import os
import contextlib

import Build
from samba_utils import *
from samba_autoconf import *
from Logs import warn
from TaskGen import extension, before, after, feature

from Configure import conf


@feature('extrapyext')
@before('apply_incpaths', 'apply_lib_vars', 'apply_type_vars', 'apply_bundle')
@after('vars_target_cshlib')
def init_extrapyext(self):
    self.default_install_path = '${PYTHONARCHDIR}'
    self.uselib = self.to_list(getattr(self, 'uselib', ''))
    if not 'EXTRAPYEXT' in self.uselib:
        self.uselib.append('EXTRAPYEXT')


@before('apply_link', 'apply_lib_vars', 'apply_type_vars')
@after('apply_bundle')
@feature('extrapyext')
def extrapyext_shlib_ext(self):
    # override shlib_PATTERN set by the osx module
    self.env['shlib_PATTERN'] = self.env['extrapyext_PATTERN']


@before('apply_incpaths', 'apply_lib_vars', 'apply_type_vars')
@feature('extrapyembed')
def init_extrapyembed(self):
    self.uselib = self.to_list(getattr(self, 'uselib', ''))
    if not 'EXTRAPYEMBED' in self.uselib:
        self.uselib.append('EXTRAPYEMBED')


# For extrapython, we store config in a separate set of env variables.
# During the configure step we swap these with the normal *PYTHON* equivalents,
# use waf's regular Python tool, and then switch them all back.
EXTRAPYTHON_ENV_KEYS = (
    ('PYTHON', 'EXTRAPYTHON'),
    ('PYTHONDIR', 'EXTRAPYTHONDIR'),
    ('PYTHONARCHDIR', 'EXTRAPYTHONARCHDIR'),
    ('PYTHON_VERSION', 'EXTRAPYTHON_VERSION'),

    ('CCFLAGS_PYEXT', 'CCFLAGS_EXTRAPYEXT'),
    ('CCFLAGS_PYEMBED', 'CCFLAGS_EXTRAPYEMBED'),

    ('LIBPATH_PYEXT', 'LIBPATH_EXTRAPYEXT'),
    ('LIBPATH_PYEMBED', 'LIBPATH_EXTRAPYEMBED'),

    ('LIB_PYEXT', 'LIB_EXTRAPYEXT'),
    ('LIB_PYEMBED', 'LIB_EXTRAPYEMBED'),

    ('CPPPATH_PYEXT', 'CPPPATH_EXTRAPYEXT'),
    ('CPPPATH_PYEMBED', 'CPPPATH_EXTRAPYEMBED'),

    ('LINKFLAGS_PYEXT', 'LINKFLAGS_EXTRAPYEXT'),
    ('LINKFLAGS_PYEMBED', 'LINKFLAGS_EXTRAPYEMBED'),

    ('HAVE_PYTHON_H', 'EXTRAPY_HAVE_PYTHON_H'),

    ('PYTHON_CONFIG', 'EXTRAPYTHON_CONFIG'),

    ('pyext_PATTERN', 'extrapyext_PATTERN'),
    ('PYCMD', 'EXTRAPYCMD'),
    ('PYFLAGS', 'EXTRAPYFLAGS'),
    ('PYFLAGS_OPT', 'EXTRAPYFLAGS_OPT'),

    ('PYTHON_SO_ABI_FLAG', 'EXTRAPYTHON_SO_ABI_FLAG'),
)
EXTRAPYTHON_DEFINES_KEYS = (
    ('PYTHONDIR', 'EXTRAPYTHONDIR'),
    ('PYTHONARCHDIR', 'EXTRAPYTHONARCHDIR'),
    ('HAVE_PYTHON_H', 'EXTRAPY_HAVE_PYTHON_H'),
)


@contextlib.contextmanager
def extrapython_map(env, keys):
    saved = {}
    for key, extrakey in keys:
        if key in env:
            saved[key] = env[key]
        if extrakey in env:
            env[key] = env[extrakey]
        else:
            env.pop(key, None)
    yield
    for key, extrakey in keys:
        if key in env:
            env[extrakey] = env[key]
        else:
            env.pop(extrakey, None)
        if key in saved:
            env[key] = saved[key]
        else:
            env.pop(key, None)


