Moved error handling into a separate cog

cogs/error.py

@@ -0,0 +1,154 @@
+# Ensō~Chan - A Multi Purpose Discord Bot That Has Everything Your Server Needs!
+# Copyright (C) 2020  Goudham Suresh
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+import string
+
+from discord import Forbidden, Embed
+from discord.ext import commands
+from discord.ext.commands import Cog
+
+
+async def send_error(ctx, perms, embed):
+    """
+    Sending error message to the user
+    Only send error message if the channel permissions allow it
+    """
+
+    if perms.send_messages and perms.embed_links:
+        await ctx.send(embed=embed)
+    else:
+        print("Error: Error Handling Message Could Not Be Sent")
+
+
+async def on_bot_forbidden(ctx, perms, args2):
+    """Handles Missing Bot Permissions Errors"""
+
+    # Convert list into string of the missing permissions
+    missing_perms = string.capwords(", ".join(args2.missing_perms).replace("_", " "))
+
+    embed = Embed(description=f"❌ I Need **{missing_perms}** Permission(s) to Execute This Command! ❌",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+async def on_command_forbidden(ctx, perms):
+    """Handles Forbidden Error"""
+
+    embed = Embed(description="**❌ I Don't Have Permissions To Execute This Command ❌**",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+async def on_command_bad_argument(ctx, perms):
+    """Handles Bad Argument Errors (Argument can't be read properly)"""
+
+    embed = Embed(description="**❌ Uh oh! Couldn't find anyone to mention! Try again! ❌**",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+async def on_command_not_found(ctx, perms):
+    """Handles the command not found error"""
+
+    embed = Embed(description=f"Command Not Found! ❌ Please use **{ctx.prefix}help** to see all commands",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+async def on_command_cooldown(ctx, perms, error):
+    """Handles Cooldown Errors"""
+
+    embed = Embed(description=f"That command is on cooldown. Try again in **{error.retry_after:,.2f}** seconds",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+async def on_command_permission(ctx, perms, args2):
+    """Handles User Missing Permissions Errors"""
+
+    # Convert list into string of the missing permissions
+    missing_perms = string.capwords(", ".join(args2.missing_perms).replace("_", " "))
+
+    embed = Embed(description=f"❌ Uh oh! You Need **{missing_perms}** Permission(s) To Execute This Command! ❌",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+async def on_command_missing_argument(ctx, perms):
+    """Handles the missing argument error"""
+
+    embed = Embed(description="Required Argument(s) Missing!"
+                              f"\nUse **{ctx.prefix}help** to find how to use **{ctx.command}**",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+async def on_not_owner(ctx, perms):
+    """Handles the error when the user is not the owner and tries to invoke owner only command"""
+
+    embed = Embed(description="**❌ Owner Only Command ❌**",
+                  colour=ctx.bot.admin_colour)
+
+    await send_error(ctx, perms, embed)
+
+
+class Errors(Cog):
+    """Moderation Commands! (Kick/Ban/Mute etc)"""
+
+    def __init__(self, bot):
+        self.bot = bot
+
+    @Cog.listener()
+    async def on_command_error(self, ctx, args2):
+        """Event to detect and handle errors"""
+
+        # Get permissions for the bot within
+        perms = ctx.guild.me.permissions_in(ctx.message.channel)
+
+        # if the user did not specify an user
+        if isinstance(args2, commands.MissingRequiredArgument):
+            await on_command_missing_argument(ctx, perms)
+        # if the user has spammed a command and invoked a cooldown
+        elif isinstance(args2, commands.CommandOnCooldown):
+            await on_command_cooldown(ctx, perms, args2)
+        # if the user tries to access a command that isn't available
+        elif isinstance(args2, commands.CommandNotFound):
+            await on_command_not_found(ctx, perms)
+        # if the user provides an argument that isn't recognised
+        elif isinstance(args2, commands.BadArgument):
+            await on_command_bad_argument(ctx, perms)
+        # if the user does not the correct permissions to call a command
+        elif isinstance(args2, commands.MissingPermissions):
+            await on_command_permission(ctx, perms, args2)
+        # if the bot is missing permissions needed
+        elif isinstance(args2, commands.BotMissingPermissions):
+            await on_bot_forbidden(ctx, perms, args2)
+        # if the bot is forbidden from performing the command
+        elif isinstance(args2, Forbidden):
+            await on_command_forbidden(ctx, perms)
+        # if the user tries to invoke a command that is only for the owner
+        elif isinstance(args2, commands.NotOwner):
+            await on_not_owner(ctx, perms)
+
+
+def setup(bot):
+    bot.add_cog(Errors(bot))