//  PrinterMonitor.cpp
//
//  Copyright (C) 2025-2026  Jaye Evins <evins@snaught.com>
//
//  This file is part of gLabels-qt.
//
//  gLabels-qt is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  gLabels-qt is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with gLabels-qt.  If not, see <http://www.gnu.org/licenses/>.
//


#include "PrinterMonitor.hpp"

#include <QDebug>
#include <QMutexLocker>
#include <QPrinterInfo>
#include <QtConcurrentRun>


namespace glabels
{

        ///
        /// Static data
        ///
        std::unique_ptr<PrinterMonitor> PrinterMonitor::mInstance;


        ///
        /// Constructor
        ///
        PrinterMonitor::PrinterMonitor()
        {
                using namespace std::chrono_literals;

                mCurrentAvailablePrinters = QPrinterInfo::availablePrinterNames();

                mTimer.reset( new QTimer( this ) );
                connect( mTimer.get(), SIGNAL(timeout()), this, SLOT(onTimerTimeout()) );
                mTimer->start( 10s );
        }


        ///
        /// Get singleton instance
        ///
        PrinterMonitor* PrinterMonitor::instance()
        {
                if ( !mInstance )
                {
                        mInstance.reset( new PrinterMonitor() );
                }

                return mInstance.get();
        }


        ///
        /// Get available printers
        ///
        QStringList PrinterMonitor::availablePrinters()
        {
                QMutexLocker mutex( &mCurrentAvailablePrintersMutex );
                return mCurrentAvailablePrinters;
        }


        ///
        /// On timer timeout
        ///
        void PrinterMonitor::onTimerTimeout()
        {
                // Make sure previous poll is complete before starting a new one
                if ( mPollStatus.isFinished() )
                {
                        mPollStatus = QtConcurrent::run( &PrinterMonitor::asyncPoll, this );
                }
        }


        ///
        /// Asynchronous poll
        ///
        void PrinterMonitor::asyncPoll()
        {
                auto newAvailablePrinters = QPrinterInfo::availablePrinterNames();
                if ( newAvailablePrinters != mCurrentAvailablePrinters )
                {
                        QMutexLocker mutex( &mCurrentAvailablePrintersMutex );

                        mCurrentAvailablePrinters = newAvailablePrinters;

                        emit availablePrintersChanged( mCurrentAvailablePrinters );
                }
        }


} // namespace glabels
