# Copyright 2019 Ram Rachum and collaborators.
# This program is distributed under the MIT license.

import abc
import re

import sys
from .pycompat import ABC, string_types, collections_abc

def _check_methods(C, *methods):
	mro = C.__mro__
	for method in methods:
		for B in mro:
			if method in B.__dict__:
				if B.__dict__[method] is None:
					return NotImplemented
				break
		else:
			return NotImplemented
	return True


class WritableStream(ABC):
	@abc.abstractmethod
	def write(self, s):
		pass

	@classmethod
	def __subclasshook__(cls, C):
		if cls is WritableStream:
			return _check_methods(C, 'write')
		return NotImplemented



file_reading_errors = (
	IOError,
	OSError,
	ValueError # IronPython weirdness.
)



def shitcode(s):
	return ''.join(
		(c if (0 < ord(c) < 256) else '?') for c in s
	)


def get_repr_function(item, custom_repr):
	for condition, action in custom_repr:
		if isinstance(condition, type):
			condition = lambda x, y=condition: isinstance(x, y)
		if condition(item):
			return action
	return repr


DEFAULT_REPR_RE = re.compile(r' at 0x[a-f0-9A-F]{4,}')


def normalize_repr(item_repr):
	"""Remove memory address (0x...) from a default python repr"""
	return DEFAULT_REPR_RE.sub('', item_repr)


def get_shortish_repr(item, custom_repr=(), max_length=None, normalize=False):
	repr_function = get_repr_function(item, custom_repr)
	try:
		r = repr_function(item)
	except Exception:
		r = 'REPR FAILED'
	r = r.replace('\r', '').replace('\n', '')
	if normalize:
		r = normalize_repr(r)
	if max_length:
		r = truncate(r, max_length)
	return r


def truncate(string, max_length):
	if (max_length is None) or (len(string) <= max_length):
		return string
	else:
		left = (max_length - 3) // 2
		right = max_length - 3 - left
		return u'{}...{}'.format(string[:left], string[-right:])


def ensure_tuple(x):
	if isinstance(x, collections_abc.Iterable) and \
											   not isinstance(x, string_types):
		return tuple(x)
	else:
		return (x,)