/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 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=========================================================
 *
 * ECOMP is a trademark and service mark of AT&T Intellectual Property.
 */
package org.onap.aai.serialization.engines;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversalSource;
import org.apache.tinkerpop.gremlin.process.traversal.strategy.verification.ReadOnlyStrategy;
import org.apache.tinkerpop.gremlin.structure.Graph;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.onap.aai.dbmap.DBConnectionType;
import org.onap.aai.introspection.Loader;
import org.onap.aai.query.builder.GremlinTraversal;
import org.onap.aai.query.builder.GremlinUnique;
import org.onap.aai.query.builder.QueryBuilder;
import org.onap.aai.query.builder.TraversalQuery;
import org.onap.aai.serialization.db.GraphSingleton;
import org.onap.aai.serialization.engines.query.GraphTraversalQueryEngine;
import org.onap.aai.serialization.engines.query.QueryEngine;

import com.thinkaurelius.titan.core.TitanGraph;
import com.thinkaurelius.titan.core.schema.TitanManagement;

public abstract class TransactionalGraphEngine {
	
	protected GraphSingleton singleton = null;
	protected QueryEngine queryEngine = null;
	protected QueryBuilder<Vertex> queryBuilder = null;
	protected QueryStyle style = null;
	protected final DBConnectionType connectionType;
	protected final Loader loader;
	protected Graph currentTx = null;
	protected GraphTraversalSource currentTraversal = null;
	protected GraphTraversalSource readOnlyTraversal = null;
	private final Admin admin;
	/**
	 * Instantiates a new transactional graph engine.
	 *
	 * @param style the style
	 * @param loader the loader
	 */
	public TransactionalGraphEngine (QueryStyle style, Loader loader, DBConnectionType connectionType, GraphSingleton singleton) {
		this.loader = loader;
		this.style = style;
		this.singleton = singleton;
		this.connectionType = connectionType;
		admin = new Admin();
		
	}
	
	public TransactionalGraphEngine (QueryStyle style, Loader loader) {
		this.loader = loader;
		this.style = style;
		this.connectionType = DBConnectionType.REALTIME;
		admin = new Admin();
	}

	/**
	 * Sets the list property.
	 *
	 * @param v the v
	 * @param name the name
	 * @param obj the obj
	 * @return true, if successful
	 */
	public abstract boolean setListProperty(Vertex v, String name, List<?> obj);
	
	/**
	 * Gets the list property.
	 *
	 * @param v the v
	 * @param name the name
	 * @return the list property
	 */
	public abstract List<Object> getListProperty(Vertex v, String name);
	
	/**
	 * Gets the graph.
	 *
	 * @return the graph
	 */
	private TitanGraph getGraph() {
		return singleton.getTxGraph(this.connectionType);
	}
	
	/**
	 * Gets the count.
	 *
	 * @return the count
	 */
	public AtomicInteger getCount() {
		return singleton.getCount();
	}
	
	
	/**
	 * Gets the query engine.
	 *
	 * @return the query engine
	 */
	public QueryEngine getQueryEngine() {
		QueryEngine engine = null;
		if (style.equals(QueryStyle.GREMLIN_TRAVERSAL)) {
			//this.queryEngine = new GremlinQueryEngine(this);
		} else if (style.equals(QueryStyle.GREMLIN_UNIQUE)) {
			//this.queryEngine = new GremlinQueryEngine(this);
		} else if (style.equals(QueryStyle.GREMLINPIPELINE_TRAVERSAL)) {
			//this.queryEngine = new GremlinPipelineQueryEngine(this);
		} else if (style.equals(QueryStyle.TRAVERSAL)) {
			
			return new GraphTraversalQueryEngine(this.asAdmin().getTraversalSource());
			
