/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache 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://www.apache.org/licenses/LICENSE-2.0
   *
   * 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.apache.syncope.core.persistence.jpa.content;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Properties;
  import javax.sql.DataSource;
  import javax.xml.XMLConstants;
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.parsers.SAXParser;
  import javax.xml.parsers.SAXParserFactory;
  import org.apache.syncope.core.persistence.api.content.ContentLoader;
  import org.apache.syncope.core.persistence.jpa.entity.JPARealm;
  import org.apache.syncope.core.spring.ApplicationContextProvider;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.core.env.Environment;
  import org.springframework.core.io.Resource;
  import org.springframework.core.io.support.PropertiesLoaderUtils;
  import org.springframework.dao.DataAccessException;
  import org.springframework.jdbc.core.JdbcTemplate;
  import org.springframework.orm.jpa.EntityManagerFactoryUtils;
  import org.xml.sax.SAXException;
  
  /**
   * Initialize Database with default content if no data is present already.
   */
  public class XMLContentLoader implements ContentLoader {
  
      protected static final Logger LOG = LoggerFactory.getLogger(XMLContentLoader.class);
  
      protected final Resource viewsXML;
  
      protected final Resource indexesXML;
  
      protected final Environment env;
  
      public XMLContentLoader(
              final Resource viewsXML,
              final Resource indexesXML,
              final Environment env) {
  
          this.viewsXML = viewsXML;
          this.indexesXML = indexesXML;
          this.env = env;
      }
  
      @Override
      public int getOrder() {
          return 400;
      }
  
      @Override
      public void load(final String domain, final DataSource datasource) {
          LOG.debug("Loading data for domain [{}]", domain);
  
          // create EntityManager so OpenJPA will build the SQL schema
          EntityManagerFactoryUtils.findEntityManagerFactory(
                  ApplicationContextProvider.getBeanFactory(), domain).createEntityManager();
  
          JdbcTemplate jdbcTemplate = new JdbcTemplate(datasource);
          boolean existingData;
          try {
              existingData = jdbcTemplate.queryForObject("SELECT COUNT(0) FROM " + JPARealm.TABLE, Integer.class) > 0;
          } catch (DataAccessException e) {
              LOG.error("[{}] Could not access table " + JPARealm.TABLE, domain, e);
              existingData = true;
          }
  
          if (existingData) {
              LOG.info("[{}] Data found in the database, leaving untouched", domain);
          } else {
              LOG.info("[{}] Empty database found, loading default content", domain);
  
              try {
                  createViews(domain, datasource);
              } catch (IOException e) {
                  LOG.error("[{}] While creating views", domain, e);
              }
              try {
                  createIndexes(domain, datasource);
              } catch (IOException e) {
                 LOG.error("[{}] While creating indexes", domain, e);
             }
             try {
                 InputStream contentXML = ApplicationContextProvider.getBeanFactory().
                         getBean(domain + "ContentXML", InputStream.class);
                 loadDefaultContent(domain, contentXML, datasource);
             } catch (Exception e) {
                 LOG.error("[{}] While loading default content", domain, e);
             }
         }
     }
 
     protected void loadDefaultContent(
             final String domain, final InputStream contentXML, final DataSource dataSource)
             throws IOException, ParserConfigurationException, SAXException {
 
         SAXParserFactory factory = SAXParserFactory.newInstance();
         factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, Boolean.TRUE);
         factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
         try (contentXML) {
             SAXParser parser = factory.newSAXParser();
             parser.parse(contentXML, new ContentLoaderHandler(dataSource, ROOT_ELEMENT, true, env));
             LOG.debug("[{}] Default content successfully loaded", domain);
         }
     }
 
     protected void createViews(final String domain, final DataSource dataSource) throws IOException {
         LOG.debug("[{}] Creating views", domain);
 
         JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
 
         Properties views = PropertiesLoaderUtils.loadProperties(viewsXML);
         views.stringPropertyNames().stream().sorted().forEach(idx -> {
             LOG.debug("[{}] Creating view {}", domain, views.get(idx).toString());
             try {
                 jdbcTemplate.execute(views.getProperty(idx).replaceAll("\\n", " "));
             } catch (DataAccessException e) {
                 LOG.error("[{}] Could not create view", domain, e);
             }
         });
 
         LOG.debug("Views created");
     }
 
     protected void createIndexes(final String domain, final DataSource dataSource) throws IOException {
         LOG.debug("[{}] Creating indexes", domain);
 
         JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
 
         Properties indexes = PropertiesLoaderUtils.loadProperties(indexesXML);
         indexes.stringPropertyNames().stream().sorted().forEach(idx -> {
             LOG.debug("[{}] Creating index {}", domain, indexes.get(idx).toString());
             try {
                 jdbcTemplate.execute(indexes.getProperty(idx));
             } catch (DataAccessException e) {
                 LOG.error("[{}] Could not create index", domain, e);
             }
         });
 
         LOG.debug("Indexes created");
     }
 }