/*
    * 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.frontend.xeditor.validation;
  
  import org.jaxen.JaxenException;
  import org.jdom2.JDOMException;
  import org.mycore.common.xml.MCRXPathBuilder;
  import org.mycore.common.xml.MCRXPathEvaluator;
  import org.mycore.frontend.xeditor.MCRBinding;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  
  import java.util.List;
  
  public abstract class MCRValidator {
  
      private static final String ATTR_RELEVANT_IF = "relevant-if";
  
      private Node ruleElement;
  
      protected String xPath;
      protected String relevantIfXPath;
  
      public void init(String baseXPath, Node ruleElement) {
          Node relativeXPath = ruleElement.getAttributes().getNamedItem("xpath");
          this.xPath = relativeXPath != null ? relativeXPath.getNodeValue() : baseXPath;
          this.ruleElement = ruleElement;
  
          if (hasRequiredAttributes()) {
              relevantIfXPath = getAttributeValue(ATTR_RELEVANT_IF);
              configure();
          }
      }
  
      public abstract boolean hasRequiredAttributes();
  
      /** If validator uses properties to configure its behavior, override this */
      public void configure() {
          // empty
      }
  
      public Node getRuleElement() {
          return ruleElement;
      }
  
      public String getAttributeValue(String name) {
          NamedNodeMap attributes = ruleElement.getAttributes();
          Node attribute = attributes.getNamedItem(name);
          return attribute == null ? null : attribute.getNodeValue();
      }
  
      public boolean hasAttributeValue(String name) {
          return (getAttributeValue(name) != null);
      }
  
      public boolean validate(MCRValidationResults results, MCRBinding root) throws JaxenException, JDOMException {
          MCRBinding binding = new MCRBinding(xPath, false, root);
          boolean isValid = validateBinding(results, binding);
          binding.detach();
          return isValid;
      }
  
      public boolean validateBinding(MCRValidationResults results, MCRBinding binding) {
          boolean isValid = true; // all nodes must validate
  
          List<Object> boundNodes = binding.getBoundNodes();
          for (int i = 0; i < boundNodes.size(); i++) {
              Object node = boundNodes.get(i);
  
              String absPath = MCRXPathBuilder.buildXPath(node);
              if (results.hasError(absPath)) {
                  continue;
              }
  
              MCRBinding nodeBinding = new MCRBinding(i + 1, binding);
              if (!isRelevant(nodeBinding)) {
                  continue;
              }
  
              String value = MCRBinding.getValue(node);
              if (value.isEmpty()) {
                  continue;
              }
 
             boolean result = isValid(value);
             results.mark(absPath, result, this);
             isValid = isValid && result;
         }
         return isValid;
     }
 
     protected boolean isRelevant(MCRBinding binding) {
         if (null == relevantIfXPath) {
             return true;
         } else {
             MCRXPathEvaluator evaluator = binding.getXPathEvaluator();
             boolean isRelevant = evaluator.test(relevantIfXPath);
             binding.detach();
             return isRelevant;
         }
     }
 
     protected boolean isValid(String value) {
         return true;
     }
 }