/*-
 * ============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.restcore.search;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.expr.ClassExpression;
import org.codehaus.groovy.ast.expr.PropertyExpression;
import org.codehaus.groovy.control.CompilerConfiguration;
import org.codehaus.groovy.control.customizers.ASTTransformationCustomizer;
import org.codehaus.groovy.control.customizers.ImportCustomizer;

import groovy.lang.Binding;
import groovy.lang.GroovyShell;
import groovy.lang.Script;
import groovy.transform.TimedInterrupt;

/**
 * Creates and returns a groovy shell with the
 * configuration to statically import graph classes
 *
 */
public class GremlinGroovyShellSingleton {

	private final GroovyShell shell;
	private GremlinGroovyShellSingleton() {
		Map<String, Object> parameters = new HashMap<>();
		parameters.put("value", 30000);
		parameters.put("unit", new PropertyExpression(new ClassExpression(ClassHelper.make(TimeUnit.class)),"MILLISECONDS"));

		ASTTransformationCustomizer custom = new ASTTransformationCustomizer(parameters, TimedInterrupt.class);
		ImportCustomizer imports = new ImportCustomizer();
		imports.addStaticStars(
            "org.apache.tinkerpop.gremlin.process.traversal.P"
		);
		imports.addImports(
				"org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.__",
				"org.apache.tinkerpop.gremlin.structure.T",
				"org.apache.tinkerpop.gremlin.process.traversal.P");
		CompilerConfiguration config = new CompilerConfiguration();
		config.addCompilationCustomizers(custom, imports);

		this.shell = new GroovyShell(config);
	}
	
	 private static class Helper {
		 private static final GremlinGroovyShellSingleton INSTANCE = new GremlinGroovyShellSingleton();
	 }

	 public static GremlinGroovyShellSingleton getInstance() {
		 
		 return Helper.INSTANCE;
	 }

	/** 
	 * @param traversal
	 * @param params
	 * @return result of graph traversal
	 */
	public GraphTraversal<?, ?> executeTraversal (String traversal, Map<String, Object> params) {
		Binding binding = new Binding(params);
		Script script = shell.parse(traversal);
		script.setBinding(binding);
		return (GraphTraversal<?, ?>) script.run();
	}
}