Rig up chat to be suitable for a Doge election. (Hopefully.) (#692)

* Integrate chat from upstream

Substantially borrowed from upstream ref: 13a208ee88e55 (before they
started editing generated artefacts instead of source).

Integrated, including:
  - Remove previously removed features: emoji, hats, and name colors
  - Compensate for lack of unified root template
  - Add React build process to Dockerfile and `bootstrap/init.sh`
  - Preliminary integration of chat websocket workers

For testing, modify `supervisord.conf.dev` to put chat on port 80 and
the site service on some other port. Then visit: http://localhost/chat

Still to do:
  - Access control for specific small-groups (and admins probably):
    Set the values somewhere (site_settings.json? Redis?) and use for
    authorization in `chat_is_allowed`.
  - Proxying only /chat to the websocket workers
  - Chat persistance across restarts: either Redis devops or to DB

* Add nginx server to do appropriate redirection.

* Add necessary columns to User.

* Wire up chat permissions.

* Reload chat on source change.

* Add a better structure for slash commands and add/remove functionality.

* Stop putting up previews of slash commands.

* We require more whitespace.

* Strip DMs out entirely, I currently do not want to deal with them.

* Change "Users Online" to just "Users".

* Clean up a little more DM detritus.

* Save chat history in database.

* Remove unnecessary hefty query to the DB.

* Clean up optimistic messages.

* Initial implementation of notification icon.

* Update readme a little bit.

* Fix notification highlight (mostly).

* Remove chat version number that will never be updated.

* Fix: Errors on logged-out users.

* Add function to nuke the chat state.

* Update DB.

* Add a dedicated deployable docker image.

* Fix: init_build.sh execute bit not set.

* Whoops, screwed up the abort() call.

* Relax chat rate limiter.

* Remove a somewhat silly comment.

* Remove an unnecessary g.db.add().

---------

Co-authored-by: TLSM <duolsm@outlook.com>

files/classes/user.py

@@ -12,6 +12,7 @@ from files.classes.alts import Alt
 from files.classes.award import AwardRelationship
 from files.classes.badges import Badge
 from files.classes.base import CreatedBase
+from files.classes.chat_message import ChatMessage
 from files.classes.clients import *  # note: imports Comment and Submission
 from files.classes.follows import Follow
 from files.classes.mod_logs import ModAction
@@ -112,6 +113,9 @@ class User(CreatedBase):
 	volunteer_last_started_utc = Column(DateTime, nullable=True)
 	volunteer_janitor_correctness = Column(Float, default=0, nullable=False)
 
+	chat_authorized = Column(Boolean, default=False, nullable=False)
+	chat_lastseen = Column(DateTime(timezone=True), default=datetime(1970, 1, 1), nullable=False)
+
 	Index(
 		'users_original_username_trgm_idx',
 		original_username,
@@ -136,6 +140,8 @@ class User(CreatedBase):
 	Index('users_subs_idx', stored_subscriber_count)
 	Index('users_unbanutc_idx', unban_utc.desc())
 
+	Index('chat_auth_index', chat_authorized)
+
 	badges = relationship("Badge", viewonly=True)
 	subscriptions = relationship("Subscription", viewonly=True)
 	following = relationship("Follow", primaryjoin="Follow.user_id==User.id", viewonly=True)
@@ -157,6 +163,30 @@ class User(CreatedBase):
 	def can_manage_reports(self):
 		return self.admin_level > 1
 	
+	@property
+	@lazy
+	def can_access_chat(self):
+		if self.is_suspended_permanently:
+			return False
+		if self.admin_level >= PERMS['CHAT_FULL_CONTROL']:
+			return True
+		if self.chat_authorized:
+			return True
+		return False
+	
+	@property
+	@lazy
+	def unread_chat_messages_count(self):
+		if not self.can_access_chat:
+			return 0
+
+		# Query for all chat messages that are newer than the user's last seen timestamp
+		unread_messages_count = g.db.query(ChatMessage)\
+			.filter(ChatMessage.created_datetimez > self.chat_lastseen)\
+			.count()
+
+		return unread_messages_count
+	
 	@property
 	def age_days(self):
 		return (datetime.now() - datetime.fromtimestamp(self.created_utc)).days