Feature: suggest command usage for misspell commands

1 files changed, 35 insertions, 0 deletions

diff --git a/bot/exts/evergreen/error_handler.py b/bot/exts/evergreen/error_handler.py
index 28902503..d5069168 100644
--- a/bot/exts/evergreen/error_handler.py
+++ b/bot/exts/evergreen/error_handler.py
@@ -1,3 +1,4 @@
+import difflib
 import logging
 import math
 import random
@@ -5,6 +6,7 @@ from typing import Iterable, Union
 
 from discord import Embed, Message
 from discord.ext import commands
+from discord.ext.commands import errors
 from sentry_sdk import push_scope
 
 from bot.constants import Channels, Colours, ERROR_REPLIES, NEGATIVE_REPLIES
@@ -14,6 +16,9 @@ from bot.utils.exceptions import UserNotPlayingError
 log = logging.getLogger(__name__)
 
 
+QUESTION_MARK_ICON = "https://cdn.discordapp.com/emojis/512367613339369475.png"
+
+
 class CommandErrorHandler(commands.Cog):
     """A error handler for the PythonDiscord server."""
 
@@ -55,6 +60,7 @@ class CommandErrorHandler(commands.Cog):
         )
 
         if isinstance(error, commands.CommandNotFound):
+            await self.send_command_suggestion(ctx, ctx.invoked_with)
             return
 
         if isinstance(error, (InChannelCheckFailure, InMonthCheckFailure)):
@@ -128,6 +134,35 @@ class CommandErrorHandler(commands.Cog):
 
             log.exception(f"Unhandled command error: {str(error)}", exc_info=error)
 
+    async def send_command_suggestion(self, ctx: commands.Context, command_name: str) -> None:
+        """Sends user similar commands if any can be found."""
+        raw_commands = []
+        for cmd in self.bot.walk_commands():
+            if not cmd.hidden:
+                raw_commands += (cmd.name, *cmd.aliases)
+        if similar_command_data := difflib.get_close_matches(command_name, raw_commands, 1):
+            similar_command_name = similar_command_data[0]
+            similar_command = self.bot.get_command(similar_command_name)
+
+            if not similar_command:
+                return
+
+            log_msg = "Cancelling attempt to suggest a command due to failed checks."
+            try:
+                if not await similar_command.can_run(ctx):
+                    log.debug(log_msg)
+                    return
+            except errors.CommandError as cmd_error:
+                log.debug(log_msg)
+                await self.on_command_error(ctx, cmd_error)
+                return
+
+            misspelled_content = ctx.message.content
+            e = Embed()
+            e.set_author(name="Did you mean:", icon_url=QUESTION_MARK_ICON)
+            e.description = f"{misspelled_content.replace(command_name, similar_command_name, 1)}"
+            await ctx.send(embed=e, delete_after=10.0)
+
 
 def setup(bot: commands.Bot) -> None:
     """Error handler Cog load."""