Okay, this should be ready to MR now.

20 files changed, 663 insertions, 74 deletions

diff --git a/Pipfile b/Pipfile
index d94234b22..b6f7aeb6f 100644
--- a/Pipfile
+++ b/Pipfile
@@ -18,7 +18,6 @@ lxml = "*"
 pyyaml = "*"
 yarl = "==1.1.1"
 fuzzywuzzy = "*"
-python-levenshtein = "*"
 pillow = "*"
 aio-pika = "*"
 python-dateutil = "*"
diff --git a/Pipfile.lock b/Pipfile.lock
index 864eb574a..8b43235bb 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "c7d1bad1549c322484f6751447115ded9299df039cb6321bcc1a1fa1359481dc"
+            "sha256": "9c22a342245c638b196b519a8afb8a2c66410d76283746cfdd89f19ff7dce94c"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -74,11 +74,13 @@
         },
         "beautifulsoup4": {
             "hashes": [
-                "sha256:11a9a27b7d3bddc6d86f59fb76afb70e921a25ac2d6cc55b40d072bd68435a76",
-                "sha256:7015e76bf32f1f574636c4288399a6de66ce08fb7b2457f628a8d70c0fbabb11",
-                "sha256:808b6ac932dccb0a4126558f7dfdcf41710dd44a4ef497a0bb59a77f9f078e89"
+                "sha256:2545357585a6cc7d050d3c43a86eba2c0b91b9e7ac8a3965e64a6ead6a1a9a3d",
+                "sha256:272081ad78c5495ba67083a0e50920163701fa6fe67fbb5eefeb21b5dd88c40b",
+                "sha256:4ddc90ad88bccc005a71d8ef32f7b1cd8f935475cd561c4122b2f87de45d28ab",
+                "sha256:5a3d659840960a4107047b6328d6d4cdaaee69939bf11adc07466a1856c99a80",
+                "sha256:bd43a3b26d2886acd63070c43da821b60dea603eb6d45bab0294aac6129adbfa"
             ],
-            "version": "==4.6.0"
+            "version": "==4.6.1"
         },
         "certifi": {
             "hashes": [
@@ -247,18 +249,30 @@
                 "sha256:026449b64e559226cdb8e6d8c931b5965d8fc90ec18ebbb0baa04c5b36503c72",
                 "sha256:03dbb224ee196ef30ed2156d41b579143e1efeb422974719a5392fc035e4f574",
                 "sha256:03eb0e04f929c102ae24bc436bf1c0c60a4e63b07ebd388e84d8b219df3e6acd",
+                "sha256:087b0551ce2d19b3f092f2b5f071a065f7379e748867d070b29999cc83db15e3",
+                "sha256:091a0656688d85fd6e10f49a73fa3ab9b37dbfcb2151f5a3ab17f8b879f467ee",
+                "sha256:0f3e2d0a9966161b7dfd06d147f901d72c3a88ea1a833359b92193b8e1f68e1c",
+                "sha256:114398d0e073b93e1d7da5b5ab92ff4b83c0180625c8031911425e51f4365d2e",
                 "sha256:1be66b9a89e367e7d20d6cae419794997921fe105090fafd86ef39e20a3baab2",
+                "sha256:1c5e93c40d4ce8cb133d3b105a869be6fa767e703f6eb1003eb4b90583e08a59",
                 "sha256:1e977a3ed998a599bda5021fb2c2889060617627d3ae228297a529a082a3cd5c",
                 "sha256:22cf3406d135cfcc13ec6228ade774c8461e125c940e80455f500638429be273",
                 "sha256:24adccf1e834f82718c7fc8e3ec1093738da95144b8b1e44c99d5fc7d3e9c554",
                 "sha256:2a3e362c97a5e6a259ee9cd66553292a1f8928a5bdfa3622fdb1501570834612",
+                "sha256:3518f9fc666cbc58a5c1f48a6a23e9e6ceef69665eab43cdad5144de9383e72c",
+                "sha256:3709339f4619e8c9b00f53079e40b964f43c5af61fb89a923fe24437167298bb",
                 "sha256:3832e26ecbc9d8a500821e3a1d3765bda99d04ae29ffbb2efba49f5f788dc934",
+                "sha256:452d159024faf37cc080537df308e8fa0026076eb38eb75185d96ed9642bd6d7",
                 "sha256:4fd1f0c2dc02aaec729d91c92cd85a2df0289d88e9f68d1e8faba750bb9c4786",
                 "sha256:4fda62030f2c515b6e2e673c57caa55cb04026a81968f3128aae10fc28e5cc27",
                 "sha256:5044d75a68b49ce36a813c82d8201384207112d5d81643937fc758c05302f05b",
                 "sha256:522184556921512ec484cb93bd84e0bab915d0ac5a372d49571c241a7f73db62",
