# -*- coding: utf-8 -*-
#
# Copyright (C) 2012 The Python Software Foundation.
# See LICENSE.txt and CONTRIBUTORS.txt.
#
"""Access to Python's configuration information."""

import codecs
import os
import re
import sys
from os.path import pardir, realpath
try:
    import configparser
except ImportError:
    import ConfigParser as configparser


__all__ = [
    'get_config_h_filename',
    'get_config_var',
    'get_config_vars',
    'get_makefile_filename',
    'get_path',
    'get_path_names',
    'get_paths',
    'get_platform',
    'get_python_version',
    'get_scheme_names',
    'parse_config_h',
]


def _safe_realpath(path):
    try:
        return realpath(path)
    except OSError:
        return path


if sys.executable:
    _PROJECT_BASE = os.path.dirname(_safe_realpath(sys.executable))
else:
    # sys.executable can be empty if argv[0] has been changed and Python is
    # unable to retrieve the real program name
    _PROJECT_BASE = _safe_realpath(os.getcwd())

if os.name == "nt" and "pcbuild" in _PROJECT_BASE[-8:].lower():
    _PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir))
# PC/VS7.1
if os.name == "nt" and "\\pc\\v" in _PROJECT_BASE[-10:].lower():
    _PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
# PC/AMD64
if os.name == "nt" and "\\pcbuild\\amd64" in _PROJECT_BASE[-14:].lower():
    _PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir, pardir))


def is_python_build():
    for fn in ("Setup.dist", "Setup.local"):
        if os.path.isfile(os.path.join(_PROJECT_BASE, "Modules", fn)):
            return True
    return False

_PYTHON_BUILD = is_python_build()

_cfg_read = False

def _ensure_cfg_read():
    global _cfg_read
    if not _cfg_read:
        from ..resources import finder
        backport_package = __name__.rsplit('.', 1)[0]
        _finder = finder(backport_package)
        _cfgfile = _finder.find('sysconfig.cfg')
        assert _cfgfile, 'sysconfig.cfg exists'
        with _cfgfile.as_stream() as s:
            _SCHEMES.readfp(s)
        if _PYTHON_BUILD:
            for scheme in ('posix_prefix', 'posix_home'):
                _SCHEMES.set(scheme, 'include', '{srcdir}/Include')
                _SCHEMES.set(scheme, 'platinclude', '{projectbase}/.')

        _cfg_read = True


_SCHEMES = configparser.RawConfigParser()
_VAR_REPL = re.compile(r'\{([^{]*?)\}')

def _expand_globals(config):
    _ensure_cfg_read()
    if config.has_section('globals'):
        globals = config.items('globals')
    else:
        globals = tuple()

    sections = config.sections()
    for section in sections:
        if section == 'globals':
            continue
        for option, value in globals:
            if config.has_option(section, option):
                continue
            config.set(section, option, value)
    config.remove_section('globals')

    # now expanding local variables defined in the cfg file
    #
    for section in config.sections():
        variables = dict(config.items(section))

        def _replacer(matchobj):
            name = matchobj.group(1)
            if name in variables:
                return variables[name]
            return matchobj.group(0)

        for option, value in config.items(section):
            config.set(section, option, _VAR_REPL.sub(_replacer, value))

#_expand_globals(_SCHEMES)

 # FIXME don't rely on sys.version here, its format is an implementation detail
 # of CPython, use sys.version_info or sys.hexversion
_PY_VERSION = sys.version.split()[0]
_PY_VERSION_SHORT = sys.version[:3]
_PY_VERSION_SHORT_NO_DOT = _PY_VERSION[0] + _PY_VERSION[2]
_PREFIX = os.path.normpath(sys.prefix)
_EXEC_PREFIX = os.path.normpath(sys.exec_prefix)
_CONFIG_VARS = None
_USER_BASE = None


def _subst_vars(path, local_vars):
    """In the string `path`, replace tokens like {some.thing} with the
    corresponding value from the map `local_vars`.

    If there is no corresponding value, leave the token unchanged.
    """
    def _replacer(matchobj):
        name = matchobj.group(1)
        if name in local_vars:
            return local_vars[name]
        elif name in os.environ:
            return os.environ[name]
        return matchobj.group(0)
    return _VAR_REPL.sub(_replacer, path)


def _extend_dict(target_dict, other_dict):
    target_keys = target_dict.keys()
    for key, value in other_dict.items():
        if key in target_keys:
            continue
        target_dict[key] = value


def _expand_vars(scheme, vars):
    res = {}
    if vars is None:
        vars = {}
    _extend_dict(vars, get_config_vars())

    for key, value in _SCHEMES.items(scheme):
        if os.name in ('posix', 'nt'):
            value = os.path.expanduser(value)
        res[key] = os.path.normpath(_subst_vars(value, vars))
    return res


def format_value(value, vars):
    def _replacer(matchobj):
        name = matchobj.group(1)
        if name in vars:
            return vars[name]
        return matchobj.group(0)
    return _VAR_REPL.sub(_replacer, value)


def _get_default_scheme():
    if os.name == 'posix':
        # the default scheme for posix is posix_prefix
        return 'posix_prefix'
    return os.name


def _getuserbase():
    env_base = os.environ.get("PYTHONUSERBASE", None)

    def joinuser(*args):
        return os.path.expanduser(os.path.join(*args))

