/*
 *
 * 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/cluster/Multicaster.h"
#include "qpid/cluster/Cpg.h"
#include "qpid/log/Statement.h"
#include "qpid/framing/AMQBody.h"
#include "qpid/framing/AMQFrame.h"
#include <boost/bind.hpp>
#include <algorithm>

namespace qpid {
namespace cluster {

static const int MCAST_IOV_MAX=63; // Limit imposed by CPG

Multicaster::Multicaster(Cpg& cpg_, 
                         const boost::shared_ptr<sys::Poller>& poller,
                         boost::function<void()> onError_) :
#if defined (QPID_LATENCY_TRACKER)
    cpgLatency("CPG"),
#endif
    onError(onError_), cpg(cpg_), 
    queue(boost::bind(&Multicaster::sendMcast, this, _1), poller),
    holding(true),
    ioVector(MCAST_IOV_MAX)
{
    queue.start();
}

void Multicaster::mcastControl(const framing::AMQBody& body, const ConnectionId& id) {
    QPID_LOG(trace, "MCAST " << id << ": " << body);
    mcast(Event::control(body, id));
}

void Multicaster::mcastControl(const framing::AMQFrame& frame, const ConnectionId& id) {
    QPID_LOG(trace, "MCAST " << id << ": " << frame);
    mcast(Event::control(frame, id));
}

void Multicaster::mcastBuffer(const char* data, size_t size, const ConnectionId& id) {
    Event e(DATA, id, size);
    memcpy(e.getData(), data, size);
    QPID_LOG(trace, "MCAST " << e);
    mcast(e);
}

void Multicaster::mcast(const Event& e) {
    {
        sys::Mutex::ScopedLock l(lock);
        LATENCY_TRACK(cpgLatency.start());
        if (e.isConnection() && holding) {
            holdingQueue.push_back(e); 
            return;
        }
    }
    queue.push(e);
}

Multicaster::PollableEventQueue::Batch::const_iterator Multicaster::sendMcast(
    const PollableEventQueue::Batch& events)
{
    PollableEventQueue::Batch::const_iterator i = events.begin();
    try {
        while (i < events.end()) {
            size_t count = std::min(MCAST_IOV_MAX, int(events.end() - i));
            std::transform(i, i+count, ioVector.begin(),
                           boost::bind(&Event::toIovec, _1));
            if (!cpg.mcast(&ioVector.front(), count)) {
                QPID_LOG(trace, "CPG flow control, will resend "
                         << events.end() - i << " events");
                break;
            }
            i += count;
        }
    }
    catch (const std::exception& e) {
        QPID_LOG(critical, "Multicast error: " << e.what());
        queue.stop();
        onError();
    }
    return i;
}

void Multicaster::release() {
    sys::Mutex::ScopedLock l(lock);
    holding = false;
    std::for_each(holdingQueue.begin(), holdingQueue.end(), boost::bind(&Multicaster::mcast, this, _1));
    holdingQueue.clear();
}

}} // namespace qpid::cluster