                 "sha256:5914cff11f3e920626da48e564be6818831713a3087586302444b9c70e8552d9",
+                "sha256:653d48fe46378f40e3c2b892be88d8440efbb2c9df78559da44c63ad5ecb4142",
                 "sha256:6661a7908d68c4a133e03dac8178287aa20a99f841ea90beeb98a233ae3fd710",
+                "sha256:6735a7e560df6f0deb78246a6fe056cf2ae392ba2dc060ea8a6f2535aec924f1",
+                "sha256:6d26a475a19cb294225738f5c974b3a24599438a67a30ed2d25638f012668026",
+                "sha256:791f07fe13937e65285f9ef30664ddf0e10a0230bdb236751fa0ca67725740dd",
                 "sha256:79258a8df3e309a54c7ef2ef4a59bb8e28f7e4a8992a3ad17c24b1889ced44f3",
                 "sha256:7d74c20b8f1c3e99d3f781d3b8ff5abfefdd7363d61e23bdeba9992ff32cc4b4",
                 "sha256:81918afeafc16ba5d9d0d4e9445905f21aac969a4ebb6f2bff4b9886da100f4b",
@@ -266,12 +280,20 @@
                 "sha256:84d5d31200b11b3c76fab853b89ac898bf2d05c8b3da07c1fcc23feb06359d6e",
                 "sha256:989981db57abffb52026b114c9a1f114c7142860a6d30a352d28f8cbf186500b",
                 "sha256:a3d7511d3fad1618a82299aab71a5fceee5c015653a77ffea75ced9ef917e71a",
+                "sha256:a4a6ac01b8c2f9d2d83719f193e6dea493e18445ce5bfd743d739174daa974d9",
+                "sha256:acb90eb6c7ed6526551a78211d84c81e33082a35642ff5fe57489abc14e6bf6e",
                 "sha256:b3ef168d4d6fd4fa6685aef7c91400f59f7ab1c0da734541f7031699741fb23f",
                 "sha256:c1c5792b6e74bbf2af0f8e892272c2a6c48efa895903211f11b8342e03129fea",
                 "sha256:c5dcb5a56aebb8a8f2585042b2f5c496d7624f0bcfe248f0cc33ceb2fd8d39e7",
+                "sha256:d16f90810106822833a19bdb24c7cb766959acf791ca0edf5edfec674d55c8ee",
+                "sha256:dcdc9cd9880027688007ff8f7c8e7ae6f24e81fae33bfd18d1e691e7bda4855f",
+                "sha256:e2807aad4565d8de15391a9548f97818a14ef32624015c7bf3095171e314445e",
                 "sha256:e2bed4a04e2ca1050bb5f00865cf2f83c0b92fd62454d9244f690fcd842e27a4",
                 "sha256:e87a527c06319428007e8c30511e1f0ce035cb7f14bb4793b003ed532c3b9333",
+                "sha256:ebcfc33a6c34984086451e230253bc33727bd17b4cdc4b39ec03032c3a6fc9e9",
                 "sha256:f63e420180cbe22ff6e32558b612e75f50616fc111c5e095a4631946c782e109",
+                "sha256:f7717eb360d40e7598c30cc44b33d98f79c468d9279379b66c1e28c568e0bf47",
+                "sha256:f8582e1ab155302ea9ef1235441a0214919f4f79c4c7c21833ce9eec58181781",
                 "sha256:f8b3d413c5a8f84b12cd4c5df1d8e211777c9852c6be3ee9c094b626644d3eab"
             ],
             "index": "pypi",
@@ -313,6 +335,11 @@
         "pyparsing": {
             "hashes": [
                 "sha256:0832bcf47acd283788593e7a0f542407bd9550a55a8a8435214a1960e04bcb04",
+                "sha256:281683241b25fe9b80ec9d66017485f6deff1af5cde372469134b56ca8447a07",
+                "sha256:8f1e18d3fd36c6795bb7e02a39fd05c611ffc2596c1e0d995d34d67630426c18",
+                "sha256:9e8143a3e15c13713506886badd96ca4b579a87fbdf49e550dbfc057d6cb218e",
+                "sha256:b8b3117ed9bdf45e14dcc89345ce638ec7e0e29b2b579fa1ecf32ce45ebac8a5",
+                "sha256:e4d45427c6e20a59bf4f88c639dcc03ce30d193112047f94012102f235853a58",
                 "sha256:fee43f17a9c4087e7ed1605bd6df994c6173c1e977d7ade7b651292fab2bd010"
             ],
             "version": "==2.2.0"
@@ -330,16 +357,8 @@
                 "sha256:a292e22c5e03105a05a746ade6209d43db1c4c763b91c75c8486e81d10904d85",
                 "sha256:e3636824d35ba6a15fc39f573588cba63cf46322a5dc86fb2f280229077e9fbe"
             ],
