/**
 * @file Common/app.cpp
 * @brief Application interface implementation
 * @author Enar Vaikene
 *
 * Copyright (c) 2011-2019 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 "app.h"
#include "globals.h"
#include "iregistry.h"
#include "ieventqueue.h"
#include "event.h"
#include "version.h"

#include <QtCore>


//-------------------------------------------------------------------

using namespace eVaf::Common;

namespace
{
    static Internal::App * singleton = nullptr;
}

iApp * iApp::instance()
{
    if (nullptr == singleton)
    {
        singleton = new Internal::App;
    }
    return singleton;
}

char const * const iApp::EV_QUIT = "iApp::quit";
char const * const iApp::EV_RESTART = "iApp::restart";
char const * const iApp::EV_READY = "iApp::ready";
char const * const iApp::EV_TERMINATING = "iApp::terminating";


//-------------------------------------------------------------------

using namespace eVaf::Common::Internal;

void App::destroyInstance()
{
    if (nullptr != singleton)
    {
        delete singleton;
        singleton = nullptr;
    }
}

App::App()
    : iApp()
    , mReady(false)
    , mName(VER_PRODUCT_NAME_STR)
    , mEvQuit(0)
    , mEvRestart(0)
    , mEvReady(0)
    , mEvTerminating(0)
{
    setObjectName(QString("%1.iApp").arg(VER_MODULE_NAME_STR));
    EVAF_INFO("%s-App created", VER_MODULE_NAME_STR);
}

App::~App()
{
    EVAF_INFO("%s-App destroyed", VER_MODULE_NAME_STR);
}

bool App::init()
{
    // Register our interface
    iRegistry::instance()->registerInterface("iApp", this);

    // Register events
    mEvQuit = iEventQueue::instance()->subscribeEvent(iEventQueue::instance()->registerEvent(EV_QUIT), this);
    mEvRestart = iEventQueue::instance()->subscribeEvent(iEventQueue::instance()->registerEvent(EV_RESTART), this);
    mEvReady = iEventQueue::instance()->registerEvent(EV_READY);
    mEvTerminating = iEventQueue::instance()->registerEvent(EV_TERMINATING);

    // Set the default application name and language
    mName = VER_PRODUCT_NAME_STR;
    mLanguage = QLocale::system().name();

    // Clear the XML file name
    mXmlFile.clear();

    // Set initial bin and root directories
    mRootDir = mBinDir = qApp->applicationDirPath();
    int t = mBinDir.lastIndexOf(QChar('/'), -1);
    if (t >= 0)
        mRootDir = mBinDir.left(t);

    if (!mBinDir.endsWith('/'))
        mBinDir.append('/');
    if (!mRootDir.endsWith('/'))
        mRootDir.append('/');

    // Clear other directories
    mDataRootDir.clear();
    mQtPluginsDir.clear();
    mEtcDir.clear();
    mLogDir.clear();
    mDocDir.clear();

    // Process environment variables
    QStringList env = QProcess::systemEnvironment();
    for (int i = 0; i < env.size(); ++i) {
        // Get the name/value pair
        QString name = env.at(i).section('=', 0, 0).trimmed();
        QString value = env.at(i).section('=', 1).trimmed();

        if (name == "EVAF_APP_NAME")
            mName = value;
        else if (name == "EVAF_LANGUAGE")
            mLanguage = value;
        else if (name == "EVAF_ROOT_DIR") {
            mRootDir = value;
            if (!mRootDir.endsWith('/'))
                mRootDir.append('/');
        }
        else if (name == "EVAF_DATA_ROOT_DIR") {
            mDataRootDir = value;
            if (!mDataRootDir.endsWith('/'))
                mDataRootDir.append('/');
        }
        else if (name == "EVAF_ETC_DIR") {
            mEtcDir = value;
            if (!mEtcDir.endsWith('/'))
                mEtcDir.append('/');
        }
        else if (name == "EVAF_LOG_DIR") {
            mLogDir = value;
            if (!mLogDir.endsWith('/'))
                mLogDir.append('/');
        }
        else if (name == "EVAF_DOC_DIR") {
            mDocDir = value;
            if (!mDocDir.endsWith('/'))
                mDocDir.append('/');
        }
        else if (name == "EVAF_QT_PLUGINS_DIR") {
            mQtPluginsDir = value;
            if (!mQtPluginsDir.endsWith('/'))
                mQtPluginsDir.append('/');
        }
    }

