/*
 * Copyright 2005-2014 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.transport.http;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;
import java.util.zip.GZIPInputStream;
import javax.xml.namespace.QName;

import org.springframework.util.FileCopyUtils;
import org.springframework.util.StringUtils;
import org.springframework.ws.transport.AbstractSenderConnection;
import org.springframework.ws.transport.FaultAwareWebServiceConnection;
import org.springframework.ws.transport.WebServiceConnection;

/**
 * Abstract base class for {@link WebServiceConnection} implementations that send request over HTTP.
 *
 * @author Arjen Poutsma
 * @since 1.0.0
 */
public abstract class AbstractHttpSenderConnection extends AbstractSenderConnection
		implements FaultAwareWebServiceConnection {

	/** Buffer used for reading the response, when the content length is invalid. */
	private byte[] responseBuffer;

	@Override
	public final boolean hasError() throws IOException {
		return getResponseCode() / 100 != 2;
	}

	@Override
	public final String getErrorMessage() throws IOException {
		StringBuilder builder = new StringBuilder();
		String responseMessage = getResponseMessage();
		if (StringUtils.hasLength(responseMessage)) {
			builder.append(responseMessage);
		}
		builder.append(" [");
		builder.append(getResponseCode());
		builder.append(']');
		return builder.toString();
	}

	/*
	 * Receiving response
	 */
	@Override
	protected final boolean hasResponse() throws IOException {
		int responseCode = getResponseCode();
		if (HttpTransportConstants.STATUS_ACCEPTED == responseCode ||
				HttpTransportConstants.STATUS_NO_CONTENT == responseCode) {
			return false;
		}
		long contentLength = getResponseContentLength();
		if (contentLength < 0) {
			if (responseBuffer == null) {
				responseBuffer = FileCopyUtils.copyToByteArray(getRawResponseInputStream());
			}
			contentLength = responseBuffer.length;
		}
		return contentLength > 0;
	}

	@Override
	protected final InputStream getResponseInputStream() throws IOException {
		InputStream inputStream;
		if (responseBuffer != null) {
			inputStream = new ByteArrayInputStream(responseBuffer);
		}
		else {
			inputStream = getRawResponseInputStream();
		}
		return isGzipResponse() ? new GZIPInputStream(inputStream) : inputStream;
	}

	/** Determine whether the response is a GZIP response. */
	private boolean isGzipResponse() throws IOException {
		Iterator<String> iterator = getResponseHeaders(HttpTransportConstants.HEADER_CONTENT_ENCODING);
		if (iterator.hasNext()) {
			String encodingHeader = iterator.next();
			return encodingHeader.toLowerCase()
					.contains(HttpTransportConstants.CONTENT_ENCODING_GZIP);
		}
		return false;
	}

	/** Returns the HTTP status code of the response. */
	protected abstract int getResponseCode() throws IOException;

	/** Returns the HTTP status message of the response. */
	protected abstract String getResponseMessage() throws IOException;

	/** Returns the length of the response. */
	protected abstract long getResponseContentLength() throws IOException;

	/** Returns the raw, possibly compressed input stream to read the response from. */
	protected abstract InputStream getRawResponseInputStream() throws IOException;

	/*
	 * Faults
	 */

	@Override
	public final boolean hasFault() throws IOException {
		// SOAP 1.1 specifies a 500 status code for faults
		// SOAP 1.2 specifies a 400 status code for sender faults, and 500 for all other faults
		switch (getResponseCode()) {
			case HttpTransportConstants.STATUS_INTERNAL_SERVER_ERROR:
				return isSoap11Response() || isSoap12Response();
			case HttpTransportConstants.STATUS_BAD_REQUEST:
				return isSoap12Response();
			default:
				return false;
		}
	}

	/** Determine whether the response is a SOAP 1.1 message. */
	private boolean isSoap11Response() throws IOException {
		Iterator<String> iterator = getResponseHeaders(HttpTransportConstants.HEADER_CONTENT_TYPE);
		if (iterator.hasNext()) {
			String contentType = iterator.next().toLowerCase();
			return contentType.contains("text/xml");
		}
		return false;
	}

	/** Determine whether the response is a SOAP 1.1 message. */
	private boolean isSoap12Response() throws IOException {
		Iterator<String> iterator = getResponseHeaders(HttpTransportConstants.HEADER_CONTENT_TYPE);
		if (iterator.hasNext()) {
			String contentType = iterator.next().toLowerCase();
			return contentType.contains("application/soap+xml");
		}
		return false;
	}

	@Override
	@Deprecated
	public final void setFault(boolean fault) {
	}

	@Override
	public final void setFaultCode(QName faultCode) throws IOException {
	}
}