"""
Path operations common to more than one OS
Do not use directly. The OS specific modules import the appropriate
functions from this module themselves.
"""
import os
import stat

__all__ = ['commonprefix', 'exists', 'getatime', 'getctime', 'getmtime',
 'getsize', 'isdir', 'isfile', 'samefile', 'sameopenfile',
 'samestat']


# Does a path exist?
# This is false for dangling symbolic links on systems that support them.
def exists(path):
 """Test whether a path exists. Returns False for broken symbolic links"""
 try:
 os.stat(path)
 except (OSError, ValueError):
 return False
 return True


# This follows symbolic links, so both islink() and isdir() can be true
# for the same path on systems that support symlinks
def isfile(path):
 """Test whether a path is a regular file"""
 try:
 st = os.stat(path)
 except (OSError, ValueError):
 return False
 return stat.S_ISREG(st.st_mode)


# Is a path a directory?
# This follows symbolic links, so both islink() and isdir()
# can be true for the same path on systems that support symlinks
def isdir(s):
 """Return true if the pathname refers to an existing directory."""
 try:
 st = os.stat(s)
 except (OSError, ValueError):
 return False
 return stat.S_ISDIR(st.st_mode)


def getsize(filename):
 """Return the size of a file, reported by os.stat()."""
 return os.stat(filename).st_size


def getmtime(filename):
 """Return the last modification time of a file, reported by os.stat()."""
 return os.stat(filename).st_mtime


def getatime(filename):
 """Return the last access time of a file, reported by os.stat()."""
 return os.stat(filename).st_atime


def getctime(filename):
 """Return the metadata change time of a file, reported by os.stat()."""
 return os.stat(filename).st_ctime


# Return the longest prefix of all list elements.
def commonprefix(m):
 "Given a list of pathnames, returns the longest common leading component"
 if not m: return ''
 # Some people pass in a list of pathname parts to operate in an OS-agnostic
 # fashion; don't try to translate in that case as that's an abuse of the
 # API and they are already doing what they need to be OS-agnostic and so
 # they most likely won't be using an os.PathLike object in the sublists.
 if not isinstance(m[0], (list, tuple)):
 m = tuple(map(os.fspath, m))
 s1 = min(m)
 s2 = max(m)
 for i, c in enumerate(s1):
 if c != s2[i]:
 return s1[:i]
 return s1

# Are two stat buffers (obtained from stat, fstat or lstat)
# describing the same file?
def samestat(s1, s2):
 """Test whether two stat buffers reference the same file"""
 return (s1.st_ino == s2.st_ino and
 s1.st_dev == s2.st_dev)


# Are two filenames really pointing to the same file?
def samefile(f1, f2):
 """Test whether two pathnames reference the same actual file or directory

 This is determined by the device number and i-node number and
 raises an exception if an os.stat() call on either pathname fails.
 """
 s1 = os.stat(f1)
 s2 = os.stat(f2)
 return samestat(s1, s2)


# Are two open files really referencing the same file?
# (Not necessarily the same file descriptor!)
def sameopenfile(fp1, fp2):
 """Test whether two open file objects reference the same file"""
 s1 = os.fstat(fp1)
 s2 = os.fstat(fp2)
 return samestat(s1, s2)


# 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.

# Generic implementation of splitext, to be parametrized with
# the separators
def _splitext(p, sep, altsep, extsep):
 """Split the extension from a pathname.

 Extension is everything from the last dot to the end, ignoring
 leading dots. Returns "(root, ext)"; ext may be empty."""
 # NOTE: This code must work for text and bytes strings.

 sepIndex = p.rfind(sep)
 if altsep:
 altsepIndex = p.rfind(altsep)
 sepIndex = max(sepIndex, altsepIndex)

 dotIndex = p.rfind(extsep)
 if dotIndex > sepIndex:
 # skip all leading dots
 filenameIndex = sepIndex + 1
 while filenameIndex < dotIndex:
 if p[filenameIndex:filenameIndex+1] != extsep:
 return p[:dotIndex], p[dotIndex:]
 filenameIndex += 1

 return p, p[:0]

def _check_arg_types(funcname, *args):
 hasstr = hasbytes = False
 for s in args:
 if isinstance(s, str):
 hasstr = True
 elif isinstance(s, bytes):
 hasbytes = True
 else:
 raise TypeError(f'{funcname}() argument must be str, bytes, or '
 f'os.PathLike object, not {s.__class__.__name__!r}') from None
 if hasstr and hasbytes:
 raise TypeError("Can't mix strings and bytes in path components") from None