# -*- coding: utf-8 -*-

# Recent changes Goat compatible Discord webhook is a project for using a webhook as recent changes page from MediaWiki.
# Copyright (C) 2018 Frisk

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import base64
import json, logging, sys, re, time, random, math
from html.parser import HTMLParser
from urllib.parse import urlparse, urlunparse, quote
import requests
from collections import defaultdict
from src.configloader import settings
from src.i18n import misc

_ = misc.gettext

# Create a custom logger

misc_logger = logging.getLogger("rcgcdw.misc")

data_template = {"rcid": None, "discussion_id": 0, "abuse_log_id": None,
                 "daily_overview": {"edits": None, "new_files": None, "admin_actions": None, "bytes_changed": None,
                                    "new_articles": None, "unique_editors": None, "day_score": None, "days_tracked": 0}}

WIKI_API_PATH: str = ""
WIKI_ARTICLE_PATH: str = ""
WIKI_SCRIPT_PATH: str = ""
WIKI_JUST_DOMAIN: str = ""
rate_limit = 0

profile_fields = {"profile-location": _("Location"), "profile-aboutme": _("About me"), "profile-link-google": _("Google link"), "profile-link-facebook":_("Facebook link"), "profile-link-twitter": _("Twitter link"), "profile-link-reddit": _("Reddit link"), "profile-link-twitch": _("Twitch link"), "profile-link-psn": _("PSN link"), "profile-link-vk": _("VK link"), "profile-link-xbl": _("XBL link"), "profile-link-steam": _("Steam link"), "profile-link-discord": _("Discord handle"), "profile-link-battlenet": _("Battle.net handle")}

class DataFile:
	"""Data class which instance of is shared by multiple modules to remain consistent and do not cause too many IO operations."""
	def __init__(self):
		self.data = self.load_datafile()
		self.changed = False

	@staticmethod
	def generate_datafile():
		"""Generate a data.json file from a template."""
		try:
			with open("data.json", 'w') as data:
				data.write(json.dumps(data_template, indent=4))
		except PermissionError:
			misc_logger.critical("Could not create a data file (no permissions). No way to store last edit.")
			sys.exit(1)

	def load_datafile(self) -> dict:
		"""Read a data.json file and return a dictionary with contents
		:rtype: dict
		"""
		try:
			with open("data.json") as data:
				return json.loads(data.read())
		except FileNotFoundError:
			self.generate_datafile()
			misc_logger.info("The data file could not be found. Generating a new one...")
			return data_template

	def save_datafile(self):
		"""Overwrites the data.json file with given dictionary"""
		if self.changed is False:  # don't cause unnecessary write operations
			return
		try:
			with open("data.json", "w") as data_file:
				data_file.write(json.dumps(self.data, indent=4))
			self.changed = False
		except PermissionError:
			misc_logger.critical("Could not modify a data file (no permissions). No way to store last edit.")
			sys.exit(1)

	def __setitem__(self, instance, value):
		self.data[instance] = value
		self.changed = True

	def __getitem__(self, item):
		return self.data[item]



class MessageQueue:
	"""Message queue class for undelivered messages"""
	def __init__(self):
		self._queue = []

	def __repr__(self):
		return self._queue

	def __len__(self):
		return len(self._queue)

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

	def clear(self):
		self._queue.clear()

	def add_message(self, message):
		self._queue.append(message)

	def cut_messages(self, item_num):
		self._queue = self._queue[item_num:]

	def resend_msgs(self):
		if self._queue:
			misc_logger.info(
				"{} messages waiting to be delivered to Discord due to Discord throwing errors/no connection to Discord servers.".format(
					len(self._queue)))
			for num, item in enumerate(self._queue):
				misc_logger.debug(
					"Trying to send a message to Discord from the queue with id of {} and content {}".format(str(num),
					                                                                                         str(item)))
				if send_to_discord_webhook(item) < 2:
					misc_logger.debug("Sending message succeeded")
				else:
					misc_logger.debug("Sending message failed")
					break
			else:
				self.clear()
				misc_logger.debug("Queue emptied, all messages delivered")
			self.cut_messages(num)
			misc_logger.debug(self._queue)


messagequeue = MessageQueue()
datafile = DataFile()


def weighted_average(value, weight, new_value):
	"""Calculates weighted average of value number with weight weight and new_value with weight 1"""
	return round(((value * weight) + new_value) / (weight + 1), 2)