    // Then process command-line arguments
    env = QCoreApplication::arguments();
    for (int i = 0; i < env.size(); ++i) {
        // Get the name and optional value
        QStringList arg = env.at(i).simplified().split('=');

        if (QRegExp("-[-]?app(lication)?").exactMatch(arg.at(0)) && arg.size() > 1)
            mName = arg.at(1);
        else if (QRegExp("-[-]?lang(uage)?").exactMatch(arg.at(0)) && arg.size() > 1)
            mLanguage = arg.at(1);
        else if (QRegExp("-[-]?root(dir)?").exactMatch(arg.at(0)) && arg.size() > 1) {
            mRootDir = arg.at(1);
            if (!mRootDir.endsWith('/'))
                mRootDir.append('/');
        }
        else if (QRegExp("-[-]?dataroot(dir)?").exactMatch(arg.at(0)) && arg.size() > 1) {
            mDataRootDir = arg.at(1);
            if (!mDataRootDir.endsWith('/'))
                mDataRootDir.append('/');
        }
        else if (QRegExp("-[-]?etc(dir)?").exactMatch(arg.at(0)) && arg.size() > 1) {
            mEtcDir = arg.at(1);
            if (!mEtcDir.endsWith('/'))
                mEtcDir.append('/');
        }
        else if (QRegExp("-[-]?log(dir)?").exactMatch(arg.at(0)) && arg.size() > 1) {
            mLogDir = arg.at(1);
            if (!mLogDir.endsWith('/'))
                mLogDir.append('/');
        }
        else if (QRegExp("-[-]?doc(dir)?").exactMatch(arg.at(0)) && arg.size() > 1) {
            mDocDir = arg.at(1);
            if (!mDocDir.endsWith('/'))
                mDocDir.append('/');
        }
        else if (QRegExp("-[-]?qtplugins(dir)?").exactMatch(arg.at(0)) && arg.size() > 1) {
            mQtPluginsDir = arg.at(1);
            if (!mQtPluginsDir.endsWith('/'))
                mQtPluginsDir.append('/');
        }
    }

    return true;
}

bool App::event(QEvent * e)
{
    if (e->type() == Event::eVafEvent) {
        Event * event = static_cast<Event *>(e);
        if (event->id() == mEvQuit)
            quit();
        else if (event->id() == mEvRestart)
            restart();

        return false;
    }
    else
        return iApp::event(e);
}

QString const App::dataRootDir() const
{
    if (mDataRootDir.isEmpty()) {
#if defined(Q_OS_LINUX) || defined(Q_OS_MACOS)
        QString dataLoc = QDir::homePath();
        if (!dataLoc.endsWith('/'))
            dataLoc.append('/');
        dataLoc.append(".local/share/data/");
        mDataRootDir = dataLoc + name();
        if (!mDataRootDir.endsWith('/'))
            mDataRootDir.append('/');
#endif
        /// @TODO: Needs local data directory on Windows
        mDataRootDir = rootDir();
    }

    return mDataRootDir;
}

QString const App::etcDir() const
{
    if (mEtcDir.isEmpty())
        mEtcDir = dataRootDir() + "etc/";
    return mEtcDir;
}

QString const App::logDir() const
{
    if (mLogDir.isEmpty())
        mLogDir = dataRootDir() + "log/";
    return mLogDir;
}

QString const App::docDir() const
{
    if (mDocDir.isEmpty())
        mDocDir = rootDir() + "doc/";
    return mDocDir;
}

QString const App::qtPluginsDir() const
{
    if (mQtPluginsDir.isEmpty())
        mQtPluginsDir = binDir();
    return mQtPluginsDir;
}

QString const App::xmlFileName() const
{
    if (mXmlFile.isEmpty()) {
        QFileInfo fi;

        // Try the full application name + country + language combination
        QString name = mName + "_" + mLanguage + ".xml";
        fi.setFile(etcDir() + name);
        if (fi.isReadable())
            mXmlFile = name;
        else {
            // Try application name + country
            name = mName + "_" + mLanguage.left(2) + ".xml";
            fi.setFile(etcDir() + name);
            if (fi.isReadable())
                mXmlFile = name;
            else
                // Fall-back to the generic name
                mXmlFile = mName + ".xml";
        }
    }
    return mXmlFile;
}

int App::exec()
{
    setReady(true);
    int rval = QCoreApplication::exec();
    setReady(false);
    return rval;
}

void App::restart()
{
    QCoreApplication::exit(RC_Restart);
}

void App::quit(bool err)
{
    QCoreApplication::exit(err ? RC_Error : RC_Quit);
}

void App::setReady(bool value)
{
    if (mReady != value) {
        mReady = value;
        iEventQueue::instance()->broadcastEvent(new Event(mReady ? mEvReady : mEvTerminating));
        if (mReady)
            emit ready();
        else
            emit terminating();
    }
}