#include <qfile.h>
#include <iostream>
#include <qcoreapplication.h>

const char* c_Usage = "Usage: qtpatcher <file> <new prefix>";
const char* c_Prefix = "d:\\qt\\4.3.1-msvc";

const QList<QByteArray> pp = QList<QByteArray>()
	<< QByteArray("qt_prfxpath=") + c_Prefix + QByteArray("")
	<< QByteArray("qt_docspath=") + c_Prefix + QByteArray("\\doc")
	<< QByteArray("qt_hdrspath=") + c_Prefix + QByteArray("\\include")
	<< QByteArray("qt_libspath=") + c_Prefix + QByteArray("\\lib")
	<< QByteArray("qt_binspath=") + c_Prefix + QByteArray("\\bin")
	<< QByteArray("qt_plugpath=") + c_Prefix + QByteArray("\\plugins")
	<< QByteArray("qt_datapath=") + c_Prefix + QByteArray("")
	<< QByteArray("qt_trnspath=") + c_Prefix + QByteArray("\\translations")
	<< QByteArray("qt_xmplpath=") + c_Prefix + QByteArray("\\examples")
	<< QByteArray("qt_demopath=") + c_Prefix + QByteArray("\\demos")
;
int findNonZeroIndex(const QByteArray & ba, int from) {
	while(ba[from++] == '\0');
	return from - 1;
}

int main(int argc, char *argv[]) {
	QCoreApplication a(argc, argv);

	if (argc != 3) {
		std::cout << c_Usage << std::endl;
		return 0;
	}

	QFile qmake(argv[1]);
	if (!qmake.open(QIODevice::ReadOnly)) {
		std::cout << "Can't open " << argv[1] << " for reading" << std::endl;
		return 0;
	}

	QByteArray ba = qmake.readAll();
	qmake.close();

	for (int i=0; i<pp.size(); i++) {
		int l = findNonZeroIndex(ba, ba.indexOf(pp[i]) + pp[i].length()) - ba.indexOf(pp[i]);

		QByteArray src = pp[i];
		while((src += '\0').length() != l);
		QByteArray dst = src;

		dst.replace(c_Prefix, argv[2]);

		if (dst.length() < l)
			while((dst += '\0').length() != l);
		else if (dst.length() > l)
			dst.remove(l, dst.length()-l);

		ba.replace(src, dst);
	}

	if (!qmake.open(QIODevice::WriteOnly)) {
		std::cout << "Can't open " << argv[1] << " for writing" << std::endl;
		return 0;
	}

	qmake.write(ba);
	qmake.close();

	return 0;
}