-            "markers": "python_version != '3.3.*' and python_version >= '2.7' and python_version != '3.1.*' and python_version != '3.0.*' and python_version != '3.2.*'",
             "version": "==0.1.9"
         },
-        "python-levenshtein": {
-            "hashes": [
-                "sha256:033a11de5e3d19ea25c9302d11224e1a1898fe5abd23c61c7c360c25195e3eb1"
-            ],
-            "index": "pypi",
-            "version": "==0.12.0"
-        },
         "pytz": {
             "hashes": [
                 "sha256:a061aa0a9e06881eb8b3b2b43f05b9439d6583c206d0a6c340ff72a7b6669053",
@@ -404,7 +423,6 @@
                 "sha256:68ca7ff70785cbe1e7bccc71a48b5b6d965d79ca50629606c7861a21b206d9dd",
                 "sha256:9de47f375baf1ea07cdb3436ff39d7a9c76042c10a769c52353ec46e4e8fc3b9"
             ],
-            "markers": "python_version != '3.3.*' and python_version >= '2.7' and python_version != '3.1.*' and python_version != '3.0.*' and python_version != '3.2.*'",
             "version": "==1.1.0"
         },
         "sympy": {
@@ -419,7 +437,6 @@
                 "sha256:a68ac5e15e76e7e5dd2b8f94007233e01effe3e50e8daddf69acfd81cb686baf",
                 "sha256:b5725a0bd4ba422ab0e66e89e030c806576753ea3ee08554382c14e685d117b5"
             ],
-            "markers": "python_version != '3.0.*' and python_version < '4' and python_version != '3.3.*' and python_version != '3.2.*' and python_version >= '2.6' and python_version != '3.1.*'",
             "version": "==1.23"
         },
         "websockets": {
@@ -592,6 +609,11 @@
         "pyparsing": {
             "hashes": [
                 "sha256:0832bcf47acd283788593e7a0f542407bd9550a55a8a8435214a1960e04bcb04",
+                "sha256:281683241b25fe9b80ec9d66017485f6deff1af5cde372469134b56ca8447a07",
+                "sha256:8f1e18d3fd36c6795bb7e02a39fd05c611ffc2596c1e0d995d34d67630426c18",
+                "sha256:9e8143a3e15c13713506886badd96ca4b579a87fbdf49e550dbfc057d6cb218e",
+                "sha256:b8b3117ed9bdf45e14dcc89345ce638ec7e0e29b2b579fa1ecf32ce45ebac8a5",
+                "sha256:e4d45427c6e20a59bf4f88c639dcc03ce30d193112047f94012102f235853a58",
                 "sha256:fee43f17a9c4087e7ed1605bd6df994c6173c1e977d7ade7b651292fab2bd010"
             ],
             "version": "==2.2.0"
@@ -622,11 +644,11 @@
         },
         "safety": {
             "hashes": [
-                "sha256:32d41b8bbd736db749aa2162de6c0bb11c2113c7bc0357476491f96cd5d58299",
-                "sha256:34227360409ffb1bc2657e5b6ff3472a32d72b917617cd3d2914ddf078c263b9"
+                "sha256:2689fe629bafe9450796d36578aa112820ff65038578aee004f60b9db1ba4ae8",
+                "sha256:cd04e57ff8cf8984ff2cb11973e1d5469dae681e25d4edfccb1ef08cc107b2c0"
             ],
             "index": "pypi",
-            "version": "==1.8.2"
+            "version": "==1.8.3"
         },
         "six": {
             "hashes": [
@@ -640,7 +662,6 @@
                 "sha256:a68ac5e15e76e7e5dd2b8f94007233e01effe3e50e8daddf69acfd81cb686baf",
                 "sha256:b5725a0bd4ba422ab0e66e89e030c806576753ea3ee08554382c14e685d117b5"
             ],
-            "markers": "python_version != '3.0.*' and python_version < '4' and python_version != '3.3.*' and python_version != '3.2.*' and python_version >= '2.6' and python_version != '3.1.*'",
             "version": "==1.23"
         }
     }
diff --git a/bot/__main__.py b/bot/__main__.py
index b39fd24d0..d6cfc5d5b 100644
--- a/bot/__main__.py
+++ b/bot/__main__.py
@@ -44,6 +44,7 @@ bot.load_extension("bot.cogs.events")
 bot.load_extension("bot.cogs.filtering")
 
