# Module 'uwppath' -- common operations on UWP pathnames
"""Common pathname manipulations, UWP version.

Instead of importing this module directly, import os and refer to this
module as os.path.
"""

import os
import sys
import stat
import genericpath
from genericpath import *

__all__ = ["normcase","isabs","join","splitdrive","split","splitext",
           "basename","dirname","commonprefix","getsize","getmtime",
           "getatime","getctime", "islink","exists","lexists","isdir","isfile",
           "ismount", "expanduser","expandvars","normpath","abspath",
           "splitunc","curdir","pardir","sep","pathsep","defpath","altsep",
           "extsep","devnull","realpath","supports_unicode_filenames","relpath",
           "samefile", "sameopenfile",]

# strings representing various path-related bits and pieces
# These are primarily for export; internally, they are hardcoded.
curdir = '.'
pardir = '..'
extsep = '.'
sep = '\\'
pathsep = ';'
altsep = '/'
defpath = '.;C:\\bin'
devnull = 'nul'

def _get_empty(path):
    if isinstance(path, bytes):
        return b''
    else:
        return ''

def _get_sep(path):
    if isinstance(path, bytes):
        return b'\\'
    else:
        return '\\'

def _get_altsep(path):
    if isinstance(path, bytes):
        return b'/'
    else:
        return '/'

def _get_bothseps(path):
    if isinstance(path, bytes):
        return b'\\/'
    else:
        return '\\/'

def _get_dot(path):
    if isinstance(path, bytes):
        return b'.'
    else:
        return '.'

def _get_colon(path):
    if isinstance(path, bytes):
        return b':'
    else:
        return ':'

def _get_special(path):
    if isinstance(path, bytes):
        return (b'\\\\.\\', b'\\\\?\\')
    else:
        return ('\\\\.\\', '\\\\?\\')

# Normalize the case of a pathname and map slashes to backslashes.
# Other normalizations (such as optimizing '../' away) are not done
# (this is done by normpath).

def normcase(s):
    """Normalize case of pathname.

    Makes all characters lowercase and all slashes into backslashes."""
    if not isinstance(s, (bytes, str)):
        raise TypeError("normcase() argument must be str or bytes, "
                        "not '{}'".format(s.__class__.__name__))
    return s.replace(_get_altsep(s), _get_sep(s)).lower()


# Return whether a path is absolute.
# Trivial in Posix, harder on Windows.
# For Windows it is absolute if it starts with a slash or backslash (current
# volume), or if a pathname after the volume-letter-and-colon or UNC-resource
# starts with a slash or backslash.

def isabs(s):
    """Test whether a path is absolute"""
    s = splitdrive(s)[1]
    return len(s) > 0 and s[:1] in _get_bothseps(s)


# Join two (or more) paths.

def join(a, *p):
    """Join two or more pathname components, inserting "\\" as needed.
    If any component is an absolute path, all previous path components
    will be discarded."""
    sep = _get_sep(a)
    seps = _get_bothseps(a)
    colon = _get_colon(a)
    path = a
    for b in p:
        b_wins = 0  # set to 1 iff b makes path irrelevant
        if not path:
            b_wins = 1

        elif isabs(b):
            # This probably wipes out path so far.  However, it's more
            # complicated if path begins with a drive letter.  You get a+b
            # (minus redundant slashes) in these four cases:
            #     1. join('c:', '/a') == 'c:/a'
            #     2. join('//computer/share', '/a') == '//computer/share/a'
            #     3. join('c:/', '/a') == 'c:/a'
            #     4. join('//computer/share/', '/a') == '//computer/share/a'
            # But b wins in all of these cases:
            #     5. join('c:/a', '/b') == '/b'
            #     6. join('//computer/share/a', '/b') == '/b'
            #     7. join('c:', 'd:/') == 'd:/'
            #     8. join('c:', '//computer/share/') == '//computer/share/'
            #     9. join('//computer/share', 'd:/') == 'd:/'
            #    10. join('//computer/share', '//computer/share/') == '//computer/share/'
            #    11. join('c:/', 'd:/') == 'd:/'
            #    12. join('c:/', '//computer/share/') == '//computer/share/'
            #    13. join('//computer/share/', 'd:/') == 'd:/'
            #    14. join('//computer/share/', '//computer/share/') == '//computer/share/'
            b_prefix, b_rest = splitdrive(b)

            # if b has a prefix, it always wins.
            if b_prefix:
                b_wins = 1
            else:
                # b doesn't have a prefix.
                # but isabs(b) returned true.
                # and therefore b_rest[0] must be a slash.
                # (but let's check that.)
                assert(b_rest and b_rest[0] in seps)

