dnl check a particular libname
AC_DEFUN([QT_TRY_LINK],
[
	SAVE_LIBS="$LIBS"
	LIBS="$LIBS $1"
	AC_TRY_LINK([
	#include <qglobal.h>
	#include <qstring.h>
		],
	[
	QString s("mangle_failure");
	#if (QT_VERSION < 400)
	break_me_(\\\);
	#endif
	],
	qt_cv_libname=$1,
	)
	LIBS="$SAVE_LIBS"
])

dnl check we can do a compile
AC_DEFUN([QT_CHECK_COMPILE],
[
	AC_MSG_CHECKING([for Qt library name])

	AC_CACHE_VAL(qt_cv_libname,
	[
		AC_LANG_CPLUSPLUS
		SAVE_CXXFLAGS=$CXXFLAGS
		CXXFLAGS="$CXXFLAGS $QT_INCLUDES $QT_LDFLAGS"
		qt_corelibs="-lQtCore -lQtCore4"
		qt_guilibs="'-lQtCore -lQtGui' '-lQtCore4 -lQtGui4'"
		if test $USE_QT5 = "yes" ; then
		    qt_corelibs="-lQt5Core"
		    qt_guilibs="-lQt5Core -lQt5Concurrent -lQt5Gui -lQt5Svg -lQt5Widgets"
		fi
		for libname in $qt_corelibs '-framework QtCore'
		do
			QT_TRY_LINK($libname)
			if test -n "$qt_cv_libname"; then
				QT_CORE_LIB="$qt_cv_libname"
				break;
			fi
		done
		qt_cv_libname=
		for libname in $qt_guilibs \
		               '-framework QtCore -framework QtConcurrent -framework QtSvg -framework QtWidgets -framework QtMacExtras -framework QtGui'\
		               '-framework QtCore -framework QtGui'
		do
			QT_TRY_LINK($libname)
			if test -n "$qt_cv_libname"; then
				break;
			fi
		done
		CXXFLAGS=$SAVE_CXXFLAGS
	])

	if test -z "$qt_cv_libname"; then
		AC_MSG_RESULT([failed])
		AC_MSG_ERROR([cannot compile a simple Qt executable. Check you have the right \$QTDIR.])
	else
		AC_MSG_RESULT([$qt_cv_libname])
	fi
])


AC_DEFUN([QT_FIND_TOOL],
[
	$1=
	qt_ext=qt4
	if test "x$USE_QT5" != "xno" ; then
		qt_ext=qt5
	fi

	if test -n "$qt_cv_bin" ; then
		AC_PATH_PROGS($1, [$2], [], $qt_cv_bin)
	elif qtchooser -l 2>/dev/null | grep -q ^$qt_ext\$ >/dev/null ; then
		AC_PATH_PROG(qtc_path, qtchooser, [], [$PATH])
		AC_PATH_PROG($2_path, $2, [], [$PATH])
		qtc_path=`dirname "$qtc_path"`
		$2_path=`dirname "$$2_path"`
		if test "$qtc_path" = "$$2_path" ; then
			AC_CHECK_PROG($1, $2, [$2 -qt=$qt_ext],, [$PATH])
		fi
	fi
	if test -z "$$1"; then
		AC_CHECK_PROGS($1, [$2-$qt_ext $2],[],$PATH)
	fi
	if test -z "$$1"; then
		AC_MSG_ERROR([cannot find $2 binary.])
	fi
])


dnl get Qt version we're using
AC_DEFUN([QT_GET_VERSION],
[
	AC_CACHE_CHECK([Qt version],lyx_cv_qtversion,
	[
		AC_LANG_CPLUSPLUS
		SAVE_CPPFLAGS=$CPPFLAGS
		CPPFLAGS="$CPPFLAGS $QT_INCLUDES"

		cat > conftest.$ac_ext <<EOF
#line __oline__ "configure"
#include "confdefs.h"
#include <qglobal.h>
"%%%"QT_VERSION_STR"%%%"
EOF
		lyx_cv_qtversion=`(eval "$ac_cpp conftest.$ac_ext") 2>&5 | \
			grep '^"%%%"'  2>/dev/null | \
			sed -e 's/"%%%"//g' -e 's/"//g'`
		rm -f conftest.$ac_ext
		CPPFLAGS=$SAVE_CPPFLAGS
	])

	QTLIB_VERSION=$lyx_cv_qtversion
	AC_SUBST(QTLIB_VERSION)
])

dnl start here
AC_DEFUN([QT_DO_IT_ALL],
[
	dnl this variable is precious
	AC_ARG_VAR(QTDIR, [the place where the Qt files are, e.g. /usr/lib/qt4])

