#  http://autoconf-archive.cryp.to/ac_python_devel.html
#
#  License:
#
#  Copyright © 2008 Sebastian Huber <sebastian-huber@web.de>
#  Copyright © 2008 Alan W. Irwin <irwin@beluga.phys.uvic.ca>
#  Copyright © 2008 Rafael Laboissiere <rafael@laboissiere.net>
#  Copyright © 2008 Andrew Collier <colliera@ukzn.ac.za>
#  Copyright © 2008 Matteo Settenvini <matteo@member.fsf.org>
#  Copyright © 2008 Horst Knorr <hk_classes@knoda.org>
#  
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or (at
#  your option) any later version.
#  
#  This program is distributed in the hope that it will be useful, but
#  WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
#  General Public License for more details.
#  
#  You should have received a copy of the GNU General Public License
#  along with this program. If not, see <http://www.gnu.org/licenses/>.
#  
#  As a special exception, the respective Autoconf Macro's copyright
#  owner gives unlimited permission to copy, distribute and modify the
#  configure scripts that are the output of Autoconf when processing the
#  Macro. You need not follow the terms of the GNU General Public
#  License when using or distributing such scripts, even though portions
#  of the text of the Macro appear in them. The GNU General Public
#  License (GPL) does govern all other use of the material that
#  constitutes the Autoconf Macro.
#  
#  This special exception to the GPL applies to versions of the Autoconf
#  Macro released by the Autoconf Macro Archive. When you make and
#  distribute a modified version of the Autoconf Macro, you may extend
#  this special exception to the GPL to apply to your modified version
#  as well.
#  

AC_DEFUN([AC_PYTHON_DEVEL],[
        #
        # Allow the use of a (user set) custom python version
        #
        AC_ARG_VAR([PYTHON_VERSION],[The installed Python
                version to use, for example '2.3'. This string
                will be appended to the Python interpreter
                canonical name.])

        AC_PATH_PROG([PYTHON],[python[$PYTHON_VERSION]])
        if test -z "$PYTHON"; then
           AC_MSG_ERROR([Cannot find python$PYTHON_VERSION in your system path])
           PYTHON_VERSION=""
        fi

        #
        # Check for a version of Python >= 2.1.0
        #
        AC_MSG_CHECKING([for a version of Python >= '2.1.0'])
        ac_supports_python_ver=`$PYTHON -c "import sys, string; \
                ver = string.split(sys.version)[[0]]; \
                print ver >= '2.1.0'"`
        if test "$ac_supports_python_ver" != "True"; then
                if test -z "$PYTHON_NOVERSIONCHECK"; then
                        AC_MSG_RESULT([no])
                        AC_MSG_FAILURE([
This version of the AC@&t@_PYTHON_DEVEL macro
doesn't work properly with versions of Python before
2.1.0. You may need to re-run configure, setting the
variables PYTHON_CPPFLAGS, PYTHON_LDFLAGS, PYTHON_SITE_PKG,
PYTHON_EXTRA_LIBS and PYTHON_EXTRA_LDFLAGS by hand.
Moreover, to disable this check, set PYTHON_NOVERSIONCHECK
to something else than an empty string.
])
                else
                        AC_MSG_RESULT([skip at user request])
                fi
        else
                AC_MSG_RESULT([yes])
        fi

        #
        # if the macro parameter ``version'' is set, honour it
        #
        if test -n "$1"; then
                AC_MSG_CHECKING([for a version of Python $1])
                ac_supports_python_ver=`$PYTHON -c "import sys, string; \
                        ver = string.split(sys.version)[[0]]; \
                        print ver $1"`
                if test "$ac_supports_python_ver" = "True"; then
                   AC_MSG_RESULT([yes])
                else
                        AC_MSG_RESULT([no])
                        AC_MSG_ERROR([this package requires Python $1.
If you have it installed, but it isn't the default Python
interpreter in your system path, please pass the PYTHON_VERSION
variable to configure. See ``configure --help'' for reference.
])
                        PYTHON_VERSION=""
                fi
        fi

        #
        # Check if you have distutils, else fail
        #
        AC_MSG_CHECKING([for the distutils Python package])
        ac_distutils_result=`$PYTHON -c "import distutils" 2>&1`
        if test -z "$ac_distutils_result"; then
                AC_MSG_RESULT([yes])
        else
                AC_MSG_RESULT([no])
                AC_MSG_ERROR([cannot import Python module "distutils".
Please check your Python installation. The error was:
$ac_distutils_result])
                PYTHON_VERSION=""
        fi

