echo: New converters for arguemnts

- Created a GlobalChannelConverter
- Accepts Union[GlobalChannelConverter, UserConverter]

Fixes #145

common.py

@@ -5,19 +5,15 @@ Copyright (C) 2019-2020 Abigail Gold, 0x5c
 
 This file is part of discord-qrm2 and is released under the terms of the GNU
 General Public License, version 2.
----
-
-`colours`: Colours used by embeds.
-
-`cat`: Category names for the HelpCommand.
 """
 
 
 import collections
 import json
+import re
 import traceback
-from pathlib import Path
 from datetime import datetime
+from pathlib import Path
 from types import SimpleNamespace
 
 import discord
@@ -26,7 +22,8 @@ import discord.ext.commands as commands
 import data.options as opt
 
 
-__all__ = ["colours", "cat", "emojis", "embed_factory", "error_embed_factory", "add_react", "check_if_owner"]
+__all__ = ["colours", "cat", "emojis", "paths", "ImageMetadata", "ImagesGroup",
+           "embed_factory", "error_embed_factory", "add_react", "check_if_owner"]
 
 
 # --- Common values ---
@@ -94,6 +91,29 @@ class ImagesGroup(collections.abc.Mapping):
         return str(self._images)
 
 
+# --- Converters ---
+
+class GlobalChannelConverter(commands.IDConverter):
+    """Converter to get any bot-acessible channel by ID/mention (global), or name (in current guild only)."""
+    async def convert(self, ctx: commands.Context, argument: str):
+        bot = ctx.bot
+        guild = ctx.guild
+        match = self._get_id_match(argument) or re.match(r'<#([0-9]+)>$', argument)
+        result = None
+        if match is None:
+            # not a mention/ID
+            if guild:
+                result = discord.utils.get(guild.text_channels, name=argument)
+            else:
+                raise commands.BadArgument(f"""Channel named "{argument}" not found in this guild.""")
+        else:
+            channel_id = int(match.group(1))
+            result = bot.get_channel(channel_id)
+        if not isinstance(result, (discord.TextChannel, discord.abc.PrivateChannel)):
+            raise commands.BadArgument(f"""Channel "{argument}" not found.""")
+        return result
+
+
 # --- Helper functions ---
 
 def embed_factory(ctx: commands.Context) -> discord.Embed:

exts/base.py

@@ -7,17 +7,19 @@ This file is part of discord-qrm2 and is released under the terms of the GNU
 General Public License, version 2.
 """
 
+
+import random
 import re
 from collections import OrderedDict
-import random
+from typing import Union
 
 import discord
 import discord.ext.commands as commands
 
 import info
+import common as cmn
 
 import data.options as opt
-import common as cmn
 
 
 class QrmHelpCommand(commands.HelpCommand):
@@ -171,8 +173,13 @@ class BaseCog(commands.Cog):
 
     @commands.command(name="echo", aliases=["e"], hidden=True)
     @commands.check(cmn.check_if_owner)
-    async def _echo(self, ctx: commands.Context, channel: commands.TextChannelConverter, *, msg: str):
+    async def _echo(self, ctx: commands.Context,
-        """Send a message in a channel as qrm. Only works within a server or DM to server, not between servers."""
+                    channel: Union[cmn.GlobalChannelConverter, commands.UserConverter], *, msg: str):
+        """Send a message in a channel as qrm. Accepts channel/user IDs/mentions.
+        Channel names are current-guild only.
+        Does not work with the ID of the bot user."""
+        if isinstance(channel, discord.ClientUser):
+            raise commands.BadArgument("Can't send to the bot user!")
         await channel.send(msg)