Add AllowDenyLists cog.

This includes commands to add, remove and show the items in the
whitelists and blacklists for the different list types.

Commands are limited to Moderators+.

2 files changed, 145 insertions, 0 deletions

diff --git a/bot/__main__.py b/bot/__main__.py
index 49388455a..932aa705c 100644
--- a/bot/__main__.py
+++ b/bot/__main__.py
@@ -53,6 +53,7 @@ bot.load_extension("bot.cogs.verification")
 
 # Feature cogs
 bot.load_extension("bot.cogs.alias")
+bot.load_extension("bot.cogs.allow_deny_lists")
 bot.load_extension("bot.cogs.defcon")
 bot.load_extension("bot.cogs.dm_relay")
 bot.load_extension("bot.cogs.duck_pond")
diff --git a/bot/cogs/allow_deny_lists.py b/bot/cogs/allow_deny_lists.py
new file mode 100644
index 000000000..d03c774ec
--- /dev/null
+++ b/bot/cogs/allow_deny_lists.py
@@ -0,0 +1,144 @@
+import logging
+
+from discord import Colour, Embed
+from discord.ext.commands import BadArgument, Cog, Context, group
+
+from bot import constants
+from bot.api import ResponseCodeError
+from bot.bot import Bot
+from bot.converters import ValidAllowDenyListType
+from bot.pagination import LinePaginator
+from bot.utils.checks import with_role_check
+
+log = logging.getLogger(__name__)
+
+
+class AllowDenyLists(Cog):
+    """Commands for blacklisting and whitelisting things."""
+
+    def __init__(self, bot: Bot) -> None:
+        self.bot = bot
+
+    async def _add_data(self, ctx: Context, allowed: bool, list_type: ValidAllowDenyListType, content: str) -> None:
+        """Add an item to an allow or denylist."""
+        payload = {
+            'allowed': allowed,
+            'type': list_type,
+            'content': content,
+        }
+        allow_type = "whitelist" if allowed else "blacklist"
+
+        # Try to add the item to the database
+        try:
+            item = await self.bot.api_client.post(
+                "bot/allow_deny_lists",
+                json=payload
+            )
+        except ResponseCodeError as e:
+            if e.status == 500:
+                await ctx.message.add_reaction("❌")
+                raise BadArgument(
+                    f"Unable to add the item to the {allow_type}. "
+                    "The item probably already exists. Keep in mind that a "
+                    "blacklist and a whitelist for the same item cannot co-exist, "
+                    "and we do not permit any duplicates."
+                )
+            raise
+
+        # Insert the item into the cache
+        type_ = item.get("type")
+        allowed = item.get("allowed")
+        metadata = {
+            "content": item.get("content"),
+            "id": item.get("id"),
+            "created_at": item.get("created_at"),
+            "updated_at": item.get("updated_at"),
+        }
+        self.bot.allow_deny_list_cache.setdefault(f"{type_}.{allowed}", []).append(metadata)
+        await ctx.message.add_reaction("✅")
+
+    async def _delete_data(self, ctx: Context, allowed: bool, list_type: ValidAllowDenyListType, content: str) -> None:
+        """Remove an item from an allow or denylist."""
+        item = None
+
+        for allow_list in self.bot.allow_deny_list_cache.get(f"{list_type}.{allowed}", []):
+            if content == allow_list.get("content"):
+                item = allow_list
+                break
+
+        if item is not None:
+            await self.bot.api_client.delete(
+                f"bot/allow_deny_lists/{item.get('id')}"
+            )
+            self.bot.allow_deny_list_cache[f"{list_type}.{allowed}"].remove(item)
+            await ctx.message.add_reaction("✅")
+
+    async def _list_all_data(self, ctx: Context, allowed: bool, list_type: ValidAllowDenyListType) -> None:
+        """Paginate and display all items in an allow or denylist."""
+        result = self.bot.allow_deny_list_cache.get(f"{list_type}.{allowed}", [])
+        lines = sorted(f"• {item.get('content')}" for item in result)
+        allowed_string = "Whitelisted" if allowed else "Blacklisted"
+        embed = Embed(
+            title=f"{allowed_string} {list_type.lower()} items ({len(result)} total)",
+            colour=Colour.blue()
+        )
+
+        if result:
+            await LinePaginator.paginate(lines, ctx, embed, max_lines=15, empty=False)
+        else:
+            embed.description = "Hmmm, seems like there's nothing here yet."
+            await ctx.send(embed=embed)
+
+    @group(aliases=("allowlist", "allow", "al", "wl"))
+    async def whitelist(self, ctx: Context) -> None:
+        """Group for whitelisting commands."""
+        if not ctx.invoked_subcommand:
+            await ctx.send_help(ctx.command)
+
+    @group(aliases=("denylist", "deny", "bl", "dl"))
+    async def blacklist(self, ctx: Context) -> None:
+        """Group for blacklisting commands."""
+        if not ctx.invoked_subcommand:
+            await ctx.send_help(ctx.command)
+
+    @whitelist.command(name="add", aliases=("a", "set"))
+    async def allow_add(self, ctx: Context, list_type: ValidAllowDenyListType, content: str) -> None:
+        """Add an item to the specified allowlist."""
+        await self._add_data(ctx, True, list_type, content)
+
+    @blacklist.command(name="add", aliases=("a", "set"))
+    async def deny_add(self, ctx: Context, list_type: ValidAllowDenyListType, content: str) -> None:
+        """Add an item to the specified denylist."""
+        await self._add_data(ctx, False, list_type, content)
+
+    @whitelist.command(name="remove", aliases=("delete", "rm",))
+    async def allow_delete(self, ctx: Context, list_type: ValidAllowDenyListType, content: str) -> None:
+        """Remove an item from the specified allowlist."""
+        await self._delete_data(ctx, True, list_type, content)
+
+    @blacklist.command(name="remove", aliases=("delete", "rm",))
+    async def deny_delete(self, ctx: Context, list_type: ValidAllowDenyListType, content: str) -> None:
+        """Remove an item from the specified denylist."""
+        await self._delete_data(ctx, False, list_type, content)
+
+    @whitelist.command(name="get", aliases=("list", "ls", "fetch", "show"))
+    async def allow_get(self, ctx: Context, list_type: ValidAllowDenyListType) -> None:
+        """Get the contents of a specified allowlist."""
+        await self._list_all_data(ctx, True, list_type)
+
+    @blacklist.command(name="get", aliases=("list", "ls", "fetch", "show"))
+    async def deny_get(self, ctx: Context, list_type: ValidAllowDenyListType) -> None:
+        """Get the contents of a specified denylist."""
+        await self._list_all_data(ctx, False, list_type)
+
+    def cog_check(self, ctx: Context) -> bool:
+        """Only allow moderators to invoke the commands in this cog."""
+        checks = [
+            with_role_check(ctx, *constants.MODERATION_ROLES),
+        ]
+        return all(checks)
+
+
+def setup(bot: Bot) -> None:
+    """Load the AllowDenyLists cog."""
+    bot.add_cog(AllowDenyLists(bot))