                # so, b still wins if path has a rest that's more than a sep.
                # you get a+b if path_rest is empty or only has a sep.
                # (see cases 1-4 for times when b loses.)
                path_rest = splitdrive(path)[1]
                b_wins = path_rest and path_rest not in seps

        if b_wins:
            path = b
        else:
            # Join, and ensure there's a separator.
            assert len(path) > 0
            if path[-1:] in seps:
                if b and b[:1] in seps:
                    path += b[1:]
                else:
                    path += b
            elif path[-1:] == colon:
                path += b
            elif b:
                if b[:1] in seps:
                    path += b
                else:
                    path += sep + b
            else:
                # path is not empty and does not end with a backslash,
                # but b is empty; since, e.g., split('a/') produces
                # ('a', ''), it's best if join() adds a backslash in
                # this case.
                path += sep

    return path


# Split a path in a drive specification (a drive letter followed by a
# colon) and the path specification.
# It is always true that drivespec + pathspec == p
def splitdrive(p):
    """Split a pathname into drive/UNC sharepoint and relative path specifiers.
    Returns a 2-tuple (drive_or_unc, path); either part may be empty.

    If you assign
        result = splitdrive(p)
    It is always true that:
        result[0] + result[1] == p

    If the path contained a drive letter, drive_or_unc will contain everything
    up to and including the colon.  e.g. splitdrive("c:/dir") returns ("c:", "/dir")

    If the path contained a UNC path, the drive_or_unc will contain the host name
    and share up to but not including the fourth directory separator character.
    e.g. splitdrive("//host/computer/dir") returns ("//host/computer", "/dir")

    Paths cannot contain both a drive letter and a UNC path.

    """
    empty = _get_empty(p)
    if len(p) > 1:
        sep = _get_sep(p)
        normp = normcase(p)
        if (normp[0:2] == sep*2) and (normp[2:3] != sep):
            # is a UNC path:
            # vvvvvvvvvvvvvvvvvvvv drive letter or UNC path
            # \\machine\mountpoint\directory\etc\...
            #           directory ^^^^^^^^^^^^^^^
            index = normp.find(sep, 2)
            if index == -1:
                return empty, p
            index2 = normp.find(sep, index + 1)
            # a UNC path can't have two slashes in a row
            # (after the initial two)
            if index2 == index + 1:
                return empty, p
            if index2 == -1:
                index2 = len(p)
            return p[:index2], p[index2:]
        if normp[1:2] == _get_colon(p):
            return p[:2], p[2:]
    return empty, p


# Parse UNC paths
def splitunc(p):
    """Deprecated since Python 3.1.  Please use splitdrive() instead;
    it now handles UNC paths.

    Split a pathname into UNC mount point and relative path specifiers.

    Return a 2-tuple (unc, rest); either part may be empty.
    If unc is not empty, it has the form '//host/mount' (or similar
    using backslashes).  unc+rest is always the input path.
    Paths containing drive letters never have an UNC part.
    """
    import warnings
    warnings.warn("ntpath.splitunc is deprecated, use ntpath.splitdrive instead",
                  DeprecationWarning)
    sep = _get_sep(p)
    if not p[1:2]:
        return p[:0], p # Drive letter present
    firstTwo = p[0:2]
    if normcase(firstTwo) == sep + sep:
        # is a UNC path:
        # vvvvvvvvvvvvvvvvvvvv equivalent to drive letter
        # \\machine\mountpoint\directories...
        #           directory ^^^^^^^^^^^^^^^
        normp = normcase(p)
        index = normp.find(sep, 2)
        if index == -1:
            ##raise RuntimeError, 'illegal UNC path: "' + p + '"'
            return (p[:0], p)
        index = normp.find(sep, index + 1)
        if index == -1:
            index = len(p)
        return p[:index], p[index:]
    return p[:0], p


# Split a path in head (everything up to the last '/') and tail (the
# rest).  After the trailing '/' is stripped, the invariant
# join(head, tail) == p holds.
# The resulting head won't end in '/' unless it is the root.

def split(p):
    """Split a pathname.

    Return tuple (head, tail) where tail is everything after the final slash.
    Either part may be empty."""

    seps = _get_bothseps(p)
    d, p = splitdrive(p)
    # set i to index beyond p's last slash
    i = len(p)
    while i and p[i-1] not in seps:
        i -= 1
    head, tail = p[:i], p[i:]  # now tail has no slashes
    # remove trailing slashes from head, unless it's all slashes
    head2 = head
    while head2 and head2[-1:] in seps:
        head2 = head2[:-1]
    head = head2 or head
    return d + head, tail


# Split a path in root and extension.
# The extension is everything starting at the last dot in the last
# pathname component; the root is everything before that.
# It is always true that root + ext == p.

