/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.pi.purl;
  
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Optional;
  import java.util.function.Consumer;
  
  import org.mycore.backend.jpa.MCREntityManagerProvider;
  import org.mycore.datamodel.metadata.MCRBase;
  import org.mycore.datamodel.metadata.MCRObjectID;
  import org.mycore.pi.MCRPIJobService;
  import org.mycore.pi.backend.MCRPI;
  import org.mycore.pi.exceptions.MCRPersistentIdentifierException;
  
  public class MCRPURLService extends MCRPIJobService<MCRPURL> {
  
      private static final String TYPE = "purl";
  
      private static final String CONTEXT_PURL = "PURL";
  
      private static final String CONTEXT_OBJECT = "ObjectID";
  
      private static final String PURL_SERVER_CONFIG = "Server";
  
      private static final String PURL_USER_CONFIG = "Username";
  
      private static final String PURL_PASSWORD_CONFIG = "Password";
  
      private static final String PURL_BASE_URL = "RegisterBaseURL";
  
      private static final String PURL_CONTEXT_CONFIG = "RegisterURLContext";
  
      private static final String PURL_MAINTAINER_CONFIG = "Maintainer";
  
      private static final String DEFAULT_CONTEXT_PATH = "receive/$ID";
  
      public MCRPURLService() {
          super(TYPE);
      }
  
      @Override
      public void registerJob(Map<String, String> parameters) throws MCRPersistentIdentifierException {
          MCRPURL purl = getPURLFromJob(parameters);
          String idString = parameters.get(CONTEXT_OBJECT);
          validateJobUserRights(MCRObjectID.getInstance(idString));
  
          doWithPURLManager(
              manager -> manager
                  .registerNewPURL(purl.getUrl().getPath(), buildTargetURL(idString), "302", getProperties().getOrDefault(
                      PURL_MAINTAINER_CONFIG, "test")));
          this.updateStartRegistrationDate(MCRObjectID.getInstance(idString), "", new Date());
      }
  
      protected String buildTargetURL(String objId) {
          String baseURL = getProperties().get(PURL_BASE_URL);
          return baseURL + getProperties().getOrDefault(PURL_CONTEXT_CONFIG, DEFAULT_CONTEXT_PATH)
              .replaceAll("\\$[iI][dD]", objId);
  
      }
  
      @Override
      protected Optional<String> getJobInformation(Map<String, String> contextParameters) {
          return Optional.empty();
      }
  
      private MCRPURL getPURLFromJob(Map<String, String> parameters)
          throws MCRPersistentIdentifierException {
          String purlString = parameters.get(CONTEXT_PURL);
  
          try {
              return new MCRPURL(new URL(purlString));
          } catch (MalformedURLException e) {
              throw new MCRPersistentIdentifierException("Cannot parse " + purlString);
          }
      }
  
      @Override
      public void updateJob(Map<String, String> parameters) throws MCRPersistentIdentifierException {
         String purlString = parameters.get(CONTEXT_PURL);
         String objId = parameters.get(CONTEXT_OBJECT);
 
         validateJobUserRights(MCRObjectID.getInstance(objId));
         MCRPURL purl;
 
         try {
             purl = new MCRPURL(
                 new URL(purlString));
         } catch (MalformedURLException e) {
             throw new MCRPersistentIdentifierException("Could not parse purl: " + purlString, e);
         }
 
         doWithPURLManager((purlManager) -> {
             if (!purlManager.isPURLTargetURLUnchanged(purl.getUrl().toString(), buildTargetURL(
                 objId))) {
                 purlManager.updateExistingPURL(purl.getUrl().getPath(), buildTargetURL(objId), "302",
                     getProperties().getOrDefault(
                         PURL_MAINTAINER_CONFIG, "test"));
             }
         });
     }
 
     @Override
     public void deleteJob(Map<String, String> parameters) {
         // deleting ist not supported
     }
 
     @Override
     public MCRPI insertIdentifierToDatabase(MCRBase obj, String additional,
         MCRPURL identifier) {
         Date registrationStarted = null;
         if (getRegistrationPredicate().test(obj)) {
             registrationStarted = new Date();
             startRegisterJob(obj, identifier);
         }
 
         MCRPI databaseEntry = new MCRPI(identifier.asString(), getType(), obj.getId().toString(), additional,
             this.getServiceID(), provideRegisterDate(obj, additional), registrationStarted);
         MCREntityManagerProvider.getCurrentEntityManager().persist(databaseEntry);
         return databaseEntry;
     }
 
     @Override
     protected void registerIdentifier(MCRBase obj, String additional, MCRPURL purl)
         throws MCRPersistentIdentifierException {
         if (!"".equals(additional)) {
             throw new MCRPersistentIdentifierException(
                 getClass().getName() + " doesn't support additional information! (" + additional + ")");
         }
     }
 
     @Override
     protected void delete(MCRPURL identifier, MCRBase obj, String additional)
         throws MCRPersistentIdentifierException {
         // not supported
     }
 
     @Override
     protected void update(MCRPURL purl, MCRBase obj, String additional)
         throws MCRPersistentIdentifierException {
         if (isRegistered(obj.getId(), additional)) {
             startUpdateJob(obj, purl);
         } else if (!hasRegistrationStarted(obj.getId(), additional)
             && getRegistrationPredicate().test(obj)) {
             this.updateStartRegistrationDate(obj.getId(), "", new Date());
             startRegisterJob(obj, purl);
         }
     }
 
     private void startUpdateJob(MCRBase obj, MCRPURL purl) {
         HashMap<String, String> contextParameters = new HashMap<>();
         contextParameters.put(CONTEXT_PURL, purl.asString());
         contextParameters.put(CONTEXT_OBJECT, obj.getId().toString());
         this.addUpdateJob(contextParameters);
     }
 
     private void startRegisterJob(MCRBase obj, MCRPURL purl) {
         HashMap<String, String> contextParameters = new HashMap<>();
         contextParameters.put(CONTEXT_PURL, purl.asString());
         contextParameters.put(CONTEXT_OBJECT, obj.getId().toString());
         this.addRegisterJob(contextParameters);
     }
 
     protected void doWithPURLManager(Consumer<MCRPURLManager> action) {
         Map<String, String> props = getProperties();
         String serverURL = props.get(PURL_SERVER_CONFIG);
         String username = props.get(PURL_USER_CONFIG);
         String password = props.get(PURL_PASSWORD_CONFIG);
 
         MCRPURLManager manager = new MCRPURLManager();
         manager.login(serverURL, username, password);
 
         try {
             action.accept(manager);
         } finally {
             manager.logout();
         }
     }
 }