/*
    * 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.serviceregistry.impl;
  
  import static org.opencastproject.db.Queries.namedQuery;
  import static org.opencastproject.util.data.Monadics.mlist;
  import static org.opencastproject.util.data.Option.none;
  import static org.opencastproject.util.data.Option.option;
  
  import org.opencastproject.db.DBSession;
  import org.opencastproject.job.api.Incident;
  import org.opencastproject.job.api.IncidentImpl;
  import org.opencastproject.job.api.IncidentTree;
  import org.opencastproject.job.api.IncidentTreeImpl;
  import org.opencastproject.job.api.Job;
  import org.opencastproject.serviceregistry.api.IncidentL10n;
  import org.opencastproject.serviceregistry.api.IncidentService;
  import org.opencastproject.serviceregistry.api.IncidentServiceException;
  import org.opencastproject.serviceregistry.api.ServiceRegistry;
  import org.opencastproject.serviceregistry.api.ServiceRegistryException;
  import org.opencastproject.util.NotFoundException;
  import org.opencastproject.util.data.Collections;
  import org.opencastproject.util.data.Function;
  import org.opencastproject.util.data.Option;
  import org.opencastproject.util.data.Tuple;
  import org.opencastproject.util.data.functions.Functions;
  import org.opencastproject.util.data.functions.Strings;
  import org.opencastproject.workflow.api.WorkflowOperationInstance;
  import org.opencastproject.workflow.api.WorkflowOperationInstance.OperationState;
  import org.opencastproject.workflow.api.WorkflowService;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.ArrayList;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Optional;
  import java.util.stream.Collectors;
  
  public abstract class AbstractIncidentService implements IncidentService {
    public static final String PERSISTENCE_UNIT_NAME = "org.opencastproject.serviceregistry";
  
    public static final String NO_TITLE = "-";
    public static final String NO_DESCRIPTION = "-";
    public static final String FIELD_TITLE = "title";
    public static final String FIELD_DESCRIPTION = "description";
  
    /** The logging instance */
    private static final Logger logger = LoggerFactory.getLogger(AbstractIncidentService.class);
  
    protected abstract ServiceRegistry getServiceRegistry();
  
    protected abstract WorkflowService getWorkflowService();
  
    protected abstract DBSession getDBSession();
  
    @Override
    public Incident storeIncident(Job job, Date timestamp, String code, Incident.Severity severity,
            Map<String, String> descriptionParameters, List<Tuple<String, String>> details)
            throws IncidentServiceException, IllegalStateException {
      try {
        job = getServiceRegistry().getJob(job.getId());
  
        final IncidentDto dto = getDBSession().execTx(namedQuery.persist(
            IncidentDto.mk(job.getId(), timestamp, code, severity, descriptionParameters, details)
        ));
        return toIncident(job, dto);
      } catch (NotFoundException e) {
        throw new IllegalStateException("Can't create incident for not-existing job");
      } catch (Exception e) {
        logger.error("Could not store job incident: {}", e.getMessage());
        throw new IncidentServiceException(e);
      }
    }
  
   @Override
   public Incident getIncident(long id) throws IncidentServiceException, NotFoundException {
     Optional<IncidentDto> dto = getDBSession().execTx(namedQuery.findByIdOpt(IncidentDto.class, id));
     if (dto.isPresent()) {
       final Job job = findJob(dto.get().getJobId());
       if (job != null) {
         return toIncident(job, dto.get());
       }
     }
     throw new NotFoundException();
   }
 
   @Override
   public List<Incident> getIncidentsOfJob(List<Long> jobIds) throws IncidentServiceException {
     List<Incident> incidents = new ArrayList<>();
     for (long jobId : jobIds) {
       try {
         incidents.addAll(getIncidentsOfJob(jobId));
       } catch (NotFoundException ignore) {
       }
     }
     return incidents;
   }
 
   @Override
   public IncidentTree getIncidentsOfJob(long jobId, boolean cascade) throws NotFoundException, IncidentServiceException {
     List<Incident> incidents = getIncidentsOfJob(jobId);
     List<IncidentTree> childIncidents = new ArrayList<>();
 
     try {
       Job job = getServiceRegistry().getJob(jobId);
       if (cascade && !"START_WORKFLOW".equals(job.getOperation())) {
         childIncidents = getChildIncidents(jobId);
       } else if (cascade && "START_WORKFLOW".equals(job.getOperation())) {
         for (WorkflowOperationInstance operation : getWorkflowService().getWorkflowById(jobId).getOperations()) {
           if (operation.getState().equals(OperationState.INSTANTIATED))
             continue;
           IncidentTree operationResult = getIncidentsOfJob(operation.getId(), true);
           if (hasIncidents(Collections.list(operationResult)))
             childIncidents.add(operationResult);
         }
       }
       return new IncidentTreeImpl(incidents, childIncidents);
     } catch (NotFoundException ignore) {
       // Workflow deleted
       return new IncidentTreeImpl(incidents, childIncidents);
     } catch (Exception e) {
       logger.error("Error loading child jobs of: {}", jobId);
       throw new IncidentServiceException(e);
     }
   }
 
   private boolean hasIncidents(List<IncidentTree> incidentResults) {
     for (IncidentTree result : incidentResults) {
       if (result.getIncidents().size() > 0 || hasIncidents(result.getDescendants()))
         return true;
     }
     return false;
   }
 
