/*
 * Copyright 2005-2011 the original author or authors.
 *
 * 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.
 */

package org.springframework.ws.soap.stroap;

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.StartElement;
import javax.xml.stream.events.XMLEvent;
import javax.xml.transform.Result;

import org.springframework.util.Assert;
import org.springframework.util.xml.StaxUtils;
import org.springframework.ws.soap.SoapHeader;
import org.springframework.ws.soap.SoapHeaderElement;
import org.springframework.ws.soap.SoapHeaderException;
import org.springframework.ws.soap.SoapVersion;
import org.springframework.xml.stream.AbstractXMLEventWriter;
import org.springframework.xml.stream.CompositeXMLEventReader;

/**
 * @author Arjen Poutsma
 */
abstract class StroapHeader extends StroapElement implements SoapHeader {

	private List<StroapHeaderElement> headerElements = new LinkedList<StroapHeaderElement>();

	protected StroapHeader(StroapMessageFactory messageFactory) {
		super(messageFactory.getSoapVersion().getHeaderName(), messageFactory);
	}

	protected StroapHeader(StartElement startElement, StroapMessageFactory messageFactory) {
		super(startElement, messageFactory);
	}

	static StroapHeader build(XMLEventReader eventReader, StroapMessageFactory messageFactory)
			throws XMLStreamException {
		XMLEvent event = eventReader.nextTag();
		if (!event.isStartElement()) {
			throw new StroapMessageCreationException("Unexpected event: " + event + ", expected StartElement");
		}
		StartElement startElement = event.asStartElement();
		SoapVersion soapVersion = messageFactory.getSoapVersion();
		if (!soapVersion.getHeaderName().equals(startElement.getName())) {
			throw new StroapMessageCreationException(
					"Unexpected name: " + startElement.getName() + ", expected " + soapVersion.getHeaderName());
		}

		if (SoapVersion.SOAP_11.equals(soapVersion)) {
			return new Stroap11Header(startElement, messageFactory);
		}
		else {
			return null;
		}

	}

	public SoapHeaderElement addHeaderElement(QName name) throws SoapHeaderException {
		StroapHeaderElement headerElement = new StroapHeaderElement(name, getMessageFactory());
		headerElements.add(headerElement);
		return headerElement;
	}

	public Iterator<SoapHeaderElement> examineAllHeaderElements() throws SoapHeaderException {
		List<SoapHeaderElement> headerElements = Collections.<SoapHeaderElement>unmodifiableList(this.headerElements);
		return headerElements.iterator();
	}

	public Iterator<SoapHeaderElement> examineHeaderElements(QName name) throws SoapHeaderException {
		List<SoapHeaderElement> result = new LinkedList<SoapHeaderElement>();
		for (StroapHeaderElement headerElement : this.headerElements) {
			if (headerElement.getName().equals(name)) {
				result.add(headerElement);
			}
		}
		return result.iterator();
	}

	public Iterator<SoapHeaderElement> examineMustUnderstandHeaderElements(String actorOrRole)
			throws SoapHeaderException {
		List<SoapHeaderElement> result = new LinkedList<SoapHeaderElement>();
		for (StroapHeaderElement headerElement : this.headerElements) {
			if (headerElement.getMustUnderstand() && headerElement.getActorOrRole().equals(actorOrRole)) {
				result.add(headerElement);
			}
		}
		return result.iterator();
	}

	public void removeHeaderElement(QName name) throws SoapHeaderException {
		Assert.notNull(name, "'name' must not be null");

		for (Iterator<StroapHeaderElement> iterator = headerElements.iterator(); iterator.hasNext();) {
			StroapHeaderElement headerElement = iterator.next();
			if (name.equals(headerElement.getName())) {
				iterator.remove();
				break;
			}
		}
	}

	@Override
	protected XMLEventReader getChildEventReader() {
		XMLEventReader[] eventReaders = new XMLEventReader[headerElements.size()];
		for (int i = 0; i < headerElements.size(); i++) {
			StroapHeaderElement headerElement = headerElements.get(i);
			eventReaders[i] = headerElement.getEventReader(false);
		}
		return new CompositeXMLEventReader(eventReaders);
	}

	public Result getResult() {
		headerElements.clear();
		return StaxUtils.createCustomStaxResult(new StroapHeaderXMLEventWriter());
	}

	class StroapHeaderXMLEventWriter extends AbstractXMLEventWriter {

		private int elementDepth = 0;

		boolean startElementSeen = false;

		private final List<XMLEvent> events = new LinkedList<XMLEvent>();

		public void add(XMLEvent event) throws XMLStreamException {
			if (event.isStartElement()) {
				startElementSeen = true;
				elementDepth++;
			}
			else if (event.isEndElement()) {
				elementDepth--;
			}
			else if (event.isStartDocument() || event.isEndDocument()) {
				return;
			}
			if (elementDepth >= 0 && startElementSeen) {
				events.add(event);
			}
			if (elementDepth == 0 && (event.isEndElement() || event.isEndDocument())) {
				StroapHeaderElement headerElement = StroapHeaderElement.build(events, getMessageFactory());
				headerElements.add(headerElement);
				events.clear();
			}
		}
	}

}