from functools import wraps
import os
from platform import system as _curos
import re
import subprocess
from warnings import warn

CUR_OS = _curos()
IS_WIN = CUR_OS in ['Windows', 'cli']
IS_NIX = (not IS_WIN) and any(
    CUR_OS.startswith(i) for i in
    ['CYGWIN', 'MSYS', 'Linux', 'Darwin', 'SunOS',
     'FreeBSD', 'NetBSD', 'OpenBSD'])
RE_ANSI = re.compile(r"\x1b\[[;\d]*[A-Za-z]")


# Py2/3 compat. Empty conditional to avoid coverage
if True:  # pragma: no cover
    try:
        _range = xrange
    except NameError:
        _range = range

    try:
        _unich = unichr
    except NameError:
        _unich = chr

    try:
        _unicode = unicode
    except NameError:
        _unicode = str

    try:
        if IS_WIN:
            import colorama
        else:
            raise ImportError
    except ImportError:
        colorama = None
    else:
        try:
            colorama.init(strip=False)
        except TypeError:
            colorama.init()

    try:
        from weakref import WeakSet
    except ImportError:
        WeakSet = set

    try:
        _basestring = basestring
    except NameError:
        _basestring = str

    try:  # py>=2.7,>=3.1
        from collections import OrderedDict as _OrderedDict
    except ImportError:
        try:  # older Python versions with backported ordereddict lib
            from ordereddict import OrderedDict as _OrderedDict
        except ImportError:  # older Python versions without ordereddict lib
            # Py2.6,3.0 compat, from PEP 372
            from collections import MutableMapping

            class _OrderedDict(dict, MutableMapping):
                # Methods with direct access to underlying attributes
                def __init__(self, *args, **kwds):
                    if len(args) > 1:
                        raise TypeError('expected at 1 argument, got %d',
                                        len(args))
                    if not hasattr(self, '_keys'):
                        self._keys = []
                    self.update(*args, **kwds)

                def clear(self):
                    del self._keys[:]
                    dict.clear(self)

                def __setitem__(self, key, value):
                    if key not in self:
                        self._keys.append(key)
                    dict.__setitem__(self, key, value)

                def __delitem__(self, key):
                    dict.__delitem__(self, key)
                    self._keys.remove(key)

                def __iter__(self):
                    return iter(self._keys)

                def __reversed__(self):
                    return reversed(self._keys)

                def popitem(self):
                    if not self:
                        raise KeyError
                    key = self._keys.pop()
                    value = dict.pop(self, key)
                    return key, value

                def __reduce__(self):
                    items = [[k, self[k]] for k in self]
                    inst_dict = vars(self).copy()
                    inst_dict.pop('_keys', None)
                    return self.__class__, (items,), inst_dict

                # Methods with indirect access via the above methods
                setdefault = MutableMapping.setdefault
                update = MutableMapping.update
                pop = MutableMapping.pop
                keys = MutableMapping.keys
                values = MutableMapping.values
                items = MutableMapping.items

                def __repr__(self):
                    pairs = ', '.join(map('%r: %r'.__mod__, self.items()))
                    return '%s({%s})' % (self.__class__.__name__, pairs)

                def copy(self):
                    return self.__class__(self)

                @classmethod
                def fromkeys(cls, iterable, value=None):
                    d = cls()
                    for key in iterable:
                        d[key] = value
                    return d


class FormatReplace(object):
    """
    >>> a = FormatReplace('something')
    >>> "{:5d}".format(a)
    'something'
    """
    def __init__(self, replace=''):
        self.replace = replace
        self.format_called = 0

    def __format__(self, _):
        self.format_called += 1
        return self.replace


class Comparable(object):
    """Assumes child has self._comparable attr/@property"""
    def __lt__(self, other):
        return self._comparable < other._comparable

    def __le__(self, other):
        return (self < other) or (self == other)

    def __eq__(self, other):
        return self._comparable == other._comparable

    def __ne__(self, other):
        return not self == other

    def __gt__(self, other):
        return not self <= other

    def __ge__(self, other):
        return not self < other


class ObjectWrapper(object):
    def __getattr__(self, name):
        return getattr(self._wrapped, name)

    def __setattr__(self, name, value):
        return setattr(self._wrapped, name, value)

    def wrapper_getattr(self, name):
        """Actual `self.getattr` rather than self._wrapped.getattr"""
        try:
            return object.__getattr__(self, name)
        except AttributeError:  # py2
            return getattr(self, name)

    def wrapper_setattr(self, name, value):
        """Actual `self.setattr` rather than self._wrapped.setattr"""
        return object.__setattr__(self, name, value)

    def __init__(self, wrapped):
        """
        Thin wrapper around a given object
        """
        self.wrapper_setattr('_wrapped', wrapped)


class SimpleTextIOWrapper(ObjectWrapper):
    """
    Change only `.write()` of the wrapped object by encoding the passed
    value and passing the result to the wrapped object's `.write()` method.
    """
    # pylint: disable=too-few-public-methods
    def __init__(self, wrapped, encoding):
        super(SimpleTextIOWrapper, self).__init__(wrapped)
        self.wrapper_setattr('encoding', encoding)