def splitext(p):
    return genericpath._splitext(p, _get_sep(p), _get_altsep(p),
                                 _get_dot(p))
splitext.__doc__ = genericpath._splitext.__doc__


# Return the tail (basename) part of a path.

def basename(p):
    """Returns the final component of a pathname"""
    return split(p)[1]


# Return the head (dirname) part of a path.

def dirname(p):
    """Returns the directory component of a pathname"""
    return split(p)[0]

# Is a path a symbolic link?
# This will always return false on systems where os.lstat doesn't exist.

def islink(path):
    """Test whether a path is a symbolic link.
    This will always return false for Windows prior to 6.0
    and for OS/2.
    """
    try:
        st = os.lstat(path)
    except (os.error, AttributeError):
        return False
    return stat.S_ISLNK(st.st_mode)

# Being true for dangling symbolic links is also useful.

def lexists(path):
    """Test whether a path exists.  Returns True for broken symbolic links"""
    try:
        st = os.lstat(path)
    except (os.error, WindowsError):
        return False
    return True

# Is a path a mount point?  Either a root (with or without drive letter)
# or an UNC path with at most a / or \ after the mount point.

def ismount(path):
    """Test whether a path is a mount point (defined as root of drive)"""
    seps = _get_bothseps(path)
    root, rest = splitdrive(path)
    if root and root[0] in seps:
        return (not rest) or (rest in seps)
    return rest in seps


# Expand paths beginning with '~' or '~user'.
# '~' means $HOME; '~user' means that user's home directory.
# If the path doesn't begin with '~', or if the user or $HOME is unknown,
# the path is returned unchanged (leaving error reporting to whatever
# function is called with the expanded path as argument).
# See also module 'glob' for expansion of *, ? and [...] in pathnames.
# (A function should also be defined to do full *sh-style environment
# variable expansion.)

def expanduser(path):
    """Expand ~ and ~user constructs.

    If user or $HOME is unknown, do nothing."""
    if isinstance(path, bytes):
        tilde = b'~'
    else:
        tilde = '~'
    if not path.startswith(tilde):
        return path
    i, n = 1, len(path)
    while i < n and path[i] not in _get_bothseps(path):
        i += 1

    if 'HOME' in os.environ:
        userhome = os.environ['HOME']
    elif 'USERPROFILE' in os.environ:
        userhome = os.environ['USERPROFILE']
    elif not 'HOMEPATH' in os.environ:
        return path
    else:
        try:
            drive = os.environ['HOMEDRIVE']
        except KeyError:
            drive = ''
        userhome = join(drive, os.environ['HOMEPATH'])

    if isinstance(path, bytes):
        userhome = userhome.encode(sys.getfilesystemencoding())

    if i != 1: #~user
        userhome = join(dirname(userhome), path[1:i])

    return userhome + path[i:]


# Expand paths containing shell variable substitutions.
# The following rules apply:
#       - no expansion within single quotes
#       - '$$' is translated into '$'
#       - '%%' is translated into '%' if '%%' are not seen in %var1%%var2%
#       - ${varname} is accepted.
#       - $varname is accepted.
#       - %varname% is accepted.
#       - varnames can be made out of letters, digits and the characters '_-'
#         (though is not verified in the ${varname} and %varname% cases)
# XXX With COMMAND.COM you can use any characters in a variable name,
# XXX except '^|<>='.

def expandvars(path):
    """Expand shell variables of the forms $var, ${var} and %var%.

