#include <iostream>
#include <thread>
#include <chrono>

#include <QtCore>
#include <QXmlQuery>

namespace {
  constexpr int bytesOfOneMB = 1024*1024;

  void wasteMemory(const int megaBytes) {
    qInfo("Wasting %d MB now...", megaBytes);
    const int arraysize = megaBytes*bytesOfOneMB;
    char* array = new char[arraysize];
    for(int i=0 ; i<arraysize; ++i) {
      array[i] = 'a';
    }
//    delete [] array; // omitted to deliberately waste memory
    qInfo("Done");
  }

  const QString xml =
      "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n""\n"
      "<root>\n""\n"

      "  <term>-1460087571.6437266</term>\n""\n"
      "  <system>minerals</system>\n""\n"
      "  <pot>become</pot>\n""\n"
      "  <bet>1014767728</bet>\n""\n"
      "  <rise>weight</rise>\n""\n"
      "  <excitement>beneath</excitement>\n""\n"
      "  <fast>1606330302.0943468</fast>\n""\n"
      "  <serious>success</serious>\n""\n"
      "  <band>56689147.3003366</band>\n""\n"
      "  <room>order</room>\n""\n"
      "  <difficult>-1846389049.7374732</difficult>\n""\n"
      "  <slabs>1080777107</slabs>\n""\n"
      "  <mile>-1429668644</mile>\n""\n"
      "  <fireplace>-883024560</fireplace>\n""\n"
      "  <exact>desk</exact>\n""\n"
      "  <church>-516291204.614336</church>\n""\n"
      "  <disappear>gift</disappear>\n""\n"
      "  <song>2128439922</song>\n""\n"
      "  <day>2076698251.2718477</day>\n""\n"
      "  <library>1169567673.2849774</library>\n""\n"
      "  <strong>slept</strong>\n""\n"
      "  <factory>friendly</factory>\n""\n"
      "  <broke>1704619180</broke>\n""\n"
      "  <broken>arrow</broken>\n""\n"
      "  <review>tank</review>\n""\n"
      "  <idea>image</idea>\n""\n"
      "  <successful>arrange</successful>\n""\n"
      "  <barn>sheet</barn>\n""\n"
      "  <sat>frame</sat>\n""\n"
      "  <bar>-995623517.5095413</bar>\n""\n"
      "  <different>-827945576.2976611</different>\n""\n"
      "  <saddle>vertical</saddle>\n""\n"
      "  <country>-1294579480</country>\n""\n"
      "  <fine>-210237458.06976008</fine>\n""\n"
      "  <people>shot</people>\n""\n"
      "  <enemy>beneath</enemy>\n""\n"
      "  <lose>wash</lose>\n""\n"
      "  <left>nodded</left>\n""\n"
      "  <underline>302480069</underline>\n""\n"
      "  <journey>349298609.9499917</journey>\n""\n"
      "  <two>855233261</two>\n""\n"
      "  <throughout>policeman</throughout>\n""\n"
      "  <safety>1101445487</safety>\n""\n"
      "  <path>783122588.9262781</path>\n""\n"
      "  <excited>-636194430</excited>\n""\n"
      "  <line>mean</line>\n""\n"
      "  <steam>908359265.9153657</steam>\n""\n"
      "  <gone>-712892793.1713428</gone>\n""\n"
      "  <pitch>684788275</pitch>\n""\n"
      "  <close>-806401825.7013865</close>\n""\n"
      "</root>\n";

  const QString xslt =
      "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n"
      "<xsl:stylesheet version=\"2.0\" xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\" xmlns:xs=\"http://www.w3.org/2001/XMLSchema\">\n"
      "  <xsl:output method=\"xml\" encoding=\"utf-8\" indent=\"yes\" omit-xml-declaration=\"no\"/>\n"
      "  <xsl:template match=\"@* | node()\">\n"
      "     <xsl:copy>\n"
      "        <xsl:apply-templates select=\"@* | node()\"/>\n"
      "     </xsl:copy>\n"
      "  </xsl:template>\n"
      "</xsl:stylesheet>\n";

  void testXmlQuery(const int repetitions) {
    qInfo("Testing QXmlQuery now...");
    QXmlQuery xmlQuery(QXmlQuery::XSLT20);
    xmlQuery.setFocus(xml);
    xmlQuery.setQuery(xslt);
    for ( int i = 0; i < repetitions; i++ ) {
      QString resString;
      // The following line seems to leak memory. Comment it out to confirm.
      xmlQuery.evaluateTo(&resString);
    }
    qInfo("Done");
  }

  void stop() {
    qInfo("Stopping...");
    std::cin.ignore();
  }
} // namespace

int main(int argc, char **argv)
{
  QCoreApplication ca(argc, argv);
//  wasteMemory(100);
  testXmlQuery(4); // leaks about 1MB per 4 repetitions
//  stop();
  std::this_thread::sleep_for(std::chrono::seconds(5));
  return 0;
}