 # Commands, etc
+# bot.load_extension("bot.cogs.antispam")
 bot.load_extension("bot.cogs.bigbrother")
 bot.load_extension("bot.cogs.bot")
 bot.load_extension("bot.cogs.clean")
diff --git a/bot/cogs/antispam.py b/bot/cogs/antispam.py
new file mode 100644
index 000000000..04b030889
--- /dev/null
+++ b/bot/cogs/antispam.py
@@ -0,0 +1,161 @@
+import asyncio
+import logging
+import textwrap
+from datetime import datetime, timedelta
+from typing import Dict, List
+
+from dateutil.relativedelta import relativedelta
+from discord import Member, Message, Object, TextChannel
+from discord.ext.commands import Bot
+
+from bot import rules
+from bot.constants import AntiSpam as AntiSpamConfig, Channels, Colours, Guild as GuildConfig, Icons
+from bot.utils.time import humanize as humanize_delta
+
+
+log = logging.getLogger(__name__)
+
+RULE_FUNCTION_MAPPING = {
+    'attachments': rules.apply_attachments,
+    'burst': rules.apply_burst,
+    'burst_shared': rules.apply_burst_shared,
+    'chars': rules.apply_chars,
+    'discord_emojis': rules.apply_discord_emojis,
+    'duplicates': rules.apply_duplicates,
+    'links': rules.apply_links,
+    'mentions': rules.apply_mentions,
+    'newlines': rules.apply_newlines,
+    'role_mentions': rules.apply_role_mentions
+}
+
+
+class AntiSpam:
+    def __init__(self, bot: Bot):
+        self.bot = bot
+        self.muted_role = None
+
+    async def on_ready(self):
+        role_id = AntiSpamConfig.punishment['role_id']
+        self.muted_role = Object(role_id)
+
+    async def on_message(self, message: Message):
+        if message.guild.id != GuildConfig.id or message.author.bot:
+            return
+
+        # Fetch the rule configuration with the highest rule interval.
+        max_interval_config = max(
+            AntiSpamConfig.rules.values(),
+            key=lambda config: config['interval']
+        )
+        max_interval = max_interval_config['interval']
+
+        # Store history messages since `interval` seconds ago in a list to prevent unnecessary API calls.
+        earliest_relevant_at = datetime.utcnow() - timedelta(seconds=max_interval)
+        relevant_messages = [
+            msg async for msg in message.channel.history(after=earliest_relevant_at, reverse=False)
+        ]
+
+        for rule_name in AntiSpamConfig.rules:
+            rule_config = AntiSpamConfig.rules[rule_name]
+            rule_function = RULE_FUNCTION_MAPPING[rule_name]
+
+            # Create a list of messages that were sent in the interval that the rule cares about.
+            latest_interesting_stamp = datetime.utcnow() - timedelta(seconds=rule_config['interval'])
+            messages_for_rule = [
+                msg for msg in relevant_messages if msg.created_at > latest_interesting_stamp
+            ]
+            result = await rule_function(message, messages_for_rule, rule_config)
+
+            # If the rule returns `None`, that means the message didn't violate it.
+            # If it doesn't, it returns a tuple in the form `(str, Iterable[discord.Member])`
+            # which contains the reason for why the message violated the rule and
+            # an iterable of all members that violated the rule.
+            if result is not None:
+                reason, members, relevant_messages = result
+                full_reason = f"`{rule_name}` rule: {reason}"
+                for member in members:
+
+                    # Fire it off as a background task to ensure
+                    # that the sleep doesn't block further tasks
+                    self.bot.loop.create_task(
+                        self.punish(message, member, rule_config, full_reason)
+                    )
+
+                await self.maybe_delete_messages(message.channel, relevant_messages)
+                break
+
+    async def punish(self, msg: Message, member: Member, rule_config: Dict[str, int], reason: str):
+        # Sanity check to ensure we're not lagging behind
+        if self.muted_role not in member.roles:
+            remove_role_after = AntiSpamConfig.punishment['remove_after']
+            duration_delta = relativedelta(seconds=remove_role_after)
+            human_duration = humanize_delta(duration_delta)
+
+            mod_alert_channel = self.bot.get_channel(Channels.mod_alerts)
+            if mod_alert_channel is not None:
+                await mod_alert_channel.send(
+                    f"<:messagefiltered:473092874289020929> Spam detected in {msg.channel.mention}. "
+                    f"See the message and mod log for further details."
+                )
+            else:
+                log.warning(
+                    "Tried logging spam event to the mod-alerts channel, but it could not be found."
+                )
+
+            await member.add_roles(self.muted_role, reason=reason)
+            description = textwrap.dedent(f"""
+            **Channel**: {msg.channel.mention}
+            **User**: {msg.author.mention} (`{msg.author.id}`)
+            **Reason**: {reason}
+            Role will be removed after {human_duration}.
+            """)
+
+            modlog = self.bot.get_cog('ModLog')
+            await modlog.send_log_message(
+                icon_url=Icons.user_mute, colour=Colours.soft_red,
+                title="User muted", text=description
+            )
+
+            await asyncio.sleep(remove_role_after)
+            await member.remove_roles(self.muted_role, reason="AntiSpam mute expired")
+
+            await modlog.send_log_message(
+                icon_url=Icons.user_mute, colour=Colours.soft_green,
+                title="User unmuted",
+                text=f"Was muted by `AntiSpam` cog for {human_duration}."
+            )
+
+    async def maybe_delete_messages(self, channel: TextChannel, messages: List[Message]):
+        # Is deletion of offending messages actually enabled?
+        if AntiSpamConfig.clean_offending:
+
+            # If we have more than one message, we can use bulk delete.
+            if len(messages) > 1:
+                await channel.delete_messages(messages)
+
+            # Otherwise, the bulk delete endpoint will throw up.
+            # Delete the message directly instead.
+            else:
+                await messages[0].delete()
+
+
+def validate_config():
+    for name, config in AntiSpamConfig.rules.items():
+        if name not in RULE_FUNCTION_MAPPING:
+            raise ValueError(
+                f"Unrecognized antispam rule `{name}`. "
+                f"Valid rules are: {', '.join(RULE_FUNCTION_MAPPING)}"
+            )
+
+        for required_key in ('interval', 'max'):
+            if required_key not in config:
+                raise ValueError(
+                    f"`{required_key}` is required but was not "
+                    f"set in rule `{name}`'s configuration."
+                )
+
+
+def setup(bot: Bot):
+    validate_config()
+    bot.add_cog(AntiSpam(bot))
+    log.info("Cog loaded: AntiSpam")
diff --git a/bot/cogs/clean.py b/bot/cogs/clean.py
index 85c9ec781..da0a5a9f2 100644
--- a/bot/cogs/clean.py
+++ b/bot/cogs/clean.py
@@ -169,6 +169,7 @@ class Clean:
 
