#!/usr/bin/env python

import os
from waflib import Options, Errors

# work out what python external libraries we need to be successful
selftest_pkgs = {
    'cryptography': 'python3-cryptography',
    'pyasn1': 'python3-pyasn1'
}

ad_dc_pkgs = {
    'markdown': 'python3-markdown',
    'dns': 'python3-dnspython (python3-dns on some systems)'
}


def find_third_party_module(conf, module, package, required=True):
    conf.COMPOUND_START("Checking for system installation of Python module %s" % module)
    try:
        __import__(module)
    except ImportError:
        conf.COMPOUND_END(False)
        if not required:
            return False
        raise Errors.WafError("""\
        Unable to find Python module '%s'. Please install the system package: %s'.
""" % (module, package))
    else:
        # Installed on the system
        conf.COMPOUND_END("system")

    return True


def configure(conf):
    if conf.env.disable_python:
        return

    kerberos_py = conf.srcnode.abspath() + "/python/samba/provision/kerberos_implementation.py"

    f = open(kerberos_py, 'w')
    try:
        header = """#
# Copyright (c) 2016      Andreas Schneider <asn@samba.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/>.
#
"""
        f.write(header)

        data = """kdb_modules_dir = "{0}"
"""

        if conf.env.HEIMDAL_KRB5_CONFIG:
            f.write(data.format(""))
        else:
            modulesdir = "%s/krb5/plugins/kdb" % conf.env.LIBDIR

            f.write(data.format(modulesdir))
    finally:
        f.close()

    if conf.CONFIG_GET('ENABLE_SELFTEST'):
        for module, package in selftest_pkgs.items():
            find_third_party_module(conf, module, package)

        # Prefer dateutil.parser which is much more widely used.
        if not find_third_party_module(conf,
                                       'dateutil.parser',
                                       'python3-dateutilis',
                                       required=False):
            if not find_third_party_module(conf,
                                           'iso8601',
                                           'python3-iso8601',
                                           required=False):
                raise Errors.WafError("Could not find Python package "
                                      "'python3-dateutils' nor "
                                      "'python3-iso8601'. Please install "
                                      "one of the packages.")

    if not Options.options.without_ad_dc:
        for module, package in ad_dc_pkgs.items():
            find_third_party_module(conf, module, package)


def build(bld):


    pytalloc_util = bld.pyembed_libname('pytalloc-util')
    pyparam_util = bld.pyembed_libname('pyparam_util')
    libpython = bld.pyembed_libname('LIBPYTHON')
    pyrpc_util = bld.pyembed_libname('pyrpc_util')
    samba_python = bld.pyembed_libname('samba_python')
    bld.SAMBA_LIBRARY(samba_python,
                      source=[],
                      deps='%s %s %s' % (libpython, pytalloc_util, pyrpc_util),
                      grouping_library=True,
                      private_library=True,
                      pyembed=True,
                      enabled=bld.PYTHON_BUILD_IS_ENABLED())
    bld.SAMBA_PYTHON('python_glue',
                     source='pyglue.c',
                     deps='''
                              %s
                              samba-util
                              netif
                              ndr
                              cmdline
                              %s
                              ''' % (pyparam_util, pytalloc_util),
                     realname='samba/_glue.so')

    bld.SAMBA_SUBSYSTEM(libpython,
                        source='modules.c',
                        public_deps='',
                        init_function_sentinel='{NULL,NULL}',
                        deps='talloc',
                        pyext=True,
                        enabled=bld.PYTHON_BUILD_IS_ENABLED())

    if bld.PYTHON_BUILD_IS_ENABLED():
        # install out various python scripts for use by make test
        bld.SAMBA_SCRIPT('samba_python_files',
                         pattern='samba/**/*.py',
                         installdir='python')

        bld.INSTALL_WILDCARD('${PYTHONARCHDIR}', 'samba/**/*.py', flat=False)