/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Licensed 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.
 * ============LICENSE_END=========================================================
 */
package org.onap.aai.schemaservice.nodeschema.validation;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import org.onap.aai.schemaservice.nodeschema.SchemaVersion;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.List;

/**
 * Default duplicate rules for A&AI -
 * node types may never have a duplicate definition
 * within the same Version's file set.
 *
 * Finds all duplicates and what files they're in.
 *
 */
public class DefaultDuplicateNodeDefinitionValidationModule implements DuplicateNodeDefinitionValidationModule {

  /* (non-Javadoc)
   * @see org.onap.aai.nodes.validation.DuplicateNodeDefinitionValidationModule#findDuplicates(java.util.List)
   */
  @Override
  public String findDuplicates(List<String> files, SchemaVersion v) {
    try {
      final DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
      docFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
            docFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
            docFactory.setFeature("http://xml.org/sax/features/external-general-entities", false);
            docFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
            docFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
            docFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
      final DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

      Multimap<String, String> types = ArrayListMultimap.create();
      boolean foundDups = false;
      for (String file : files) {
        InputStream inputStream = new FileInputStream(file);
        final Document doc = docBuilder.parse(inputStream);
        final NodeList list = doc.getElementsByTagName("java-type");

        for (int i = 0; i < list.getLength(); i++) {
          String type = list.item(i).getAttributes().getNamedItem("name").getNodeValue();
          if (types.containsKey(type)) {
            foundDups = true;
          }
          types.put(type, file);
        }
      }

      if (foundDups) {
        return buildErrorMsg(types, v);
      } else {
        return "";
      }
    } catch (ParserConfigurationException | SAXException | IOException e) {
      // TODO something useful with this information
      return e.getMessage();
    }
  }

  private String buildErrorMsg(Multimap<String, String> types, SchemaVersion v) {
    StringBuilder errorMsg = new StringBuilder().append("Duplicates found in version ").append(v.toString()).append(". ");
    for (String nodeType : types.keySet()) {
      Collection<String> files = types.get(nodeType);
      if (files.size() == 1) {
        continue; //only record the duplicated ones
      }
      errorMsg.append(nodeType).append(" has definitions in ");
      for (String file : files) {
        errorMsg.append(file).append(" ");
      }
    }
    return errorMsg.toString();
  }

}