             # Always start by deleting the invocation
             if not invocation_deleted:
+                self.mod_log.ignore_message_deletion(message.id)
                 await message.delete()
                 invocation_deleted = True
                 continue
diff --git a/bot/cogs/events.py b/bot/cogs/events.py
index a7111b8a0..0b9b75a00 100644
--- a/bot/cogs/events.py
+++ b/bot/cogs/events.py
@@ -1,20 +1,24 @@
 import logging
 
-from discord import Embed, Member
+from discord import Colour, Embed, Member, Object
 from discord.ext.commands import (
     BadArgument, Bot, BotMissingPermissions,
     CommandError, CommandInvokeError, Context,
     NoPrivateMessage, UserInputError
 )
 
+from bot.cogs.modlog import ModLog
 from bot.constants import (
-    Channels, DEBUG_MODE, Guild,
-    Keys, Roles, URLs
+    Channels, Colours, DEBUG_MODE,
+    Guild, Icons, Keys,
+    Roles, URLs
 )
 from bot.utils import chunks
 
 log = logging.getLogger(__name__)
 
+RESTORE_ROLES = (str(Roles.muted), str(Roles.announcements))
+
 
 class Events:
     """No commands, just event handlers."""
@@ -22,6 +26,10 @@ class Events:
     def __init__(self, bot: Bot):
         self.bot = bot
 
+    @property
+    def mod_log(self) -> ModLog:
+        return self.bot.get_cog("ModLog")
+
     async def send_updated_users(self, *users, replace_all=False):
         users = list(filter(lambda user: str(Roles.verified) in user["roles"], users))
 
@@ -85,6 +93,16 @@ class Events:
             log.exception(f"Failed to delete {len(users)} users")
             return {}
 
+    async def get_user(self, user_id):
+        response = await self.bot.http_session.get(
+            url=URLs.site_user_api,
+            params={"user_id": user_id},
+            headers={"X-API-Key": Keys.site_api}
+        )
+
+        resp = await response.json()
+        return resp["data"]
+
     async def on_command_error(self, ctx: Context, e: CommandError):
         command = ctx.command
         parent = None
@@ -194,6 +212,29 @@ class Events:
 
     async def on_member_join(self, member: Member):
         role_ids = [str(r.id) for r in member.roles]  # type: List[str]
+        new_roles = []
+
+        try:
+            user_objs = await self.get_user(str(member.id))
+        except Exception as e:
+            log.exception("Failed to persist roles")
+
+            await self.mod_log.send_log_message(
+                Icons.crown_red, Colour(Colours.soft_red), "Failed to persist roles",
+                f"```py\n{e}\n```",
+                member.avatar_url_as(static_format="png")
+            )
+        else:
+            if user_objs:
+                old_roles = user_objs[0].get("roles", [])
+
+                for role in RESTORE_ROLES:
+                    if role in old_roles:
+                        new_roles.append(Object(int(role)))
+
+                for role in new_roles:
+                    if str(role) not in role_ids:
+                        role_ids.append(str(role.id))
 
         changes = await self.send_updated_users({
             "avatar": member.avatar_url_as(format="png"),
@@ -205,6 +246,18 @@ class Events:
 
         log.debug(f"User {member.id} joined; changes: {changes}")
 
+        if new_roles:
+            await member.add_roles(
+                *new_roles,
+                reason="Roles restored"
+            )
+
+            await self.mod_log.send_log_message(
+                Icons.crown_blurple, Colour.blurple(), "Roles restored",
+                f"Restored {len(new_roles)} roles",
+                member.avatar_url_as(static_format="png")
+            )
+
     async def on_member_remove(self, member: Member):
         changes = await self.send_delete_users({
             "user_id": str(member.id)
diff --git a/bot/cogs/filtering.py b/bot/cogs/filtering.py
index 1ef797445..d9cb2bb82 100644
--- a/bot/cogs/filtering.py
+++ b/bot/cogs/filtering.py
@@ -1,11 +1,14 @@
 import logging
 import re
 
