add ?invite command

fixes #356

CHANGELOG.md

@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - The ability to answer ❓ to a HamStudy question to get the answer.
 - The list of available prefixes to `?help` when there is more than one.
 - `?donate` command to show ways to support qrm's development.
+- `?invite` command to invite qrm to your server.
 ### Changed
 - New colour theme for `?greyline`.
 - Moved great circle distance and bearing calculation from `?ungrid` to `?griddistance`.

exts/base.py

@@ -125,6 +125,8 @@ class BaseCog(commands.Cog):
             "Ko-Fi": "https://ko-fi.com/miaowware",
             "LiberaPay": "https://liberapay.com/miaowware",
         }
+        self.bot_invite = (f"https://discordapp.com/oauth2/authorize?client_id={self.bot.user.id}"
+                           f"&scope=bot&permissions={opt.invite_perms}")
 
     @commands.command(name="info", aliases=["about"])
     async def _info(self, ctx: commands.Context):
@@ -212,6 +214,14 @@ class BaseCog(commands.Cog):
             embed.add_field(name=title, value=url, inline=False)
         await ctx.send(embed=embed)
 
+    @commands.command(name="invite", enabled=opt.enable_invite_cmd)
+    async def _invite(self, ctx: commands.Context):
+        """Generates a link to invite the bot to a server."""
+        embed = cmn.embed_factory(ctx)
+        embed.title = "Invite qrm to Your Server!"
+        embed.description = self.bot_invite
+        await ctx.send(embed=embed)
+
     @commands.command(name="echo", aliases=["e"], category=cmn.cat.admin)
     @commands.check(cmn.check_if_owner)
     async def _echo(self, ctx: commands.Context,

templates/data/options.py

@@ -46,6 +46,12 @@ exts = [
     "propagation",
 ]
 
+# enable a command that provides a link to add the bot to a server
+enable_invite_cmd = True
+
+# the default permissions for the bot, to be included in the invite link for ?invite
+# this probably does not need to be changed
+invite_perms = 67488832
 
 # Either "time", "random", or "fixed" (first item in statuses)
 status_mode = "fixed"