#! /usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Useful miscellaneous tools and shortcuts for Sopel modules

*Availability: 3+*
"""
import sys
import os
import re
import threading
import codecs
import traceback
from collections import defaultdict

from tools._events import events  # NOQA

iteritems = dict.items
itervalues = dict.values
iterkeys = dict.keys

_channel_prefixes = ('#', '&', '+', '!')


def get_input(prompt):
	"""Get decoded input from the terminal (equivalent to python 3's ``input``).
	"""
	return input(prompt)


def get_raising_file_and_line(tb=None):
	"""Return the file and line number of the statement that raised the tb.

	Returns: (filename, lineno) tuple

	"""
	if not tb:
		tb = sys.exc_info()[2]

	filename, lineno, _context, _line = traceback.extract_tb(tb)[-1]

	return filename, lineno


def get_command_regexp(prefix, command):
	"""Return a compiled regexp object that implements the command."""
	# Escape all whitespace with a single backslash. This ensures that regexp
	# in the prefix is treated as it was before the actual regexp was changed
	# to use the verbose syntax.
	prefix = re.sub(r"(\s)", r"\\\1", prefix)

	# This regexp match equivalently and produce the same
	# groups 1 and 2 as the old regexp: r'^%s(%s)(?: +(.*))?$'
	# The only differences should be handling all whitespace
	# like spaces and the addition of groups 3-6.
	pattern = r"""
		(?:{prefix})({command}) # Command as group 1.
		(?:\s+              # Whitespace to end command.
		(                   # Rest of the line as group 2.
		(?:(\S+))?          # Parameters 1-4 as groups 3-6.
		(?:\s+(\S+))?
		(?:\s+(\S+))?
		(?:\s+(\S+))?
		.*                  # Accept anything after the parameters.
							# Leave it up to the module to parse
							# the line.
		))?                 # Group 2 must be None, if there are no
							# parameters.
		$                   # EoL, so there are no partial matches.
		""".format(prefix=prefix, command=command)
	return re.compile(pattern, re.IGNORECASE | re.VERBOSE)


def deprecated(old):
	def new(*args, **kwargs):
		print('Function %s is deprecated.' % old.__name__, file=sys.stderr)
		trace = traceback.extract_stack()
		for line in traceback.format_list(trace[:-1]):
			stderr(line[:-1])
		return old(*args, **kwargs)
	new.__doc__ = old.__doc__
	new.__name__ = old.__name__
	return new


# from
# http://parand.com/say/index.php/2007/07/13/simple-multi-dimensional-dictionaries-in-python/
# A simple class to make mutli dimensional dict easy to use
class Ddict(dict):

	"""Class for multi-dimensional ``dict``.

	A simple helper class to ease the creation of multi-dimensional ``dict``\s.

	"""

	def __init__(self, default=None):
		self.default = default

	def __getitem__(self, key):
		if key not in self:
			self[key] = self.default()
		return dict.__getitem__(self, key)


class Identifier(str):
	"""A `str` subclass which acts appropriately for IRC identifiers.

	When used as normal `str` objects, case will be preserved.
	However, when comparing two Identifier objects, or comparing a Identifier
	object with a `str` object, the comparison will be case insensitive.
	This case insensitivity includes the case convention conventions regarding
	``[]``, ``{}``, ``|``, ``\\``, ``^`` and ``~`` described in RFC 2812.
	"""

	def __new__(cls, identifier):
		# According to RFC2812, identifiers have to be in the ASCII range.
		# However, I think it's best to let the IRCd determine that, and we'll
		# just assume str. It won't hurt anything, and is more internally
		# consistent. And who knows, maybe there's another use case for this
		# weird case convention.
		s = str.__new__(cls, identifier)
		s._lowered = Identifier._lower(identifier)
		return s

	def lower(self):
		"""Return the identifier converted to lower-case per RFC 2812."""
		return self._lowered

	@staticmethod
	def _lower(identifier):
		"""Returns `identifier` in lower case per RFC 2812."""
		# The tilde replacement isn't needed for identifiers, but is for
		# channels, which may be useful at some point in the future.
		low = identifier.lower().replace('{', '[').replace('}', ']')
		low = low.replace('|', '\\').replace('^', '~')
		return low

	def __repr__(self):
		return "%s(%r)" % (
			self.__class__.__name__,
			self.__str__()
		)

	def __hash__(self):
		return self._lowered.__hash__()

	def __lt__(self, other):
		if isinstance(other, Identifier):
			return self._lowered < other._lowered
		return self._lowered < Identifier._lower(other)

	def __le__(self, other):
		if isinstance(other, Identifier):
			return self._lowered <= other._lowered
		return self._lowered <= Identifier._lower(other)

	def __gt__(self, other):
		if isinstance(other, Identifier):
			return self._lowered > other._lowered
		return self._lowered > Identifier._lower(other)

	def __ge__(self, other):
		if isinstance(other, Identifier):
			return self._lowered >= other._lowered
		return self._lowered >= Identifier._lower(other)

	def __eq__(self, other):
		if isinstance(other, Identifier):
			return self._lowered == other._lowered
		return self._lowered == Identifier._lower(other)

