// **********************************************************************
//
// Copyright (c) 2003-2007 ZeroC, Inc. All rights reserved.
//
// This copy of Ice is licensed to you under the terms described in the
// ICE_LICENSE file included in this distribution.
//
// **********************************************************************

#include <Ice/Application.h>
#include <IceUtil/StaticMutex.h>
#include <IceUtil/CtrlCHandler.h>
#include <IceUtil/Cond.h>
#include <IceUtil/ArgVector.h>
#include <Ice/GC.h>
#include <memory>

using namespace std;
using namespace Ice;
using namespace IceUtil;
using namespace IceUtilInternal;

//
// _mutex and _condVar are used to synchronize the main thread and
// the CtrlCHandler thread
//
static StaticMutex _mutex = ICE_STATIC_MUTEX_INITIALIZER;
static auto_ptr<Cond> _condVar;

//
// Variables than can change while run() and communicator->destroy() are running!
//
static bool _callbackInProgress = false;
static bool _destroyed = false;
static bool _interrupted = false;
static bool _released = false;
static CtrlCHandlerCallback _previousCallback = 0;

//
// Variables that are immutable during run() and until communicator->destroy() has returned;
// before and after run(), and once communicator->destroy() has returned, we assume that 
// only the main thread and CtrlCHandler threads are running.
//
static const char* _appName = 0;
static Application* _application;
static CommunicatorPtr _communicator;
static CtrlCHandler* _ctrlCHandler = 0;
static bool _nohup = false;
static Application::SignalPolicy _signalPolicy = Application::HandleSignals;

#ifdef _WIN32
const DWORD SIGHUP = CTRL_LOGOFF_EVENT;
#else
#   include <csignal>
#endif

//
// Compaq C++ defines signal() as a macro, causing problems with the _condVar->signal()
// statement, which the compiler for some reason replaces by the macro.
//
#if defined (__digital__) && defined (__unix__)
#   undef signal
#endif

//
// CtrlCHandler callbacks.
//

static void
holdInterruptCallback(int signal)
{
    CtrlCHandlerCallback callback = 0;
    {
        StaticMutex::Lock lock(_mutex);
        while(!_released)
        {
            _condVar->wait(lock);
        }
        
        if(_destroyed)
        {
            //
            // Being destroyed by main thread
            //
            return;
        }
        assert(_ctrlCHandler != 0);
        callback = _ctrlCHandler->getCallback();
    }
    
    if(callback != 0)
    {
        callback(signal);
    }
}

static void
destroyOnInterruptCallback(int signal)
{
    {
        StaticMutex::Lock lock(_mutex);
        if(_destroyed)
        {
            //
            // Being destroyed by main thread
            //
            return;
        }
        if(_nohup && signal == SIGHUP)
        {
            return;
        }

        assert(!_callbackInProgress);
        _callbackInProgress = true;
        _interrupted = true;
        _destroyed = true;
    }
        
    assert(_communicator != 0);
    
    try
    {
        _communicator->destroy();
    }
    catch(const std::exception& ex)
    {
        cerr << _appName << " (while destroying in response to signal " << signal 
             << "): " << ex.what() << endl;
    }
    catch(const std::string& msg)
    {
        cerr << _appName << " (while destroying in response to signal " << signal
             << "): " << msg << endl;
    }
    catch(const char * msg)
    {
        cerr << _appName << " (while destroying in response to signal " << signal
             << "): " << msg << endl;
    }
    catch(...)
    {
        cerr << _appName << " (while destroying in response to signal " << signal 
             << "): unknown exception" << endl;
    }

    {
        StaticMutex::Lock lock(_mutex);
        _callbackInProgress = false;
    }
    _condVar->signal();
}


static void
shutdownOnInterruptCallback(int signal)
{
    {
        StaticMutex::Lock lock(_mutex);
        if(_destroyed)
        {
            //
            // Being destroyed by main thread
            //
            return;
        }
        if(_nohup && signal == SIGHUP)
        {
            return;
        }
        assert(!_callbackInProgress);
        _callbackInProgress = true;
        _interrupted = true;
    }

    assert(_communicator != 0);
    try
    {
        _communicator->shutdown();
    }
    catch(const std::exception& ex)
    {
        cerr << _appName << " (while shutting down in response to signal " << signal 
             << "): std::exception: " << ex.what() << endl;
    }
    catch(const std::string& msg)
    {
        cerr << _appName << " (while shutting down in response to signal " << signal
             << "): " << msg << endl;
    }
    catch(const char * msg)
    {
        cerr << _appName << " (while shutting down in response to signal " << signal
             << "): " << msg << endl;
    }
    catch(...)
    {
        cerr << _appName << " (while shutting down in response to signal " << signal 
             << "): unknown exception" << endl;
    }

