#! /usr/bin/env python3
# -*- coding: utf-8 -*-
"""
The core bot class. Say good bye to PYthon 2.
"""
import collections
import os
import re
import sys
import threading
import time

import tools
import irc
from db import SopelDB
from tools import stderr, Identifier
import tools.jobs
from trigger import Trigger
from module import NOLIMIT
from logger import get_logger
import loader


LOGGER = get_logger(__name__)


class _CapReq(object):
	def __init__(self, prefix, module, failure=None, arg=None, success=None):
		def nop(bot, cap):
			pass
		# TODO at some point, reorder those args to be sane
		self.prefix = prefix
		self.module = module
		self.arg = arg
		self.failure = failure or nop
		self.success = success or nop


class Sopel(irc.Bot):
	def __init__(self, config, daemon=False):
		irc.Bot.__init__(self, config)
		self._daemon = daemon  # Used for iPython. TODO something saner here
		# `re.compile('.*') is re.compile('.*')` because of caching, so we need
		# to associate a list with each regex, since they are unexpectedly
		# indistinct.
		self._callables = {
			'high': collections.defaultdict(list),
			'medium': collections.defaultdict(list),
			'low': collections.defaultdict(list)
		}
		self.config = config
		"""The :class:`sopel.config.Config` for the current Sopel instance."""
		self.doc = {}
		"""
		A dictionary of command names to their docstring and example, if
		declared. The first item in a callable's commands list is used as the
		key in version *3.2* onward. Prior to *3.2*, the name of the function
		as declared in the source code was used.
		"""
		self._command_groups = collections.defaultdict(list)
		"""A mapping of module names to a list of commands in it."""
		self._times = {}
		"""
		A dictionary mapping lower-case'd nicks to dictionaries which map
		funtion names to the time which they were last used by that nick.
		"""

		self.server_capabilities = {}
		"""A dict mapping supported IRCv3 capabilities to their options.

		For example, if the server specifies the capability ``sasl=EXTERNAL``,
		it will be here as ``{"sasl": "EXTERNAL"}``. Capabilities specified
		without any options will have ``None`` as the value.

		For servers that do not support IRCv3, this will be an empty set."""
		self.enabled_capabilities = set()
		"""A set containing the IRCv3 capabilities that the bot has enabled."""
		self._cap_reqs = dict()
		"""A dictionary of capability names to a list of requests"""

		self.privileges = dict()
		"""A dictionary of channels to their users and privilege levels

		The value associated with each channel is a dictionary of
		:class:`sopel.tools.Identifier`\s to
		a bitwise integer value, determined by combining the appropriate
		constants from :mod:`sopel.module`.

		.. deprecated:: 6.2.0
			Use :attr:`channels` instead.
		"""

		self.channels = tools.SopelMemory()  # name to chan obj
		"""A map of the channels that Sopel is in.

		The keys are Identifiers of the channel names, and map to
		:class:`sopel.tools.target.Channel` objects which contain the users in
		the channel and their permissions.
		"""
		self.users = tools.SopelMemory()  # name to user obj
		"""A map of the users that Sopel is aware of.

		The keys are Identifiers of the nicknames, and map to
		:class:`sopel.tools.target.User` instances. In order for Sopel to be
		aware of a user, it must be in at least one channel which they are also
		in.
		"""

		self.db = SopelDB(config)
		"""The bot's database, as a :class:`sopel.db.SopelDB` instance."""

		self.memory = tools.SopelMemory()
		"""
		A thread-safe dict for storage of runtime data to be shared between
		modules. See :class:`sopel.tools.Sopel.SopelMemory`
		"""

		self.scheduler = tools.jobs.JobScheduler(self)
		self.scheduler.start()

		# Set up block lists
		# Default to empty
		if not self.config.core.nick_blocks:
			self.config.core.nick_blocks = []
		if not self.config.core.host_blocks:
			self.config.core.host_blocks = []
		self.setup()

	# Backwards-compatibility aliases to attributes made private in 6.2. Remove
	# these in 7.0
	times = property(lambda self: getattr(self, '_times'))
	command_groups = property(lambda self: getattr(self, '_command_groups'))

	def write(self, args, text=None):  # Shim this in here for autodocs
		"""Send a command to the server.

