#!/usr/bin/env python
# -*- coding: utf-8 -*-

from __future__ import print_function

from collections import Iterable
import errno
from itertools import islice
import os
import platform
import re
import shutil
import sys
import unicodedata


def create_dir(path):
    """Creates a directory atomically."""
    try:
        os.makedirs(path)
    except OSError as exception:
        if exception.errno != errno.EEXIST:
            raise


def decode(string):
    """Converts byte string to Unicode string."""
    if is_python2():
        return string.decode('utf-8', errors='replace')
    return string


def encode(string):
    """Converts Unicode string to byte string."""
    if is_python2():
        return string.encode('utf-8', errors='replace')
    return string


def encode_local(string, encoding=None):
    """Converts string into local filesystem encoding."""
    if is_python2():
        return decode(string).encode(encoding or sys.getfilesystemencoding())
    return string


def first(xs):
    it = iter(xs)
    try:
        return it.next()
    except StopIteration:
        return None


def get_needle_and_index(tab_entry, separator):
    """
    Given a tab entry in the following format return the needle and index:

        [needle]__[index]__[possible_match]
    """
    matches = re.search(
            r'(.*)' + \
            separator + \
            r'([0-9]{1})' + \
            separator, tab_entry)
    return matches.group(1), int(matches.group(2))



def get_pwd():
    try:
        return os.getcwdu()
    except OSError:
        print("Current directory no longer exists.", file=sys.stderr)
        sys.exit(1)


def has_uppercase(string):
    return any(unicodedata.category(c) == 'Lu' for c in unicode(string))


def in_bash():
    return 'bash' in os.getenv('SHELL')


def is_python2():
    return sys.version_info[0] == 2


def is_linux():
    return platform.system() == 'Linux'


def is_osx():
    return platform.system() == 'Darwin'


def is_tab_entry(needle, separator):
    """
    Valid tab entry:

        [needle]__[index]__[possible_match]
    """
    pattern = re.compile(
            '.*' + \
            separator + \
            '[0-9]{1}' + \
            separator)
    return re.search(pattern, needle)


def is_tab_partial_match(needle, separator):
    return re.match(r'(.*)'+separator, needle)


def is_windows():
    return platform.system() == 'Windows'


def last(xs):
    it = iter(xs)
    tmp = None
    try:
        while True:
            tmp = it.next()
    except StopIteration:
        return tmp


def move_file(src, dst):
    """
    Atomically move file.

    Windows does not allow for atomic file renaming (which is used by
    os.rename / shutil.move) so destination paths must first be deleted.
    """
    if is_windows() and os.path.exists(dst):
        # raises exception if file is in use on Windows
        os.remove(dst)
    shutil.move(src, dst)


def print_entry(entry):
    print(encode_local("%.1f:\t%s" % (entry.weight, entry.path)))


def print_tab_menu(needle, tab_entries, separator):
    """
    Prints the tab completion menu according to the following format:

        [needle]__[index]__[possible_match]

    The needle (search pattern) and index are necessary to recreate the results
    on subsequent calls.
    """
    for i, entry in enumerate(tab_entries):
        print(encode_local(surround_quotes(
            '%s%s%d%s%s' % (
                needle,
                separator,
                i+1,
                separator,
                entry.path))))


def sanitize(directories):
    clean = lambda x: decode(x).rstrip(os.sep)
    return map(clean, directories)


def second(xs):
    it = iter(xs)
    try:
        it.next()
        return it.next()
    except StopIteration:
        return None


def surround_quotes(string):
    if in_bash():
        return '"{}"'.format(string)
    return string


def take(n, iterable):
    """Return first n items of an iterable."""
    return islice(iterable, n)