/*******************************************************************************
 * ============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.rosetta.marshal;

import java.util.Iterator;

import org.onap.aaf.rosetta.Ladder;
import org.onap.aaf.rosetta.Marshal;
import org.onap.aaf.rosetta.ParseException;
import org.onap.aaf.rosetta.Parsed;

public class DocMarshal<T> extends Marshal<T> {
	private Marshal<T> root;
	
	public DocMarshal(Marshal<T> root) {
		this.root = root;
	}
	
	@Override
	public Parsed<State> parse(T t, Parsed<State> parsed) throws ParseException {
		Ladder<Iterator<?>> ladder = parsed.state.ladder;
		Iterator<?> iter = ladder.peek();
		if(iter==null) {
			ladder.push(PENDING_ITERATOR);
			parsed.event = START_DOC;
		} else if (DONE_ITERATOR.equals(iter)) {
		} else {
			ladder.ascend(); // look at field info
				Iterator<?> currFieldIter = ladder.peek();
				if(!DONE_ITERATOR.equals(currFieldIter)){
					parsed = root.parse(t, parsed);
				}
			ladder.descend();
			if(DONE_ITERATOR.equals(currFieldIter) || parsed.event==NONE) {
				parsed.event = END_DOC;
				ladder.push(DONE_ITERATOR);
			}
		}
		return parsed; // if unchanged, then it will end process

	}

	public static final Iterator<Void> PENDING_ITERATOR = new Iterator<Void>() {
		@Override
		public boolean hasNext() {
			return false;
		}

		@Override
		public Void next() {
			return null;
		}

		@Override
		public void remove() {
		}
	};

	public static<T> DocMarshal<T> root(Marshal<T> m) {
		return (DocMarshal<T>)new DocMarshal<T>(m);
	}

}