		``args`` is an iterable of strings, which are joined by spaces.
		``text`` is treated as though it were the final item in ``args``, but
		is preceeded by a ``:``. This is a special case which  means that
		``text``, unlike the items in ``args`` may contain spaces (though this
		constraint is not checked by ``write``).

		In other words, both ``sopel.write(('PRIVMSG',), 'Hello, world!')``
		and ``sopel.write(('PRIVMSG', ':Hello, world!'))`` will send
		``PRIVMSG :Hello, world!`` to the server.

		Newlines and carriage returns ('\\n' and '\\r') are removed before
		sending. Additionally, if the message (after joining) is longer than
		than 510 characters, any remaining characters will not be sent.
		"""
		irc.Bot.write(self, args, text=text)

	def setup(self):
		stderr("\nWelcome to Sopel. Loading modules...\n\n")

		modules = loader.enumerate_modules(self.config)

		error_count = 0
		success_count = 0
		for name in modules:
			path, type_ = modules[name]

			try:
				module, _ = loader.load_module(name, path, type_)
			except Exception as e:
				error_count = error_count + 1
				filename, lineno = tools.get_raising_file_and_line()
				rel_path = os.path.relpath(filename, os.path.dirname(__file__))
				raising_stmt = "%s:%d" % (rel_path, lineno)
				stderr("Error loading %s: %s (%s)" % (name, e, raising_stmt))
			else:
				try:
					if hasattr(module, 'setup'):
						module.setup(self)
					relevant_parts = loader.clean_module(
						module, self.config)
				except Exception as e:
					error_count = error_count + 1
					filename, lineno = tools.get_raising_file_and_line()
					rel_path = os.path.relpath(
						filename, os.path.dirname(__file__)
					)
					raising_stmt = "%s:%d" % (rel_path, lineno)
					stderr("Error in %s setup procedure: %s (%s)"
						   % (name, e, raising_stmt))
				else:
					self.register(*relevant_parts)
					success_count += 1

		if len(modules) > 1:  # coretasks is counted
			stderr('\n\nRegistered %d modules,' % (success_count - 1))
			stderr('%d modules failed to load\n\n' % error_count)
		else:
			stderr("Warning: Couldn't load any modules")

	def unregister(self, obj):
		if not callable(obj):
			return
		if hasattr(obj, 'rule'):  # commands and intents have it added
			for rule in obj.rule:
				callb_list = self._callables[obj.priority][rule]
				if obj in callb_list:
					callb_list.remove(obj)
		if hasattr(obj, 'interval'):
			# TODO this should somehow find the right job to remove, rather than
			# clearing the entire queue. Issue #831
			self.scheduler.clear_jobs()
		if (getattr(obj, '__name__', None) == 'shutdown'
				and obj in self.shutdown_methods):
			self.shutdown_methods.remove(obj)

	def register(self, callables, jobs, shutdowns, urls):
		self.shutdown_methods = shutdowns
		for callbl in callables:
			for rule in callbl.rule:
				self._callables[callbl.priority][rule].append(callbl)
			if hasattr(callbl, 'commands'):
				module_name = callbl.__module__.rsplit('.', 1)[-1]
				# TODO doc and make decorator for this. Not sure if this is how
				# it should work yet, so not making it public for 6.0.
				category = getattr(callbl, 'category', module_name)
				self._command_groups[category].append(callbl.commands[0])
			for command, docs in callbl._docs.items():
				self.doc[command] = docs
		for func in jobs:
			for interval in func.interval:
				job = tools.jobs.Job(interval, func)
				self.scheduler.add_job(job)

		if not self.memory.contains('url_callbacks'):
			self.memory['url_callbacks'] = tools.SopelMemory()
		for func in urls:
			self.memory['url_callbacks'][func.url_regex] = func

	def part(self, channel, msg=None):
		"""Part a channel."""
		self.write(['PART', channel], msg)

	def join(self, channel, password=None):
		"""Join a channel

		If `channel` contains a space, and no `password` is given, the space is
		assumed to split the argument into the channel to join and its
		password.  `channel` should not contain a space if `password` is given.

