RcGcDb/src/wiki.py

from __future__ import annotations

import functools
import json
import time
import re
import logging, aiohttp
import asyncio
import requests
from functools import cache

from api.util import default_message
from src.discord.queue import messagequeue, QueueEntry
from mw_messages import MWMessages
from src.exceptions import *
from src.queue_handler import dbmanager
from src.api.hooks import formatter_hooks
from src.api.client import Client
from src.api.context import Context
from src.discord.message import DiscordMessage, DiscordMessageMetadata, StackedDiscordMessage
from src.i18n import langs
from src.statistics import Statistics, Log, LogType
from src.config import settings
# noinspection PyPackageRequirements
from bs4 import BeautifulSoup
from collections import OrderedDict, defaultdict, namedtuple
from typing import Union, Optional, TYPE_CHECKING

Settings = namedtuple("Settings", ["lang", "display"])
logger = logging.getLogger("rcgcdb.wiki")

# wiki_reamoval_reasons = {410: _("wiki deleted"), 404: _("wiki deleted"), 401: _("wiki inaccessible"),
# 				           402: _("wiki inaccessible"), 403: _("wiki inaccessible"), 1000: _("discussions disabled")}

if TYPE_CHECKING:
	from src.domain import Domain

MESSAGE_LIMIT = settings.get("message_limit", 30)


class Wiki:
	def __init__(self, script_url: str, rc_id: Optional[int], discussion_id: Optional[int]):
		self.script_url: str = script_url
		self.session: aiohttp.ClientSession = aiohttp.ClientSession(headers=settings["header"], timeout=aiohttp.ClientTimeout(total=6))
		self.statistics: Statistics = Statistics(rc_id, discussion_id)
		self.mw_messages: Optional[MWMessages] = None
		self.tags: dict[str, Optional[str]] = {}  # Tag can be None if hidden
		self.first_fetch_done: bool = False
		self.domain: Optional[Domain] = None
		self.targets: Optional[defaultdict[Settings, list[str]]] = None
		self.client: Client = Client(formatter_hooks, self)
		self.message_history: list[StackedDiscordMessage] = list()
		self.namespaces: Optional[dict] = None
		self.recache_requested: bool = False
		self.session_requests = requests.Session()
		self.session_requests.headers.update(settings["header"])

	@property
	def rc_id(self):
		return self.statistics.last_action

	@property
	def last_request(self):
		return self.statistics.last_request

	@last_request.setter
	def last_request(self, value):
		self.statistics.last_request = value

	# async def remove(self, reason):
	# 	logger.info("Removing a wiki {}".format(self.script_url))
	# 	await src.discord.wiki_removal(self.script_url, reason)
	# 	await src.discord.wiki_removal_monitor(self.script_url, reason)
	# 	async with db.pool().acquire() as connection:
	# 		result = await connection.execute('DELETE FROM rcgcdw WHERE wiki = $1', self.script_url)
	# 	logger.warning('{} rows affected by DELETE FROM rcgcdw WHERE wiki = "{}"'.format(result, self.script_url))

	def add_message(self, message: StackedDiscordMessage):
		self.message_history.append(message)
		if len(self.message_history) > MESSAGE_LIMIT*len(self.targets):
			self.message_history = self.message_history[len(self.message_history)-MESSAGE_LIMIT*len(self.targets):]

	def set_domain(self, domain: Domain):
		self.domain = domain

	# def find_middle_next(ids: List[str], pageid: int) -> set:  # TODO Properly re-implement for RcGcDb
	# 	"""To address #235 RcGcDw should now remove diffs in next revs relative to redacted revs to protect information in revs that revert revdeleted information.
	#
	# 	:arg ids - list
	# 	:arg pageid - int
	#
	# 	:return list"""
	# 	ids = [int(x) for x in ids]
	# 	result = set()
	# 	ids.sort()  # Just to be sure, sort the list to make sure it's always sorted
	# 	messages = db_cursor.execute("SELECT revid FROM event WHERE pageid = ? AND revid >= ? ORDER BY revid",
	# 								 (pageid, ids[0],))
	# 	all_in_page = [x[0] for x in messages.fetchall()]
	# 	for id in ids:
	# 		try:
	# 			result.add(all_in_page[all_in_page.index(id) + 1])
	# 		except (KeyError, ValueError):
	# 			logger.debug(f"Value {id} not in {all_in_page} or no value after that.")
	# 	return result - set(ids)

