Initial version

Timer.py

@@ -0,0 +1,48 @@
+import discord
+from discord.ext import commands, tasks
+import time
+
+class TrackTimer():
+    def __init__(self, duration, users, channel, author):
+        self.end = time.time() + duration
+        self.users = users
+        self.channel = channel
+        self.author = author
+    def __str__(self):
+        return str(self.end - time.time()) + "s remaining."
+    def valid(self):
+        return time.time() < (self.end)
+
+class Timer(commands.Cog):
+    """Timer commands."""
+    def __init__(self, bot):
+        self.bot = bot
+        self.check_timers.start()
+        self.timers = []
+
+    @tasks.loop(seconds=2.0)
+    async def check_timers(self):
+        for timer in self.timers:
+            if not timer.valid():
+                msg = "Pencils down! "
+                msg += timer.author.mention + " "
+                for user in timer.users:
+                    msg += user.mention + " "
+                await timer.channel.send(msg)
+                self.timers.remove(timer)
+
+    @commands.command(pass_context=True, hidden=False)
+    async def timer(self, ctx, minutes: int, mentions: str):
+        """Starts a timer for a given number of minutes. 
+        Tags mentioned users when timer expires.
+        Always tags the user that called this function"""
+        self.timers.append(TrackTimer(minutes*60, ctx.message.mentions, ctx.channel, ctx.author))
+        msg = "Okay "
+        for user in ctx.message.mentions:
+            msg += user.display_name + ", "
+        msg += ctx.author.display_name + "; "
+        msg += "your " + str(minutes) + " minutes start now."
+        await ctx.channel.send(msg)
+
+def setup(bot):
+    bot.add_cog(Timer(bot))