def link_formatter(link):
	"""Formats a link to not embed it"""
	return "<" + quote(link.replace(" ", "_"), "/:?") + ">"


def escape_formatting(data):
	"""Escape Discord formatting"""
	return re.sub(r"([`_*~<>{}@/|\\])", "\\\\\\1", data, 0)


class ContentParser(HTMLParser):
	more = _("\n__And more__")
	current_tag = ""
	small_prev_ins = ""
	small_prev_del = ""
	ins_length = len(more)
	del_length = len(more)
	added = False

	def handle_starttag(self, tagname, attribs):
		if tagname == "ins" or tagname == "del":
			self.current_tag = tagname
		if tagname == "td" and 'diff-addedline' in attribs[0]:
			self.current_tag = tagname + "a"
		if tagname == "td" and 'diff-deletedline' in attribs[0]:
			self.current_tag = tagname + "d"
		if tagname == "td" and 'diff-marker' in attribs[0]:
			self.added = True

	def handle_data(self, data):
		data = re.sub(r"([`_*~<>{}@/|\\])", "\\\\\\1", data, 0)
		if self.current_tag == "ins" and self.ins_length <= 1000:
			self.ins_length += len("**" + data + '**')
			if self.ins_length <= 1000:
				self.small_prev_ins = self.small_prev_ins + "**" + data + '**'
			else:
				self.small_prev_ins = self.small_prev_ins + self.more
		if self.current_tag == "del" and self.del_length <= 1000:
			self.del_length += len("~~" + data + '~~')
			if self.del_length <= 1000:
				self.small_prev_del = self.small_prev_del + "~~" + data + '~~'
			else:
				self.small_prev_del = self.small_prev_del + self.more
		if (self.current_tag == "afterins" or self.current_tag == "tda") and self.ins_length <= 1000:
			self.ins_length += len(data)
			if self.ins_length <= 1000:
				self.small_prev_ins = self.small_prev_ins + data
			else:
				self.small_prev_ins = self.small_prev_ins + self.more
		if (self.current_tag == "afterdel" or self.current_tag == "tdd") and self.del_length <= 1000:
			self.del_length += len(data)
			if self.del_length <= 1000:
				self.small_prev_del = self.small_prev_del + data
			else:
				self.small_prev_del = self.small_prev_del + self.more
		if self.added:
			if data == '+' and self.ins_length <= 1000:
				self.ins_length += 1
				if self.ins_length <= 1000:
					self.small_prev_ins = self.small_prev_ins + '\n'
				else:
					self.small_prev_ins = self.small_prev_ins + self.more
			if data == '−' and self.del_length <= 1000:
				self.del_length += 1
				if self.del_length <= 1000:
					self.small_prev_del = self.small_prev_del + '\n'
				else:
					self.small_prev_del = self.small_prev_del + self.more
			self.added = False

	def handle_endtag(self, tagname):
		if tagname == "ins":
			self.current_tag = "afterins"
		elif tagname == "del":
			self.current_tag = "afterdel"
		else:
			self.current_tag = ""


def safe_read(request, *keys):
	if request is None:
		return None
	try:
		request = request.json()
		for item in keys:
			request = request[item]
	except KeyError:
		misc_logger.warning(
			"Failure while extracting data from request on key {key} in {change}".format(key=item, change=request))
		return None
	except ValueError:
		misc_logger.warning("Failure while extracting data from request in {change}".format(change=request))
		return None
	return request


def handle_discord_http(code, formatted_embed, result):
	if 300 > code > 199:  # message went through
		return 0
	elif code == 400:  # HTTP BAD REQUEST result.status_code, data, result, header
		misc_logger.error(
			"Following message has been rejected by Discord, please submit a bug on our bugtracker adding it:")
		misc_logger.error(formatted_embed)
		misc_logger.error(result.text)
		return 1
	elif code == 401 or code == 404:  # HTTP UNAUTHORIZED AND NOT FOUND
		misc_logger.error("Webhook URL is invalid or no longer in use, please replace it with proper one.")
		sys.exit(1)
	elif code == 429:
		misc_logger.error("We are sending too many requests to the Discord, slowing down...")
		return 2
	elif 499 < code < 600:
		misc_logger.error(
			"Discord have trouble processing the event, and because the HTTP code returned is {} it means we blame them.".format(
				code))
		return 3


