/*-
 * ============LICENSE_START=======================================================
 * ONAP : APP-C
 * ================================================================================
 * Copyright (C) 2017 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.openecomp.sdnc.dg.loader;
import java.io.File;
import java.util.ArrayList;
import java.util.List;

import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class DGXMLGenerator {
    private final static Logger logger = LoggerFactory.getLogger(DGXMLGenerator.class);

    public static String STRING_ENCODING = "utf-8";
    public static String JS_INTERFACE_DG_CONVERTOR = "dgconverter";
    public static String JS_METHOD_GET_NODE_TO_XML = "getNodeToXml";
    public static String GENERATOR_TEMPLATE_FILE = "js/dg_xml2json.js";

    public void generateXMLFromJSON(String jsonPath, String xmlpath, String propertyPath) throws Exception {
        try{
            ScriptEngineManager manager = new ScriptEngineManager();
            ScriptEngine engine = manager.getEngineByName("JavaScript");
            if (!(engine instanceof Invocable)) {
                logger.error("Invoking methods is not supported.");
                return;
            }
            Invocable inv = (Invocable) engine;
            //        engine.eval(new FileReader(DGXMLGenerator.class.getClassLoader().getResource(GENERATOR_TEMPLATE_FILE).getPath()));
            String js = IOUtils.toString(DGXMLGenerator.class.getClassLoader().getResourceAsStream(GENERATOR_TEMPLATE_FILE),STRING_ENCODING);
            engine.eval(js);

            Object dgconverter = engine.get(JS_INTERFACE_DG_CONVERTOR);

            List<File> files = new ArrayList<File>();
            if(dgconverter != null){
                File jsonPathFile = new File(jsonPath);
                if(jsonPathFile.isDirectory()){
                    String[] extensions = new String[] { "json", "JSON" };
                    files = (List<File>) FileUtils.listFiles(jsonPathFile, extensions, true);
                }else if(jsonPathFile.isFile()){
                    files.add(jsonPathFile);
                }else{
                    throw new Exception("Failed to get the nature of the JSON path :"+ jsonPath);
                }

                logger.info("JSON Files identified "+ files.size());

                if(files.size() > 0){
                    boolean isXmlPathDeleted = FileUtils.deleteQuietly(new File(xmlpath));
                    logger.info("Cleaning old DG XML under : " + xmlpath + ", delete status :" + isXmlPathDeleted);

                    for (File file : files) {
                        String dgJson = FileUtils.readFileToString(file,STRING_ENCODING);
                        logger.info("Generating XML from  :" + file.getName());
                        String xmlFileName = xmlpath +"/"+file.getName().replace(".json", ".xml");

                        Object dgXMl = inv.invokeMethod(dgconverter, JS_METHOD_GET_NODE_TO_XML, dgJson);
                        // Write the XML File
                        if(dgXMl != null){
                            File xmlFile = new File(xmlFileName);
                            FileUtils.writeStringToFile(xmlFile, dgXMl.toString(), STRING_ENCODING);
                            logger.info("Generated XML File under  :" + xmlFile.getCanonicalPath());
                        }
                    }

                }else{
                    logger.info("No JSON Files to generate XML");
                }
            }else{
                logger.error("Couldn't get Java Script Engine..");
            }
        }catch (Exception e) {
            logger.error("Failed to generate generateXMLFromJSON :"+e.getMessage());
        }
    }


    public static void main(String[] args) {
        try {
            DGXMLGenerator application = new DGXMLGenerator();
            String jsonPath = null;
            String xmlPath = null;
            String propertyPath = null;
            // Generate, GenerateLoad, GenerateLoadActivate
            //args = new String[]{"src/main/resources/json","src/test/resources/xml"};
            logger.info("DGXML Conversion Started with arguments :"+ args[0] +":"+ args[1]);
            if(args != null && args.length >= 2){
                jsonPath = args[0];
                xmlPath = args[1];
            }else{
                throw new Exception("Sufficient inputs are missing <jsonPath> <xmlPath>");
            }

            application.generateXMLFromJSON(jsonPath, xmlPath, propertyPath);
            logger.info("DGXML Conversion Completed...");
        } catch (Exception e) {
            logger.error("Failed in DG XML Generation :"+e.getMessage());
            e.printStackTrace();
        }

    }

}