	AC_ARG_WITH(qt-dir, [AC_HELP_STRING([--with-qt-dir], [where the root of Qt is installed])],
		[ qt_cv_dir=`eval echo "$withval"/` ])

	AC_ARG_WITH(qt-includes, [AC_HELP_STRING([--with-qt-includes], [where the Qt includes are])],
		[ qt_cv_includes=`eval echo "$withval"` ])

	AC_ARG_WITH(qt-libraries, [AC_HELP_STRING([--with-qt-libraries], [where the Qt library is installed])],
		[  qt_cv_libraries=`eval echo "$withval"` ])

	dnl pay attention to $QTDIR unless overridden
	if test -z "$qt_cv_dir"; then
		qt_cv_dir=$QTDIR
	fi

	dnl derive inc/lib if needed
	if test -n "$qt_cv_dir"; then
		if test -z "$qt_cv_includes"; then
			qt_cv_includes=$qt_cv_dir/include
		fi
		if test -z "$qt_cv_libraries"; then
			qt_cv_libraries=$qt_cv_dir/lib
		fi
	fi

	dnl compute the binary dir too
	if test -n "$qt_cv_dir"; then
		qt_cv_bin=$qt_cv_dir/bin
	fi

	dnl Preprocessor flags
	QT_CPPFLAGS="-DQT_NO_STL -DQT_NO_KEYWORDS"
	case ${host} in
	*mingw*) QT_CPPFLAGS="-DQT_DLL $QT_CPPFLAGS";;
	esac
	AC_SUBST(QT_CPPFLAGS)

	dnl Check if it possible to do a pkg-config
	PKG_PROG_PKG_CONFIG
	if test -n "$PKG_CONFIG" ; then
		QT_DO_PKG_CONFIG
	fi
	if test "$pkg_failed" != "no" ; then
		QT_DO_MANUAL_CONFIG
	fi

	if test -z "$QT_LIB"; then
	  AC_MSG_ERROR([cannot find qt libraries.])
	fi

	dnl Check qt version
	AS_VERSION_COMPARE($QTLIB_VERSION, $1,
	[AC_MSG_ERROR([LyX requires at least version $1 of Qt. Only version $QTLIB_VERSION has been found.])
	])

	if test x$USE_QT5 = xyes ; then
	  save_CPPFLAGS=$CPPFLAGS
	  AC_MSG_CHECKING([whether Qt uses the X Window system])
	  CPPFLAGS="$save_CPPFLAGS $QT_CORE_INCLUDES"
	  AC_EGREP_CPP(xcb,
	    [#include <qconfig.h>
	    QT_QPA_DEFAULT_PLATFORM_NAME],
	    [AC_MSG_RESULT(yes)
	     AC_DEFINE(QPA_XCB, 1, [Define if Qt uses the X Window System])],
	    [AC_MSG_RESULT(no)])
	  CPPFLAGS=$save_CPPFLAGS
	fi

	QT_FIND_TOOL([QT_MOC], [moc])
	QT_FIND_TOOL([QT_UIC], [uic])
	QT_FIND_TOOL([QT_RCC], [rcc])

	dnl Safety check
	mocqtver=`$QT_MOC -v 2>&1 | sed -e 's/.*\([[0-9]]\.[[0-9]]\.[[0-9]]\).*/\1/'`
	if test "x$mocqtver" != "x$QTLIB_VERSION"; then
		LYX_WARNING([The found moc compiler is for Qt $mocqtver but the Qt library version is $QTLIB_VERSION.])
	fi
])

