/**
    * This file Copyright (c) 2016-2018 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.delta;
  
  import static java.util.stream.Collectors.joining;
  
  import info.magnolia.cms.util.QueryUtil;
  import info.magnolia.jcr.function.NodeFunctions;
  import info.magnolia.jcr.util.NodeUtil;
  import info.magnolia.module.InstallContext;
  
  import java.util.List;
  import java.util.function.Function;
  import java.util.function.Predicate;
  
  import javax.jcr.Node;
  import javax.jcr.RepositoryException;
  import javax.jcr.query.Query;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.google.common.collect.Lists;
  
  /**
   * Displays user a warning message based on the query statement and workspace passed in.
   *
   * <p>A warning is displayed <b>only</b> if there is at least one node found by given query.</p>
   */
  public class QueryElementsAndDisplayWarningTask extends AbstractRepositoryTask {
  
      private static final Logger log = LoggerFactory.getLogger(QueryElementsAndDisplayWarningTask.class);
  
      private final String workspace;
      private final String queryStatement;
      private final String nodeType;
      private final String baseMessageFormat;
      private final List<String> exclusionLists;
  
      /**
       * Default constructor.
       *
       * @param name Name of the task
       * @param description Description of the task
       * @param workspace Name of the workspace to search in
       * @param queryStatement Full query statement
       * @param nodeType The node type of the nodes to aggregate; provide {@code null} to display every item
       * @param baseMessageFormat The message format to be displayed, make sure to provide it with a {@code %s} placeholder, e.g. {@code "Message start\n%s\nMessage end."}
       * @param exclusionLists A list of paths to exclude from being mentioned in warning
       */
      public QueryElementsAndDisplayWarningTask(String name, String description, String workspace, String queryStatement, String nodeType, String baseMessageFormat, List<String> exclusionLists) {
          super(name, description);
          this.workspace = workspace;
          this.queryStatement = queryStatement;
          this.baseMessageFormat = baseMessageFormat;
          this.exclusionLists = exclusionLists;
          this.nodeType = nodeType;
      }
  
      public QueryElementsAndDisplayWarningTask(String name, String description, String workspace, String queryStatement, String baseMessageFormat, List<String> exclusionLists) {
          this(name, description, workspace, queryStatement, null, baseMessageFormat, exclusionLists);
      }
  
      @SuppressWarnings("unchecked")
      @Override
      protected void doExecute(InstallContext installContext) throws RepositoryException, TaskExecutionException {
          List<Node> nodes = Lists.newArrayList(QueryUtil.search(workspace, queryStatement, Query.JCR_SQL2));
  
         String matchingPaths = nodes.stream()
                 .map(nodeType == null ? NodeFunctions::toPath : toPathOfNearestAncestorOf(nodeType))
                 .filter(filterPaths(exclusionLists))
                 .distinct()
                 .collect(joining("\n"));
 
         if (!matchingPaths.isEmpty()) {
             String message = String.format(baseMessageFormat, matchingPaths);
             installContext.warn(message);
         }
     }
 
     private Function<Node, String> toPathOfNearestAncestorOf(final String nodeType) {
         return node -> {
             try {
                 Node nearestNode = NodeUtil.getNearestAncestorOfType(node, nodeType);
                 return nearestNode != null ? nearestNode.getPath() : node.getPath();
             } catch (RepositoryException e) {
                 log.warn("An error occurred when trying to get the nearest ancestor of type {} for node {}.", nodeType, node, e);
                 return null;
             }
         };
     }
 
     private Predicate<String> filterPaths(final List<String> exclusionLists) {
         return path -> {
             for (String exclusionPath : exclusionLists) {
                 if (path.equals(exclusionPath)) {
                     return false;
                 }
             }
             return true;
         };
     }
 }