/*-
 * ============LICENSE_START=======================================================
 * org.openecomp.aai
 * ================================================================================
 * 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.aai.dbmap;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.lang.exception.ExceptionUtils;
import org.apache.tinkerpop.gremlin.structure.io.IoCore;

import org.openecomp.aai.dbgen.SchemaGenerator;
import org.openecomp.aai.exceptions.AAIException;
import org.openecomp.aai.util.AAIConstants;
import com.att.eelf.configuration.EELFLogger;
import com.att.eelf.configuration.EELFManager;
import com.thinkaurelius.titan.core.TitanFactory;
import com.thinkaurelius.titan.core.TitanGraph;
import com.thinkaurelius.titan.core.TitanTransaction;
import com.thinkaurelius.titan.core.schema.TitanManagement;

/**
 * Database Mapping class which acts as the middle man between the REST
 * interface objects and Titan DB objects. This class provides methods to commit
 * the objects received on the REST interface into the Titan graph database as
 * vertices and edges. Transactions are also managed here by using a TitanGraph
 * object to load, commit/rollback and shutdown for each request. The data model
 * rules such as keys/required properties are handled by calling DBMeth methods
 * which are driven by a specification file in json.
 * 
 
 */
public class AAIGraph {

	protected Map<String, TitanGraph> graphs = new HashMap<>();
	protected static final String COMPONENT = "aaidbmap";
	private final String REALTIME_DB = "realtime";
	private final String CACHED_DB = "cached";
	private final EELFLogger logger = EELFManager.getInstance().getLogger(this.getClass().getSimpleName());


	/**
	 * Instantiates a new AAI graph.
	 */
	private AAIGraph() {
		try {
			String rtConfig = System.getProperty("realtime.db.config");
			String cachedConfig = System.getProperty("cached.db.config");
			if (rtConfig == null) {
				rtConfig = AAIConstants.REALTIME_DB_CONFIG;
			}
			if (cachedConfig == null) {
				cachedConfig = AAIConstants.CACHED_DB_CONFIG;
			}
			this.loadGraph(REALTIME_DB, rtConfig);
			this.loadGraph(CACHED_DB, cachedConfig);
		} catch (Exception e) {
			throw new RuntimeException("Failed to instantiate graphs", e);
		}
	}
	
	private static class Helper {
		private static final AAIGraph INSTANCE = new AAIGraph();
	}
	
	/**
	 * Gets the single instance of AAIGraph.
	 *
	 * @return single instance of AAIGraph
	 */
	public static AAIGraph getInstance() {
		return Helper.INSTANCE;
	}
	
	private void loadGraph(String name, String configPath) throws AAIException {
		try {
			final TitanGraph graph = TitanFactory.open(configPath);
			InputStream is = new FileInputStream(configPath);
	        Properties graphProps = new Properties();
	        graphProps.load(is);
	        
			if (graphProps.get("storage.backend").equals("inmemory")) { 
				// Load the propertyKeys, indexes and edge-Labels into the DB
				loadSchema(graph);
				if (graphProps.containsKey("load.snapshot.file")) {
					String value = graphProps.getProperty("load.snapshot.file");
					if ("true".equals(value)) {
						try {
							String location = System.getProperty("snapshot.location");
							logAndPrint(logger, "Loading snapshot to inmemory graph.");
							TitanTransaction transaction = graph.newTransaction();
							transaction.io(IoCore.graphson()).readGraph(location);
							transaction.commit();
							logAndPrint(logger, "Snapshot loaded to inmemory graph.");
						} catch (IOException e) {
							graph.close();
							logAndPrint(logger, "ERROR: Could not load datasnapshot to in memory graph. \n" + ExceptionUtils.getFullStackTrace(e));
							System.exit(0);
						}
					}
				}
			}
			
			if (graph == null) {
				throw new AAIException("AAI_5102");
			}
			
			graphs.put(name, graph);
		} catch (FileNotFoundException fnfe) {
			throw new AAIException("AAI_4001");
	    } catch (IOException e) {
			throw new AAIException("AAI_4002");

	    }
	}
	
	private void loadSchema(TitanGraph graph) {
		// Load the propertyKeys, indexes and edge-Labels into the DB
		TitanManagement graphMgt = graph.openManagement();
		
		System.out.println("-- loading schema into Titan");
		SchemaGenerator.loadSchemaIntoTitan( graph, graphMgt );
	}

	/**
	 * Graph shutdown.
	 */
	public void graphShutdown() {
		graphs.get(REALTIME_DB).close();
	}

	/**
	 * Gets the graph.
	 *
	 * @return the graph
	 */
	public TitanGraph getGraph() {
		return graphs.get(REALTIME_DB);
	}
	
	public void graphShutdown(DBConnectionType connectionType) {
		
		graphs.get(this.getGraphName(connectionType)).close();
	}
	
	public TitanGraph getGraph(DBConnectionType connectionType) {
		return graphs.get(this.getGraphName(connectionType));
	}
	
	private String getGraphName(DBConnectionType connectionType) {
		String graphName = "";
		if (DBConnectionType.CACHED.equals(connectionType)) {
			graphName = this.CACHED_DB;
		} else if (DBConnectionType.REALTIME.equals(connectionType)) {
			graphName = this.REALTIME_DB;
		}
		
		return graphName;
	}
	
	private void logAndPrint(EELFLogger logger, String msg) {
		System.out.println(msg);
		logger.info(msg);
	}
}