AC_DEFUN([QT_DO_PKG_CONFIG],
[
	dnl tell pkg-config to look also in $qt_cv_dir/lib.
	save_PKG_CONFIG_PATH=$PKG_CONFIG_PATH
	if test -n "$qt_cv_dir" ; then
	  PKG_CONFIG_PATH=$qt_cv_dir/lib:$qt_cv_dir/lib/pkgconfig:$PKG_CONFIG_PATH
	  export PKG_CONFIG_PATH
	fi
	qt_corelibs="QtCore"
	qt_guilibs="QtCore QtGui QtSvg"
	if test "x$USE_QT5" != "xno" ; then
		qt_corelibs="Qt5Core"
		qt_guilibs="Qt5Core Qt5Concurrent Qt5Gui Qt5Svg Qt5Widgets"
		lyx_use_winextras=false
		PKG_CHECK_EXISTS(Qt5WinExtras, [lyx_use_winextras=true], [])
		if $lyx_use_winextras; then
			qt_guilibs="$qt_guilibs Qt5WinExtras"
		fi
		lyx_use_macextras=false
		PKG_CHECK_EXISTS(Qt5MacExtras, [lyx_use_macextras=true], [])
		if $lyx_use_macextras; then
			qt_guilibs="$qt_guilibs Qt5MacExtras"
		fi
	fi
	PKG_CHECK_MODULES(QT_CORE, $qt_corelibs,,[:])
	if test "$pkg_failed" = "no" ; then
		QT_CORE_INCLUDES=$QT_CORE_CFLAGS
		AC_SUBST(QT_CORE_INCLUDES)
		QT_CORE_LDFLAGS=`$PKG_CONFIG --libs-only-L $qt_corelibs`
		AC_SUBST(QT_CORE_LDFLAGS)
		QT_CORE_LIB=`$PKG_CONFIG --libs-only-l $qt_corelibs`
		AC_SUBST(QT_CORE_LIB)
	fi
	PKG_CHECK_MODULES(QT_FRONTEND, $qt_guilibs,,[:])
	if test "$pkg_failed" = "no" ; then
		QT_INCLUDES=$QT_FRONTEND_CFLAGS
		dnl QT_LDFLAGS=$QT_FRONTEND_LIBS
		QT_LDFLAGS=`$PKG_CONFIG --libs-only-L $qt_guilibs`
		AC_SUBST(QT_INCLUDES)
		AC_SUBST(QT_LDFLAGS)
		QTLIB_VERSION=`$PKG_CONFIG --modversion $qt_corelibs`
		AC_SUBST(QTLIB_VERSION)
		QT_LIB=`$PKG_CONFIG --libs-only-l $qt_guilibs`
		AC_SUBST(QT_LIB)
		dnl LIBS="$LIBS `$PKG_CONFIG --libs-only-other $qt_guilibs`"
	fi
	PKG_CONFIG_PATH=$save_PKG_CONFIG_PATH
	dnl Actually, the values of QT_LIB and QT_CORE_LIB can be completely
	dnl wrong on OS X, where everything goes to --libs-only-other.
	dnl As a quick workaround, let us assign better values. A better patch
	dnl exists for next cycle.
	QT_CORE_LIB=$QT_CORE_LIBS
	QT_CORE_LDFLAGS=
	QT_LIB=$QT_FRONTEND_LIBS
	QT_LDFLAGS=
])

AC_DEFUN([QT_DO_MANUAL_CONFIG],
[
	dnl Check for X libraries
	AC_PATH_X
	AC_PATH_XTRA
	case $have_x in
	    yes) LIBS="$X_PRE_LIBS $LIBS $X_LIBS -lX11 $X_EXTRA_LIBS"
	         CPPFLAGS="$CPPFLAGS $X_CFLAGS";;
	     no) AC_MSG_ERROR([cannot find X window libraries and/or headers.]);;
	disable) ;;
	esac

	dnl flags for compilation
	QT_INCLUDES=
	QT_LDFLAGS=
	QT_CORE_INCLUDES=
	QT_CORE_LDFLAGS=
	if test -n "$qt_cv_includes"; then
		QT_INCLUDES="-I$qt_cv_includes"
		for i in Qt QtCore QtGui QtWidgets QtSvg QtConcurrent QtMacExtras; do
			QT_INCLUDES="$QT_INCLUDES -I$qt_cv_includes/$i"
		done
		QT_CORE_INCLUDES="-I$qt_cv_includes -I$qt_cv_includes/QtCore"
	fi
	case "$qt_cv_libraries" in
	*framework*)
		QT_LDFLAGS="-F$qt_cv_libraries"
		QT_CORE_LDFLAGS="-F$qt_cv_libraries"
		;;
	"")
		;;
	*)
		QT_LDFLAGS="-L$qt_cv_libraries"
		QT_CORE_LDFLAGS="-L$qt_cv_libraries"
		;;
	esac
	AC_SUBST(QT_INCLUDES)
	AC_SUBST(QT_CORE_INCLUDES)
	AC_SUBST(QT_LDFLAGS)
	AC_SUBST(QT_CORE_LDFLAGS)

	QT_CHECK_COMPILE

	QT_LIB=$qt_cv_libname;
	AC_SUBST(QT_LIB)
	AC_SUBST(QT_CORE_LIB)

	if test -n "$qt_cv_libname"; then
		QT_GET_VERSION
	fi
])