		"""
		if password is None:
			self.write(('JOIN', channel))
		else:
			self.write(['JOIN', channel, password])

	def say(self, text, recipient, max_messages=1):
		"""Send ``text`` as a PRIVMSG to ``recipient``.

		In the context of a triggered callable, the ``recipient`` defaults to
		the channel (or nickname, if a private message) from which the message
		was received.

		By default, this will attempt to send the entire ``text`` in one
		message. If the text is too long for the server, it may be truncated.
		If ``max_messages`` is given, the ``text`` will be split into at most
		that many messages, each no more than 400 bytes. The split is made at
		the last space character before the 400th byte, or at the 400th byte if
		no such space exists. If the ``text`` is too long to fit into the
		specified number of messages using the above splitting, the final
		message will contain the entire remainder, which may be truncated by
		the server.
		"""
		# We're arbitrarily saying that the max is 400 bytes of text when
		# messages will be split. Otherwise, we'd have to acocunt for the bot's
		# hostmask, which is hard.
		max_text_length = 400
		max_messages=1000
		# Encode to bytes, for propper length calculation
		if isinstance(text, str):
			encoded_text = text.encode('utf-8')
		else:
			encoded_text = text
		excess = ''
		if b'\n' in encoded_text:
			excess = encoded_text.split(b"\n", 1)[1]
			encoded_text = encoded_text.split(b"\n", 1)[0]

		if max_messages > 1 and len(encoded_text) > max_text_length:
			last_space = encoded_text.rfind(' '.encode('utf-8'), 0, max_text_length)
			if last_space == -1:
				excess = encoded_text[max_text_length:]
				encoded_text = encoded_text[:max_text_length]
			else:
				excess = encoded_text[last_space + 1:]
				encoded_text = encoded_text[:last_space]
		# We'll then send the excess at the end
		# Back to str again, so we don't screw things up later.
		text = encoded_text.decode('utf-8')
		try:
			self.sending.acquire()

			# No messages within the last 3 seconds? Go ahead!
			# Otherwise, wait so it's been at least 0.8 seconds + penalty

			recipient_id = Identifier(recipient)

			if recipient_id not in self.stack:
				self.stack[recipient_id] = []

			self.write(('PRIVMSG', recipient), text)
			self.stack[recipient_id].append((time.time(), self.safe(text)))
			self.stack[recipient_id] = self.stack[recipient_id][-10:]
		finally:
			self.sending.release()
		# Now that we've sent the first part, we need to send the rest. Doing
		# this recursively seems easier to me than iteratively
		if excess:
			self.say(recipient, excess, max_messages - 1)

	def notice(self, text, dest):
		"""Send an IRC NOTICE to a user or a channel.

		Within the context of a triggered callable, ``dest`` will default to
		the channel (or nickname, if a private message), in which the trigger
		happened.
		"""
		self.write(('NOTICE', dest), text)

	def action(self, text, dest):
		"""Send ``text`` as a CTCP ACTION PRIVMSG to ``dest``.

		The same loop detection and length restrictions apply as with
		:func:`say`, though automatic message splitting is not available.

		Within the context of a triggered callable, ``dest`` will default to
		the channel (or nickname, if a private message), in which the trigger
		happened.
		"""
		self.say('\001ACTION {}\001'.format(text), dest)

	def reply(self, text, dest, reply_to, notice=False):
		"""Prepend ``reply_to`` to ``text``, and send as a PRIVMSG to ``dest``.

		If ``notice`` is ``True``, send a NOTICE rather than a PRIVMSG.

		The same loop detection and length restrictions apply as with
		:func:`say`, though automatic message splitting is not available.

		Within the context of a triggered callable, ``reply_to`` will default to
		the nickname of the user who triggered the call, and ``dest`` to the
		channel (or nickname, if a private message), in which the trigger
		happened.
		"""
		text = '%s: %s' % (reply_to, text)
		if notice:
			self.notice(text, dest)
		else:
			self.say(text, dest)

	class SopelWrapper(object):
		def __init__(self, sopel, trigger):
			# The custom __setattr__ for this class sets the attribute on the
			# original bot object. We don't want that for these, so we set them
			# with the normal __setattr__.
			object.__setattr__(self, '_bot', sopel)
			object.__setattr__(self, '_trigger', trigger)

