/*
 *  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.synapse.core.axis2;

import org.apache.axis2.AxisFault;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.synapse.*;
import org.apache.synapse.aspects.ComponentType;
import org.apache.synapse.aspects.statistics.StatisticsReporter;
import org.apache.synapse.endpoints.Endpoint;
import org.apache.synapse.mediators.MediatorFaultHandler;

/**
 * This is the MessageReceiver set to act on behalf of Proxy services.
 */
public class ProxyServiceMessageReceiver extends SynapseMessageReceiver {

    private static final Log log = LogFactory.getLog(ProxyServiceMessageReceiver.class);
    private static final Log trace = LogFactory.getLog(SynapseConstants.TRACE_LOGGER);

    /**
     * LogFactory instance used to look up the service log. Note that the lookup of the LogFactory
     * is relatively expensive, while the lookup of the Log instance is very fast.
     */
    private static final LogFactory logFactory = LogFactory.getFactory();
    
    /** The name of the Proxy Service */
    private String name = null;
    /** The proxy service */
    private ProxyService proxy = null;

    public void receive(org.apache.axis2.context.MessageContext mc) throws AxisFault {

        boolean traceOn = proxy.getTraceState() == SynapseConstants.TRACING_ON;
        boolean traceOrDebugOn = traceOn || log.isDebugEnabled();

        String remoteAddr = (String) mc.getProperty(
            org.apache.axis2.context.MessageContext.REMOTE_ADDR);

        if (traceOrDebugOn) {
            traceOrDebug(traceOn, "Proxy Service " + name + " received a new message" +
                (remoteAddr != null ? " from : " + remoteAddr : "..."));
            traceOrDebug(traceOn, ("Message To: " +
                (mc.getTo() != null ? mc.getTo().getAddress() : "null")));
            traceOrDebug(traceOn, ("SOAPAction: " +
                (mc.getSoapAction() != null ? mc.getSoapAction() : "null")));
            traceOrDebug(traceOn, ("WSA-Action: " +
                (mc.getWSAAction() != null ? mc.getWSAAction() : "null")));

            if (traceOn && trace.isTraceEnabled()) {
                String[] cids = mc.getAttachmentMap().getAllContentIDs();
                if (cids != null && cids.length > 0) {
                    for (String cid : cids) {
                        trace.trace("With attachment content ID : " + cid);
                    }
                }
                trace.trace("Envelope : " + mc.getEnvelope());
            }
        }

        MessageContext synCtx = MessageContextCreatorForAxis2.getSynapseMessageContext(mc);

        StatisticsReporter.reportForComponent(synCtx,
                proxy.getAspectConfiguration(),
                ComponentType.PROXYSERVICE);
        
        // get service log for this message and attach to the message context also set proxy name
        Log serviceLog = logFactory.getInstance(SynapseConstants.SERVICE_LOGGER_PREFIX + name);
        ((Axis2MessageContext) synCtx).setServiceLog(serviceLog);

        synCtx.setProperty(SynapseConstants.PROXY_SERVICE, name);
        synCtx.setTracingState(proxy.getTraceState());

        try {            

            Mediator mandatorySeq = synCtx.getConfiguration().getMandatorySequence();
            if (mandatorySeq != null) {
                if (log.isDebugEnabled()) {
                    log.debug("Start mediating the message in the " +
                        "pre-mediate state using the mandatory sequence");
                }

                if(!mandatorySeq.mediate(synCtx)) {
                    if(log.isDebugEnabled()) {
                        log.debug("Request message for the proxy service " + name + " dropped in " +
                                "the pre-mediation state by the mandatory sequence : \n" + synCtx);
                    }
                    return;
                }
            }

            // setup fault sequence - i.e. what happens when something goes wrong with this message
            if (proxy.getTargetFaultSequence() != null) {

                Mediator faultSequence = synCtx.getSequence(proxy.getTargetFaultSequence());
                if (faultSequence != null) {
                    if (traceOrDebugOn) {
                        traceOrDebug(traceOn,
                            "Setting the fault-sequence to : " + faultSequence);
                    }
                    synCtx.pushFaultHandler(new MediatorFaultHandler(
                        synCtx.getSequence(proxy.getTargetFaultSequence())));