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

	def is_nick(self):
		"""Returns True if the Identifier is a nickname (as opposed to channel)
		"""
		return self and not self.startswith(_channel_prefixes)


class OutputRedirect(object):

	"""Redirect te output to the terminal and a log file.

	A simplified object used to write to both the terminal and a log file.

	"""

	def __init__(self, logpath, stderr=False, quiet=False):
		"""Create an object which will to to a file and the terminal.

		Create an object which will log to the file at ``logpath`` as well as
		the terminal.
		If ``stderr`` is given and true, it will write to stderr rather than
		stdout.
		If ``quiet`` is given and True, data will be written to the log file
		only, but not the terminal.

		"""
		self.logpath = logpath
		self.stderr = stderr
		self.quiet = quiet

	def write(self, string):
		"""Write the given ``string`` to the logfile and terminal."""
		if not self.quiet:
			try:
				if self.stderr:
					sys.__stderr__.write(string)
				else:
					sys.__stdout__.write(string)
			except:
				pass

		with codecs.open(self.logpath, 'ab', encoding="utf8",
						 errors='xmlcharrefreplace') as logfile:
			try:
				logfile.write(string)
			except strDecodeError:
				# we got an invalid string, safely encode it to utf-8
				logfile.write(str(string, 'utf8', errors="replace"))

	def flush(self):
		if self.stderr:
			sys.__stderr__.flush()
		else:
			sys.__stdout__.flush()


# These seems to trace back to when we thought we needed a try/except on prints,
# because it looked like that was why we were having problems. We'll drop it in
# 4.0^H^H^H5.0^H^H^H6.0^H^H^Hsome version when someone can be bothered.
@deprecated
def stdout(string):
	print(string)


def stderr(string):
	"""Print the given ``string`` to stderr.

	This is equivalent to ``print >> sys.stderr, string``

	"""
	print(string, file=sys.stderr)


def check_pid(pid):
	"""Check if a process is running with the given ``PID``.

	*Availability: Only on POSIX systems*

	Return ``True`` if there is a process running with the given ``PID``.

	"""
	try:
		os.kill(pid, 0)
	except OSError:
		return False
	else:
		return True


def get_hostmask_regex(mask):
	"""Return a compiled `re.RegexObject` for an IRC hostmask"""
	mask = re.escape(mask)
	mask = mask.replace(r'\*', '.*')
	return re.compile(mask + '$', re.I)


class SopelMemory(dict):

	"""A simple thread-safe dict implementation.

	*Availability: 4.0; available as ``Sopel.SopelMemory`` in 3.1.0 - 3.2.0*

	In order to prevent exceptions when iterating over the values and changing
	them at the same time from different threads, we use a blocking lock on
	``__setitem__`` and ``contains``.

	"""
	def __init__(self, *args):
		dict.__init__(self, *args)
		self.lock = threading.Lock()

	def __setitem__(self, key, value):
		self.lock.acquire()
		result = dict.__setitem__(self, key, value)
		self.lock.release()
		return result

	def __contains__(self, key):
		"""Check if a key is in the dict.

		It locks it for writes when doing so.

		"""
		self.lock.acquire()
		result = dict.__contains__(self, key)
		self.lock.release()
		return result

	def contains(self, key):
		"""Backwards compatability with 3.x, use `in` operator instead."""
		return self.__contains__(key)


class SopelMemoryWithDefault(defaultdict):
	"""Same as SopelMemory, but subclasses from collections.defaultdict."""
	def __init__(self, *args):
		defaultdict.__init__(self, *args)
		self.lock = threading.Lock()

	def __setitem__(self, key, value):
		self.lock.acquire()
		result = defaultdict.__setitem__(self, key, value)
		self.lock.release()
		return result

	def __contains__(self, key):
		"""Check if a key is in the dict.

		It locks it for writes when doing so.

		"""
		self.lock.acquire()
		result = defaultdict.__contains__(self, key)
		self.lock.release()
		return result

	def contains(self, key):
		"""Backwards compatability with 3.x, use `in` operator instead."""
		return self.__contains__(key)