		def __dir__(self):
			classattrs = [attr for attr in self.__class__.__dict__
						  if not attr.startswith('__')]
			return list(self.__dict__) + classattrs + dir(self._bot)

		def __getattr__(self, attr):
			return getattr(self._bot, attr)

		def __setattr__(self, attr, value):
			return setattr(self._bot, attr, value)

		def say(self, message, destination=None, max_messages=1):
			if destination is None:
				destination = self._trigger.sender
			self._bot.say(message, destination, max_messages)

		def action(self, message, destination=None):
			if destination is None:
				destination = self._trigger.sender
			self._bot.action(message, destination)

		def notice(self, message, destination=None):
			if destination is None:
				destination = self._trigger.sender
			self._bot.notice(message, destination)

		def reply(self, message, destination=None, reply_to=None, notice=False):
			if destination is None:
				destination = self._trigger.sender
			if reply_to is None:
				reply_to = self._trigger.nick
			self._bot.reply(message, destination, reply_to, notice)

	def call(self, func, sopel, trigger):
		nick = trigger.nick
		current_time = time.time()
		if nick not in self._times:
			self._times[nick] = dict()
		if self.nick not in self._times:
			self._times[self.nick] = dict()
		if not trigger.is_privmsg and trigger.sender not in self._times:
			self._times[trigger.sender] = dict()

		if not trigger.admin and not func.unblockable:
			if func in self._times[nick]:
				usertimediff = current_time - self._times[nick][func]
				if func.rate > 0 and usertimediff < func.rate:
					#self._times[nick][func] = current_time
					LOGGER.info(
						"%s prevented from using %s in %s due to user limit: %d < %d",
						trigger.nick, func.__name__, trigger.sender, usertimediff,
						func.rate
					)
					return
			if func in self._times[self.nick]:
				globaltimediff = current_time - self._times[self.nick][func]
				if func.global_rate > 0 and globaltimediff < func.global_rate:
					#self._times[self.nick][func] = current_time
					LOGGER.info(
						"%s prevented from using %s in %s due to global limit: %d < %d",
						trigger.nick, func.__name__, trigger.sender, globaltimediff,
						func.global_rate
					)
					return

			if not trigger.is_privmsg and func in self._times[trigger.sender]:
				chantimediff = current_time - self._times[trigger.sender][func]
				if func.channel_rate > 0 and chantimediff < func.channel_rate:
					#self._times[trigger.sender][func] = current_time
					LOGGER.info(
						"%s prevented from using %s in %s due to channel limit: %d < %d",
						trigger.nick, func.__name__, trigger.sender, chantimediff,
						func.channel_rate
					)
					return

		try:
			exit_code = func(sopel, trigger)
		except Exception:
			exit_code = None
			self.error(trigger)

		if exit_code != NOLIMIT:
			self._times[nick][func] = current_time
			self._times[self.nick][func] = current_time
			if not trigger.is_privmsg:
				self._times[trigger.sender][func] = current_time

	def dispatch(self, pretrigger):
		args = pretrigger.args
		event, args, text = pretrigger.event, args, args[-1] if args else ''

		if self.config.core.nick_blocks or self.config.core.host_blocks:
			nick_blocked = self._nick_blocked(pretrigger.nick)
			host_blocked = self._host_blocked(pretrigger.host)
		else:
			nick_blocked = host_blocked = None

		list_of_blocked_functions = []
		for priority in ('high', 'medium', 'low'):
			items = self._callables[priority].items()

			for regexp, funcs in items:
				match = regexp.match(text)
				if not match:
					continue
				user_obj = self.users.get(pretrigger.nick)
				account = user_obj.account if user_obj else None
				trigger = Trigger(self.config, pretrigger, match, account)
				wrapper = self.SopelWrapper(self, trigger)

				for func in funcs:
					if (not trigger.admin and
							not func.unblockable and
							(nick_blocked or host_blocked)):
						function_name = "%s.%s" % (
							func.__module__, func.__name__
						)
						list_of_blocked_functions.append(function_name)
						continue

					if event not in func.event:
						continue
					if (hasattr(func, 'intents') and
							trigger.tags.get('intent') not in func.intents):
						continue
					if func.thread:
						targs = (func, wrapper, trigger)
						t = threading.Thread(target=self.call, args=targs)
						t.start()
					else:
						self.call(func, wrapper, trigger)

