"""
To ensure compatibility from Python ``2.7`` - ``3.x``, a module has been
created. Clearly there is huge need to use conforming syntax.
"""
from __future__ import print_function
import errno
import sys
import os
import warnings
import subprocess
import pickle

try:
    import importlib
except ImportError:
    pass
from zipimport import zipimporter

from jedi.file_io import KnownContentFileIO, ZipFileIO

is_py3 = sys.version_info[0] >= 3
is_py35 = is_py3 and sys.version_info[1] >= 5
py_version = int(str(sys.version_info[0]) + str(sys.version_info[1]))


def find_module(string, path=None, full_name=None, is_global_search=True):
    """
    Provides information about a module.

    This function isolates the differences in importing libraries introduced with
    python 3.3 on; it gets a module name and optionally a path. It will return a
    tuple containin an open file for the module (if not builtin), the filename
    or the name of the module if it is a builtin one and a boolean indicating
    if the module is contained in a package.
    """
    spec = None
    loader = None

    for finder in sys.meta_path:
        if is_global_search and finder != importlib.machinery.PathFinder:
            p = None
        else:
            p = path
        try:
            find_spec = finder.find_spec
        except AttributeError:
            # These are old-school clases that still have a different API, just
            # ignore those.
            continue

        spec = find_spec(string, p)
        if spec is not None:
            loader = spec.loader
            if loader is None and not spec.has_location:
                # This is a namespace package.
                full_name = string if not path else full_name
                implicit_ns_info = ImplicitNSInfo(full_name, spec.submodule_search_locations._path)
                return implicit_ns_info, True
            break

    return find_module_py33(string, path, loader)


def find_module_py33(string, path=None, loader=None, full_name=None, is_global_search=True):
    loader = loader or importlib.machinery.PathFinder.find_module(string, path)

    if loader is None and path is None:  # Fallback to find builtins
        try:
            with warnings.catch_warnings(record=True):
                # Mute "DeprecationWarning: Use importlib.util.find_spec()
                # instead." While we should replace that in the future, it's
                # probably good to wait until we deprecate Python 3.3, since
                # it was added in Python 3.4 and find_loader hasn't been
                # removed in 3.6.
                loader = importlib.find_loader(string)
        except ValueError as e:
            # See #491. Importlib might raise a ValueError, to avoid this, we
            # just raise an ImportError to fix the issue.
            raise ImportError("Originally  " + repr(e))

    if loader is None:
        raise ImportError("Couldn't find a loader for {}".format(string))

    return _from_loader(loader, string)


def _from_loader(loader, string):
    try:
        is_package_method = loader.is_package
    except AttributeError:
        is_package = False
    else:
        is_package = is_package_method(string)
    try:
        get_filename = loader.get_filename
    except AttributeError:
        return None, is_package
    else:
        module_path = cast_path(get_filename(string))

    # To avoid unicode and read bytes, "overwrite" loader.get_source if
    # possible.
    try:
        f = type(loader).get_source
    except AttributeError:
        raise ImportError("get_source was not defined on loader")

    if is_py3 and f is not importlib.machinery.SourceFileLoader.get_source:
        # Unfortunately we are reading unicode here, not bytes.
        # It seems hard to get bytes, because the zip importer
        # logic just unpacks the zip file and returns a file descriptor
        # that we cannot as easily access. Therefore we just read it as
        # a string in the cases where get_source was overwritten.
        code = loader.get_source(string)
    else:
        code = _get_source(loader, string)

    if code is None:
        return None, is_package
    if isinstance(loader, zipimporter):
        return ZipFileIO(module_path, code, cast_path(loader.archive)), is_package

    return KnownContentFileIO(module_path, code), is_package


def _get_source(loader, fullname):
    """
    This method is here as a replacement for SourceLoader.get_source. That
    method returns unicode, but we prefer bytes.
    """
    path = loader.get_filename(fullname)
    try:
        return loader.get_data(path)
    except OSError:
        raise ImportError('source not available through get_data()',
                          name=fullname)


class ImplicitNSInfo(object):
    """Stores information returned from an implicit namespace spec"""
    def __init__(self, name, paths):
        self.name = name
        self.paths = paths


if is_py3:
    all_suffixes = importlib.machinery.all_suffixes
else:
    def all_suffixes():
        # Is deprecated and raises a warning in Python 3.6.
        import imp
        return [suffix for suffix, _, _ in imp.get_suffixes()]


# unicode function
try:
    unicode = unicode
except NameError:
    unicode = str


try:
    encoding = sys.stdout.encoding
    if encoding is None:
        encoding = 'utf-8'
except AttributeError:
    encoding = 'ascii'


def u(string, errors='strict'):
    """Cast to unicode DAMMIT!
    Written because Python2 repr always implicitly casts to a string, so we
    have to cast back to a unicode (and we now that we always deal with valid
    unicode, because we check that in the beginning).
    """
    if isinstance(string, bytes):
        return unicode(string, encoding='UTF-8', errors=errors)
    return string


def cast_path(obj):
    """
    Take a bytes or str path and cast it to unicode.

    Apparently it is perfectly fine to pass both byte and unicode objects into
    the sys.path. This probably means that byte paths are normal at other
    places as well.

