/*
 *
 * 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.
 *
 */
#include "qpid/broker/SessionState.h"
#include "qpid/broker/Broker.h"
#include "qpid/broker/ConnectionState.h"
#include "qpid/broker/DeliveryRecord.h"
#include "qpid/broker/SessionManager.h"
#include "qpid/broker/SessionHandler.h"
#include "qpid/broker/RateFlowcontrol.h"
#include "qpid/broker/Timer.h"
#include "qpid/framing/AMQContentBody.h"
#include "qpid/framing/AMQHeaderBody.h"
#include "qpid/framing/AMQMethodBody.h"
#include "qpid/framing/reply_exceptions.h"
#include "qpid/framing/ServerInvoker.h"
#include "qpid/log/Statement.h"
#include "qpid/management/ManagementAgent.h"
#include "qpid/framing/AMQP_ClientProxy.h"

#include <boost/bind.hpp>
#include <boost/lexical_cast.hpp>

namespace qpid {
namespace broker {

using namespace framing;
using sys::Mutex;
using boost::intrusive_ptr;
using qpid::management::ManagementAgent;
using qpid::management::ManagementObject;
using qpid::management::Manageable;
using qpid::management::Args;
using qpid::sys::AbsTime;
namespace _qmf = qmf::org::apache::qpid::broker;

SessionState::SessionState(
    Broker& b, SessionHandler& h, const SessionId& id, const SessionState::Configuration& config)
    : qpid::SessionState(id, config),
      broker(b), handler(&h),
      semanticState(*this, *this),
      adapter(semanticState),
      msgBuilder(&broker.getStore(), broker.getStagingThreshold()),
      enqueuedOp(boost::bind(&SessionState::enqueued, this, _1)),
      mgmtObject(0),
      rateFlowcontrol(0)
{
    uint32_t maxRate = broker.getOptions().maxSessionRate;
    if (maxRate) {
        if (handler->getConnection().getClientThrottling()) {
            rateFlowcontrol.reset(new RateFlowcontrol(maxRate));
        } else {
            QPID_LOG(warning, getId() << ": Unable to flow control client - client doesn't support");
        }
    }
    Manageable* parent = broker.GetVhostObject ();
    if (parent != 0) {
        ManagementAgent* agent = getBroker().getManagementAgent();
        if (agent != 0) {
            mgmtObject = new _qmf::Session
                (agent, this, parent, getId().getName());
            mgmtObject->set_attached (0);
            mgmtObject->set_detachedLifespan (0);
            mgmtObject->clr_expireTime();
            if (rateFlowcontrol) mgmtObject->set_maxClientRate(maxRate);
            agent->addObject (mgmtObject, agent->allocateId(this));
        }
    }
    attach(h);
}

SessionState::~SessionState() {
    if (mgmtObject != 0)
        mgmtObject->resourceDestroy ();

    if (flowControlTimer)
        flowControlTimer->cancel();
}

AMQP_ClientProxy& SessionState::getProxy() {
    assert(isAttached());
    return handler->getProxy();
}

uint16_t SessionState::getChannel() const {
    assert(isAttached());
    return handler->getChannel();
}

ConnectionState& SessionState::getConnection() {
    assert(isAttached());
    return handler->getConnection();
}

bool SessionState::isLocal(const ConnectionToken* t) const
{
    return isAttached() && &(handler->getConnection()) == t;
}

void SessionState::detach() {
    QPID_LOG(debug, getId() << ": detached on broker.");
    disableOutput();
    handler = 0;
    if (mgmtObject != 0)
        mgmtObject->set_attached  (0);
}

void SessionState::disableOutput()
{
    semanticState.detached(); //prevents further activateOutput calls until reattached
}

void SessionState::attach(SessionHandler& h) {
    QPID_LOG(debug, getId() << ": attached on broker.");
    handler = &h;
    if (mgmtObject != 0)
    {
        mgmtObject->set_attached (1);
        mgmtObject->set_connectionRef (h.getConnection().GetManagementObject()->getObjectId());
        mgmtObject->set_channelId (h.getChannel());
    }
}

void SessionState::abort() {
    if (isAttached())
        getConnection().outputTasks.abort();
}

void SessionState::activateOutput() {
    if (isAttached())
        getConnection().outputTasks.activateOutput();
}

void SessionState::giveReadCredit(int32_t credit) {
    if (isAttached())
        getConnection().outputTasks.giveReadCredit(credit);
}