		if list_of_blocked_functions:
			if nick_blocked and host_blocked:
				block_type = 'both'
			elif nick_blocked:
				block_type = 'nick'
			else:
				block_type = 'host'
			LOGGER.info(
				"[%s]%s prevented from using %s.",
				block_type,
				trigger.nick,
				', '.join(list_of_blocked_functions)
			)

	def _host_blocked(self, host):
		bad_masks = self.config.core.host_blocks
		for bad_mask in bad_masks:
			bad_mask = bad_mask.strip()
			if not bad_mask:
				continue
			if (re.match(bad_mask + '$', host, re.IGNORECASE) or
					bad_mask == host):
				return True
		return False

	def _nick_blocked(self, nick):
		bad_nicks = self.config.core.nick_blocks
		for bad_nick in bad_nicks:
			bad_nick = bad_nick.strip()
			if not bad_nick:
				continue
			if (re.match(bad_nick + '$', nick, re.IGNORECASE) or
					Identifier(bad_nick) == nick):
				return True
		return False

	def _shutdown(self):
		stderr(
			'Calling shutdown for %d modules.' % (len(self.shutdown_methods),)
		)

		for shutdown_method in self.shutdown_methods:
			try:
				stderr(
					"calling %s.%s" % (
						shutdown_method.__module__, shutdown_method.__name__,
					)
				)
				shutdown_method(self)
			except Exception as e:
				stderr(
					"Error calling shutdown method for module %s:%s" % (
						shutdown_method.__module__, e
					)
				)

	def cap_req(self, module_name, capability, arg=None, failure_callback=None,
				success_callback=None):
		"""Tell Sopel to request a capability when it starts.

		By prefixing the capability with `-`, it will be ensured that the
		capability is not enabled. Simmilarly, by prefixing the capability with
		`=`, it will be ensured that the capability is enabled. Requiring and
		disabling is "first come, first served"; if one module requires a
		capability, and another prohibits it, this function will raise an
		exception in whichever module loads second. An exception will also be
		raised if the module is being loaded after the bot has already started,
		and the request would change the set of enabled capabilities.

		If the capability is not prefixed, and no other module prohibits it, it
		will be requested.  Otherwise, it will not be requested. Since
		capability requests that are not mandatory may be rejected by the
		server, as well as by other modules, a module which makes such a
		request should account for that possibility.

		The actual capability request to the server is handled after the
		completion of this function. In the event that the server denies a
		request, the `failure_callback` function will be called, if provided.
		The arguments will be a `Sopel` object, and the capability which was
		rejected. This can be used to disable callables which rely on the
		capability. It will be be called either if the server NAKs the request,
		or if the server enabled it and later DELs it.

		The `success_callback` function will be called upon acknowledgement of
		the capability from the server, whether during the initial capability
		negotiation, or later.

		If ``arg`` is given, and does not exactly match what the server
		provides or what other modules have requested for that capability, it is
		considered a conflict.
		"""
		# TODO raise better exceptions
		cap = capability[1:]
		prefix = capability[0]

		entry = self._cap_reqs.get(cap, [])
		if any((ent.arg != arg for ent in entry)):
			raise Exception('Capability conflict')

		if prefix == '-':
			if self.connection_registered and cap in self.enabled_capabilities:
				raise Exception('Can not change capabilities after server '
								'connection has been completed.')
			if any((ent.prefix != '-' for ent in entry)):
				raise Exception('Capability conflict')
			entry.append(_CapReq(prefix, module_name, failure_callback, arg,
								 success_callback))
			self._cap_reqs[cap] = entry
		else:
			if prefix != '=':
				cap = capability
				prefix = ''
			if self.connection_registered and (cap not in
											   self.enabled_capabilities):
				raise Exception('Can not change capabilities after server '
								'connection has been completed.')
			# Non-mandatory will callback at the same time as if the server
			# rejected it.
			if any((ent.prefix == '-' for ent in entry)) and prefix == '=':
				raise Exception('Capability conflict')
			entry.append(_CapReq(prefix, module_name, failure_callback, arg,
								 success_callback))
			self._cap_reqs[cap] = entry