/**
 * @file Common/config.cpp
 * @brief eVaf configuration 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 "config.h"
#include "inifile.h"
#include "iregistry.h"
#include "ilogger.h"
#include "iapp.h"
#include "version.h"

#include <QtCore>

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

using namespace eVaf::Common;

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

iConfig * iConfig::instance()
{
    if (nullptr == singleton)
    {
        singleton = new Internal::Config;
    }
    return singleton->_interface();
}


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

using namespace eVaf::Common::Internal;

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

Config::Config()
    : iConfig()
{
    setObjectName(QString("%1.iConfig").arg(VER_MODULE_NAME_STR));

    // Register the iConfig interface
    iRegistry::instance()->registerInterface("iConfig", this);

    EVAF_INFO("%s-Config created", VER_MODULE_NAME_STR);
}

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

iConfig * Config::_interface() const
{
    return evafQueryInterface<iConfig>("iConfig");
}

bool Config::init()
{
    // Finalize first in case this is not the first time init() is called
    done();

    return true;
}

void Config::done()
{
    // Commit any queued parameters
    commitValues();

    // Clear the list of opened INI files
    QHash<QString, IniFile *>::iterator it = mIniFiles.begin();
    while (it != mIniFiles.end()) {
        delete it.value();
        it = mIniFiles.erase(it);
    }
}

QVariant Config::getValue(QString const & paramName, QVariant const & defaultValue) const
{
    // Get the optional file part
    int idx = paramName.indexOf('/');
    if (idx < 0) {
        EVAF_ERROR("Invalid parameter name '%s'", qPrintable(paramName));
        return defaultValue;
    }
    QString file = paramName.left(idx);
    QString name = paramName.mid(idx + 1);

    // Ignore the optional backend identifier in the file name
    idx = file.indexOf(':');
    if (idx >= 0)
        file.remove(0, idx + 1);

    // If the file name is empty or '*', use the application's name
    if (file.isEmpty() || file == "*")
        file = iApp::instance()->name();

    IniFile * ini = nullptr;

    // Is this INI file already opened?
    QHash<QString, IniFile *>::const_iterator it = mIniFiles.constFind(file);

    // The file is opened and we can reuse it
    if (it != mIniFiles.constEnd()) {
        ini = *it;
    }

    // The file is not opened
    else {
        ini = new IniFile(QString("%1/%2.ini").arg(iApp::instance()->etcDir()).arg(file));
        if (!ini->isValid()) {
            EVAF_ERROR("Failed to open '%s' : %s", qPrintable(name), qPrintable(ini->errorString()));
            delete ini;
            return defaultValue;
        }
        mIniFiles.insert(file, ini);
    }

    // Read the value
    return ini->getValue(name.toLocal8Bit(), defaultValue);
}

bool Config::setValue(QString const & paramName, QVariant const & value, bool commit)
{
    if (!commit) {
        // Queue the write operation
        mCommitQueue.enqueue(NameValuePair(paramName, value));
    }
    else {
        // Commit any queued parameters
        if (!commitValues())
            return false;

        // Write the parameter
        if (!writeValue(paramName, value))
            return false;
    }

    return true;
}

bool Config::commitValues()
{
    while (!mCommitQueue.isEmpty()) {
        if (!writeValue(mCommitQueue.dequeue())) {
            mCommitQueue.clear();
            return false;
        }
    }
    return true;
}

bool Config::writeValue(QString const & paramName, QVariant const & value)
{
    // Get the optional file part
    int idx = paramName.indexOf('/');
    if (idx < 0) {
        EVAF_ERROR("Invalid parameter name '%s'", qPrintable(paramName));
        return false;
    }
    QString file = paramName.left(idx);
    QString name = paramName.mid(idx + 1);

    // Ignore the optional backend identifier in the file name
    idx = file.indexOf(':');
    if (idx >= 0)
        file.remove(0, idx + 1);

    // If the file name is empty or '*', use the application's name
    if (file.isEmpty() || file == "*")
        file = iApp::instance()->name();

    IniFile * ini = nullptr;

    // Is this INI file already opened?
    QHash<QString, IniFile *>::const_iterator it = mIniFiles.constFind(file);

    // The file is opened and we can reuse it
    if (it != mIniFiles.constEnd()) {
        ini = *it;
    }

    // The file is not opened
    else {
        ini = new IniFile(QString("%1/%2.ini").arg(iApp::instance()->etcDir()).arg(file));
        if (!ini->isValid()) {
            EVAF_ERROR("Failed to open '%s' : %s", qPrintable(name), qPrintable(ini->errorString()));
            delete ini;
            return false;
        }
        mIniFiles.insert(file, ini);
    }

    // Write the value
    if (!ini->setValue(name.toLocal8Bit(), value))
        return false;

    return true;
}