    # what about 'os2emx', 'riscos' ?
    if os.name == "nt":
        base = os.environ.get("APPDATA") or "~"
        if env_base:
            return env_base
        else:
            return joinuser(base, "Python")

    if sys.platform == "darwin":
        framework = get_config_var("PYTHONFRAMEWORK")
        if framework:
            if env_base:
                return env_base
            else:
                return joinuser("~", "Library", framework, "%d.%d" %
                                sys.version_info[:2])

    if env_base:
        return env_base
    else:
        return joinuser("~", ".local")


def _parse_makefile(filename, vars=None):
    """Parse a Makefile-style file.

    A dictionary containing name/value pairs is returned.  If an
    optional dictionary is passed in as the second argument, it is
    used instead of a new dictionary.
    """
    # Regexes needed for parsing Makefile (and similar syntaxes,
    # like old-style Setup files).
    _variable_rx = re.compile(r"([a-zA-Z][a-zA-Z0-9_]+)\s*=\s*(.*)")
    _findvar1_rx = re.compile(r"\$\(([A-Za-z][A-Za-z0-9_]*)\)")
    _findvar2_rx = re.compile(r"\${([A-Za-z][A-Za-z0-9_]*)}")

    if vars is None:
        vars = {}
    done = {}
    notdone = {}

    with codecs.open(filename, encoding='utf-8', errors="surrogateescape") as f:
        lines = f.readlines()

    for line in lines:
        if line.startswith('#') or line.strip() == '':
            continue
        m = _variable_rx.match(line)
        if m:
            n, v = m.group(1, 2)
            v = v.strip()
            # `$$' is a literal `$' in make
            tmpv = v.replace('$$', '')

            if "$" in tmpv:
                notdone[n] = v
            else:
                try:
                    v = int(v)
                except ValueError:
                    # insert literal `$'
                    done[n] = v.replace('$$', '$')
                else:
                    done[n] = v

    # do variable interpolation here
    variables = list(notdone.keys())

    # Variables with a 'PY_' prefix in the makefile. These need to
    # be made available without that prefix through sysconfig.
    # Special care is needed to ensure that variable expansion works, even
    # if the expansion uses the name without a prefix.
    renamed_variables = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS')

    while len(variables) > 0:
        for name in tuple(variables):
            value = notdone[name]
            m = _findvar1_rx.search(value) or _findvar2_rx.search(value)
            if m is not None:
                n = m.group(1)
                found = True
                if n in done:
                    item = str(done[n])
                elif n in notdone:
                    # get it on a subsequent round
                    found = False
                elif n in os.environ:
                    # do it like make: fall back to environment
                    item = os.environ[n]

                elif n in renamed_variables:
                    if (name.startswith('PY_') and
                        name[3:] in renamed_variables):
                        item = ""

                    elif 'PY_' + n in notdone:
                        found = False

                    else:
                        item = str(done['PY_' + n])

                else:
                    done[n] = item = ""

                if found:
                    after = value[m.end():]
                    value = value[:m.start()] + item + after
                    if "$" in after:
                        notdone[name] = value
                    else:
                        try:
                            value = int(value)
                        except ValueError:
                            done[name] = value.strip()
                        else:
                            done[name] = value
                        variables.remove(name)

                        if (name.startswith('PY_') and
                            name[3:] in renamed_variables):

                            name = name[3:]
                            if name not in done:
                                done[name] = value

            else:
                # bogus variable reference (e.g. "prefix=$/opt/python");
                # just drop it since we can't deal
                done[name] = value
                variables.remove(name)

    # strip spurious spaces
    for k, v in done.items():
        if isinstance(v, str):
            done[k] = v.strip()

    # save the results in the global dictionary
    vars.update(done)
    return vars


def get_makefile_filename():
    """Return the path of the Makefile."""
    if _PYTHON_BUILD:
        return os.path.join(_PROJECT_BASE, "Makefile")
    if hasattr(sys, 'abiflags'):
        config_dir_name = 'config-%s%s' % (_PY_VERSION_SHORT, sys.abiflags)
    else:
        config_dir_name = 'config'
    return os.path.join(get_path('stdlib'), config_dir_name, 'Makefile')


def _init_posix(vars):
    """Initialize the module as appropriate for POSIX systems."""