@contextlib.contextmanager
def extrapython_env(env):
    with extrapython_map(env, EXTRAPYTHON_ENV_KEYS):
        with extrapython_map(env['defines'], EXTRAPYTHON_DEFINES_KEYS):
            yield


@conf
def SAMBA_CHECK_PYTHON(conf, mandatory=True, version=(2,4,2)):
    # enable tool to build python extensions
    interpreters = []

    if conf.env['EXTRA_PYTHON']:
        with extrapython_env(conf.env):
            conf.env['PYTHON'] = conf.env['EXTRA_PYTHON']
            conf.find_program('python', var='PYTHON', mandatory=True)
            conf.check_tool('python')
            try:
                conf.check_python_version((3, 3, 0))
            except Exception:
                warn('extra-python needs to be Python 3.3 or later')
                raise
        interpreters.append(conf.env['EXTRA_PYTHON'])

    conf.find_program('python', var='PYTHON', mandatory=mandatory)
    conf.check_tool('python')
    path_python = conf.find_program('python')
    conf.env.PYTHON_SPECIFIED = (conf.env.PYTHON != path_python)
    conf.check_python_version(version)

    interpreters.append(conf.env['PYTHON'])
    conf.env.python_interpreters = interpreters


def check_python_headers(conf, mandatory):
    conf.check_python_headers(mandatory=mandatory)

    if conf.env['PYTHON_VERSION'] > '3':
        abi_pattern = os.path.splitext(conf.env['pyext_PATTERN'])[0]
        conf.env['PYTHON_SO_ABI_FLAG'] = abi_pattern % ''
    else:
        conf.env['PYTHON_SO_ABI_FLAG'] = ''


@conf
def SAMBA_CHECK_PYTHON_HEADERS(conf, mandatory=True):
    if conf.env["python_headers_checked"] == []:
        pre_dict = conf.env.get_merged_dict()
        if conf.env['EXTRA_PYTHON']:
            with extrapython_env(conf.env):
                check_python_headers(conf, mandatory=True)
        check_python_headers(conf, mandatory=mandatory)
        conf.env["python_headers_checked"] = "yes"

        if conf.env['EXTRAPYTHON_VERSION'] == conf.env['PYTHON_VERSION']:
            raise Utils.WafError("extrapython %s is same as main python %s" % (
                conf.env['EXTRAPYTHON_VERSION'], conf.env['PYTHON_VERSION']))
    else:
        conf.msg("python headers", "using cache")


def SAMBA_PYTHON(bld, name,
                 source='',
                 deps='',
                 public_deps='',
                 realname=None,
                 cflags='',
                 includes='',
                 init_function_sentinel=None,
                 local_include=True,
                 vars=None,
                 install=True,
                 enabled=True,
                 extra_python=False):
    '''build a python extension for Samba'''

    # when we support static python modules we'll need to gather
    # the list from all the SAMBA_PYTHON() targets
    if init_function_sentinel is not None:
        cflags += '-DSTATIC_LIBPYTHON_MODULES=%s' % init_function_sentinel

    source = bld.EXPAND_VARIABLES(source, vars=vars)

    if realname is not None:
        link_name = 'python_modules/%s' % realname
    else:
        link_name = None

    if extra_python:
        pyfeature = 'extrapyext'
        target_type = 'EXTRAPYTHON'
        install_path = '${EXTRAPYTHONARCHDIR}'
    else:
        pyfeature = 'pyext'
        target_type = 'PYTHON'
        install_path = '${PYTHONARCHDIR}'
    bld.SAMBA_LIBRARY(name,
                      source=source,
                      deps=deps,
                      public_deps=public_deps,
                      includes=includes,
                      cflags=cflags,
                      local_include=local_include,
                      vars=vars,
                      realname=realname,
                      link_name=link_name,
                      pyfeature=pyfeature,
                      target_type=target_type,
                      install_path=install_path,
                      allow_undefined_symbols=True,
                      allow_warnings=True,
                      install=install,
                      enabled=enabled)

Build.BuildContext.SAMBA_PYTHON = SAMBA_PYTHON


def pyembed_libname(bld, name, extrapython=False):
    if extrapython:
        return name + bld.env['EXTRAPYTHON_SO_ABI_FLAG']
    else:
        return name + bld.env['PYTHON_SO_ABI_FLAG']

    return name

Build.BuildContext.pyembed_libname = pyembed_libname