def add_to_dict(dictionary, key):
	if key in dictionary:
		dictionary[key] += 1
	else:
		dictionary[key] = 1
	return dictionary

def prepare_paths(path, dry=False):
	global WIKI_API_PATH
	global WIKI_ARTICLE_PATH
	global WIKI_SCRIPT_PATH
	global WIKI_JUST_DOMAIN
	"""Set the URL paths for article namespace and script namespace
	WIKI_API_PATH will be: WIKI_DOMAIN/api.php
	WIKI_ARTICLE_PATH will be: WIKI_DOMAIN/articlepath/$1 where $1 is the replaced string
	WIKI_SCRIPT_PATH will be: WIKI_DOMAIN/
	WIKI_JUST_DOMAIN will be: WIKI_DOMAIN"""
	def quick_try_url(url):
		"""Quickly test if URL is the proper script path,
		False if it appears invalid
		dictionary when it appears valid"""
		try:
			request = requests.get(url, timeout=5)
			if request.status_code == requests.codes.ok:
				if request.json()["query"]["general"] is not None:
					return request
			return False
		except (KeyError, requests.exceptions.ConnectionError):
			return False
	try:
		parsed_url = urlparse(path)
	except KeyError:
		misc_logger.critical("wiki_url is not specified in the settings. Please provide the wiki url in the settings and start the script again.")
		sys.exit(1)
	for url_scheme in (path, path.split("wiki")[0], urlunparse((*parsed_url[0:2], "", "", "", ""))):  # check different combinations, it's supposed to be idiot-proof
		tested = quick_try_url(url_scheme + "/api.php?action=query&format=json&meta=siteinfo")
		if tested:
			if not dry:
				WIKI_API_PATH = urlunparse((*parsed_url[0:2], "", "", "", "")) + tested.json()["query"]["general"]["scriptpath"] + "/api.php"
				WIKI_SCRIPT_PATH = urlunparse((*parsed_url[0:2], "", "", "", "")) + tested.json()["query"]["general"]["scriptpath"] + "/"
				WIKI_ARTICLE_PATH = urlunparse((*parsed_url[0:2], "", "", "", "")) + tested.json()["query"]["general"]["articlepath"]
				WIKI_JUST_DOMAIN = urlunparse((*parsed_url[0:2], "", "", "", ""))
				break
			return urlunparse((*parsed_url[0:2], "", "", "", ""))

	else:
		misc_logger.critical("Could not verify wikis paths. Please make sure you have given the proper wiki URLs in settings.json ({path} should be script path to your wiki) and your Internet connection is working.".format(path=path))
		sys.exit(1)


prepare_paths(settings["wiki_url"])


def create_article_path(article: str) -> str:
	"""Takes the string and creates an URL with it as the article name"""
	return WIKI_ARTICLE_PATH.replace("$1", article)


def send_simple(msgtype, message, name, avatar):
	discord_msg = DiscordMessage("compact", msgtype, settings["webhookURL"], content=message)
	discord_msg.set_avatar(avatar)
	discord_msg.set_name(name)
	messagequeue.resend_msgs()
	send_to_discord(discord_msg)


def update_ratelimit(request):
	"""Updates rate limit time"""
	global rate_limit
	rate_limit = 0 if int(request.headers.get('x-ratelimit-remaining', "-1")) > 0 else int(request.headers.get(
		'x-ratelimit-reset-after', 0))
	rate_limit += settings.get("discord_message_cooldown", 0)


def send_to_discord_webhook(data):
	global rate_limit
	header = settings["header"]
	header['Content-Type'] = 'application/json'
	try:
		time.sleep(rate_limit)
		rate_limit = 0
		result = requests.post(data.webhook_url, data=repr(data),
		                       headers=header, timeout=10)
		update_ratelimit(result)
	except requests.exceptions.Timeout:
		misc_logger.warning("Timeouted while sending data to the webhook.")
		return 3
	except requests.exceptions.ConnectionError:
		misc_logger.warning("Connection error while sending the data to a webhook")
		return 3
	else:
		return handle_discord_http(result.status_code, data, result)