    def write(self, s):
        """
        Encode `s` and pass to the wrapped object's `.write()` method.
        """
        return self._wrapped.write(s.encode(self.wrapper_getattr('encoding')))

    def __eq__(self, other):
        return self._wrapped == getattr(other, '_wrapped', other)


class CallbackIOWrapper(ObjectWrapper):
    def __init__(self, callback, stream, method="read"):
        """
        Wrap a given `file`-like object's `read()` or `write()` to report
        lengths to the given `callback`
        """
        super(CallbackIOWrapper, self).__init__(stream)
        func = getattr(stream, method)
        if method == "write":
            @wraps(func)
            def write(data, *args, **kwargs):
                res = func(data, *args, **kwargs)
                callback(len(data))
                return res
            self.wrapper_setattr('write', write)
        elif method == "read":
            @wraps(func)
            def read(*args, **kwargs):
                data = func(*args, **kwargs)
                callback(len(data))
                return data
            self.wrapper_setattr('read', read)
        else:
            raise KeyError("Can only wrap read/write methods")


def _is_utf(encoding):
    try:
        u'\u2588\u2589'.encode(encoding)
    except UnicodeEncodeError:  # pragma: no cover
        return False
    except Exception:  # pragma: no cover
        try:
            return encoding.lower().startswith('utf-') or ('U8' == encoding)
        except:
            return False
    else:
        return True


def _supports_unicode(fp):
    try:
        return _is_utf(fp.encoding)
    except AttributeError:
        return False


def _is_ascii(s):
    if isinstance(s, str):
        for c in s:
            if ord(c) > 255:
                return False
        return True
    return _supports_unicode(s)


def _screen_shape_wrapper():  # pragma: no cover
    """
    Return a function which returns console dimensions (width, height).
    Supported: linux, osx, windows, cygwin.
    """
    _screen_shape = None
    if IS_WIN:
        _screen_shape = _screen_shape_windows
        if _screen_shape is None:
            _screen_shape = _screen_shape_tput
    if IS_NIX:
        _screen_shape = _screen_shape_linux
    return _screen_shape


def _screen_shape_windows(fp):  # pragma: no cover
    try:
        from ctypes import windll, create_string_buffer
        import struct
        from sys import stdin, stdout

        io_handle = -12  # assume stderr
        if fp == stdin:
            io_handle = -10
        elif fp == stdout:
            io_handle = -11

        h = windll.kernel32.GetStdHandle(io_handle)
        csbi = create_string_buffer(22)
        res = windll.kernel32.GetConsoleScreenBufferInfo(h, csbi)
        if res:
            (_bufx, _bufy, _curx, _cury, _wattr, left, top, right, bottom,
             _maxx, _maxy) = struct.unpack("hhhhHhhhhhh", csbi.raw)
            return right - left, bottom - top  # +1
    except:
        pass
    return None, None


def _screen_shape_tput(*_):  # pragma: no cover
    """cygwin xterm (windows)"""
    try:
        import shlex
        return [int(subprocess.check_call(shlex.split('tput ' + i))) - 1
                for i in ('cols', 'lines')]
    except:
        pass
    return None, None


def _screen_shape_linux(fp):  # pragma: no cover

    try:
        from termios import TIOCGWINSZ
        from fcntl import ioctl
        from array import array
    except ImportError:
        return None
    else:
        try:
            rows, cols = array('h', ioctl(fp, TIOCGWINSZ, '\0' * 8))[:2]
            return cols, rows
        except:
            try:
                return [int(os.environ[i]) - 1 for i in ("COLUMNS", "LINES")]
            except KeyError:
                return None, None


def _environ_cols_wrapper():  # pragma: no cover
    """
    Return a function which returns console width.
    Supported: linux, osx, windows, cygwin.
    """
    warn("Use `_screen_shape_wrapper()(file)[0]` instead of"
         " `_environ_cols_wrapper()(file)`", DeprecationWarning, stacklevel=2)
    shape = _screen_shape_wrapper()
    if not shape:
        return None

    @wraps(shape)
    def inner(fp):
        return shape(fp)[0]

    return inner


def _term_move_up():  # pragma: no cover
    return '' if (os.name == 'nt') and (colorama is None) else '\x1b[A'


try:
    # TODO consider using wcswidth third-party package for 0-width characters
    from unicodedata import east_asian_width
except ImportError:
    _text_width = len
else:
    def _text_width(s):
        return sum(
            2 if east_asian_width(ch) in 'FW' else 1 for ch in _unicode(s))


def disp_len(data):
    """
    Returns the real on-screen length of a string which may contain
    ANSI control codes and wide chars.
    """
    return _text_width(RE_ANSI.sub('', data))


def disp_trim(data, length):
    """
    Trim a string which may contain ANSI control characters.
    """
    if len(data) == disp_len(data):
        return data[:length]

    ansi_present = bool(RE_ANSI.search(data))
    while disp_len(data) > length:  # carefully delete one char at a time
        data = data[:-1]
    if ansi_present and bool(RE_ANSI.search(data)):
        # assume ANSI reset is required
        return data if data.endswith("\033[0m") else data + "\033[0m"
    return data