-from discord import Message
+from discord import Colour, Message
 from discord.ext.commands import Bot
 
 from bot.cogs.modlog import ModLog
-from bot.constants import Channels, Colours, Filter, Icons
+from bot.constants import (
+    Channels, Colours, DEBUG_MODE,
+    Filter, Icons
+)
 
 log = logging.getLogger(__name__)
 
@@ -84,7 +87,9 @@ class Filtering:
             and not msg.author.bot                          # Author not a bot
         )
 
-        filter_message = not msg.author.bot and msg.channel.id == Channels.modlog  # for testing
+        # If we're running the bot locally, ignore role whitelist and only listen to #dev-test
+        if DEBUG_MODE:
+            filter_message = not msg.author.bot and msg.channel.id == Channels.devtest
 
         # If none of the above, we can start filtering.
         if filter_message:
@@ -95,53 +100,33 @@ class Filtering:
                     triggered = await _filter["function"](msg.content)
 
                     if triggered:
-
-                        # If a filter is triggered, we should automod it.
+                        message = (
+                            f"The {filter_name} {_filter['type']} was triggered "
+                            f"by **{msg.author.name}#{msg.author.discriminator}** in "
+                            f"<#{msg.channel.id}> with the following message:\n\n"
+                            f"{msg.content}"
+                        )
+
+                        log.debug(message)
+                        log.debug(Channels.mod_alerts)
+
+                        # Send pretty mod log embed to mod-alerts
+                        await self.mod_log.send_log_message(
+                            icon_url=Icons.filtering,
+                            colour=Colour(Colours.soft_red),
+                            title=f"{_filter['type'].title()} triggered!",
+                            text=message,
+                            thumbnail=msg.author.avatar_url_as(static_format="png"),
+                            channel_id=Channels.mod_alerts,
+                            ping_everyone=Filter.ping_everyone,
+                        )
+
+                        # If this is a filter (not a watchlist), we should delete the message.
                         if _filter["type"] == "filter":
-                            log.debug(
-                                f"The {filter_name} filter was triggered "
-                                f"by {msg.author.name} in {msg.channel.name} with "
-                                f"the following message:\n{msg.content}."
-                            )
-
-                            # Replace this with actual automod
-                            await self.bot.get_channel(msg.channel.id).send(
-                                content=f"The **{filter_name}** filter triggered!"
-                            )
-
-                        # If a watchlist triggers, we should send a mod alert.
-                        elif _filter["type"] == "watchlist":
-                            await self._mod_alert(filter_name, msg)
+                            await msg.delete()
 
                         break  # We don't want multiple filters to trigger
 
-    async def _auto_mod(self, filter_name: str, msg: Message):
-        """
-        Removes a message and sends a
-        """
-
-    async def _mod_alert(self, watchlist_name: str, msg: Message):
-        """
-        Send a mod alert into the #mod-alert channel.
-
-        Ping staff so they can take action.
-        """
-
-        message = (
-            f"The {watchlist_name} watchlist was triggered "
-            f"by {msg.author.name} in {msg.channel.name} with "
-            f"the following message:\n{msg.content}."
-        )
-
-        log.debug(message)
-
-        # Send pretty modlog embed to mod-alerts
-        await self.mod_log.send_log_message(
-            Icons., Colours.soft_red, "Watchlist triggered!",
-            message, msg.author.avatar_url_as(static_format="png"),
-            ping_everyone=True
-        )
-
     @staticmethod
     async def _has_watchlist_words(text: str) -> bool:
         """
diff --git a/bot/constants.py b/bot/constants.py
index ee9e8b4a2..54d37b3f0 100644
--- a/bot/constants.py
+++ b/bot/constants.py
@@ -14,7 +14,7 @@ import logging
 import os
 from collections.abc import Mapping
 from pathlib import Path
-from typing import List
+from typing import Dict, List
 
 import yaml
 from yaml.constructor import ConstructorError
@@ -200,6 +200,7 @@ class Filter(metaclass=YAMLGetter):
     watch_words: bool
     watch_tokens: bool
 
+    ping_everyone: bool
     guild_invite_whitelist: List[str]
     vanity_url_whitelist: List[str]
     domain_blacklist: List[str]
@@ -250,10 +251,12 @@ class Icons(metaclass=YAMLGetter):
     crown_green: str
     crown_red: str
 
-    defcon_denied: str  # noqa: E704
+    defcon_denied: str    # noqa: E704
     defcon_disabled: str  # noqa: E704
-    defcon_enabled: str  # noqa: E704
-    defcon_updated: str  # noqa: E704
+    defcon_enabled: str   # noqa: E704
+    defcon_updated: str   # noqa: E704
+
+    filtering: str
 
     guild_update: str
 
@@ -300,6 +303,7 @@ class Channels(metaclass=YAMLGetter):
     help_5: int
     helpers: int
     message_log: int
+    mod_alerts: int
     modlog: int
     off_topic_1: int
     off_topic_2: int
@@ -320,6 +324,7 @@ class Roles(metaclass=YAMLGetter):
     devops: int
     jammer: int
     moderator: int
+    muted: int
     owner: int
     verified: int
     muted: int
@@ -389,6 +394,13 @@ class URLs(metaclass=YAMLGetter):
     paste_service: str
 