        #
        # Check for Python include path
        #
        AC_MSG_CHECKING([for Python include path])
        if test -z "$PYTHON_CPPFLAGS"; then
                python_path=`$PYTHON -c "import distutils.sysconfig; \
                        print distutils.sysconfig.get_python_inc();"`
                if test -n "${python_path}"; then
                        python_path="-I$python_path"
                fi
                PYTHON_CPPFLAGS=$python_path
        fi
        AC_MSG_RESULT([$PYTHON_CPPFLAGS])
        AC_SUBST([PYTHON_CPPFLAGS])

        #
        # Check for Python library path
        #
        AC_MSG_CHECKING([for Python library path])
        if test -z "$PYTHON_LDFLAGS"; then
                # (makes two attempts to ensure we've got a version number
                # from the interpreter)
                py_version=`$PYTHON -c "from distutils.sysconfig import *; \
                        from string import join; \
                        print join(get_config_vars('VERSION'))"`
                if test "$py_version" == "[None]"; then
                        if test -n "$PYTHON_VERSION"; then
                                py_version=$PYTHON_VERSION
                        else
                                py_version=`$PYTHON -c "import sys; \
                                        print sys.version[[:3]]"`
                        fi
                fi

                PYTHON_LDFLAGS=`$PYTHON -c "from distutils.sysconfig import *; \
                        from string import join; \
                        print '-L' + get_config_var('LIBPL'), \
                        '-lpython';"`$py_version
        fi
        AC_MSG_RESULT([$PYTHON_LDFLAGS])
        AC_SUBST([PYTHON_LDFLAGS])

        #
        # Check for site packages
        #
        AC_MSG_CHECKING([for Python site-packages path])
        if test -z "$PYTHON_SITE_PKG"; then
                PYTHON_SITE_PKG=`$PYTHON -c "import distutils.sysconfig; \
                        print distutils.sysconfig.get_python_lib(0,0);"`
        fi
        AC_MSG_RESULT([$PYTHON_SITE_PKG])
        AC_SUBST([PYTHON_SITE_PKG])

        #
        # libraries which must be linked in when embedding
        #
        AC_MSG_CHECKING(python extra libraries)
        if test -z "$PYTHON_EXTRA_LIBS"; then
           PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
                conf = distutils.sysconfig.get_config_var; \
                print conf('LOCALMODLIBS'), conf('LIBS'), conf('SYSLIBS')"`
        fi

        AC_MSG_RESULT([$PYTHON_EXTRA_LIBS])
        AC_SUBST(PYTHON_EXTRA_LIBS)

        #
        # linking flags needed when embedding
        #
        AC_MSG_CHECKING(python extra linking flags)
        if test -z "$PYTHON_EXTRA_LDFLAGS"; then
                PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "import distutils.sysconfig; \
                        conf = distutils.sysconfig.get_config_var; \
                        print conf('LINKFORSHARED')"`
        fi
        AC_MSG_RESULT([$PYTHON_EXTRA_LDFLAGS])
        AC_SUBST(PYTHON_EXTRA_LDFLAGS)

        #
        # final check to see if everything compiles alright
        #
        AC_MSG_CHECKING([consistency of all components of python development environment])
        AC_LANG_PUSH([C])
        # save current global flags
        LIBS="$ac_save_LIBS $PYTHON_LDFLAGS $PYTHON_EXTRA_LIBS"
        CPPFLAGS="$ac_save_CPPFLAGS $PYTHON_CPPFLAGS"
        AC_TRY_LINK([
                #include <Python.h>
        ],[
                Py_Initialize();
        ],[pythonexists=yes],[pythonexists=no])

        AC_MSG_RESULT([$pythonexists])

        if test ! "$pythonexists" = "yes"; then
           AC_MSG_ERROR([
  Could not link test program to Python. Maybe the main Python library has been
  installed in some non-standard library path. If so, pass it to configure,
  via the LDFLAGS environment variable.
  Example: ./configure LDFLAGS="-L/usr/non-standard-path/python/lib"
  ============================================================================
   ERROR!
   You probably have to install the development version of the Python package
   for your distribution.  The exact name of this package varies among them.
  ============================================================================
           ])
          PYTHON_VERSION=""
        fi
        AC_LANG_POP
        # turn back to default flags
        CPPFLAGS="$ac_save_CPPFLAGS"
        LIBS="$ac_save_LIBS"

        #
        # all done!
        #
])
