#include <QCoreApplication>
#include <QFileSystemWatcher>
#include <QRandomGenerator>
#include <QTemporaryDir>
#include <QTemporaryFile>

#include <QDebug>

QString generageRandomFileName(const QString &prefix);
void onChanged(const QString &path);

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QTemporaryDir tmpDir(QLatin1Literal("qtfsw_test"));
    QFile tmpFile1(tmpDir.filePath(generageRandomFileName("tmpf")));
    QFile tmpFile2(tmpDir.filePath(generageRandomFileName("tmpf")));
    tmpFile1.open(QIODevice::ReadWrite);
    tmpFile2.open(QIODevice::ReadWrite);
    QFileSystemWatcher fsw({tmpDir.path()
                           //tmpFile2.fileName()
                           // comment out above line and test again..
                           });
    QObject::connect(&fsw, &QFileSystemWatcher::directoryChanged, &onChanged);
    {
        QTextStream tmpStream1(&tmpFile1);
        QTextStream tmpStream2(&tmpFile2);
        tmpStream1 << "test";
        tmpStream2 << "test";
        tmpFile2.close();
        tmpFile1.close();
    }
    return a.exec();
}

QString generageRandomFileName(const QString& prefix)
{
    QString fileName = prefix + ".";
    for(int i = 0; i < 6; ++i) {
        auto num = QRandomGenerator::global()->bounded(0, 26);
        fileName.append(QLatin1Char(static_cast<char>('a' + num)));
    }
    return fileName;
}

void onChanged(const QString &path)
{
    qInfo() << path;
}