"""Filename globbing utility."""

import os
import re
import fnmatch
import sys

__all__ = ["glob", "iglob", "escape"]

def glob(pathname, *, recursive=False):
 """Return a list of paths matching a pathname pattern.

 The pattern may contain simple shell-style wildcards a la
 fnmatch. However, unlike fnmatch, filenames starting with a
 dot are special cases that are not matched by '*' and '?'
 patterns.

 If recursive is true, the pattern '**' will match any files and
 zero or more directories and subdirectories.
 """
 return list(iglob(pathname, recursive=recursive))

def iglob(pathname, *, recursive=False):
 """Return an iterator which yields the paths matching a pathname pattern.

 The pattern may contain simple shell-style wildcards a la
 fnmatch. However, unlike fnmatch, filenames starting with a
 dot are special cases that are not matched by '*' and '?'
 patterns.

 If recursive is true, the pattern '**' will match any files and
 zero or more directories and subdirectories.
 """
 sys.audit("glob.glob", pathname, recursive)
 it = _iglob(pathname, recursive, False)
 if recursive and _isrecursive(pathname):
 s = next(it) # skip empty string
 assert not s
 return it

def _iglob(pathname, recursive, dironly):
 dirname, basename = os.path.split(pathname)
 if not has_magic(pathname):
 assert not dironly
 if basename:
 if os.path.lexists(pathname):
 yield pathname
 else:
 # Patterns ending with a slash should match only directories
 if os.path.isdir(dirname):
 yield pathname
 return
 if not dirname:
 if recursive and _isrecursive(basename):
 yield from _glob2(dirname, basename, dironly)
 else:
 yield from _glob1(dirname, basename, dironly)
 return
 # `os.path.split()` returns the argument itself as a dirname if it is a
 # drive or UNC path. Prevent an infinite recursion if a drive or UNC path
 # contains magic characters (i.e. r'\\?\C:').
 if dirname != pathname and has_magic(dirname):
 dirs = _iglob(dirname, recursive, True)
 else:
 dirs = [dirname]
 if has_magic(basename):
 if recursive and _isrecursive(basename):
 glob_in_dir = _glob2
 else:
 glob_in_dir = _glob1
 else:
 glob_in_dir = _glob0
 for dirname in dirs:
 for name in glob_in_dir(dirname, basename, dironly):
 yield os.path.join(dirname, name)

# These 2 helper functions non-recursively glob inside a literal directory.
# They return a list of basenames. _glob1 accepts a pattern while _glob0
# takes a literal basename (so it only has to check for its existence).

def _glob1(dirname, pattern, dironly):
 names = list(_iterdir(dirname, dironly))
 if not _ishidden(pattern):
 names = (x for x in names if not _ishidden(x))
 return fnmatch.filter(names, pattern)

def _glob0(dirname, basename, dironly):
 if not basename:
 # `os.path.split()` returns an empty basename for paths ending with a
 # directory separator. 'q*x/' should match only directories.
 if os.path.isdir(dirname):
 return [basename]
 else:
 if os.path.lexists(os.path.join(dirname, basename)):
 return [basename]
 return []

# Following functions are not public but can be used by third-party code.

def glob0(dirname, pattern):
 return _glob0(dirname, pattern, False)

def glob1(dirname, pattern):
 return _glob1(dirname, pattern, False)

# This helper function recursively yields relative pathnames inside a literal
# directory.

def _glob2(dirname, pattern, dironly):
 assert _isrecursive(pattern)
 yield pattern[:0]
 yield from _rlistdir(dirname, dironly)

# If dironly is false, yields all file names inside a directory.
# If dironly is true, yields only directory names.
def _iterdir(dirname, dironly):
 if not dirname:
 if isinstance(dirname, bytes):
 dirname = bytes(os.curdir, 'ASCII')
 else:
 dirname = os.curdir
 try:
 with os.scandir(dirname) as it:
 for entry in it:
 try:
 if not dironly or entry.is_dir():
 yield entry.name
 except OSError:
 pass
 except OSError:
 return

# Recursively yields relative pathnames inside a literal directory.
def _rlistdir(dirname, dironly):
 names = list(_iterdir(dirname, dironly))
 for x in names:
 if not _ishidden(x):
 yield x
 path = os.path.join(dirname, x) if dirname else x
 for y in _rlistdir(path, dironly):
 yield os.path.join(x, y)


magic_check = re.compile('([*?[])')
magic_check_bytes = re.compile(b'([*?[])')

def has_magic(s):
 if isinstance(s, bytes):
 match = magic_check_bytes.search(s)
 else:
 match = magic_check.search(s)
 return match is not None

def _ishidden(path):
 return path[0] in ('.', b'.'[0])

def _isrecursive(pattern):
 if isinstance(pattern, bytes):
 return pattern == b'**'
 else:
 return pattern == '**'

def escape(pathname):
 """Escape all special characters.
 """
 # Escaping is done by wrapping any of "*?[" between square brackets.
 # Metacharacters do not work in the drive part and shouldn't be escaped.
 drive, pathname = os.path.splitdrive(pathname)
 if isinstance(pathname, bytes):
 pathname = magic_check_bytes.sub(br'[1円]', pathname)
 else:
 pathname = magic_check.sub(r'[1円]', pathname)
 return drive + pathname