//
// This file is part of an OMNeT++/OMNEST simulation example.
//
// Copyright (C) 2006-2015 OpenSim Ltd.
//
// This file is distributed WITHOUT ANY WARRANTY. See the file
// `license' for details on this and other legal matters.
//

#include "Server.h"
#include "Job.h"
#include "SelectionStrategies.h"
#include "IPassiveQueue.h"

namespace queueing {

Define_Module(Server);

Server::Server()
{
    selectionStrategy = nullptr;
    jobServiced = nullptr;
    endServiceMsg = nullptr;
    allocated = false;
}

Server::~Server()
{
    delete selectionStrategy;
    delete jobServiced;
    cancelAndDelete(endServiceMsg);
}

void Server::initialize()
{
    busySignal = registerSignal("busy");
    emit(busySignal, false);

    endServiceMsg = new cMessage("end-service");
    jobServiced = nullptr;
    allocated = false;
    selectionStrategy = SelectionStrategy::create(par("fetchingAlgorithm"), this, true);
    if (!selectionStrategy)
        throw cRuntimeError("invalid selection strategy");
}

void Server::handleMessage(cMessage *msg)
{
    if (msg == endServiceMsg) {
        ASSERT(jobServiced != nullptr);
        ASSERT(allocated);
        simtime_t d = simTime() - endServiceMsg->getSendingTime();
        jobServiced->setTotalServiceTime(jobServiced->getTotalServiceTime() + d);
        send(jobServiced, "out");
        jobServiced = nullptr;
        allocated = false;
        emit(busySignal, false);

        // examine all input queues, and request a new job from a non empty queue
        int k = selectionStrategy->select();
        if (k >= 0) {
            EV << "requesting job from queue " << k << endl;
            cGate *gate = selectionStrategy->selectableGate(k);
            check_and_cast<IPassiveQueue *>(gate->getOwnerModule())->request(gate->getIndex());
        }
    }
    else {
        if (!allocated)
            error("job arrived, but the sender did not call allocate() previously");
        if (jobServiced)
            throw cRuntimeError("a new job arrived while already servicing one");

        jobServiced = check_and_cast<Job *>(msg);
        simtime_t serviceTime = par("serviceTime");
        scheduleAt(simTime()+serviceTime, endServiceMsg);
        emit(busySignal, true);
    }
}

void Server::refreshDisplay() const
{
    getDisplayString().setTagArg("i2", 0, jobServiced ? "status/execute" : "");
}

void Server::finish()
{
}

bool Server::isIdle()
{
    return !allocated;  // we are idle if nobody has allocated us for processing
}

void Server::allocate()
{
    allocated = true;
}

}; //namespace