/*-
 * ============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.introspection;

import com.att.eelf.configuration.EELFLogger;
import com.att.eelf.configuration.EELFManager;
import org.openecomp.aai.exceptions.AAIException;
import org.openecomp.aai.introspection.exceptions.AAIUnknownObjectException;

import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

public class IntrospectorWalker {

	private static final EELFLogger LOGGER = EELFManager.getInstance().getLogger(IntrospectorWalker.class);

	private Wanderer w = null;
	private Set<String> blacklist = null;
	private boolean preventCycles = false;
	private final PropertyPredicate<Introspector, String> propVisibility;
	
	/**
	 * Instantiates a new introspector walker.
	 *
	 * @param w the w
	 * @param llBuilder the ll builder
	 */
	public IntrospectorWalker(Wanderer w) {
		this.w = w;
		this.blacklist = new HashSet<>();
		this.propVisibility = null;
	}
	
	public IntrospectorWalker(Wanderer w, PropertyPredicate<Introspector, String> p) {
		this.w = w;
		this.blacklist = new HashSet<>();
		this.propVisibility = p;
	}
	
	
	/**
	 * Sets the blacklist.
	 *
	 * @param list the new blacklist
	 */
	public void setBlacklist(List<String> list) {
		blacklist.addAll(list);
	}
	
	/**
	 * Prevent cycles.
	 *
	 * @param prevent the prevent
	 */
	public void preventCycles(boolean prevent) {
		this.preventCycles = prevent;
	}
	
	/**
	 * Walk.
	 *
	 * @param obj the obj
	 * @throws AAIException 
	 */
	public void walk(Introspector obj) throws AAIException {
		Set<String> visited = new HashSet<>();

		walk(obj, null, visited);
	}
	
	/**
	 * Walk.
	 *
	 * @param obj the obj
	 * @param parent the parent
	 * @throws AAIException 
	 */
	private void walk(Introspector obj, Introspector parent, Set<String> visited) throws AAIException {
		boolean stopRecursion = false;
		Set<String> localVisited = new HashSet<>();
		localVisited.addAll(visited);
		if (preventCycles) {
			if (visited.contains(obj.getName())) {
				stopRecursion = true;
			}
			if (!obj.isContainer()) {
				localVisited.add(obj.getName()); //so we don't recurse while walking its children
			}
		}
		Set<String> props;
		//props must duplicate the result from getProperties because
		//it is unmodifiable
		if (this.propVisibility == null) {
			props = new LinkedHashSet<>(obj.getProperties());
		} else {
			props = new LinkedHashSet<>(obj.getProperties(this.propVisibility));
		}

		w.processComplexObj(obj);
		props.removeAll(blacklist);
		if (!obj.isContainer()) {
			parent = obj;
		}
		for (String prop : props) {
			
			if (obj.isSimpleType(prop)) {
				
				w.processPrimitive(prop, obj);
			} else if (obj.isListType(prop) && !stopRecursion) {
				
				List<Object> listReference = obj.getValue(prop);
				boolean isComplexType = obj.isComplexGenericType(prop);
				if (isComplexType) {
					List<Introspector> list = obj.getWrappedListValue(prop);
					try {
						Introspector child = obj.newIntrospectorInstanceOfNestedProperty(prop);
						w.modifyComplexList(list, listReference, parent, child);
						for (Object item : listReference) {
							child = IntrospectorFactory.newInstance(obj.getModelType(), item);
							walk(child, parent, localVisited);
						}
					} catch (AAIUnknownObjectException e) {
						LOGGER.warn("Skipping property " + prop + " (Unknown Object)", e);
					}
				} else {
					w.processPrimitiveList(prop, obj);
				}
				if (listReference.size() == 0) {
					if (isComplexType) {
						try {
							Introspector child = obj.newIntrospectorInstanceOfNestedProperty(prop);
							int size = w.createComplexListSize(parent, child);
							for (int i = 0; i < size; i++) {
								child = obj.newIntrospectorInstanceOfNestedProperty(prop);
								walk(child, parent, localVisited);
								listReference.add(child.getUnderlyingObject());
							}

							obj.setValue(prop, listReference);
						} catch (AAIUnknownObjectException e) {
							LOGGER.warn("Skipping property " + prop + " (Unknown Object)", e);
						}
					} else if (!isComplexType){
						w.processPrimitiveList(prop, obj);
					}
				}
			
			} else if (obj.isComplexType(prop) && !stopRecursion) {
				Introspector child = null;
				if (obj.getValue(prop) != null) {
					child = IntrospectorFactory.newInstance(obj.getModelType(), obj.getValue(prop));
				} else {
					if (w.createComplexObjIfNull()) {
						try {
							child = obj.newIntrospectorInstanceOfProperty(prop);
							obj.setValue(prop, child.getUnderlyingObject());
						} catch (AAIUnknownObjectException e) {
							LOGGER.warn("Skipping property " + prop + " (Unknown Object)", e);
						}
					}
				}
				if (child != null) {
					walk(child, obj, localVisited);
				}
			}
			
		}
		/*
		if (preventCycles && !obj.isContainer()) {
			visited.remove(obj.getName()); //so we can see it down another path that isn't in danger of recursing over it
		}*/
	}
}