# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

import posixpath
import os
import re

'''
Like os.path, with a reduced set of functions, and with normalized path
separators (always use forward slashes).
Also contains a few additional utilities not found in os.path.
'''


def normsep(path):
    '''
    Normalize path separators, by using forward slashes instead of whatever
    os.sep is.
    '''
    if os.sep != '/':
        path = path.replace(os.sep, '/')
    return path


def relpath(path, start):
    rel = normsep(os.path.relpath(path, start))
    return '' if rel == '.' else rel


def join(*paths):
    paths = [normsep(p) for p in paths]
    return posixpath.join(*paths)


def normpath(path):
    return posixpath.normpath(normsep(path))


def dirname(path):
    return posixpath.dirname(normsep(path))


def commonprefix(paths):
    return posixpath.commonprefix([normsep(path) for path in paths])


def basename(path):
    return os.path.basename(path)


def splitext(path):
    return posixpath.splitext(normsep(path))


def split(path):
    '''
    Return the normalized path as a list of its components.
        split('foo/bar/baz') returns ['foo', 'bar', 'baz']
    '''
    return normsep(path).split('/')


def basedir(path, bases):
    '''
    Given a list of directories (bases), return which one contains the given
    path. If several matches are found, the deepest base directory is returned.
        basedir('foo/bar/baz', ['foo', 'baz', 'foo/bar']) returns 'foo/bar'
        ('foo' and 'foo/bar' both match, but 'foo/bar' is the deepest match)
    '''
    path = normsep(path)
    bases = [normsep(b) for b in bases]
    if path in bases:
        return path
    for b in sorted(bases, reverse=True):
        if b == '' or path.startswith(b + '/'):
            return b


def match(path, pattern):
    '''
    Return whether the given path matches the given pattern.
    An asterisk can be used to match any string, including the null string, in
    one part of the path:
        'foo' matches '*', 'f*' or 'fo*o'
    However, an asterisk matching a subdirectory may not match the null string:
        'foo/bar' does *not* match 'foo/*/bar'
    If the pattern matches one of the ancestor directories of the path, the
    patch is considered matching:
        'foo/bar' matches 'foo'
    Two adjacent asterisks can be used to match files and zero or more
    directories and subdirectories.
        'foo/bar' matches 'foo/**/bar', or '**/bar'
    '''
    if not pattern:
        return True
    if isinstance(path, basestring):
        path = split(path)
    if isinstance(pattern, basestring):
        pattern = split(pattern)

    if pattern[0] == '**':
        if len(pattern) == 1:
            return True
        return any(match(path[n:], pattern[1:]) for n in xrange(len(path)))
    if len(pattern) > 1:
        return match(path[:1], pattern[:1]) and match(path[1:], pattern[1:])
    if path:
        return re.match(translate(pattern[0]), path[0]) is not None
    return False


def translate(pattern):
    '''
    Translate the globbing pattern to a regular expression.
    '''
    return re.escape(pattern).replace('\*', '.*') + '$'


def rebase(oldbase, base, relativepath):
    '''
    Return relativepath relative to base instead of oldbase.
    '''
    if base == oldbase:
        return relativepath
    if len(base) < len(oldbase):
        assert basedir(oldbase, [base]) == base
        relbase = relpath(oldbase, base)
        result = join(relbase, relativepath)
    else:
        assert basedir(base, [oldbase]) == oldbase
        relbase = relpath(base, oldbase)
        result = relpath(relativepath, relbase)
    result = normpath(result)
    if relativepath.endswith('/') and not result.endswith('/'):
        result += '/'
    return result