    {
        StaticMutex::Lock lock(_mutex);
        _callbackInProgress = false;
    }
    _condVar->signal();
}

static void
callbackOnInterruptCallback(int signal)
{
    {
        StaticMutex::Lock lock(_mutex);
        if(_destroyed)
        {
            //
            // Being destroyed by main thread
            //
            return;
        }
        // For SIGHUP the user callback is always called. It can
        // decide what to do.
        assert(!_callbackInProgress);
        _callbackInProgress = true;
        _interrupted = true;
    }

    assert(_application != 0);
    try
    {
        _application->interruptCallback(signal);
    }
    catch(const std::exception& ex)
    {
        cerr << _appName << " (while interrupting in response to signal " << signal 
             << "): std::exception: " << ex.what() << endl;
    }
    catch(const std::string& msg)
    {
        cerr << _appName << " (while interrupting in response to signal " << signal
             << "): " << msg << endl;
    }
    catch(const char * msg)
    {
        cerr << _appName << " (while interrupting in response to signal " << signal
             << "): " << msg << endl;
    }
    catch(...)
    {
        cerr << _appName << " (while interrupting in response to signal " << signal 
             << "): unknown exception" << endl;
    }

    {
        StaticMutex::Lock lock(_mutex);
        _callbackInProgress = false;
    }
    _condVar->signal();
}


Ice::Application::Application(SignalPolicy signalPolicy)
{
    _signalPolicy = signalPolicy;
}

Ice::Application::~Application()
{
}

int
Ice::Application::main(int argc, char* argv[])
{
    return main(argc, argv, InitializationData());
}

int
Ice::Application::main(int argc, char* argv[], const char* configFile)
{
    //
    // We don't call the main below to avoid a deprecated warning
    //

    InitializationData initData;
    if(configFile)
    {
        try
        {
            initData.properties = createProperties();
            initData.properties->load(configFile);
        }
        catch(const std::exception& ex)
        {
            cerr << argv[0] << ": " << ex.what() << endl;
            return EXIT_FAILURE;
        }
        catch(...)
        {
            cerr << argv[0] << ": unknown exception" << endl;
            return EXIT_FAILURE;
        }
    }
    return main(argc, argv, initData);
}


int
Ice::Application::main(int argc, char* argv[], const InitializationData& initData)
{
    if(_communicator != 0)
    {
        cerr << argv[0] << ": only one instance of the Application class can be used" << endl;
        return EXIT_FAILURE;
    }
    int status;

    if(_signalPolicy == HandleSignals)
    {
        try
        {
            //
            // The ctrlCHandler must be created before starting any thread, in particular
            // before initializing the communicator.
            //
            CtrlCHandler ctrCHandler;
            _ctrlCHandler = &ctrCHandler;

            status = mainInternal(argc, argv, initData);

            //
            // Set _ctrlCHandler to 0 only once communicator->destroy() has completed.
            // 
            _ctrlCHandler = 0;
        }
        catch(const CtrlCHandlerException&)
        {
            cerr << argv[0] << ": only one instance of the Application class can be used" << endl;
            status = EXIT_FAILURE;
        }
    }
    else
    {
        status = mainInternal(argc, argv, initData);
    }
   
    return status;
}

int
Ice::Application::main(int argc, char* argv[], const char* configFile, const Ice::LoggerPtr& logger)
{
    InitializationData initData;
    if(configFile)
    {
        try
        {
            initData.properties = createProperties();
            initData.properties->load(configFile);
        }
        catch(const std::exception& ex)
        {
            cerr << argv[0] << ex.what() << endl;
            return EXIT_FAILURE;
        }
        catch(...)
        {
            cerr << argv[0] << ": unknown exception" << endl;
            return EXIT_FAILURE;
        }
    }
    initData.logger = logger;
    return main(argc, argv, initData);
}

int
Ice::Application::main(const StringSeq& args)
{
    ArgVector av(args);
    return main(av.argc, av.argv);
}

int
Ice::Application::main(const StringSeq& args, const char* configFile)
{
    ArgVector av(args);
    return main(av.argc, av.argv, configFile);
}

int
Ice::Application::main(const StringSeq& args, const InitializationData& initData)
{
    ArgVector av(args);
    return main(av.argc, av.argv, initData);
}

void
Ice::Application::interruptCallback(int)
{
}

const char*
Ice::Application::appName()
{
    return _appName;
}

CommunicatorPtr
Ice::Application::communicator()
{
    return _communicator;
}

void
Ice::Application::destroyOnInterrupt()
{
    if(_signalPolicy == HandleSignals)
    {
        if(_ctrlCHandler != 0)
        {
            StaticMutex::Lock lock(_mutex); // we serialize all the interrupt-setting
            if(_ctrlCHandler->getCallback() == holdInterruptCallback)
            {
                _released = true;
                _condVar->signal();
            }
            _ctrlCHandler->setCallback(destroyOnInterruptCallback);
        }
    }
    else
    {
        cerr << _appName << ": warning: interrupt method called on Application configured to not handle interrupts." 
             << endl;
    }
}

void
Ice::Application::shutdownOnInterrupt()
{
    if(_signalPolicy == HandleSignals)
    {
        if(_ctrlCHandler != 0)
        {
            StaticMutex::Lock lock(_mutex); // we serialize all the interrupt-setting
            if(_ctrlCHandler->getCallback() == holdInterruptCallback)
            {
                _released = true;
                _condVar->signal();
            }
            _ctrlCHandler->setCallback(shutdownOnInterruptCallback);
        }
    }
    else
    {
        cerr << _appName << ": warning: interrupt method called on Application configured to not handle interrupts." 
             << endl;
    }
}