ManagementObject* SessionState::GetManagementObject (void) const
{
    return (ManagementObject*) mgmtObject;
}

Manageable::status_t SessionState::ManagementMethod (uint32_t methodId,
                                                     Args&    /*args*/,
                                                     string&  /*text*/)
{
    Manageable::status_t status = Manageable::STATUS_UNKNOWN_METHOD;

    switch (methodId)
    {
    case _qmf::Session::METHOD_DETACH :
        if (handler != 0) {
            handler->sendDetach();
        }
        status = Manageable::STATUS_OK;
        break;

    case _qmf::Session::METHOD_CLOSE :
        /*
          if (handler != 0)
          {
          handler->getConnection().closeChannel(handler->getChannel());
          }
          status = Manageable::STATUS_OK;
          break;
        */

    case _qmf::Session::METHOD_SOLICITACK :
    case _qmf::Session::METHOD_RESETLIFESPAN :
        status = Manageable::STATUS_NOT_IMPLEMENTED;
        break;
    }

    return status;
}

void SessionState::handleCommand(framing::AMQMethodBody* method, const SequenceNumber& id) {
    Invoker::Result invocation = invoke(adapter, *method);
    receiverCompleted(id);
    if (!invocation.wasHandled()) {
        throw NotImplementedException(QPID_MSG("Not implemented: " << *method));
    } else if (invocation.hasResult()) {
        getProxy().getExecution().result(id, invocation.getResult());
    }
    if (method->isSync()) {
        incomplete.process(enqueuedOp, true);
        sendAcceptAndCompletion();
    }
}

struct ScheduledCreditTask : public TimerTask {
    Timer& timer;
    SessionState& sessionState;
    ScheduledCreditTask(const qpid::sys::Duration& d, Timer& t,
                        SessionState& s) :
        TimerTask(d),
        timer(t),
        sessionState(s)
    {}

    void fire() {
        // This is the best we can currently do to avoid a destruction/fire race
        if (!isCancelled()) {
            sessionState.getConnection().requestIOProcessing(boost::bind(&ScheduledCreditTask::sendCredit, this));
        }
    }

    void sendCredit() {
        if ( !sessionState.processSendCredit(0) ) {
            QPID_LOG(warning, sessionState.getId() << ": Reschedule sending credit");
            reset();
            timer.add(this);
        }
    }
};

void SessionState::handleContent(AMQFrame& frame, const SequenceNumber& id)
{
    if (frame.getBof() && frame.getBos()) //start of frameset
        msgBuilder.start(id);
    intrusive_ptr<Message> msg(msgBuilder.getMessage());
    msgBuilder.handle(frame);
    if (frame.getEof() && frame.getEos()) {//end of frameset
        if (frame.getBof()) {
            //i.e this is a just a command frame, add a dummy header
            AMQFrame header((AMQHeaderBody()));
            header.setBof(false);
            header.setEof(false);
            msg->getFrames().append(header);
        }
        msg->setPublisher(&getConnection());
        semanticState.handle(msg);
        msgBuilder.end();

        if (msg->isEnqueueComplete()) {
            enqueued(msg);
        } else {
            incomplete.add(msg);
        }

        //hold up execution until async enqueue is complete
        if (msg->getFrames().getMethod()->isSync()) {
            incomplete.process(enqueuedOp, true);
            sendAcceptAndCompletion();
        } else {
            incomplete.process(enqueuedOp, false);
        }
    }

    // Handle producer session flow control
    if (rateFlowcontrol && frame.getBof() && frame.getBos()) {
        if ( !processSendCredit(1) ) {
            QPID_LOG(debug, getId() << ": Schedule sending credit");
            Timer& timer = getBroker().getTimer();
            // Use heuristic for scheduled credit of time for 50 messages, but not longer than 500ms
            sys::Duration d = std::min(sys::TIME_SEC * 50 / rateFlowcontrol->getRate(), 500 * sys::TIME_MSEC);
            flowControlTimer = new ScheduledCreditTask(d, timer, *this);
            timer.add(flowControlTimer);
        }
    }
}