	def search_message_history(self, params: dict) -> list[tuple[StackedDiscordMessage, list[int]]]:
		"""Search self.message_history for messages which match all properties in params and return them in a list"""
		output = []
		for message in self.message_history:
			returned_matches_for_stacked = message.filter(params)
			if returned_matches_for_stacked:
				output.append((message, [x[0] for x in returned_matches_for_stacked]))
		return output

	def delete_messages(self, params: dict):
		"""Delete certain messages from message_history which DiscordMessageMetadata matches all properties in params"""
		# Delete all messages with given IDs
		for stacked_message, ids in self.search_message_history(params):
			stacked_message.delete_message_by_id(ids)
			# If all messages were removed, send a DELETE to Discord
			if len(stacked_message.message_list) == 0:
				messagequeue.add_message(QueueEntry(stacked_message, [stacked_message.webhook], self, method="DELETE"))
			else:
				messagequeue.add_message(QueueEntry(stacked_message, [stacked_message.webhook], self, method="PATCH"))

	def redact_messages(self, ids: list[int], mode: str, censored_properties: dict):
		# ids can refer to multiple events, and search does not support additive mode, so we have to loop it for all ids
		for revlogid in ids:
			for stacked_message, ids in self.search_message_history({mode: revlogid}):  # This might not work depending on how Python handles it, but hey, learning experience
				for message in [message for num, message in enumerate(stacked_message.message_list) if num in ids]:
					if "user" in censored_properties and "url" in message["author"]:
						message["author"]["name"] = _("hidden")
						message["author"].pop("url")
					if "action" in censored_properties and "url" in message:
						message["title"] = _("~~hidden~~")
						message["embed"].pop("url")
					if "content" in censored_properties and "fields" in message:
						message["embed"].pop("fields")
					if "comment" in censored_properties:
						message["description"] = _("~~hidden~~")
				messagequeue.add_message(QueueEntry(stacked_message, [stacked_message.webhook], self, method="PATCH"))

	# async def downtime_controller(self, down, reason=None):
	# 	if down:
	# 		self.fail_times += 1
	# 		if self.fail_times > 20:
	# 			await self.remove(reason)
	# 	else:
	# 		self.fail_times -= 1

	async def update_targets(self) -> None:
		"""This function generates all possible varations of outputs that we need to generate messages for.

		:returns defaultdict[namedtuple, list[str]] - where namedtuple is a named tuple with settings for given webhooks in list"""
		Settings = namedtuple("Settings", ["lang", "display"])
		target_settings: defaultdict[Settings, list[str]] = defaultdict(list)
		async for webhook in dbmanager.fetch_rows("SELECT webhook, lang, display FROM rcgcdw WHERE wiki = $1 AND (rcid != -1 OR rcid IS NULL)", self.script_url):
			target_settings[Settings(webhook["lang"], webhook["display"])].append(webhook["webhook"])
		self.targets = target_settings

	def parse_mw_request_info(self, request_data: dict, url: str):
		"""A function parsing request JSON message from MediaWiki logging all warnings and raising on MediaWiki errors"""
		# any([True for k in request_data.keys() if k in ("error", "errors")])
		errors: list = request_data.get("errors", {})  # Is it ugly? I don't know tbh
		if errors:
			raise MediaWikiError(str(errors))
		warnings: list = request_data.get("warnings", {})
		if warnings:
			for warning in warnings:
				logger.warning("MediaWiki returned the following warning: {code} - {text} on {url}.".format(
					code=warning["code"], text=warning.get("text", warning.get("*", "")), url=url
				))
		return request_data

	async def api_request(self, params: Union[str, OrderedDict], *json_path: str, timeout: int = 10,
					allow_redirects: bool = False) -> dict:
		"""Method to GET request data from the wiki's API with error handling including recognition of MediaWiki errors.

