Add toggleable notification of deleted messages count in Cleanup (#5218)

* Addition of cleanup notification.

* black

* subtract invoking message from count

* Update redbot/cogs/cleanup/cleanup.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* be explicity about kwarg

* address review

* style

* Fix type hints

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

redbot/cogs/cleanup/cleanup.py

@@ -5,7 +5,7 @@ from typing import Callable, List, Optional, Set, Union
 import discord
 
 from redbot.cogs.mod.converters import RawUserIds
-from redbot.core import checks, commands
+from redbot.core import checks, commands, Config
 from redbot.core.bot import Red
 from redbot.core.i18n import Translator, cog_i18n
 from redbot.core.utils.chat_formatting import humanize_number
@@ -33,6 +33,8 @@ class Cleanup(commands.Cog):
     def __init__(self, bot: Red):
         super().__init__()
         self.bot = bot
+        self.config = Config.get_conf(self, 8927348724, force_registration=True)
+        self.config.register_guild(notify=True)
 
     async def red_delete_data_for_user(self, **kwargs):
         """ Nothing to delete """
@@ -72,7 +74,7 @@ class Cleanup(commands.Cog):
     @staticmethod
     async def get_messages_for_deletion(
         *,
-        channel: discord.TextChannel,
+        channel: Union[discord.TextChannel, discord.DMChannel],
         number: Optional[PositiveInt] = None,
         check: Callable[[discord.Message], bool] = lambda x: True,
         limit: Optional[PositiveInt] = None,
@@ -123,6 +125,27 @@ class Cleanup(commands.Cog):
 
         return collected
 
+    async def send_optional_notification(
+        self,
+        num: int,
+        channel: Union[discord.TextChannel, discord.DMChannel],
+        *,
+        subtract_invoking: bool = False,
+    ) -> None:
+        """
+        Sends a notification to the channel that a certain number of messages have been deleted.
+        """
+        if not hasattr(channel, "guild") or await self.config.guild(channel.guild).notify():
+            if subtract_invoking:
+                num -= 1
+            if num == 1:
+                await channel.send(_("1 message was deleted."), delete_after=5)
+            else:
+                await channel.send(
+                    _("{num} messages were deleted.").format(num=humanize_number(num)),
+                    delete_after=5,
+                )
+
     @staticmethod
     async def get_message_from_reference(
         channel: discord.TextChannel, reference: discord.MessageReference
@@ -199,6 +222,7 @@ class Cleanup(commands.Cog):
         log.info(reason)
 
         await mass_purge(to_delete, channel)
+        await self.send_optional_notification(len(to_delete), channel, subtract_invoking=True)
 
     @cleanup.command()
     @commands.guild_only()
@@ -269,6 +293,7 @@ class Cleanup(commands.Cog):
         log.info(reason)
 
         await mass_purge(to_delete, channel)
+        await self.send_optional_notification(len(to_delete), channel, subtract_invoking=True)
 
     @cleanup.command()
     @commands.guild_only()
@@ -321,6 +346,7 @@ class Cleanup(commands.Cog):
         log.info(reason)
 
         await mass_purge(to_delete, channel)
+        await self.send_optional_notification(len(to_delete), channel)
 
     @cleanup.command()
     @commands.guild_only()
@@ -376,6 +402,7 @@ class Cleanup(commands.Cog):
         log.info(reason)
 
         await mass_purge(to_delete, channel)
+        await self.send_optional_notification(len(to_delete), channel, subtract_invoking=True)
 
     @cleanup.command()
     @commands.guild_only()
@@ -428,6 +455,7 @@ class Cleanup(commands.Cog):
         log.info(reason)
 
         await mass_purge(to_delete, channel)
+        await self.send_optional_notification(len(to_delete), channel, subtract_invoking=True)
 
     @cleanup.command()
     @commands.guild_only()
@@ -466,6 +494,7 @@ class Cleanup(commands.Cog):
         log.info(reason)
 
         await mass_purge(to_delete, channel)
+        await self.send_optional_notification(len(to_delete), channel, subtract_invoking=True)
 
     @cleanup.command(name="bot")
     @commands.guild_only()
@@ -552,6 +581,7 @@ class Cleanup(commands.Cog):
         log.info(reason)
 
         await mass_purge(to_delete, channel)
+        await self.send_optional_notification(len(to_delete), channel, subtract_invoking=True)
 
     @cleanup.command(name="self")
     @check_self_permissions()
@@ -640,6 +670,9 @@ class Cleanup(commands.Cog):
             await mass_purge(to_delete, channel)
         else:
             await slow_deletion(to_delete)
+        await self.send_optional_notification(
+            len(to_delete), channel, subtract_invoking=can_mass_purge
+        )
 
     @cleanup.command(name="duplicates", aliases=["spam"])
     @commands.guild_only()
@@ -690,3 +723,21 @@ class Cleanup(commands.Cog):
 
         to_delete.append(ctx.message)
         await mass_purge(to_delete, ctx.channel)
+        await self.send_optional_notification(len(to_delete), ctx.channel, subtract_invoking=True)
+
+    @commands.group()
+    @commands.admin_or_permissions(manage_messages=True)
+    async def cleanupset(self, ctx: commands.Context):
+        """Manage the settings for the cleanup command."""
+        pass
+
+    @cleanupset.command(name="notify")
+    async def cleanupset_notify(self, ctx: commands.Context):
+        """Toggle clean up notification settings."""
+        toggle = await self.config.guild(ctx.guild).notify()
+        if toggle:
+            await self.config.guild(ctx.guild).notify.set(False)
+            await ctx.send(_("I will no longer notify of message deletions."))
+        else:
+            await self.config.guild(ctx.guild).notify.set(True)
+            await ctx.send(_("I will now notify of message deletions."))