bool SessionState::processSendCredit(uint32_t msgs)
{
    qpid::sys::ScopedLock<Mutex> l(rateLock);
    // Check for violating flow control
    if ( msgs > 0 && rateFlowcontrol->flowStopped() ) {
        QPID_LOG(warning, getId() << ": producer throttling violation");
        // TODO: Probably do message.stop("") first time then disconnect
        // See comment on getClusterOrderProxy() in .h file
        getClusterOrderProxy().getMessage().stop("");
        return true;
    }
    AbsTime now = AbsTime::now();
    uint32_t sendCredit = rateFlowcontrol->receivedMessage(now, msgs);
    if (mgmtObject) mgmtObject->dec_clientCredit(msgs);
    if ( sendCredit>0 ) {
        QPID_LOG(debug, getId() << ": send producer credit " << sendCredit);
        getClusterOrderProxy().getMessage().flow("", 0, sendCredit);
        rateFlowcontrol->sentCredit(now, sendCredit);
        if (mgmtObject) mgmtObject->inc_clientCredit(sendCredit);
        return true;
    } else {
        return !rateFlowcontrol->flowStopped() ;
    }
}

void SessionState::sendAcceptAndCompletion()
{
    if (!accepted.empty()) {
        getProxy().getMessage().accept(accepted);
        accepted.clear();
    }
    sendCompletion();
}

void SessionState::enqueued(boost::intrusive_ptr<Message> msg)
{
    receiverCompleted(msg->getCommandId());
    if (msg->requiresAccept())
        accepted.add(msg->getCommandId());
}

void SessionState::handleIn(AMQFrame& frame) {
    SequenceNumber commandId = receiverGetCurrent();
    //TODO: make command handling more uniform, regardless of whether
    //commands carry content.
    AMQMethodBody* m = frame.getMethod();
    if (m == 0 || m->isContentBearing()) {
        handleContent(frame, commandId);
    } else if (frame.getBof() && frame.getEof()) {
        handleCommand(frame.getMethod(), commandId);
    } else {
        throw InternalErrorException("Cannot handle multi-frame command segments yet");
    }
}

void SessionState::handleOut(AMQFrame& frame) {
    assert(handler);
    handler->out(frame);
}

void SessionState::deliver(DeliveryRecord& msg, bool sync)
{
    uint32_t maxFrameSize = getConnection().getFrameMax();
    assert(senderGetCommandPoint().offset == 0);
    SequenceNumber commandId = senderGetCommandPoint().command;
    msg.deliver(getProxy().getHandler(), commandId, maxFrameSize);
    assert(senderGetCommandPoint() == SessionPoint(commandId+1, 0)); // Delivery has moved sendPoint.
    if (sync) {
        AMQP_ClientProxy::Execution& p(getProxy().getExecution());
        Proxy::ScopedSync s(p);
        p.sync();
    }
}

void SessionState::sendCompletion() {
    handler->sendCompletion();
}

void SessionState::senderCompleted(const SequenceSet& commands) {
    qpid::SessionState::senderCompleted(commands);
    for (SequenceSet::RangeIterator i = commands.rangesBegin(); i != commands.rangesEnd(); i++)
        semanticState.completed(i->first(), i->last());
}

void SessionState::readyToSend() {
    QPID_LOG(debug, getId() << ": ready to send, activating output.");
    assert(handler);
    semanticState.attached();
    if (rateFlowcontrol) {
        qpid::sys::ScopedLock<Mutex> l(rateLock);
        // Issue initial credit - use a heuristic here issue min of 300 messages or 1 secs worth
        uint32_t credit = std::min(rateFlowcontrol->getRate(), 300U);
        QPID_LOG(debug, getId() << ": Issuing producer message credit " << credit);
        // See comment on getClusterOrderProxy() in .h file
        getClusterOrderProxy().getMessage().setFlowMode("", 0);
        getClusterOrderProxy().getMessage().flow("", 0, credit);
        rateFlowcontrol->sentCredit(AbsTime::now(), credit);
        if (mgmtObject) mgmtObject->inc_clientCredit(credit);
    }
}

Broker& SessionState::getBroker() { return broker; }

framing::AMQP_ClientProxy& SessionState::getClusterOrderProxy() {
    return handler->getClusterOrderProxy();
}

}} // namespace qpid::broker