 
+class AntiSpam(metaclass=YAMLGetter):
+    section = 'anti_spam'
+
+    punishment: Dict[str, Dict[str, int]]
+    rules: Dict[str, Dict[str, int]]
+
+
 # Debug mode
 DEBUG_MODE = True if 'local' in os.environ.get("SITE_URL", "local") else False
 
diff --git a/bot/rules/__init__.py b/bot/rules/__init__.py
new file mode 100644
index 000000000..a01ceae73
--- /dev/null
+++ b/bot/rules/__init__.py
@@ -0,0 +1,12 @@
+# flake8: noqa
+
+from .attachments import apply as apply_attachments
+from .burst import apply as apply_burst
+from .burst_shared import apply as apply_burst_shared
+from .chars import apply as apply_chars
+from .discord_emojis import apply as apply_discord_emojis
+from .duplicates import apply as apply_duplicates
+from .links import apply as apply_links
+from .mentions import apply as apply_mentions
+from .newlines import apply as apply_newlines
+from .role_mentions import apply as apply_role_mentions
diff --git a/bot/rules/attachments.py b/bot/rules/attachments.py
new file mode 100644
index 000000000..47b927101
--- /dev/null
+++ b/bot/rules/attachments.py
@@ -0,0 +1,30 @@
+"""Detects total attachments exceeding the limit sent by a single user."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if (
+            msg.author == last_message.author
+            and len(msg.attachments) > 0
+        )
+    )
+    total_recent_attachments = sum(len(msg.attachments) for msg in relevant_messages)
+
+    if total_recent_attachments > config['max']:
+        return (
+            f"sent {total_recent_attachments} attachments in {config['max']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/burst.py b/bot/rules/burst.py
new file mode 100644
index 000000000..80c79be60
--- /dev/null
+++ b/bot/rules/burst.py
@@ -0,0 +1,27 @@
+"""Detects repeated messages sent by a single user."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if msg.author == last_message.author
+    )
+    total_relevant = len(relevant_messages)
+
+    if total_relevant > config['max']:
+        return (
+            f"sent {total_relevant} messages in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/burst_shared.py b/bot/rules/burst_shared.py
new file mode 100644
index 000000000..2cb7b5200
--- /dev/null
+++ b/bot/rules/burst_shared.py
@@ -0,0 +1,22 @@
+"""Detects repeated messages sent by multiple users."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    total_recent = len(recent_messages)
+
+    if total_recent > config['max']:
+        return (
+            f"sent {total_recent} messages in {config['interval']}s",
+            set(msg.author for msg in recent_messages),
+            recent_messages
+        )
+    return None
diff --git a/bot/rules/chars.py b/bot/rules/chars.py
new file mode 100644
index 000000000..d05e3cd83
--- /dev/null
+++ b/bot/rules/chars.py
@@ -0,0 +1,28 @@
+"""Detects total message char count exceeding the limit sent by a single user."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if msg.author == last_message.author
+    )
+
+    total_recent_chars = sum(len(msg.content) for msg in relevant_messages)
+
+    if total_recent_chars > config['max']:
+        return (
+            f"sent {total_recent_chars} characters in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/discord_emojis.py b/bot/rules/discord_emojis.py
new file mode 100644
index 000000000..e4f957ddb
--- /dev/null
+++ b/bot/rules/discord_emojis.py
@@ -0,0 +1,35 @@
+"""Detects total Discord emojis (excluding Unicode emojis) exceeding the limit sent by a single user."""
+
+import re
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+DISCORD_EMOJI_RE = re.compile(r"<:\w+:\d+>")
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if msg.author == last_message.author
+    )
+
+    total_emojis = sum(
+        len(DISCORD_EMOJI_RE.findall(msg.content))
+        for msg in relevant_messages
+    )
+
+    if total_emojis > config['max']:
+        return (
+            f"sent {total_emojis} emojis in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/duplicates.py b/bot/rules/duplicates.py
new file mode 100644
index 000000000..763fc9983
--- /dev/null
+++ b/bot/rules/duplicates.py
@@ -0,0 +1,31 @@
+"""Detects duplicated messages sent by a single user."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if (
+            msg.author == last_message.author
+            and msg.content == last_message.content
+        )
+    )
+
+    total_duplicated = len(relevant_messages)
+
+    if total_duplicated > config['max']:
+        return (
+            f"sent {total_duplicated} duplicated messages in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/links.py b/bot/rules/links.py
new file mode 100644
index 000000000..dfeb38c61
--- /dev/null
+++ b/bot/rules/links.py
@@ -0,0 +1,31 @@
+"""Detects total links exceeding the limit sent by a single user."""
+
+import re
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+LINK_RE = re.compile(r"(https?://[^\s]+)")
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if msg.author == last_message.author
+    )
+    total_links = sum(len(LINK_RE.findall(msg.content)) for msg in relevant_messages)
+
+    if total_links > config['max']:
+        return (
+            f"sent {total_links} links in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/mentions.py b/bot/rules/mentions.py
new file mode 100644
index 000000000..45c47b6ba
--- /dev/null
+++ b/bot/rules/mentions.py
@@ -0,0 +1,28 @@
+"""Detects total mentions exceeding the limit sent by a single user."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if msg.author == last_message.author
+    )
+
+    total_recent_mentions = sum(len(msg.mentions) for msg in relevant_messages)
+
+    if total_recent_mentions > config['max']:
+        return (
+            f"sent {total_recent_mentions} mentions in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/newlines.py b/bot/rules/newlines.py
new file mode 100644
index 000000000..a6a1a52d0
--- /dev/null
+++ b/bot/rules/newlines.py
@@ -0,0 +1,28 @@
+"""Detects total newlines exceeding the set limit sent by a single user."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if msg.author == last_message.author
+    )
+
+    total_recent_newlines = sum(msg.content.count('\n') for msg in relevant_messages)
+
+    if total_recent_newlines > config['max']:
+        return (
+            f"sent {total_recent_newlines} newlines in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/bot/rules/role_mentions.py b/bot/rules/role_mentions.py
new file mode 100644
index 000000000..2177a73b5
--- /dev/null
+++ b/bot/rules/role_mentions.py
@@ -0,0 +1,28 @@
+"""Detects total role mentions exceeding the limit sent by a single user."""
+
+from typing import Dict, Iterable, List, Optional, Tuple
+
+from discord import Member, Message
+
+
+async def apply(
+    last_message: Message,
+    recent_messages: List[Message],
+    config: Dict[str, int]
+) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
+
+    relevant_messages = tuple(
+        msg
+        for msg in recent_messages
+        if msg.author == last_message.author
+    )
+
+    total_recent_mentions = sum(len(msg.role_mentions) for msg in relevant_messages)
+
+    if total_recent_mentions > config['max']:
+        return (
+            f"sent {total_recent_mentions} role mentions in {config['interval']}s",
+            (last_message.author,),
+            relevant_messages
+        )
+    return None
diff --git a/config-default.yml b/config-default.yml
index eaff5d56d..2beb4edbf 100644
--- a/config-default.yml
+++ b/config-default.yml
@@ -59,6 +59,9 @@ style:
         user_unban:  "https://cdn.discordapp.com/emojis/469952898692808704.png"
         user_update: "https://cdn.discordapp.com/emojis/469952898684551168.png"
 
