public void setUserDirectoryService(UserDirectoryService userDirectoryService) {
     this.userDirectoryService = userDirectoryService;
   }
 
   /**
    * Sets a reference to the organization directory service.
    *
    * @param organizationDirectory
    *          the organization directory
    */
   @Reference
   public void setOrganizationDirectoryService(OrganizationDirectoryService organizationDirectory) {
     this.organizationDirectory = organizationDirectory;
   }
 
   /**
    * @see org.opencastproject.job.api.AbstractJobProducer#getOrganizationDirectoryService()
    */
   @Override
   protected OrganizationDirectoryService getOrganizationDirectoryService() {
     return organizationDirectory;
   }
 
   /**
    * @see org.opencastproject.job.api.AbstractJobProducer#getSecurityService()
    */
   @Override
   protected SecurityService getSecurityService() {
     return securityService;
   }
 
   /**
    * @see org.opencastproject.job.api.AbstractJobProducer#getServiceRegistry()
    */
   @Override
   protected ServiceRegistry getServiceRegistry() {
     return serviceRegistry;
   }
 
   /**
    * @see org.opencastproject.job.api.AbstractJobProducer#getUserDirectoryService()
    */
   @Override
   protected UserDirectoryService getUserDirectoryService() {
     return userDirectoryService;
   }
 
   @Modified
   public void modified(Map<String, Object> properties) {
     if (properties == null) {
       logger.info("No configuration available, using defaults");
       properties = Map.of();
     }
 
     logger.info("Configuring SearchServiceImpl");
     addJobLoad = LoadUtil.getConfiguredLoadValue(properties, ADD_JOB_LOAD_KEY, DEFAULT_ADD_JOB_LOAD, serviceRegistry);
     deleteJobLoad = LoadUtil.getConfiguredLoadValue(
         properties, DELETE_JOB_LOAD_KEY, DEFAULT_DELETE_JOB_LOAD, serviceRegistry);
   }
 
   @Override
   public List<Pattern> getProtectedUrlPattern() {
     return Collections.singletonList(staticFilePattern);
   }
 
   private boolean loadUrlAccess(final String mediaPackageId) {
     logger.debug("Check if user `{}` has access to media package `{}`", securityService.getUser(), mediaPackageId);
     try {
       persistence.getMediaPackage(mediaPackageId);
     } catch (NotFoundException | SearchServiceDatabaseException | UnauthorizedException e) {
       return false;
     }
     return true;
   }
 
   @Override
   public boolean verifyUrlAccess(final String path) {
     // Always allow access for admin
     final User user = securityService.getUser();
     if (user.hasRole(GLOBAL_ADMIN_ROLE)) {
       logger.debug("Allow access for admin `{}`", user);
       return true;
     }
 
     // Check pattern
     final Matcher m = staticFilePattern.matcher(path);
     if (!m.matches()) {
       logger.debug("Path does not match pattern. Preventing access.");
       return false;
     }
 
     // Check organization
     final String organizationId = m.group(1);
     if (!securityService.getOrganization().getId().equals(organizationId)) {
       logger.debug("The user's organization does not match. Preventing access.");
       return false;
     }
 
     // Check search index/cache
     final String mediaPackageId = m.group(2);
     final boolean access = cache.getUnchecked(Tuple.tuple(user, mediaPackageId));
     logger.debug("Check if user `{}` has access to media package `{}` using cache: {}", user, mediaPackageId, access);
     return access;
   }
 }