def send_to_discord(data):
	for regex in settings["disallow_regexes"]:
		if data.webhook_object.get("content", None):
			if re.search(re.compile(regex), data.webhook_object["content"]):
				misc_logger.info("Message {} has been rejected due to matching filter ({}).".format(data.webhook_object["content"], regex))
				return  # discard the message without anything
		else:
			for to_check in [data.webhook_object.get("description", ""), data.webhook_object.get("title", ""), *[x["value"] for x in data["fields"]], data.webhook_object.get("author", {"name": ""}).get("name", "")]:
				if re.search(re.compile(regex), to_check):
					misc_logger.info("Message \"{}\" has been rejected due to matching filter ({}).".format(
						to_check, regex))
					return  # discard the message without anything
	if messagequeue:
		messagequeue.add_message(data)
	else:
		code = send_to_discord_webhook(data)
		if code == 3:
			messagequeue.add_message(data)
		elif code == 2:
			time.sleep(5.0)
			messagequeue.add_message(data)
		elif code < 2:
			pass

class DiscordMessage():
	"""A class defining a typical Discord JSON representation of webhook payload."""
	def __init__(self, message_type: str, event_type: str, webhook_url: str, content=None):
		self.webhook_object = dict(allowed_mentions={"parse": []}, avatar_url=settings["avatars"].get(message_type, ""))
		self.webhook_url = webhook_url

		if message_type == "embed":
			self.__setup_embed()
		elif message_type == "compact":
			self.webhook_object["content"] = content

		self.event_type = event_type

	def __setitem__(self, key, value):
		"""Set item is used only in embeds."""
		try:
			self.embed[key] = value
		except NameError:
			raise TypeError("Tried to assign a value when message type is plain message!")

	def __getitem__(self, item):
		return self.embed[item]

	def __repr__(self):
		"""Return the Discord webhook object ready to be sent"""
		return json.dumps(self.webhook_object)

	def __setup_embed(self):
		self.embed = defaultdict(dict)
		if "embeds" not in self.webhook_object:
			self.webhook_object["embeds"] = [self.embed]
		else:
			self.webhook_object["embeds"].append(self.embed)
		self.embed["color"] = None

	def add_embed(self):
		self.finish_embed()
		self.__setup_embed()

	def finish_embed(self):
		if self.embed["color"] is None:
			if settings["appearance"]["embed"].get(self.event_type, {"color": None})["color"] is None:
				self.embed["color"] = random.randrange(1, 16777215)
			else:
				self.embed["color"] = settings["appearance"]["embed"][self.event_type]["color"]
		else:
			self.embed["color"] = math.floor(self.embed["color"])

	def set_author(self, name, url, icon_url=""):
		self.embed["author"]["name"] = name
		self.embed["author"]["url"] = url
		self.embed["author"]["icon_url"] = icon_url

	def add_field(self, name, value, inline=False):
		if "fields" not in self.embed:
			self.embed["fields"] = []
		self.embed["fields"].append(dict(name=name, value=value, inline=inline))

	def set_avatar(self, url):
		self.webhook_object["avatar_url"] = url

	def set_name(self, name):
		self.webhook_object["username"] = name


def profile_field_name(name, embed):
	try:
		return profile_fields[name]
	except KeyError:
		if embed:
			return _("Unknown")
		else:
			return _("unknown")


class LinkParser(HTMLParser):
	new_string = ""
	recent_href = ""

	def handle_starttag(self, tag, attrs):
		for attr in attrs:
			if attr[0] == 'href':
				self.recent_href = attr[1]
				if self.recent_href.startswith("//"):
					self.recent_href = "https:{rest}".format(rest=self.recent_href)
				elif not self.recent_href.startswith("http"):
					self.recent_href = WIKI_JUST_DOMAIN + self.recent_href
				self.recent_href = self.recent_href.replace(")", "\\)")
			elif attr[0] == 'data-uncrawlable-url':
				self.recent_href = attr[1].encode('ascii')
				self.recent_href = base64.b64decode(self.recent_href)
				self.recent_href = WIKI_JUST_DOMAIN + self.recent_href.decode('ascii')

	def handle_data(self, data):
		if self.recent_href:
			self.new_string = self.new_string + "[{}](<{}>)".format(data.replace("//", "/\\/"), self.recent_href)
			self.recent_href = ""
		else:
			self.new_string = self.new_string + data.replace("//", "/\\/")

	def handle_comment(self, data):
		self.new_string = self.new_string + data.replace("//", "/\\/")

	def handle_endtag(self, tag):
		misc_logger.debug(self.new_string)