Implemented forget command

VocalMaisBot.py

@@ -4,7 +4,7 @@ import logging
 import sys
 from pathlib import Path
 import json
-from typing import TextIO, Any, List, Dict
+from typing import TextIO, Any, List, Dict, Union
 import textwrap
 
 import discord
@@ -26,6 +26,25 @@ class VocalMaisBot(discord.Client):
 			logger.critical(f"Impossible to parse watched channels file, JSON error: {e}")
 			sys.exit(1)
 
+	@staticmethod
+	async def _check_administrator_for_command(message: discord.Message) -> bool:
+		if message.author.guild_permissions.administrator:
+			return True
+		else:
+			await message.channel.send(f":dragon_face: Only an administrator can control me!")
+			return False
+
+	def write_watched_channels_file(self):
+		logger.debug("Writing watched channels information to file")
+		self.watched_channels_file.seek(0)
+		self.watched_channels_file.truncate()
+		json.dump(self.watched_channels, self.watched_channels_file, indent = 2)
+		self.watched_channels_file.flush()
+		logger.debug("Written watched channels information to file")
+
+	async def sorry_do_not_understand(self, message: discord.Message):
+		await message.channel.send(f"Sorry I did not understand this message. Try `@{self.user.display_name} help` for help")
+
 	async def on_ready(self):
 		logger.info("Connected and ready!")
 		logger.debug(f"Logged as {self.user}")
@@ -49,36 +68,30 @@ class VocalMaisBot(discord.Client):
 			return await message.channel.send(":ping_pong:")
 		elif _check_list_element(contents, 1, "register"):
 			return await self.register_channel(message)
+		elif _check_list_element(contents, 1, "forget"):
+			return await self.forget_channel(message)
 		elif _check_list_element(contents, 1, "list"):
 			return await self.list_watched_channels(message)
 		else:
 			return self.sorry_do_not_understand(message)
 
-	async def sorry_do_not_understand(self, message: discord.Message):
-		await message.channel.send(f"Sorry I did not understand this message. Try `@{self.user.display_name} help` for help")
-
 	async def print_help(self, channel: discord.TextChannel):
 		me = self.user.display_name
 		message = f"""
 			**·** `@{me} register channel_id` : make me watch the voice channel with id `channel_id`
-			**·** `@{me} help` : print this help
+			**·** `@{me} forget channel_id` : make me stop watching the voice channel with id `channel_id`
 			**·** `@{me} list` : list watched channels
+			**·** `@{me} help` : print this help
 			**·** `@{me} ping` : pong
 		"""
 		await channel.send(embed = discord.Embed(title = "Available commands", description = textwrap.dedent(message)))
 
 	async def register_channel(self, message: discord.Message):
-		message_elements = message.content.split()
-		if len(message_elements) < 3:
-			return await self.sorry_do_not_understand(message)
-		channel_id = message_elements[2]
-		try:
-			channel_id = int(channel_id)
-		except ValueError:
-			return await message.channel.send(f":x: {channel_id} can not be converted to number")
-
-		if not message.author.guild_permissions.administrator:
-			return await message.channel.send(f":dragon_face: Only an administrator can control me!")
+		channel_id = await self._get_channel_id_for_command(message)
+		if channel_id is None:
+			return
+		if not await self._check_administrator_for_command(message):
+			return
 
 		# Retrieving the channel
 		channel = self.get_channel(channel_id)
@@ -101,13 +114,52 @@ class VocalMaisBot(discord.Client):
 			self.loop.call_soon(self.write_watched_channels_file)
 			return await message.channel.send(f":white_check_mark: I am now watching {channel.name}")
 
-	def write_watched_channels_file(self):
-		logger.debug("Writing watched channels information to file")
-		self.watched_channels_file.seek(0)
-		self.watched_channels_file.truncate()
-		json.dump(self.watched_channels, self.watched_channels_file, indent = 2)
-		self.watched_channels_file.flush()
-		logger.debug("Written watched channels information to file")
+	async def forget_channel(self, message: discord.Message):
+		channel_id = await self._get_channel_id_for_command(message)
+		if channel_id is None:
+			return
+		if not await self._check_administrator_for_command(message):
+			return
+
+		did_something = False
+		guild_id = str(message.guild.id)
+		if guild_id in self.watched_channels:
+			guild_info = self.watched_channels[guild_id]
+			if "watched_channels" in guild_info:
+				watched_channels_ids = guild_info["watched_channels"]
+				try:
+					watched_channels_ids.remove(channel_id)
+					did_something = True
+				except ValueError:
+					pass  # The channel already was not in the list
+
+		# Getting the channel name (if it exists), for pretty printing
+		channel = self.get_channel(channel_id)
+		if channel is None:  # Channel does not exist
+			channel_name = str(channel_id)
+		else:
+			channel_name = f"{channel.name} ({channel_id})"
+
+		if did_something:
+			self.write_watched_channels_file()
+			await message.channel.send(f":white_check_mark: I am no longer watching {channel_name}")
+		else:
+			await message.channel.send(f":thumbsup: I already was not watching {channel_name}")
+
+	async def _get_channel_id_for_command(self, message: discord.Message) -> Union[int, None]:
+		"""
+		Get the channel id from a command message in the form "@Bot command channel_id", or answer with an error message and return None if not possible.
+		"""
+		message_elements = message.content.split()
+		if len(message_elements) < 3:
+			await self.sorry_do_not_understand(message)
+			return None
+		channel_id = message_elements[2]
+		try:
+			return int(channel_id)
+		except ValueError:
+			await message.channel.send(f":x: {channel_id} can not be converted to number")
+			return None
 
 	async def list_watched_channels(self, message: discord.Message):
 		guild_id = str(message.guild.id)