   @Override
   public IncidentL10n getLocalization(long id, Locale locale) throws IncidentServiceException, NotFoundException {
     final Incident incident = getIncident(id);
 
     final List<String> loc = localeToList(locale);
     // check if cache map is empty
     // fill cache from
     final String title = findText(loc, incident.getCode(), FIELD_TITLE).getOrElse(NO_TITLE);
     final String description = findText(loc, incident.getCode(), FIELD_DESCRIPTION).map(
             replaceVarsF(incident.getDescriptionParameters())).getOrElse(NO_DESCRIPTION);
     return new IncidentL10n() {
       @Override
       public String getTitle() {
         return title;
       }
 
       @Override
       public String getDescription() {
         return description;
       }
     };
   }
 
   /**
    * Find a localization text in the database. The keys to look for are made from the locale, the incident code and the
    * type.
    *
    * @param locale
    *          The locale as a list. See {@link AbstractIncidentService#localeToList(java.util.Locale)}
    * @param incidentCode
    *          The incident code. See {@link org.opencastproject.job.api.Incident#getCode()}
    * @param field
    *          The field, e.g. "title" or "description"
    * @return the found text wrapped in an option
    */
   private Option<String> findText(List<String> locale, String incidentCode, String field) {
     final List<String> keys = genDbKeys(locale, incidentCode + "." + field);
     for (String key : keys) {
       final Option<String> text = getText(key);
       if (text.isSome()) {
         return text;
       }
     }
     return none();
   }
 
   private final Map<String, String> textCache = new HashMap<>();
 
   /** Get a text. */
   private Option<String> getText(String key) {
     synchronized (textCache) {
       if (textCache.isEmpty()) {
         textCache.putAll(fetchTextsFromDb());
       }
     }
     return option(textCache.get(key));
   }
 
   /** Fetch all localizations from the database. */
   private Map<String, String> fetchTextsFromDb() {
     final Map<String, String> locs = new HashMap<String, String>();
     for (IncidentTextDto a : getDBSession().execTx(IncidentTextDto.findAllQuery)) {
       locs.put(a.getId(), a.getText());
     }
     return locs;
   }
 
   private List<IncidentTree> getChildIncidents(long jobId) throws NotFoundException, ServiceRegistryException,
           IncidentServiceException {
     List<Job> childJobs = getServiceRegistry().getChildJobs(jobId);
     List<IncidentTree> incidentResults = new ArrayList<>();
     for (Job childJob : childJobs) {
       if (childJob.getParentJobId() != jobId)
         continue;
       List<Incident> incidentsForJob = getIncidentsOfJob(childJob.getId());
       IncidentTree incidentTree = new IncidentTreeImpl(incidentsForJob, getChildIncidents(childJob.getId()));
       if (hasIncidents(Collections.list(incidentTree)))
         incidentResults.add(incidentTree);
     }
     return incidentResults;
   }
 
   private List<Incident> getIncidentsOfJob(long jobId) throws NotFoundException, IncidentServiceException {
     final Job job = findJob(jobId);
     try {
       return getDBSession().execTx(IncidentDto.findByJobIdQuery(jobId)).stream()
           .map(i -> toIncident(job, i))
           .collect(Collectors.toList());
     } catch (Exception e) {
       logger.error("Could not retrieve incidents of job '{}': {}", job.getId(), e.getMessage());
       throw new IncidentServiceException(e);
     }
   }
 
   private Job findJob(long jobId) throws NotFoundException, IncidentServiceException {
     try {
       return getServiceRegistry().getJob(jobId);
     } catch (NotFoundException e) {
       logger.info("Job with Id {} does not exist", jobId);
       throw e;
     } catch (ServiceRegistryException e) {
       logger.error("Could not retrieve job {}: {}", jobId, e.getMessage());
       throw new IncidentServiceException(e);
     }
   }
 
   private static Incident toIncident(Job job, IncidentDto dto) {
     return new IncidentImpl(dto.getId(), job.getId(), job.getJobType(), job.getProcessingHost(), dto.getTimestamp(),
             dto.getSeverity(), dto.getCode(), dto.getTechnicalInformation(), dto.getParameters());
   }
 
   /**
    * Create a list of localization database keys from a base key and a locale split into its part, e.g. ["de", "DE"] or
    * ["en"]. The returned list starts with the most specific key getting more common, e.g.
    * ["org.opencastproject.composer.1.title.de.DE", "org.opencastproject.composer.1.title.de",
    * "org.opencastproject.composer.1.title"]
    */
   public static List<String> genDbKeys(List<String> locale, String base) {
     List<String> result = new LinkedList<>();
     StringBuilder key = new StringBuilder(base);
     result.add(base);
     for (String s: locale) {
       key.append('.').append(s);
       result.add(0, key.toString());
     }
     return result;
   }
 
   /** Convert a locale into a list of strings, [language, country, variant] */
   public static List<String> localeToList(Locale locale) {
     return mlist(Strings.trimToNone(locale.getLanguage()), Strings.trimToNone(locale.getCountry()),
             Strings.trimToNone(locale.getVariant()))
     // flatten
             .bind(Functions.<Option<String>> identity()).value();
   }
 
   /** Replace variables of the form #{xxx} in a string template. */
   public static String replaceVars(String template, Map<String, String> params) {
     String s = template;
     for (Map.Entry<String, String> e : params.entrySet()) {
       s = s.replace("#{" + e.getKey() + "}", e.getValue());
     }
     return s;
   }
 
   /**
    * {@link org.opencastproject.serviceregistry.impl.AbstractIncidentService#replaceVars(String, java.util.Map)} as a
    * function.
    */
   public static Function<String, String> replaceVarsF(final Map<String, String> params) {
     return new Function<String, String>() {
       @Override
       public String apply(String s) {
         return replaceVars(s, params);
       }
     };
   }
 }