Add a command for deleting usernames and nicknames to Mod cog (#4827)

* mod delete names

* sTyLe fOrMAttInG

* Remove `[p]deletemodkeys` and have `[p]deletenames` remove empty keys

* Rename `[p]deletenames` to `[p]modset deletenames`

* Fix wrong variable being used

* Add confirmation to avoid mistakes

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

redbot/cogs/mod/settings.py

@@ -1,9 +1,11 @@
+import asyncio
 from collections import defaultdict, deque
 from typing import Optional
 from datetime import timedelta
 
 from redbot.core import commands, i18n, checks
-from redbot.core.utils.chat_formatting import box, humanize_timedelta
+from redbot.core.utils import AsyncIter
+from redbot.core.utils.chat_formatting import box, humanize_timedelta, inline
 
 from .abc import MixinMeta
 
@@ -398,3 +400,62 @@ class ModSettings(MixinMeta):
                 duration=humanize_timedelta(timedelta=duration)
             )
         )
+
+    @modset.command()
+    @commands.max_concurrency(1, commands.BucketType.default)
+    @commands.is_owner()
+    async def deletenames(self, ctx: commands.Context, confirmation: bool = False) -> None:
+        """Delete all stored usernames and nicknames.
+
+        Examples:
+            - `[p]modset deletenames` - Did not confirm. Shows the help message.
+            - `[p]modset deletenames yes` - Deletes all stored usernames and nicknames.
+
+        **Arguments**
+
+        - `<confirmation>` This will default to false unless specified.
+        """
+        if not confirmation:
+            await ctx.send(
+                _(
+                    "This will delete all stored usernames and nicknames the bot has stored."
+                    "\nIf you're sure, type {command}"
+                ).format(command=inline(f"{ctx.clean_prefix}modset deletenames yes"))
+            )
+            return
+
+        async with ctx.typing():
+            # Nickname data
+            async with self.config._get_base_group(self.config.MEMBER).all() as mod_member_data:
+                guilds_to_remove = []
+                for guild_id, guild_data in mod_member_data.items():
+                    await asyncio.sleep(0)
+                    members_to_remove = []
+
+                    async for member_id, member_data in AsyncIter(guild_data.items(), steps=100):
+                        if "past_nicks" in member_data:
+                            del member_data["past_nicks"]
+                        if not member_data:
+                            members_to_remove.append(member_id)
+
+                    async for member_id in AsyncIter(members_to_remove, steps=100):
+                        del guild_data[member_id]
+                    if not guild_data:
+                        guilds_to_remove.append(guild_id)
+
+                async for guild_id in AsyncIter(guilds_to_remove, steps=100):
+                    del mod_member_data[guild_id]
+
+            # Username data
+            async with self.config._get_base_group(self.config.USER).all() as mod_user_data:
+                users_to_remove = []
+                async for user_id, user_data in AsyncIter(mod_user_data.items(), steps=100):
+                    if "past_names" in user_data:
+                        del user_data["past_names"]
+                    if not user_data:
+                        users_to_remove.append(user_id)
+
+                async for user_id in AsyncIter(users_to_remove, steps=100):
+                    del mod_user_data[user_id]
+
+        await ctx.send(_("Usernames and nicknames have been deleted from Mod config."))