                } else {
                    // when we can not find the reference to the fault sequence of the proxy
                    // service we should not throw an exception because still we have the global
                    // fault sequence and the message mediation can still continue
                    traceOrDebug(traceOn, "Unable to find fault-sequence : " +
                        proxy.getTargetFaultSequence() + "; using default fault sequence");
                    synCtx.pushFaultHandler(new MediatorFaultHandler(synCtx.getFaultSequence()));
                }

            } else if (proxy.getTargetInLineFaultSequence() != null) {
                if (traceOrDebugOn) {
                    traceOrDebug(traceOn, "Setting specified anonymous fault-sequence for proxy");
                }
                synCtx.pushFaultHandler(
                    new MediatorFaultHandler(proxy.getTargetInLineFaultSequence()));
            }

            boolean inSequenceResult = true;

            // Using inSequence for the incoming message mediation
            if (proxy.getTargetInSequence() != null) {

                Mediator inSequence = synCtx.getSequence(proxy.getTargetInSequence());
                if (inSequence != null) {
                    traceOrDebug(traceOn, "Using sequence named : "
                        + proxy.getTargetInSequence() + " for incoming message mediation");
                    inSequenceResult = inSequence.mediate(synCtx);

                } else {
                    handleException("Unable to find in-sequence : "
                            + proxy.getTargetInSequence(), synCtx);
                }

            } else if (proxy.getTargetInLineInSequence() != null) {
                traceOrDebug(traceOn, "Using the anonymous " +
                    "in-sequence of the proxy service for mediation");
                inSequenceResult = proxy.getTargetInLineInSequence().mediate(synCtx);
            }

            // if inSequence returns true, forward message to endpoint
            if(inSequenceResult) {
                if (proxy.getTargetEndpoint() != null) {
                    Endpoint endpoint = synCtx.getEndpoint(proxy.getTargetEndpoint());

                    if (endpoint != null) {
                        traceOrDebug(traceOn, "Forwarding message to the endpoint : "
                            + proxy.getTargetEndpoint());
                        endpoint.send(synCtx);

                    } else {
                        handleException("Unable to find the endpoint specified : " +
                            proxy.getTargetEndpoint(), synCtx);
                    }

                } else if (proxy.getTargetInLineEndpoint() != null) {
                    traceOrDebug(traceOn, "Forwarding the message to the anonymous " +
                        "endpoint of the proxy service");
                    proxy.getTargetInLineEndpoint().send(synCtx);
                }
            }

        } catch (SynapseException syne) {

            if (!synCtx.getFaultStack().isEmpty()) {
                warn(traceOn, "Executing fault handler due to exception encountered", synCtx);
                (synCtx.getFaultStack().pop()).handleFault(synCtx, syne);
            } else {
                warn(traceOn, "Exception encountered but no fault handler found - " +
                    "message dropped", synCtx);
            }
            throw syne;
        } finally {
            StatisticsReporter.endReportForAllOnRequestProcessed(synCtx);
        }
    }

    /**
     * Set the name of the corresponding proxy service
     *
     * @param name the proxy service name
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * Set reference to actual proxy service
     * @param proxy  ProxyService instance
     */
    public void setProxy(ProxyService proxy) {
        this.proxy = proxy;
    }

    private void traceOrDebug(boolean traceOn, String msg) {
        if (traceOn) {
            trace.info(msg);
        }
        if (log.isDebugEnabled()) {
            log.debug(msg);
        }
    }

    private void warn(boolean traceOn, String msg, MessageContext msgContext) {
        if (traceOn) {
            trace.warn(msg);
        }
        if (log.isDebugEnabled()) {
            log.warn(msg);
        }
        if (msgContext.getServiceLog() != null) {
            msgContext.getServiceLog().warn(msg);
        }
    }

    private void handleException(String msg, MessageContext msgContext) {
        log.error(msg);
        if (msgContext.getServiceLog() != null) {
            msgContext.getServiceLog().error(msg);
        }
        if (proxy.getTraceState() == SynapseConstants.TRACING_ON) {
            trace.error(msg);
        }
        throw new SynapseException(msg);
    }

}
