/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.camel.component.jetty;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.Serializable;
import java.net.URI;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.camel.AsyncCallback;
import org.apache.camel.AsyncProcessor;
import org.apache.camel.Endpoint;
import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.component.http.HttpConstants;
import org.apache.camel.component.http.HttpMethods;
import org.apache.camel.component.http.helper.HttpHelper;
import org.apache.camel.impl.DefaultAsyncProducer;
import org.apache.camel.spi.HeaderFilterStrategy;
import org.apache.camel.util.ExchangeHelper;
import org.apache.camel.util.IOHelper;
import org.apache.camel.util.ObjectHelper;
import org.apache.camel.util.URISupport;
import org.eclipse.jetty.client.HttpClient;
import org.eclipse.jetty.util.component.LifeCycle;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @version 
 */
public class JettyHttpProducer extends DefaultAsyncProducer implements AsyncProcessor {
    private static final Logger LOG = LoggerFactory.getLogger(JettyHttpProducer.class);
    private HttpClient client;
    private boolean sharedClient;
    private JettyHttpBinding binding;

    /**
     * Creates this producer.
     * <p/>
     * A client must be set before use, eg either {@link #setClient(org.eclipse.jetty.client.HttpClient)}
     * or {@link #setSharedClient(org.eclipse.jetty.client.HttpClient)}.
     *
     * @param endpoint  the endpoint
     */
    public JettyHttpProducer(Endpoint endpoint) {
        super(endpoint);
    }

    /**
     * Creates this producer
     *
     * @param endpoint  the endpoint
     * @param client    the non-shared client to use
     */
    public JettyHttpProducer(Endpoint endpoint, HttpClient client) {
        super(endpoint);
        setClient(client);
    }

    @Override
    public JettyHttpEndpoint getEndpoint() {
        return (JettyHttpEndpoint) super.getEndpoint();
    }

    public boolean process(Exchange exchange, final AsyncCallback callback) {
        try {
            processInternal(exchange, callback);
        } catch (Exception e) {
            // error occurred before we had a chance to go async
            // so set exception and invoke callback true
            exchange.setException(e);
            callback.done(true);
            return true;
        }

        // we should continue processing this asynchronously
        return false;
    }

    private void processInternal(Exchange exchange, AsyncCallback callback) throws Exception {
        // creating the url to use takes 2-steps
        String url = HttpHelper.createURL(exchange, getEndpoint());
        URI uri = HttpHelper.createURI(exchange, url, getEndpoint());
        // get the url from the uri
        url = uri.toASCIIString();

        // execute any custom url rewrite
        String rewriteUrl = HttpHelper.urlRewrite(exchange, url, getEndpoint(), this);
        if (rewriteUrl != null) {
            // update url and query string from the rewritten url
            url = rewriteUrl;
        }

        HttpMethods methodToUse = HttpHelper.createMethod(exchange, getEndpoint(), exchange.getIn().getBody() != null);
        String method = methodToUse.createMethod(url).getName();

        JettyContentExchange httpExchange = getEndpoint().createContentExchange();
        httpExchange.init(exchange, getBinding(), client, callback);
        httpExchange.setURL(url); // Url has to be set first
        httpExchange.setMethod(method);
        
        if (getEndpoint().getHttpClientParameters() != null) {
            // For jetty 9 these parameters can not be set on the client
            // so we need to set them on the httpExchange
            String timeout = (String)getEndpoint().getHttpClientParameters().get("timeout");
            if (timeout != null) {
                httpExchange.setTimeout(new Long(timeout));
            }
            String supportRedirect = (String)getEndpoint().getHttpClientParameters().get("supportRedirect");
            if (supportRedirect != null) {
                httpExchange.setSupportRedirect(new Boolean(supportRedirect));
            }
        }

        LOG.trace("Using URL: {} with method: {}", url, method);

        // if there is a body to send as data
        if (exchange.getIn().getBody() != null) {
            String contentType = ExchangeHelper.getContentType(exchange);
            if (contentType != null) {
                httpExchange.setRequestContentType(contentType);
            }
            if (contentType != null && HttpConstants.CONTENT_TYPE_JAVA_SERIALIZED_OBJECT.equals(contentType)) {
                if (getEndpoint().getComponent().isAllowJavaSerializedObject() || getEndpoint().isTransferException()) {
                    // serialized java object
                    Serializable obj = exchange.getIn().getMandatoryBody(Serializable.class);
                    // write object to output stream
                    ByteArrayOutputStream bos = new ByteArrayOutputStream();
                    try {
                        HttpHelper.writeObjectToStream(bos, obj);
                        httpExchange.setRequestContent(bos.toByteArray());
                    } finally {
                        IOHelper.close(bos, "body", LOG);
                    }
                } else {
                    throw new RuntimeCamelException("Content-type " + HttpConstants.CONTENT_TYPE_JAVA_SERIALIZED_OBJECT + " is not allowed");
                }
            } else {
                Object body = exchange.getIn().getBody();
                if (body instanceof String) {
                    String data = (String) body;
                    // be a bit careful with String as any type can most likely be converted to String
                    // so we only do an instanceof check and accept String if the body is really a String
                    // do not fallback to use the default charset as it can influence the request
                    // (for example application/x-www-form-urlencoded forms being sent)
                    String charset = IOHelper.getCharsetName(exchange, false);
                    httpExchange.setRequestContent(data, charset);
                } else {
                    // then fallback to input stream
                    InputStream is = exchange.getContext().getTypeConverter().mandatoryConvertTo(InputStream.class, exchange, exchange.getIn().getBody());
                    httpExchange.setRequestContent(is);
                    // setup the content length if it is possible
                    String length = exchange.getIn().getHeader(Exchange.CONTENT_LENGTH, String.class);
                    if (ObjectHelper.isNotEmpty(length)) {
                        httpExchange.addRequestHeader(Exchange.CONTENT_LENGTH, length);
                    }
                }
            }
        }

