/**
 * @file main/GUI/exithandler.cpp
 * @brief Exit handlers for the eVaf main executable
 * @author Enar Vaikene
 *
 * Copyright (c) 2011 Enar Vaikene
 *
 * This file is part of the eVaf C++ cross-platform application development framework.
 *
 * This file can be used under the terms of the GNU General Public License
 * version 3.0 as published by the Free Software Foundation and appearing in
 * the file LICENSE included in the packaging of this file. Please review the
 * the following information to ensure the GNU General Public License version
 * 3.0 requirements will be met: http://www.gnu.org/copyleft/gpl.html.
 *
 * Alternatively, this file may be used in accordance with the Commercial License
 * Agreement provided with the Software.
 */

#include "exithandler.h"

#include <Common/iLogger>
#include <Common/iApp>

#include <QtCore>

#ifdef Q_OS_LINUX
#  include <signal.h>
#endif

#ifdef Q_OS_WIN32
#  include <windows.h>
#endif

namespace eVaf {
namespace GUI {
namespace Internal {

#ifdef Q_OS_LINUX

/**
 * Signal handler on Linux
 *
 * Handles TERM and HUP signals and either quits or restarts the application.
 *
 * @TODO According to the signal(7) documentation, only "safe" functions can be called from the
 * signal handler. We don't know how safe it is to call iApp::quit() and iApp::restart() and
 * probably have to implement "safe" versions of these functions.
 */
static void signalHandler(int sig)
{
    eVaf::Common::iApp * app = eVaf::Common::iApp::instance();

    switch (sig) {
        case SIGTERM:
            if (app)
                app->quit();
            else
                exit(0);
            break;
        case SIGHUP:
            if (app)
                app->restart();
            break;
    }
}

#endif

#ifdef Q_OS_WIN32

/**
 * Signal handler on Windows
 *
 * Either quits or restarts the application.
 *
 * @TODO Is there a similar concept of "safe" functions for Windows signal handlers?
 */
static BOOL WINAPI signalHandler(DWORD sig)
{
    eVaf::Common::iApp * app = eVaf::Common::iApp::instance();

    switch (sig) {
        case CTRL_C_EVENT:
        case CTRL_CLOSE_EVENT:
        case CTRL_LOGOFF_EVENT:
        case CTRL_SHUTDOWN_EVENT:
            if (app)
                app->quit();
            else
                exit(0);
            return true;
            break;
        case CTRL_BREAK_EVENT:
            if (app)
                app->restart();
            return true;
            break;
    }

    return false;
}

#endif

} // namespace eVaf::GUI::Internal
} // namespace eVaf::GUI
} // namespace eVaf

using namespace eVaf::GUI::Internal;

bool installExitHandler()
{

#ifdef Q_OS_LINUX
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    sa.sa_handler = signalHandler;
    if (sigaction(SIGTERM, &sa, NULL) != 0) {
        EVAF_FATAL_ERROR("sigaction() failed: %m");
        return false;
    }
    if (sigaction(SIGHUP, &sa, NULL) != 0) {
        EVAF_FATAL_ERROR("sigaction() failed: %m");
        return false;
    }
#endif

#ifdef Q_OS_WIN32
    if (SetConsoleCtrlHandler(signalHandler, true) == 0) {
        EVAF_FATAL_ERROR("SetConsoleCtrlHandler() failed");
        return false;
    }
#endif

    return true;
}