		Parameters:

			params (str, OrderedDict): a string or collections.OrderedDict object containing query parameters
			json_path (str): *args taking strings as values. After request is parsed as json it will extract data from given json path
			timeout (int, float) (default=10): int or float limiting time required for receiving a full response from a server before returning TimeoutError
			allow_redirects (bool) (default=False): switches whether the request should follow redirects or not

		Returns:

			request_content (dict): a dict resulting from json extraction of HTTP GET request with given json_path
			OR
			One of the following exceptions:
			ServerError: When connection with the wiki failed due to server error
			ClientError: When connection with the wiki failed due to client error
			KeyError: When json_path contained keys that weren't found in response JSON response
			BadRequest: When params argument is of wrong type
			MediaWikiError: When MediaWiki returns an error
		"""
		# Making request
		try:
			if isinstance(params, str):
				request = await self.session.get(self.script_url + "api.php?" + params + "&errorformat=raw", timeout=timeout,
										   allow_redirects=allow_redirects)
			elif isinstance(params, OrderedDict):
				params["errorformat"] = "raw"
				request = await self.session.get(self.script_url + "api.php", params=params, timeout=timeout,
										   allow_redirects=allow_redirects)
			else:
				raise BadRequest(params)
		except (aiohttp.ServerConnectionError, aiohttp.ServerTimeoutError) as exc:
			logger.warning("Reached {error} error for request on link {url}".format(error=repr(exc),
																					url=self.script_url + str(params)))
			raise ServerError
		# Catching HTTP errors
		if 499 < request.status < 600:
			raise ServerError
		elif request.status == 302:
			logger.critical(
				"Redirect detected! Either the wiki given in the script settings (wiki field) is incorrect/the wiki got removed or is giving us the false value. Please provide the real URL to the wiki, current URL redirects to {}".format(
					request.url))
		elif 399 < request.status < 500:
			logger.error("Request returned ClientError status code on {url}".format(url=request.url))
			self.statistics.update(Log(type=LogType.HTTP_ERROR, title="{} error".format(request.status), details=str(request.headers) + "\n" + str(request.url)))
			raise ClientError(request)
		else:
			# JSON Extraction
			try:
				request_json = self.parse_mw_request_info(await request.json(encoding="UTF-8"), str(request.url))
				for item in json_path:
					request_json = request_json[item]
			except ValueError:
				logger.warning("ValueError when extracting JSON data on {url}".format(url=request.url))
				raise ServerError
			except MediaWikiError:
				logger.exception("MediaWiki error on request: {}".format(request.url))
				raise
			except KeyError:
				logger.exception("KeyError while iterating over json_path, full response: {}".format(request.json()))
				raise
		return request_json

	def sync_api_request(self, params: Union[str, OrderedDict], *json_path: str, timeout: int = 10,
						 allow_redirects: bool = False) -> dict:
		"""Synchronous function based on api_request created for compatibility reasons with RcGcDw API"""
		try:
			if isinstance(params, str):
				request = self.session_requests.get(self.script_url + "api.php?" + params + "&errorformat=raw", timeout=10, allow_redirects=allow_redirects)
			elif isinstance(params, OrderedDict):
				request = self.session_requests.get(self.script_url + "api.php", params=params, timeout=10, allow_redirects=allow_redirects)
			else:
				raise BadRequest(params)
		except (requests.exceptions.Timeout, requests.exceptions.ConnectionError, requests.exceptions.ChunkedEncodingError) as exc:
			logger.warning("Reached {error} error for request on link {url}".format(error=repr(exc),
																					url=self.client.WIKI_API_PATH + str(params)))
			raise ServerError
		if 499 < request.status_code < 600:
			raise ServerError
		elif request.status_code == 302:
			logger.critical(
				"Redirect detected! Either the wiki given in the script settings (wiki field) is incorrect/the wiki got removed or is giving us the false value. Please provide the real URL to the wiki, current URL redirects to {}".format(
					request.url))
		elif 399 < request.status_code < 500:
			logger.error("Request returned ClientError status code on {url}".format(url=request.url))
			self.statistics.update(Log(type=LogType.HTTP_ERROR, title="{} error".format(request.status_code), details=str(request.headers) + "\n" + str(request.url)))
			raise ClientError(request)
		else:
			try:
				request_json = self.parse_mw_request_info(request.json(), request.url)
				for item in json_path:
					request_json = request_json[item]
			except ValueError:
				logger.warning("ValueError when extracting JSON data on {url}".format(url=request.url))
				raise ServerError
			except MediaWikiError:
				logger.exception("MediaWiki error on request: {}".format(request.url))
				raise
			except KeyError:
				logger.exception("KeyError while iterating over json_path, full response: {}".format(request.json()))
				raise
		return request_json