    Unknown variables are left unchanged."""
    if isinstance(path, bytes):
        if ord('$') not in path and ord('%') not in path:
            return path
        import string
        varchars = bytes(string.ascii_letters + string.digits + '_-', 'ascii')
        quote = b'\''
        percent = b'%'
        brace = b'{'
        dollar = b'$'
    else:
        if '$' not in path and '%' not in path:
            return path
        import string
        varchars = string.ascii_letters + string.digits + '_-'
        quote = '\''
        percent = '%'
        brace = '{'
        dollar = '$'
    res = path[:0]
    index = 0
    pathlen = len(path)
    while index < pathlen:
        c = path[index:index+1]
        if c == quote:   # no expansion within single quotes
            path = path[index + 1:]
            pathlen = len(path)
            try:
                index = path.index(c)
                res += c + path[:index + 1]
            except ValueError:
                res += path
                index = pathlen - 1
        elif c == percent:  # variable or '%'
            if path[index + 1:index + 2] == percent:
                res += c
                index += 1
            else:
                path = path[index+1:]
                pathlen = len(path)
                try:
                    index = path.index(percent)
                except ValueError:
                    res += percent + path
                    index = pathlen - 1
                else:
                    var = path[:index]
                    if isinstance(path, bytes):
                        var = var.decode('ascii')
                    if var in os.environ:
                        value = os.environ[var]
                    else:
                        value = '%' + var + '%'
                    if isinstance(path, bytes):
                        value = value.encode('ascii')
                    res += value
        elif c == dollar:  # variable or '$$'
            if path[index + 1:index + 2] == dollar:
                res += c
                index += 1
            elif path[index + 1:index + 2] == brace:
                path = path[index+2:]
                pathlen = len(path)
                try:
                    if isinstance(path, bytes):
                        index = path.index(b'}')
                    else:
                        index = path.index('}')
                    var = path[:index]
                    if isinstance(path, bytes):
                        var = var.decode('ascii')
                    if var in os.environ:
                        value = os.environ[var]
                    else:
                        value = '${' + var + '}'
                    if isinstance(path, bytes):
                        value = value.encode('ascii')
                    res += value
                except ValueError:
                    if isinstance(path, bytes):
                        res += b'${' + path
                    else:
                        res += '${' + path
                    index = pathlen - 1
            else:
                var = ''
                index += 1
                c = path[index:index + 1]
                while c and c in varchars:
                    if isinstance(path, bytes):
                        var += c.decode('ascii')
                    else:
                        var += c
                    index += 1
                    c = path[index:index + 1]
                if var in os.environ:
                    value = os.environ[var]
                else:
                    value = '$' + var
                if isinstance(path, bytes):
                    value = value.encode('ascii')
                res += value
                if c:
                    index -= 1
        else:
            res += c
        index += 1
    return res


# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A\B.
# Previously, this function also truncated pathnames to 8+3 format,
# but as this module is called "ntpath", that's obviously wrong!

def normpath(path):
    """Normalize path, eliminating double slashes, etc."""
    sep = _get_sep(path)
    dotdot = _get_dot(path) * 2
    special_prefixes = _get_special(path)
    if path.startswith(special_prefixes):
        # in the case of paths with these prefixes:
        # \\.\ -> device names
        # \\?\ -> literal paths
        # do not do any normalization, but return the path unchanged
        return path
    path = path.replace(_get_altsep(path), sep)
    prefix, path = splitdrive(path)

    # collapse initial backslashes
    if path.startswith(sep):
        prefix += sep
        path = path.lstrip(sep)

    comps = path.split(sep)
    i = 0
    while i < len(comps):
        if not comps[i] or comps[i] == _get_dot(path):
            del comps[i]
        elif comps[i] == dotdot:
            if i > 0 and comps[i-1] != dotdot:
                del comps[i-1:i+1]
                i -= 1
            elif i == 0 and prefix.endswith(_get_sep(path)):
                del comps[i]
            else:
                i += 1
        else:
            i += 1
    # If the path is now empty, substitute '.'
    if not prefix and not comps:
        comps.append(_get_dot(path))
    return prefix + sep.join(comps)


# Return an absolute path.
def abspath(path):
    """Return the absolute version of a path."""
    if not isabs(path):
        cwd = os.environ.get("INSTALLPATH")
        path = join(cwd, path)
    return normpath(path)

# realpath is a no-op on systems without islink support
realpath = abspath
# Windows App Store apps always have Unicode filename support.
supports_unicode_filenames = True

def relpath(path, start=curdir):
    """Return a relative version of a path"""
    sep = _get_sep(path)

    if start is curdir:
        start = _get_dot(path)

    if not path:
        raise ValueError("no path specified")

    start_abs = abspath(normpath(start))
    path_abs = abspath(normpath(path))
    start_drive, start_rest = splitdrive(start_abs)
    path_drive, path_rest = splitdrive(path_abs)
    if normcase(start_drive) != normcase(path_drive):
        error = "path is on mount '{0}', start on mount '{1}'".format(
            path_drive, start_drive)
        raise ValueError(error)

    start_list = [x for x in start_rest.split(sep) if x]
    path_list = [x for x in path_rest.split(sep) if x]
    # Work out how much of the filepath is shared by start and path.
    i = 0
    for e1, e2 in zip(start_list, path_list):
        if normcase(e1) != normcase(e2):
            break
        i += 1

    if isinstance(path, bytes):
        pardir = b'..'
    else:
        pardir = '..'
    rel_list = [pardir] * (len(start_list)-i) + path_list[i:]
    if not rel_list:
        return _get_dot(path)
    return join(*rel_list)


# determine if two files are in fact the same file
def _getfinalpathname(f):
    return normcase(abspath(f))

def samefile(f1, f2):
    "Test whether two pathnames reference the same actual file"
    return _getfinalpathname(f1) == _getfinalpathname(f2)


def _getfileinformation(fd):
    return fd

def sameopenfile(f1, f2):
    """Test whether two file objects reference the same file"""
    return _getfileinformation(f1) == _getfileinformation(f2)