    Since this just really complicates everything and Python 2.7 will be EOL
    soon anyway, just go with always strings.
    """
    return u(obj, errors='replace')


def force_unicode(obj):
    # Intentionally don't mix those two up, because those two code paths might
    # be different in the future (maybe windows?).
    return cast_path(obj)


try:
    import builtins  # module name in python 3
except ImportError:
    import __builtin__ as builtins  # noqa: F401


import ast  # noqa: F401


def literal_eval(string):
    return ast.literal_eval(string)


try:
    from itertools import zip_longest
except ImportError:
    from itertools import izip_longest as zip_longest  # Python 2  # noqa: F401

try:
    IsADirectoryError = IsADirectoryError
except NameError:
    IsADirectoryError = IOError

try:
    PermissionError = PermissionError
except NameError:
    PermissionError = IOError

try:
    NotADirectoryError = NotADirectoryError
except NameError:
    class NotADirectoryError(Exception):
        # Don't implement this for Python 2 anymore.
        pass


def utf8_repr(func):
    """
    ``__repr__`` methods in Python 2 don't allow unicode objects to be
    returned. Therefore cast them to utf-8 bytes in this decorator.
    """
    def wrapper(self):
        result = func(self)
        if isinstance(result, unicode):
            return result.encode('utf-8')
        else:
            return result

    if is_py3:
        return func
    else:
        return wrapper


def pickle_load(file):
    try:
        return pickle.load(file)
    # Python on Windows don't throw EOF errors for pipes. So reraise them with
    # the correct type, which is caught upwards.
    except OSError:
        if sys.platform == 'win32':
            raise EOFError()
        raise


def pickle_dump(data, file, protocol):
    try:
        pickle.dump(data, file, protocol)
        # On Python 3.3 flush throws sometimes an error even though the writing
        # operation should be completed.
        file.flush()
    # Python on Windows don't throw EPIPE errors for pipes. So reraise them with
    # the correct type and error number.
    except OSError:
        if sys.platform == 'win32':
            raise IOError(errno.EPIPE, "Broken pipe")
        raise


# Determine the highest protocol version compatible for a given list of Python
# versions.
def highest_pickle_protocol(python_versions):
    protocol = 4
    for version in python_versions:
        if version[0] == 2:
            # The minimum protocol version for the versions of Python that we
            # support (2.7 and 3.3+) is 2.
            return 2
        if version[1] < 4:
            protocol = 3
    return protocol


class GeneralizedPopen(subprocess.Popen):
    def __init__(self, *args, **kwargs):
        if os.name == 'nt':
            try:
                # Was introduced in Python 3.7.
                CREATE_NO_WINDOW = subprocess.CREATE_NO_WINDOW
            except AttributeError:
                CREATE_NO_WINDOW = 0x08000000
            kwargs['creationflags'] = CREATE_NO_WINDOW
        # The child process doesn't need file descriptors except 0, 1, 2.
        # This is unix only.
        kwargs['close_fds'] = 'posix' in sys.builtin_module_names
        super(GeneralizedPopen, self).__init__(*args, **kwargs)


# shutil.which is not available on Python 2.7.
def which(cmd, mode=os.F_OK | os.X_OK, path=None):
    """Given a command, mode, and a PATH string, return the path which
    conforms to the given mode on the PATH, or None if there is no such
    file.

    `mode` defaults to os.F_OK | os.X_OK. `path` defaults to the result
    of os.environ.get("PATH"), or can be overridden with a custom search
    path.

    """
    # Check that a given file can be accessed with the correct mode.
    # Additionally check that `file` is not a directory, as on Windows
    # directories pass the os.access check.
    def _access_check(fn, mode):
        return (os.path.exists(fn) and os.access(fn, mode)
                and not os.path.isdir(fn))

    # If we're given a path with a directory part, look it up directly rather
    # than referring to PATH directories. This includes checking relative to the
    # current directory, e.g. ./script
    if os.path.dirname(cmd):
        if _access_check(cmd, mode):
            return cmd
        return None

    if path is None:
        path = os.environ.get("PATH", os.defpath)
    if not path:
        return None
    path = path.split(os.pathsep)

    if sys.platform == "win32":
        # The current directory takes precedence on Windows.
        if os.curdir not in path:
            path.insert(0, os.curdir)

        # PATHEXT is necessary to check on Windows.
        pathext = os.environ.get("PATHEXT", "").split(os.pathsep)
        # See if the given file matches any of the expected path extensions.
        # This will allow us to short circuit when given "python.exe".
        # If it does match, only test that one, otherwise we have to try
        # others.
        if any(cmd.lower().endswith(ext.lower()) for ext in pathext):
            files = [cmd]
        else:
            files = [cmd + ext for ext in pathext]
    else:
        # On other platforms you don't have things like PATHEXT to tell you
        # what file suffixes are executable, so just pass on cmd as-is.
        files = [cmd]

    seen = set()
    for dir in path:
        normdir = os.path.normcase(dir)
        if normdir not in seen:
            seen.add(normdir)
            for thefile in files:
                name = os.path.join(dir, thefile)
                if _access_check(name, mode):
                    return name
    return None