/**
 * 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.
 */
package org.jivesoftware.smackx.pubsub.provider;

import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.provider.PacketExtensionProvider;
import org.jivesoftware.smack.provider.ProviderManager;
import org.jivesoftware.smack.util.PacketParserUtils;
import org.jivesoftware.smackx.pubsub.Item;
import org.jivesoftware.smackx.pubsub.PayloadItem;
import org.jivesoftware.smackx.pubsub.SimplePayload;
import org.jivesoftware.smackx.pubsub.packet.PubSubNamespace;
import org.xmlpull.v1.XmlPullParser;

/**
 * Parses an <b>item</b> element as is defined in both the
 * {@link PubSubNamespace#BASIC} and {@link PubSubNamespace#EVENT} namespaces.
 * To parse the item contents, it will use whatever
 * {@link PacketExtensionProvider} is registered in <b>smack.providers</b> for
 * its element name and namespace. If no provider is registered, it will return
 * a {@link SimplePayload}.
 * 
 * @author Robin Collier
 */
public class ItemProvider implements PacketExtensionProvider {
	@Override
	public PacketExtension parseExtension(XmlPullParser parser)
			throws Exception {
		final String id = parser.getAttributeValue(null, "id");
		final String node = parser.getAttributeValue(null, "node");
		final String elem = parser.getName();

		int tag = parser.next();

		if (tag == XmlPullParser.END_TAG) {
			return new Item(id, node);
		} else {
			final String payloadElemName = parser.getName();
			final String payloadNS = parser.getNamespace();

			if (ProviderManager.getInstance().getExtensionProvider(
					payloadElemName, payloadNS) == null) {
				boolean done = false;
				final StringBuilder payloadText = new StringBuilder();

				while (!done) {
					if (tag == XmlPullParser.END_TAG
							&& parser.getName().equals(elem)) {
						done = true;
					} else if (!((tag == XmlPullParser.START_TAG) && parser
							.isEmptyElementTag())) {
						payloadText.append(parser.getText());
					}

					if (!done) {
						tag = parser.next();
					}
				}
				return new PayloadItem<SimplePayload>(id, node,
						new SimplePayload(payloadElemName, payloadNS,
								payloadText.toString()));
			} else {
				return new PayloadItem<PacketExtension>(id, node,
						PacketParserUtils.parsePacketExtension(payloadElemName,
								payloadNS, parser));
			}
		}
	}

}