        // if we bridge endpoint then we need to skip matching headers with the HTTP_QUERY to avoid sending
        // duplicated headers to the receiver, so use this skipRequestHeaders as the list of headers to skip
        Map<String, Object> skipRequestHeaders = null;
        if (getEndpoint().isBridgeEndpoint()) {
            exchange.setProperty(Exchange.SKIP_GZIP_ENCODING, Boolean.TRUE);
            String queryString = exchange.getIn().getHeader(Exchange.HTTP_QUERY, String.class);
            if (queryString != null) {
                skipRequestHeaders = URISupport.parseQuery(queryString, false, true);
            }
            // Need to remove the Host key as it should be not used 
            exchange.getIn().getHeaders().remove("host");
        }

        // propagate headers as HTTP headers
        Message in = exchange.getIn();
        HeaderFilterStrategy strategy = getEndpoint().getHeaderFilterStrategy();
        for (Map.Entry<String, Object> entry : in.getHeaders().entrySet()) {
            String key = entry.getKey();
            Object headerValue = in.getHeader(key);

            if (headerValue != null) {
                // use an iterator as there can be multiple values. (must not use a delimiter, and allow empty values)
                final Iterator<?> it = ObjectHelper.createIterator(headerValue, null, true);

                // the values to add as a request header
                final List<String> values = new ArrayList<String>();

                // if its a multi value then check each value if we can add it and for multi values they
                // should be combined into a single value
                while (it.hasNext()) {
                    String value = exchange.getContext().getTypeConverter().convertTo(String.class, it.next());

                    // we should not add headers for the parameters in the uri if we bridge the endpoint
                    // as then we would duplicate headers on both the endpoint uri, and in HTTP headers as well
                    if (skipRequestHeaders != null && skipRequestHeaders.containsKey(key)) {
                        continue;
                    }
                    if (value != null && strategy != null && !strategy.applyFilterToCamelHeaders(key, value, exchange)) {
                        values.add(value);
                    }
                }

                // add the value(s) as a http request header
                if (values.size() > 0) {
                    // use the default toString of a ArrayList to create in the form [xxx, yyy]
                    // if multi valued, for a single value, then just output the value as is
                    String s = values.size() > 1 ? values.toString() : values.get(0);
                    httpExchange.addRequestHeader(key, s);
                }
            }
        }

        // set the callback, which will handle all the response logic
        if (LOG.isDebugEnabled()) {
            LOG.debug("Sending HTTP request to: {}", httpExchange.getUrl());
        }
        httpExchange.send(client);
    }

    public JettyHttpBinding getBinding() {
        return binding;
    }

    public void setBinding(JettyHttpBinding binding) {
        this.binding = binding;
    }

    public HttpClient getClient() {
        return client;
    }

    public void setClient(HttpClient client) {
        this.client = client;
        this.sharedClient = false;
    }

    public HttpClient getSharedClient() {
        if (sharedClient) {
            return client;
        } else {
            return null;
        }
    }

    public void setSharedClient(HttpClient sharedClient) {
        this.client = sharedClient;
        this.sharedClient = true;
    }

    private Object getClientThreadPool() {
        try {
            return client.getClass().getMethod("getThreadPool").invoke(client);
        } catch (Throwable t) {
            // not found in Jetty 9 which is OK as the threadpool is auto started on Jetty 9
        }
        return null;
    }
    
    @Override
    protected void doStart() throws Exception {
        // only start non-shared client
        if (!sharedClient && client != null) {
            client.start();
            // start the thread pool
            Object tp = getClientThreadPool();
            if (tp instanceof LifeCycle) {
                LOG.debug("Starting client thread pool {}", tp);
                ((LifeCycle) tp).start();
            }
        }
        super.doStart();
    }

    @Override
    protected void doStop() throws Exception {
        super.doStop();
        // only stop non-shared client
        if (!sharedClient && client != null) {
            client.stop();
            // stop thread pool
            Object tp = getClientThreadPool();
            if (tp instanceof LifeCycle) {
                LOG.debug("Stopping client thread pool {}", tp);
                ((LifeCycle) tp).stop();
            }
        }
    }
}