void
Ice::Application::ignoreInterrupt()
{
    if(_signalPolicy == HandleSignals)
    {
        if(_ctrlCHandler != 0)
        {
            StaticMutex::Lock lock(_mutex); // we serialize all the interrupt-setting
            if(_ctrlCHandler->getCallback() == holdInterruptCallback)
            {
                _released = true;
                _condVar->signal();
            }
            _ctrlCHandler->setCallback(0);
        }
    }
    else
    {
        cerr << _appName << ": warning: interrupt method called on Application configured to not handle interrupts." 
             << endl;
    }
}

void
Ice::Application::callbackOnInterrupt()
{
    if(_signalPolicy == HandleSignals)
    {
        if(_ctrlCHandler != 0)
        {
            StaticMutex::Lock lock(_mutex); // we serialize all the interrupt-setting
            if(_ctrlCHandler->getCallback() == holdInterruptCallback)
            {
                _released = true;
                _condVar->signal();
            }
            _ctrlCHandler->setCallback(callbackOnInterruptCallback);
        }
    }
    else
    {
        cerr << _appName << ": warning: interrupt method called on Application configured to not handle interrupts." 
             << endl;
    }
}

void
Ice::Application::holdInterrupt()
{
    if(_signalPolicy == HandleSignals)
    {
        if(_ctrlCHandler != 0)
        {
            StaticMutex::Lock lock(_mutex); // we serialize all the interrupt-setting
            if(_ctrlCHandler->getCallback() != holdInterruptCallback)
            {
                _previousCallback = _ctrlCHandler->getCallback();
                _released = false;
                _ctrlCHandler->setCallback(holdInterruptCallback);
            }
            // else, we were already holding signals
        }
    }
    else
    {
        cerr << _appName << ": warning: interrupt method called on Application configured to not handle interrupts." 
             << endl;
    }
}

void
Ice::Application::releaseInterrupt()
{
    if(_signalPolicy == HandleSignals)
    {
        if(_ctrlCHandler != 0)
        {
            StaticMutex::Lock lock(_mutex); // we serialize all the interrupt-setting
            if(_ctrlCHandler->getCallback() == holdInterruptCallback)
            {
                //
                // Note that it's very possible no signal is held;
                // in this case the callback is just replaced and
                // setting _released to true and signalling _condVar
                // do no harm.
                //
            
                _released = true;
                _ctrlCHandler->setCallback(_previousCallback);
                _condVar->signal();
            }
            // Else nothing to release.
        }
    }
    else
    {
        cerr << _appName << ": warning: interrupt method called on Application configured to not handle interrupts." 
             << endl;
    }
}

bool
Ice::Application::interrupted()
{
    StaticMutex::Lock lock(_mutex);
    return _interrupted;
}

int
Ice::Application::mainInternal(int argc, char* argv[], const InitializationData& initData)
{
    int status;

    try
    {
        if(_condVar.get() == 0)
        {
            _condVar.reset(new Cond);
        }

        _interrupted = false;
        _appName = argv[0];
            
        _application = this;
        _communicator = initialize(argc, argv, initData);
        _destroyed = false;

        //
        // Used by destroyOnInterruptCallback and shutdownOnInterruptCallback.
        //
        _nohup = (_communicator->getProperties()->getPropertyAsInt("Ice.Nohup") > 0);
    
        //
        // The default is to destroy when a signal is received.
        //
        destroyOnInterrupt();
        status = run(argc, argv);
    }
    catch(const std::exception& ex)
    {
        cerr << _appName << ": " << ex.what() << endl;
        status = EXIT_FAILURE;
    }
    catch(const std::string& msg)
    {
        cerr << _appName << ": " << msg << endl;
        status = EXIT_FAILURE;
    }
    catch(const char* msg)
    {
        cerr << _appName << ": " << msg << endl;
        status = EXIT_FAILURE;
    }
    catch(...)
    {
        cerr << _appName << ": unknown exception" << endl;
        status = EXIT_FAILURE;
    }

    //
    // Don't want any new interrupt and at this point (post-run),
    // it would not make sense to release a held signal to run
    // shutdown or destroy.
    //
    ignoreInterrupt();

    {
        StaticMutex::Lock lock(_mutex);
        while(_callbackInProgress)
        {
            _condVar->wait(lock);
        }
        if(_destroyed)
        {
            _communicator = 0;
        }
        else
        {
            _destroyed = true;
            //
            // And _communicator != 0, meaning will be destroyed
            // next, _destroyed = true also ensures that any
            // remaining callback won't do anything
            //
        }
        _application = 0;
    }

    if(_communicator != 0)
    {  
        try
        {
            _communicator->destroy();
        }
        catch(const std::exception& ex)
        {
            cerr << _appName << ex.what() << endl;
            status = EXIT_FAILURE;
        }
        catch(...)
        {
            cerr << _appName << ": unknown exception" << endl;
            status = EXIT_FAILURE;
        }
        _communicator = 0;
    }

    return status;
}