/**
 * ============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.queries;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.onap.aai.aaf.auth.FileWatcher;
import org.onap.aai.logging.LogFormatTools;
import org.onap.aai.util.AAIConstants;

import org.springframework.beans.factory.annotation.Value;
import javax.annotation.PostConstruct;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

public class GremlinServerSingleton {

    private static Logger logger = LoggerFactory.getLogger(GremlinServerSingleton.class);

    private boolean timerSet;
    private Timer timer;

    private GetCustomQueryConfig queryConfig;

    @Value("${schema.queries.location}")
    private String storedQueriesLocation;

    /**
     * Initializes the gremlin server singleton
     * Loads the configuration of the gremlin server and creates a cluster
     * Loads the gremlin query file into the properties object
     * Then creates a file watcher to watch the file every ten seconds
     * and if there is a change in the file, then reloads the file into
     * the properties object
     *
     */
    @PostConstruct
    public void init() {

    try {
      String filepath = storedQueriesLocation + AAIConstants.AAI_FILESEP + "stored-queries.json";
      Path path = Paths.get(filepath);
      String customQueryConfigJson = new String(Files.readAllBytes(path));


      queryConfig = new GetCustomQueryConfig(customQueryConfigJson);
    } catch (IOException e) {
      logger.error("Error occurred during the processing of query json file: " + LogFormatTools.getStackTop(e));
    }


        TimerTask task = new FileWatcher(new File(storedQueriesLocation)) {
            @Override
            protected void onChange(File file) {
            try {
              String filepath = storedQueriesLocation;
              Path path = Paths.get(filepath);
              String customQueryConfigJson = new String(Files.readAllBytes(path));
              queryConfig = new GetCustomQueryConfig(customQueryConfigJson);
            } catch (IOException e) {
              logger.error("Error occurred during the processing of query json file: " + LogFormatTools.getStackTop(e));
            }
            }
        };

        if (!timerSet) {
            timerSet = true;
            timer = new Timer();
            timer.schedule( task , new Date(), 10000 );
        }

    }

    /**
     * Gets the query using CustomQueryConfig
     * @param key
     * @return
     */
    public String getStoredQueryFromConfig(String key){
      CustomQueryConfig customQueryConfig = queryConfig.getStoredQuery(key);
      if ( customQueryConfig == null ) {
        return null;
      }
      return customQueryConfig.getQuery();
    }

    public CustomQueryConfig getCustomQueryConfig(String key) {
      return queryConfig.getStoredQuery(key);
    }


}