/**
 * ============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.serialization.engines;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
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.apache.tinkerpop.gremlin.structure.VertexProperty;

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.InMemoryGraphSingleton;
import org.onap.aai.serialization.engines.query.GraphTraversalQueryEngine;
import org.onap.aai.serialization.engines.query.QueryEngine;
import org.onap.aai.serialization.engines.TransactionalGraphEngine;

import com.thinkaurelius.titan.core.TitanGraph;

public class InMemoryDBEngine extends TransactionalGraphEngine {

	/**
	 * Instantiates a new titan DB engine.
	 *
	 * @param style
	 *            the style
	 * @param loader
	 *            the loader
	 */
	private TitanGraph graph = null;

	private static final TransactionalGraphEngine.Admin admin = null;

	public InMemoryDBEngine(QueryStyle style, DBConnectionType connectionType, Loader loader, TitanGraph graph) {
		super(style, loader, connectionType, InMemoryGraphSingleton.getInstance(graph));
		this.graph = graph;
	}

	/**
	 * Instantiates a new titan DB engine.
	 *
	 * @param style
	 *            the style
	 * @param loader
	 *            the loader
	 * @param connect
	 *            the connect
	 */
	public InMemoryDBEngine(QueryStyle style, Loader loader, boolean connect, TitanGraph graph) {
		super(style, loader);
		if (connect) {
			this.singleton = InMemoryGraphSingleton.getInstance(graph);
		}
		this.graph = graph;
	}

	@Override
	public QueryEngine getQueryEngine() {

		if (style.equals(QueryStyle.TRAVERSAL)) {

			GraphTraversalSource traversalSource = graph.traversal();
			return new GraphTraversalQueryEngine(traversalSource);

		} else {
			throw new IllegalArgumentException("Query Engine type not recognized");
		}

	}

	@Override
	public QueryBuilder<Vertex> getQueryBuilder(QueryStyle style, Loader loader) {
		if (style.equals(QueryStyle.GREMLIN_TRAVERSAL)) {
			return new GremlinTraversal<>(loader, graph.traversal());
		} else if (style.equals(QueryStyle.TRAVERSAL)) {
			return new TraversalQuery<>(loader, graph.traversal());

		} else {
			throw new IllegalArgumentException("Query Builder type is Not recognized");
		}

	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public boolean setListProperty(Vertex v, String name, List<?> objs) {

		// clear out list full replace style

		Iterator<VertexProperty<Object>> iterator = v.properties(name);
		while (iterator.hasNext()) {
			iterator.next().remove();
		}
		if (objs != null) {
			for (Object obj : objs) {
				v.property(name, obj);
			}
		}
		return true;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public List<Object> getListProperty(Vertex v, String name) {

		List<Object> result = new ArrayList<>();

		Iterator<VertexProperty<Object>> iterator = v.properties(name);

		while (iterator.hasNext()) {
			result.add(iterator.next().value());
		}

		if (result.isEmpty()) {
			result = null;
		}

		return result;

	}

	@Override
	public QueryBuilder<Vertex> getQueryBuilder() {
		return getQueryBuilder(this.loader);
	}

	@Override
	public QueryBuilder<Vertex> getQueryBuilder(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.TRAVERSAL)) {
			return new TraversalQuery<>(loader, graph.traversal());
		} else {
			throw new IllegalArgumentException("Query Builder type not recognized");
		}

	}

	@Override
	public QueryBuilder<Vertex> getQueryBuilder(Vertex start) {
		return getQueryBuilder(this.loader, start);
	}

	public GraphTraversalSource getTraversalSource() {
		return graph.traversal();
	}

	@Override
	public QueryBuilder<Vertex> getQueryBuilder(Loader loader, Vertex start) {
		if (style.equals(QueryStyle.GREMLIN_TRAVERSAL)) {
			return new GremlinTraversal<>(loader, graph.traversal(), start);
		} else if (style.equals(QueryStyle.GREMLIN_UNIQUE)) {
			return new GremlinUnique<>(loader, this.asAdmin().getTraversalSource(), start);
		} else if (style.equals(QueryStyle.TRAVERSAL)) {
			return new TraversalQuery<>(loader, graph.traversal(), start);
		} else {
			throw new IllegalArgumentException("Query Builder type not recognized");
		}

	}

	@Override
	public Graph startTransaction() {
		if (this.tx() == null) {
			this.currentTx = graph.newTransaction();
			this.currentTraversal = this.tx().traversal();
			this.readOnlyTraversal = this.tx()
					.traversal(GraphTraversalSource.build().with(ReadOnlyStrategy.instance()));
		}
		return currentTx;
	}

	

}