/*

  * 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.any23.validator.rule;

 import org.apache.any23.validator.DOMDocument;

 import org.apache.any23.validator.Rule;

 import org.apache.any23.validator.RuleContext;

 import org.apache.any23.validator.ValidationReport;

 import org.apache.any23.validator.ValidationReportBuilder;

 import org.w3c.dom.Node;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.util.ArrayList;

 import java.util.List;

 /**

  * This rule is able to detect whether an about value is a valid URL

  * or otherwise is a valid relative URL.

  *

  * @author Michele Mostarda (mostarda@fbk.eu)

  * @author Davide Palmisano (palmisano@fbk.eu)

  */

 public class AboutNotURIRule implements Rule {

     public static final String NODES_WITH_INVALID_ABOUT = "nodes-with-invalid-about";

     public String getHRName() {

         return "about-not-uri-rule";

     }

     public boolean applyOn(

             DOMDocument document,

             RuleContext context,

             ValidationReportBuilder validationReportBuilder

     ) {

         final List<Node> nodesWithAbout = document.getNodesWithAttribute("about");

         final List<Node> nodesWithInvalidAbout = new ArrayList<Node>();

         for(Node nodeWithAbout : nodesWithAbout) {

             if ( ! aboutIsValid(nodeWithAbout) ) {

                 validationReportBuilder.reportIssue(

                         ValidationReport.IssueLevel.error,

                         "Invalid about value for node, expected valid URL.",

                         nodeWithAbout

                 );

                 nodesWithInvalidAbout.add(nodeWithAbout);

             }

         }

         if(nodesWithInvalidAbout.isEmpty()) {

             return false;

         }

         context.putData(NODES_WITH_INVALID_ABOUT, nodesWithInvalidAbout);

         return true;

     }

     private boolean aboutIsValid(Node n) {

         final String aboutContent = n.getAttributes().getNamedItem("about").getTextContent();

         if( isURL(aboutContent) ) {

             return true;

         }

         final char firstChar = aboutContent.charAt(0);

         return firstChar == '#' || firstChar == '/';

     }

     private boolean isURL(String candidateURIStr) {

         try {

             new URL(candidateURIStr);

         } catch (MalformedURLException murle) {

             return false;

         }

         return true;

     }

 }