Add protection against user typos or wrong commands (#880)

* add protection against user typos or wrong commands

* black refactoring

discordbot/discordbot.py

@@ -1,5 +1,6 @@
 import os
 import sys
+import difflib
 import discord
 import discord_components
 import pyimgur
@@ -15,6 +16,12 @@ gst_bot = discord.ext.commands.Bot(
 )
 discord_components.DiscordComponents(gst_bot)
 
+if cfg.IMGUR_CLIENT_ID == "REPLACE_ME" or cfg.DISCORD_BOT_TOKEN == "REPLACE_ME":
+    print(
+        f"Update IMGUR_CLIENT_ID or DISCORD_BOT_TOKEN or both in { os.path.join('discordbot', 'config_discordot') } \n"
+    )
+    sys.exit()
+
 
 async def on_ready():
     print("GST Discord Bot Ready to Gamestonk!")
@@ -27,11 +34,28 @@ gst_bot.load_extension("generic_commands")
 gst_bot.load_extension("economy.economy_menu")
 gst_bot.load_extension("stocks.dark_pool_shorts.dps_menu")
 
-if cfg.IMGUR_CLIENT_ID == "REPLACE_ME" or cfg.DISCORD_BOT_TOKEN == "REPLACE_ME":
-    print(
-        f"Update IMGUR_CLIENT_ID or DISCORD_BOT_TOKEN or both in { os.path.join('discordbot', 'config_discordot') } \n"
-    )
-    sys.exit()
+# Get all command names
+all_cmds = gst_bot.all_commands.keys()
+
+# In case the user inserts a wrong command we check for similarity with
+# available commands, and if there is we suggest one, otherwise we
+# report list of all commands available
+
+
+@gst_bot.event
+async def on_command_error(ctx, error):
+    if isinstance(error, discord.ext.commands.CommandNotFound):
+        cmd = str(error).split('"')[1]
+        similar_cmd = difflib.get_close_matches(cmd, all_cmds, n=1, cutoff=0.7)
+
+        if similar_cmd:
+            error_help = f"Did you mean '**!{similar_cmd[0]}**'?"
+        else:
+            # TODO: This can be improved by triggering help menu
+            error_help = f"**Possible commands are:** {', '.join(all_cmds)}"
+
+        await ctx.send(f"_{error}_\n{error_help}\n")
+
 
 # Runs the bot
 gst_bot.run(cfg.DISCORD_BOT_TOKEN)