	async def fetch_wiki(self, amount=10) -> dict:
		if self.mw_messages is None:
			params = OrderedDict({"action": "query", "format": "json", "uselang": "content", "list": "tags|recentchanges",
					  "meta": "allmessages|siteinfo",
					  "utf8": 1, "tglimit": "max", "tgprop": "displayname",
					  "rcprop": "title|redirect|timestamp|ids|loginfo|parsedcomment|sizes|flags|tags|user",
					  "rclimit": amount, "rcshow": "!bot", "rctype": "edit|new|log|categorize",
					  "ammessages": "recentchanges-page-added-to-category|recentchanges-page-removed-from-category|recentchanges-page-added-to-category-bundled|recentchanges-page-removed-from-category-bundled",
					  "amenableparser": 1, "amincludelocal": 1, "siprop": "namespaces|general"})
		else:
			params = OrderedDict({"action": "query", "format": "json", "uselang": "content", "list": "tags|recentchanges",
					  "meta": "siteinfo", "utf8": 1, "rcshow": "!bot",
					  "rcprop": "title|redirect|timestamp|ids|loginfo|parsedcomment|sizes|flags|tags|user",
					  "rclimit": amount, "rctype": "edit|new|log|categorize", "siprop": "namespaces|general"})
		try:
			response = await self.api_request(params=params)
		except (aiohttp.ClientConnectionError, aiohttp.ServerTimeoutError, asyncio.TimeoutError) as e:
			logger.error("A connection error occurred while requesting {}".format(params))
			raise WikiServerError(e)
		return response

	async def scan(self, amount=10):
		"""Main track of fetching RecentChanges of a wiki.

		:raises WikiServerError
		"""
		while True:  # Trap event in case there are more changes needed to be fetched
			try:
				request = await self.fetch_wiki(amount=amount)
				self.client.last_request = request
			except WikiServerError as e:
				# If WikiServerError comes up 2 times in recent 2 minutes, this will reraise the exception, otherwise waits 2 seconds and retries
				self.statistics.update(Log(type=LogType.CONNECTION_ERROR, title=str(e.exception)))
				if self.statistics.recent_connection_errors() > 1:
					raise
				await asyncio.sleep(2.0)
				continue
			if not self.mw_messages or self.recache_requested:
				process_cachable(request, self)
			try:
				recent_changes = request["query"]["recentchanges"]
				recent_changes.reverse()
			except KeyError:
				raise WikiError
			if self.rc_id in (0, None, -1):
				if len(recent_changes) > 0:
					self.statistics.last_action = recent_changes[-1]["rcid"]
					dbmanager.add(("UPDATE rcgcdw SET rcid = $1 WHERE wiki = $2 AND ( rcid != -1 OR rcid IS NULL )",
								   (recent_changes[-1]["rcid"], self.script_url)))
				else:
					self.statistics.last_action = 0
					dbmanager.add(("UPDATE rcgcdw SET rcid = 0 WHERE wiki = $1 AND ( rcid != -1 OR rcid IS NULL )", (self.script_url)))
				return   # TODO Add a log entry?
			categorize_events = {}
			new_events = 0
			self.statistics.last_checked_rc = int(time.time())
			highest_id = self.rc_id  # Pretty sure that will be faster
			for change in recent_changes:
				if change["rcid"] > highest_id and amount != 450:
					new_events += 1
					if new_events == 10:
						# call the function again with max limit for more results, ignore the ones in this request
						logger.debug("There were too many new events, queuing wiki with 450 limit.")
						amount = 450
						break
				await process_cats(change, self, categorize_events)
			else:  # adequate amount of changes
				message_list = []  # Collect all messages so they can be efficiently merged in Discord message sender
				for change in recent_changes:  # Yeah, second loop since the categories require to be all loaded up
					if change["rcid"] > self.rc_id:
						if highest_id is None or change["rcid"] > highest_id:  # make sure that the highest_rc is really highest rcid but do allow other entries with potentially lesser rcids come after without breaking the cycle
							highest_id = change["rcid"]
						for combination, webhooks in self.targets.items():
							message = await rc_processor(self, change, categorize_events.get(change.get("revid"), None), combination, webhooks)
							if message is None:
								break
							message.wiki = self
							message_list.append(QueueEntry(message, webhooks, self))
				messagequeue.add_messages(message_list)
				return