		} else {
			throw new IllegalArgumentException("Query Engine type not recognized");
		}
		
		return engine;
	}
	
	/**
	 * Gets the query builder.
	 *
	 * @return the query builder
	 */
	public QueryBuilder<Vertex> getQueryBuilder() {
		return getQueryBuilder(this.loader);
	}
	
	public QueryBuilder<Vertex> getQueryBuilder(QueryStyle style) {
		return getQueryBuilder(style, this.loader);
	}
	
	public QueryBuilder<Vertex> getQueryBuilder(Loader loader) {
		return getQueryBuilder(this.style, loader);
	}
	
	public  QueryBuilder<Vertex> getQueryBuilder(QueryStyle style, Loader loader) {
		if (style.equals(QueryStyle.GREMLIN_TRAVERSAL)) {
			return new GremlinTraversal<>(loader, this.asAdmin().getTraversalSource());
		} else if (style.equals(QueryStyle.GREMLIN_UNIQUE)) {
			return new GremlinUnique<>(loader, this.asAdmin().getTraversalSource());
		} else if (style.equals(QueryStyle.GREMLINPIPELINE_TRAVERSAL)) {
			//return new GremlinPipelineTraversal(loader);
		} else if (style.equals(QueryStyle.TRAVERSAL)) {
			return new TraversalQuery<>(loader, this.asAdmin().getTraversalSource());
		}  else {
			throw new IllegalArgumentException("Query Builder type not recognized");
		}
		return queryBuilder;
	}
	/**
	 * Gets the query builder.
	 *
	 * @param start the start
	 * @return the query builder
	 */
	public QueryBuilder<Vertex> getQueryBuilder(Vertex start) {
		return getQueryBuilder(this.loader, start);
	}
	
	public QueryBuilder<Vertex> getQueryBuilder(Loader loader, Vertex start) {
		return getQueryBuilder(this.style, loader, start);
	}
	
	public QueryBuilder<Vertex> getQueryBuilder(QueryStyle style, Loader loader, Vertex start) {
		if (style.equals(QueryStyle.GREMLIN_TRAVERSAL)) {
			return new GremlinTraversal<>(loader, this.asAdmin().getTraversalSource(), start);
		} else if (style.equals(QueryStyle.GREMLIN_UNIQUE)) {
			return new GremlinUnique<>(loader, this.asAdmin().getTraversalSource(), start);
		} else if (style.equals(QueryStyle.GREMLINPIPELINE_TRAVERSAL)) {
			//return new GremlinPipelineTraversal(loader,start);
		} else if (style.equals(QueryStyle.TRAVERSAL)) {
			return new TraversalQuery<>(loader, this.asAdmin().getTraversalSource(), start);
		} else {
			throw new IllegalArgumentException("Query Builder type not recognized");
		}
		return queryBuilder;
	}
	public Graph startTransaction() {
		if (this.tx() == null) {
			this.currentTx = this.getGraph().newTransaction();
			this.currentTraversal = this.tx().traversal();
			this.readOnlyTraversal = this.tx().traversal(GraphTraversalSource.build().with(ReadOnlyStrategy.instance()));
		}
		return currentTx;
	}
	
	public void rollback() {
		if (this.tx() != null) {
			this.tx().tx().rollback();
			this.currentTx = null;
			this.currentTraversal = null;
			this.readOnlyTraversal = null;
		}
	}
	public void commit() {
		if (this.tx() != null) {
			this.tx().tx().commit();
			this.currentTx = null;
			this.currentTraversal = null;
			this.readOnlyTraversal = null;
		}
	}
	
	public Graph tx() {
		return this.currentTx;
	}
	
	public Admin asAdmin() {
		return admin;
	}
	
	public class Admin {
		
		public GraphTraversalSource getTraversalSource() {
			return currentTraversal;
		}
		public GraphTraversalSource getReadOnlyTraversalSource() {
			return readOnlyTraversal;
		}
		
		public TitanManagement getManagementSystem() {
			return getGraph().openManagement();
		}
	}
}