import discord
import io
import sys

client = discord.Client()

@client.event
async def on_ready():
    print('logged in as {0.user}'.format(client), file=sys.stderr)

@client.event
async def on_message(message):
    if message.author == client.user:
        return
    if not isinstance(message.channel, discord.TextChannel):
        return
    if not (client.user in message.mentions or [client.user] in [role.members for role in message.role_mentions]):
        return

    await message.channel.send('generating channel archive...')

    with io.StringIO() as buf:
        async for m in message.channel.history(limit=None, oldest_first=True):
            buf.write('@{0.author.name}#{0.author.discriminator} {0.created_at}\n{0.clean_content}\n\n'.format(m))
        buf.seek(0)
        f = discord.File(buf, '{}_{}.txt'.format(message.channel.guild.name, message.channel.name))
        await message.channel.send('complete:', files=[f])

with open('token') as f:
    token = f.read().strip()
client.run(token)