/*
 * Copyright (c) 2010-2012 Sonatype, Inc. All rights reserved.
 *
 * This program is licensed to you under the Apache License Version 2.0,
 * and you may not use this file except in compliance with the Apache License Version 2.0.
 * You may obtain a copy of the Apache License Version 2.0 at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the Apache License Version 2.0 is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Apache License Version 2.0 for the specific language governing permissions and limitations there under.
 */

package com.ning.http.client.webdav;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import com.ning.http.client.AsyncHandler;
import com.ning.http.client.HttpResponseBodyPart;
import com.ning.http.client.HttpResponseHeaders;
import com.ning.http.client.HttpResponseStatus;
import com.ning.http.client.Response;

/**
 * Simple {@link AsyncHandler} that add support for WebDav's response
 * manipulation.
 * 
 * @param <T>
 */
public abstract class WebDavCompletionHandlerBase<T> implements AsyncHandler<T> {

	private final Collection<HttpResponseBodyPart> bodies = Collections
			.synchronizedCollection(new ArrayList<HttpResponseBodyPart>());
	private HttpResponseStatus status;
	private HttpResponseHeaders headers;

	/**
	 * {@inheritDoc}
	 */
	/* @Override */
	@Override
	public final STATE onBodyPartReceived(final HttpResponseBodyPart content)
			throws Exception {
		bodies.add(content);
		return STATE.CONTINUE;
	}

	/**
	 * {@inheritDoc}
	 */
	/* @Override */
	@Override
	public final STATE onStatusReceived(final HttpResponseStatus status)
			throws Exception {
		this.status = status;
		return STATE.CONTINUE;
	}

	/**
	 * {@inheritDoc}
	 */
	/* @Override */
	@Override
	public final STATE onHeadersReceived(final HttpResponseHeaders headers)
			throws Exception {
		this.headers = headers;
		return STATE.CONTINUE;
	}

	/**
	 * {@inheritDoc}
	 */
	/* @Override */
	@Override
	public final T onCompleted() throws Exception {
		if (status != null) {
			final Response response = status.provider().prepareResponse(status,
					headers, bodies);
			Document document = null;
			if (status.getStatusCode() == 207) {
				document = readXMLResponse(response.getResponseBodyAsStream());
			}
			return onCompleted(new WebDavResponse(status.provider()
					.prepareResponse(status, headers, bodies), document));
		} else {
			throw new IllegalStateException("Status is null");
		}
	}

	/**
	 * {@inheritDoc}
	 */
	/* @Override */
	@Override
	public void onThrowable(final Throwable t) {

	}

	/**
	 * Invoked once the HTTP response has been fully read.
	 * 
	 * @param response
	 *            The {@link com.ning.http.client.Response}
	 * @return Type of the value that will be returned by the associated
	 *         {@link java.util.concurrent.Future}
	 */
	abstract public T onCompleted(WebDavResponse response) throws Exception;

	private class HttpStatusWrapper extends HttpResponseStatus {

		private final HttpResponseStatus wrapper;

		private final String statusText;

		private final int statusCode;

		public HttpStatusWrapper(final HttpResponseStatus wrapper,
				final String statusText, final int statusCode) {
			super(wrapper.getUrl(), wrapper.provider());
			this.wrapper = wrapper;
			this.statusText = statusText;
			this.statusCode = statusCode;
		}

		@Override
		public int getStatusCode() {
			return (statusText == null ? wrapper.getStatusCode() : statusCode);
		}

		@Override
		public String getStatusText() {
			return (statusText == null ? wrapper.getStatusText() : statusText);
		}

		@Override
		public String getProtocolName() {
			return wrapper.getProtocolName();
		}

		@Override
		public int getProtocolMajorVersion() {
			return wrapper.getProtocolMajorVersion();
		}

		@Override
		public int getProtocolMinorVersion() {
			return wrapper.getProtocolMinorVersion();
		}

		@Override
		public String getProtocolText() {
			return wrapper.getStatusText();
		}
	}

	private Document readXMLResponse(final InputStream stream) {
		final DocumentBuilderFactory factory = DocumentBuilderFactory
				.newInstance();
		Document document = null;
		try {
			document = factory.newDocumentBuilder().parse(stream);
			parse(document);
		} catch (final SAXException e) {

			throw new RuntimeException(e);
		} catch (final IOException e) {

			throw new RuntimeException(e);
		} catch (final ParserConfigurationException e) {

			throw new RuntimeException(e);
		}
		return document;
	}

	private void parse(final Document document) {
		final Element element = document.getDocumentElement();
		final NodeList statusNode = element.getElementsByTagName("status");
		for (int i = 0; i < statusNode.getLength(); i++) {
			final Node node = statusNode.item(i);

			final String value = node.getFirstChild().getNodeValue();
			final int statusCode = Integer.valueOf(value.substring(
					value.indexOf(" "), value.lastIndexOf(" ")).trim());
			final String statusText = value.substring(value.lastIndexOf(" "));
			status = new HttpStatusWrapper(status, statusText, statusCode);
		}
	}
}