/*******************************************************************************
 * ============LICENSE_START====================================================
 * * org.onap.aaf
 * * ===========================================================================
 * * 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.aaf.cadi.wsse;

import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.XMLEvent;

/**
 * Match Class allows you to build an automatic Tree of StAX (or StAX like) 
 * Objects for frequent use.
 * 
 * OBJECT is a type which you which to do some end Actions on, similar to a Visitor pattern, see Action
 * 
 * Note: We have implemented with XReader and XEvent, rather than StAX for performance reasons.
 * 
 * @see Action
 * @see Match
 * @see XEvent
 * @see XReader
 * 
 *
 * @param <OUTPUT>
 */
//@SuppressWarnings("restriction")
public class Match<OUTPUT> {
	private QName qname;
	private Match<OUTPUT>[] next;
	private Match<OUTPUT> prev;
	private Action<OUTPUT> action = null;
	private boolean stopAfter;
	private boolean exclusive;
	

	@SafeVarargs
	public Match(String ns, String name, Match<OUTPUT> ... next) {
		this.qname = new QName(ns,name);
		this.next = next;
		stopAfter = exclusive = false;
		for(Match<OUTPUT> m : next) { // add the possible tags to look for
			if(!m.stopAfter)m.prev = this;
		}
	}
	
	public Match<OUTPUT> onMatch(OUTPUT output, XReader reader) throws XMLStreamException {
		while(reader.hasNext()) {
			XEvent event = reader.nextEvent();
			switch(event.getEventType()) {
				case XMLEvent.START_ELEMENT:
					QName e_qname = event.asStartElement().getName();
					//System.out.println("Start - " + e_qname);
					boolean match = false;
					for(Match<OUTPUT> m : next) {
						if(e_qname.equals(m.qname)) {
							match=true;
							if(m.onMatch(output, reader)==null) {
								return null; // short circuit Parsing
							}
							break;
						}
					}
					if(exclusive && !match) // When Tag MUST be present, i.e. the Root Tag, versus info we're not interested in
						return null;
					break;
				case XMLEvent.CHARACTERS:
					//System.out.println("Data - " +event.asCharacters().getData());
					if(action!=null) {
						if(!action.content(output,event.asCharacters().getData())) {
							return null;
						}
					}
					break;
				case XMLEvent.END_ELEMENT:
					//System.out.println("End - " + event.asEndElement().getName());
					if(event.asEndElement().getName().equals(qname)) {
						return prev;
					}
					break;
				case XMLEvent.END_DOCUMENT:
					return null; // Exit Chain
			}
		}
		return this;
	}

	/**
	 * When this Matched Tag has completed, Stop parsing and end
	 * @return
	 */
	public Match<OUTPUT> stopAfter() {
		stopAfter = true;
		return this;
	}
	
	/**
	 * Mark that this Object MUST be matched at this level or stop parsing and end
	 * 
	 * @param action
	 * @return
	 */
	public Match<OUTPUT> exclusive() {
		exclusive = true;
		return this;
	}

	public Match<OUTPUT> set(Action<OUTPUT> action) {
		this.action = action;
		return this;
	}
}