# SYNOPSIS
#
#   AX_CXX_CHECK_QT([qt_prefix], [list-of-qt-modules])
#
# DESCRIPTIONS
#
#    qt_prefix
#
#      Each call to AX_CXX_CHECK_QT should have a different prefix
#      value (with a few exceptions discussed later on). This value,
#      usually provided in uppercase, is used as prefix to the
#      variables holding the compiler flags and libraries reported by
#      pkg-config.
#
#      For instance, if your prefix was to be FOO you'll be provided
#      two variables FOO_CFLAGS and FOO_LIBS.
#
#      This will also be used as message during the configure checks:
#      checking for FOO....
#
#    list-of-modules
#
#      A single call to the macro can check for the presence of one or
#      more qt modules; you'll see later how to make good use of this
#      feature. Each entry in the list can have a version comparison
#      specifier, with the same syntax as the Requires keyword in the
#      data files themselves.

AC_DEFUN([AX_CXX_QT_TOOL], [
  if test -z "$HAVE_$1"; then
    HAVE_$1=1
    AC_MSG_CHECKING([for $2])
    AC_ARG_VAR([$1], [path to Qt tool $2])
    $1=${$1:-$(pkg-config --variable=$2_location Qt5Core)}
    $1=${$1:-$(pkg-config --variable=host_bins Qt5Core)/$2}
    $1=${$1:-$(pkg-config --variable=$2_location QtCore)}
    $1=${$1:-$(pkg-config --variable=host_bins QtCore)/$2}
    if ! which "${$1%% *}" > /dev/null; then
      if which "$2" > /dev/null; then
        $1=$2
      else
        HAVE_$1=0
        $1=""
      fi
    fi
    AC_SUBST($1)
    AM_CONDITIONAL(HAVE_$1, test $HAVE_$1 -eq 1)
    if test $HAVE_$1 -eq 1; then
      AC_MSG_RESULT([$$1])
    else
      AC_MSG_RESULT([not found])
    fi
  fi
])

AC_DEFUN([AX_CXX_QT_TOOLS], [
  AX_CXX_QT_TOOL(QMAKE, qmake)
  AX_CXX_QT_TOOL(MOC, moc)
  AX_CXX_QT_TOOL(UIC, uic)
  AX_CXX_QT_TOOL(RCC, rcc)
  AX_CXX_QT_TOOL(LUPDATE, lupdate)
  AX_CXX_QT_TOOL(LRELEASE, lrelease)
])

AC_DEFUN([AX_CHECK_VALID_FLAG], [
  AC_MSG_CHECKING([m4_default([$2], [for valid flag in "$1"])])
  save_cxxflags="$CXXFLAGS"
  newflag="no"
  for test_flag in $1; do
    CXXFLAGS+=" ${test_flag}"
    AC_COMPILE_IFELSE([AC_LANG_PROGRAM()], [
      newflag="$test_flag"
      AM_CXXFLAGS+=" ${test_flag}"
      CXXFLAGS="$save_cxxflags"
      break;
    ])
    CXXFLAGS="$save_cxxflags"
  done
  AC_SUBST(AM_CXXFLAGS)
  AC_MSG_RESULT([$newflag])
])

AC_DEFUN([AX_CHECK_QT], [
  qt_modules="$2"
  AX_CXX_QT_TOOLS
  HAVE_$1=0
  PKG_PROG_PKG_CONFIG
  PKG_CHECK_MODULES([$1]5, [${qt_modules//Qt/Qt5}], [
    HAVE_$1=1
    AC_DEFINE([HAVE_$1])
    AM_CPPFLAGS+=" ${[$1]5_CFLAGS}"
    AM_CXXFLAGS+=" ${[$1]5_CFLAGS}"
    LIBS+=" ${[$1]5_LIBS}"
  ], [
    PKG_CHECK_MODULES([$1], [${qt_modules}], [
      HAVE_$1=1
      AC_DEFINE([HAVE_$1])
      AM_CPPFLAGS+=" ${$1_CFLAGS}"
      AM_CXXFLAGS+=" ${$1_CFLAGS}"
      LIBS+=" ${$1_LIBS}"
    ], [HAVE_$1=0])
  ])
  AM_CONDITIONAL(HAVE_$1, test $HAVE_$1 -eq 1)
  AX_CHECK_VALID_FLAG([-fPIC -fPIE], [position independent code flag])
  AC_SUBST(AM_CPPFLAGS)
  AC_SUBST(AM_CXXFLAGS)
  AX_ADDITIONAL_QT_RULES_HACK='
ui_%.hxx: %.ui
	${UIC} -o [$][@] $<

moc_%.cxx: %.hxx
	${MOC} -o [$][@] $<

qrc_%.cxx: %.qrc
	${RCC} -o [$][@] $<'
  AC_SUBST(AX_ADDITIONAL_QT_RULES_HACK)
])

AC_DEFUN([AX_REQUIRE_QT], [
  AX_CHECK_QT([$1], [$2])
  if ! test "$HAVE_$1" -eq 1; then
     AC_MSG_ERROR([Required Qt modules not found: $2])
  fi
])