@cache
def prepare_settings(display_mode: int) -> dict:
	"""Prepares dict of RcGcDw compatible settings based on a template and display mode of given call"""
	with open("src/api/template_settings.json", "r") as template_json:
		template = json.load(template_json)
	template["appearance"]["embed"]["embed_images"] = True if display_mode > 1 else False
	template["appearance"]["embed"]["show_edit_changes"] = True if display_mode > 2 else False
	return template


def process_cachable(response: dict, wiki_object: Wiki) -> None:
	"""This function processes cachable objects – such as MediaWiki system messages and wiki tag display names to be used
	for processing of DiscordMessages and saves them in a wiki object."""
	mw_messages = response.get("query", {}).get("allmessages", [])
	final_mw_messages = dict()
	for msg in mw_messages:
		if "missing" not in msg:  # ignore missing strings
			final_mw_messages[msg["name"]] = re.sub(r'\[\[.*?]]', '', msg["*"])
		else:
			logger.warning("Could not fetch the MW message translation for: {}".format(msg["name"]))
	wiki_object.mw_messages = MWMessages(final_mw_messages)
	for tag in response["query"]["tags"]:
		try:
			wiki_object.tags[tag["name"]] = (BeautifulSoup(tag["displayname"], "lxml")).get_text()
		except KeyError:
			wiki_object.tags[tag["name"]] = None
	wiki_object.namespaces = response["query"]["namespaces"]
	wiki_object.recache_requested = False


async def rc_processor(wiki: Wiki, change: dict, changed_categories: dict, display_options: namedtuple("Settings", ["lang", "display"]), webhooks: list) -> Optional[DiscordMessage]:
	"""This function takes more vital information, communicates with a formatter and constructs DiscordMessage with it.
	It creates DiscordMessageMetadata object, LinkParser and Context. Prepares a comment """
	from src.misc import LinkParser
	LinkParser = LinkParser()
	metadata = DiscordMessageMetadata("POST", rev_id=change.get("revid", None), log_id=change.get("logid", None),
													  page_id=change.get("pageid", None))
	context = Context("embed" if display_options.display > 0 else "compact", "recentchanges", webhooks, wiki.client, langs[display_options.lang]["rc_formatters"], prepare_settings(display_options.display))
	if ("actionhidden" in change or "suppressed" in change) and "suppressed" not in settings["ignored"]:  # if event is hidden using suppression
		context.event = "suppressed"
		try:
			discord_message: Optional[DiscordMessage] = await asyncio.get_event_loop().run_in_executor(
				None, functools.partial(default_message("suppressed", context.message_type, formatter_hooks), context, change))
		except:
			if settings.get("error_tolerance", 1) > 0:
				discord_message: Optional[DiscordMessage] = None  # It's handled by send_to_discord, we still want other code to run
			else:
				raise
	else:
		if "commenthidden" not in change:
			LinkParser.feed(change.get("parsedcomment", ""))
			parsed_comment = LinkParser.new_string
		else:
			parsed_comment = context._("~~hidden~~")
		if not parsed_comment and context.message_type == "embed" and settings["appearance"].get("embed", {}).get(
				"show_no_description_provided", True):
			parsed_comment = context._("No description provided")
		context.set_parsedcomment(parsed_comment)
		if "userhidden" in change:
			change["user"] = context._("hidden")
		if change.get("ns", -1) in settings.get("ignored_namespaces", ()):
			return
		if change["type"] in ["edit", "new"]:
			logger.debug("List of categories in essential_info: {}".format(changed_categories))
			identification_string = change["type"]
			context.set_categories(changed_categories)
		elif change["type"] == "categorize":
			return
		elif change["type"] == "log":
			identification_string = "{logtype}/{logaction}".format(logtype=change["logtype"],
																   logaction=change["logaction"])
		else:
			identification_string = change.get("type", "unknown")  # If event doesn't have a type
		if identification_string in settings["ignored"]:
			return
		context.event = identification_string
		try:
			discord_message: Optional[DiscordMessage] = await asyncio.get_event_loop().run_in_executor(None,
				functools.partial(default_message(identification_string, context.message_type, formatter_hooks), context,
								  change))
		except:
			if settings.get("error_tolerance", 1) > 0:
				discord_message: Optional[DiscordMessage] = None  # It's handled by send_to_discord, we still want other code to run
			else:
				raise
		if identification_string in ("delete/delete", "delete/delete_redir"):  # TODO Move it into a hook?
			wiki.delete_messages(dict(pageid=change.get("pageid")))
		elif identification_string == "delete/event":
			logparams = change.get('logparams', {"ids": []})
			if settings["appearance"]["mode"] == "embed":
				wiki.redact_messages(logparams.get("ids", []), "rev_id", logparams.get("new", {}))
			else:
				for logid in logparams.get("ids", []):
					wiki.delete_messages(dict(logid=logid))
		elif identification_string == "delete/revision":
			logparams = change.get('logparams', {"ids": []})
			if settings["appearance"]["mode"] == "embed":
				wiki.redact_messages(logparams.get("ids", []), "log_id", logparams.get("new", {}))
			else:
				for revid in logparams.get("ids", []):
					wiki.delete_messages(dict(revid=revid))
	if discord_message:  # TODO How to react when none? (crash in formatter), probably bad handling atm
		discord_message.finish_embed()
		discord_message.metadata = metadata
	return discord_message