+        user_mute:   "https://cdn.discordapp.com/emojis/472472640100106250.png"
+        user_unmute: "https://cdn.discordapp.com/emojis/472472640100106250.png"
+
 
 guild:
     id: 267624335836053506
@@ -80,6 +83,7 @@ guild:
         help_5:                           454941769734422538
         helpers:                          385474242440986624
         message_log:       &MESSAGE_LOG   467752170159079424
+        mod_alerts:                       473092532147060736
         modlog:            &MODLOG        282638479504965634
         off_topic_0:                      291284109232308226
         off_topic_1:                      463035241142026251
@@ -99,7 +103,7 @@ guild:
         devops:            &DEVOPS_ROLE   409416496733880320
         jammer:                           423054537079783434
         moderator:         &MOD_ROLE      267629731250176001
-        muted:                            277914926603829249
+        muted:             &MUTED_ROLE    277914926603829249
         owner:             &OWNER_ROLE    267627879762755584
         verified:                         352427296948486144
         helpers:                          267630620367257601
@@ -115,6 +119,8 @@ filter:
     watch_tokens:   true
 
     # Filter configuration
+    ping_everyone: true  # Ping @everyone when we send a mod-alert?
+
     guild_invite_whitelist:
         - vywQPxd            # Code Monkeys
         - kWJYurV            # Functional Programming
@@ -226,3 +232,53 @@ urls:
     gitlab_bot_repo: "https://gitlab.com/python-discord/projects/bot"
     omdb:            "http://omdbapi.com"
     paste_service:   "https://paste.pydis.com/{key}"
+
+
+anti_spam:
+    # Clean messages that violate a rule.
+    clean_offending: true
+
+    punishment:
+        role_id: *MUTED_ROLE
+        remove_after: 600
+
+    rules:
+        attachments:
+            interval: 10
+            max: 3
+
+        burst:
+            interval: 10
+            max: 7
+
+        burst_shared:
+            interval: 10
+            max: 20
+
+        chars:
+            interval: 5
+            max: 3_000
+
+        duplicates:
+            interval: 10
+            max: 3
+
+        discord_emojis:
+            interval: 10
+            max: 6
+
+        links:
+            interval: 10
+            max: 4
+
+        mentions:
+            interval: 10
+            max: 5
+
+        newlines:
+            interval: 10
+            max: 100
+
+        role_mentions:
+            interval: 10
+            max: 3