Add support for INVITE after getting KICKed from a channel

http2irc.py

@@ -360,6 +360,7 @@ class IRCClientProtocol(asyncio.Protocol):
 		self.buffer = b''
 		self.connected = False
 		self.channels = channels # Currently joined/supposed-to-be-joined channels; set(str)
+		self.kickedChannels = set() # Channels the bot got KICKed from (for re-INVITE purposes; reset on config reloading)
 		self.unconfirmedMessages = []
 		self.pongReceivedEvent = asyncio.Event()
 		self.sasl = bool(self.config['irc']['certfile'] and self.config['irc']['certkeyfile'])
@@ -432,6 +433,7 @@ class IRCClientProtocol(asyncio.Protocol):
 		channelsToPart = self.channels - channels
 		channelsToJoin = channels - self.channels
 		self.channels = channels
+		self.kickedChannels = set()
 
 		if self.connected:
 			if channelsToPart:
@@ -710,6 +712,17 @@ class IRCClientProtocol(asyncio.Protocol):
 			for channel in self.channels:
 				if self.server.casefold(channel) == kickedChannel:
 					self.channels.remove(channel)
+					self.kickedChannels.add(channel) # Non-folded version so the set comparison in update_channels doesn't break.
+					break
+
+		# Bot getting INVITEd after a KICK
+		elif line.command == 'INVITE' and line.source and self.server.casefold(line.params[0]) == self.server.casefold(self.server.nickname):
+			invitedChannel = self.server.casefold(line.params[1])
+			for channel in self.kickedChannels:
+				if self.server.casefold(channel) == invitedChannel:
+					self.channels.add(channel)
+					self.kickedChannels.remove(channel)
+					self._send_join_part(b'JOIN', {channel})
 					break
 
 		# WHOX on successful JOIN if supported to fetch account information