/*
    SPDX-FileCopyrightText: 1998-2007 Sebastian Trueg <trueg@k3b.org>
    SPDX-License-Identifier: GPL-2.0-or-later
*/


#include "k3bthroughputestimator.h"

#include <QDateTime>
#include <QDebug>
#include <QElapsedTimer>

class K3b::ThroughputEstimator::Private
{
public:
    Private()
        : started(false) {
    }

    QElapsedTimer firstDataTime;
    unsigned long firstData;
    QElapsedTimer lastDataTime;
    unsigned long lastData;

    int lastThroughput;

    bool started;
};


K3b::ThroughputEstimator::ThroughputEstimator( QObject* parent )
    : QObject( parent )
{
    d = new Private();
}


K3b::ThroughputEstimator::~ThroughputEstimator()
{
    delete d;
}


int K3b::ThroughputEstimator::average() const
{
    int msecs = d->firstDataTime.msecsTo( d->lastDataTime );
    if( msecs > 0 )
        return (int)( 1000.0*(double)(d->lastData - d->firstData)/(double)msecs);
    else
        return 0;
}


void K3b::ThroughputEstimator::reset()
{
    d->started = false;
}


void K3b::ThroughputEstimator::dataWritten( unsigned long data )
{
    if( !d->started ) {
        d->started = true;
        d->firstData = d->lastData = data;
        d->firstDataTime.start();
        d->lastDataTime.start();
        d->lastThroughput = 0;
    }
    else if( data > d->lastData ) {
        unsigned long diff = data - d->lastData;
        int msecs = d->lastDataTime.elapsed();

        //if( msecs > 0 ) {
        // down the update sequence a little bit
        if( msecs > 500 ) {
            d->lastData = data;
            d->lastDataTime.start();
            int t = (int)(1000.0*(double)diff/(double)msecs);
            if( t != d->lastThroughput ) {
                d->lastThroughput = t;
                emit throughput( t );
            }
        }
    }
}