async def process_cats(event: dict, local_wiki: Wiki, categorize_events: dict):
	"""Process categories based on local MW messages. """
	if event["type"] == "categorize":
		if "commenthidden" not in event:
			if local_wiki.mw_messages is not None:
				cat_title = event["title"].split(':', 1)[1]
				# I so much hate this, blame Markus for making me do this
				if event["revid"] not in categorize_events:
					categorize_events[event["revid"]] = {"new": set(), "removed": set()}
				comment_to_match = re.sub(r'<.*?a>', '', event["parsedcomment"])
				if local_wiki.mw_messages["recentchanges-page-added-to-category"] in comment_to_match or local_wiki.mw_messages["recentchanges-page-added-to-category-bundled"] in comment_to_match:  # Added to category
					categorize_events[event["revid"]]["new"].add(cat_title)
					#logger.debug("Matched {} to added category for {}".format(cat_title, event["revid"]))
				elif local_wiki.mw_messages["recentchanges-page-removed-from-category"] in comment_to_match or local_wiki.mw_messages["recentchanges-page-removed-from-category-bundled"] in comment_to_match:  # Removed from category
					categorize_events[event["revid"]]["removed"].add(cat_title)
					#logger.debug("Matched {} to removed category for {}".format(cat_title, event["revid"]))
				else:
					logger.debug(
						"Unknown match for category change with messages {} and comment_to_match {}".format(local_wiki.mw_messages,comment_to_match))
			else:
				logger.warning(
					"Init information not available, could not read category information. Please restart the bot.")
		else:
			logger.debug("Log entry got suppressed, ignoring entry.")

# This function has been removed. While its implementation seems sound, it should be considered only if we find performance
# concerns with RcGcDb
# async def process_mwmsgs(wiki_response: dict, local_wiki: Wiki, mw_msgs: dict):
# 	"""
# 	This function is made to parse the initial wiki extended information to update local_wiki.mw_messages that stores the key
# 	to mw_msgs that is a dict storing id: tuple where tuple is a set of MW messages for categories.
# 	The reason it's constructed this way is to prevent duplication of data in memory so Markus doesn't complain about
# 	high RAM usage. It does however affect CPU performance as every wiki requires to check the list for the matching
# 	tuples of MW messages.
#
# 	:param wiki_response:
# 	:param local_wiki:
# 	:param mw_msgs:
# 	:return:
# 	"""
# 	msgs = []
# 	for message in wiki_response["query"]["allmessages"]:
# 		if not "missing" in message:  # ignore missing strings
# 			msgs.append((message["name"], re.sub(r'\[\[.*?\]\]', '', message["*"])))
# 		else:
# 			logger.warning("Could not fetch the MW message translation for: {}".format(message["name"]))
# 	msgs = tuple(msgs)
# 	for key, set in mw_msgs.items():
# 		if msgs == set:
# 			local_wiki.mw_messages = key
# 			return
# 	# if same entry is not in mw_msgs
# 	key = len(mw_msgs)
# 	mw_msgs[key] = msgs  # it may be a little bit messy for sure, however I don't expect any reason to remove mw_msgs entries by one
# 	local_wiki.mw_messages = key


async def essential_feeds(change: dict, comment_pages: dict, db_wiki, target: tuple) -> DiscordMessage:
	"""Prepares essential information for both embed and compact message format."""
	appearance_mode = feeds_embed_formatter if target[0][1] > 0 else feeds_compact_formatter
	identification_string = change["_embedded"]["thread"][0]["containerType"]
	comment_page = None
	if identification_string == "ARTICLE_COMMENT" and comment_pages is not None:
		comment_page = comment_pages.get(change["forumId"], None)
		if comment_page is not None:
			comment_page["fullUrl"] = "/".join(db_wiki["wiki"].split("/", 3)[:3]) + comment_page["relativeUrl"]
	return await appearance_mode(identification_string, change, target, db_wiki["wiki"], article_page=comment_page)