#!/usr/bin/env python3
"""
Reminds of things.
"""
import os
import re
from datetime import datetime, timedelta

import config
import module

regex = (
	"(?=\d+[ywdhms])"
	"(\d+y)?"
	"(\d+w)?"
	"(\d+d)?"
	"(\d+h)?"
	"(\d+m)?"
	"(\d+s)?"
)
shorthand = {
	'y': 'years',
	'w': 'weeks',
	'd': 'days',
	'h': 'hours',
	'm': 'minutes',
	's': 'seconds',
}

@module.commands('remind')
@module.example('.remind 3h45m Go to class')
def remind(bot, trigger):
	"""Gives you a reminder in the given amount of time."""
	if len(trigger.args) == 1:
		return bot.msg("Missing arguments for reminder command.")

	reg = re.search(regex, trigger.args[1])
	if not reg:
		return bot.reply("I didn't understand that.")
	args = {shorthand[g[-1]]: int(g[:-1]) for g in reg.groups() if g}
	delta = timedelta(**args)
	dt = datetime.now() + delta
	reminder = ' '.join(trigger.args[2:])
	args = (trigger.channel, trigger.nick, reminder)
	bot.scheduler.add_task(announce_reminder, dt, args)
	bot.reply("Okay, will remind at " + dt.strftime('[%Y-%m-%d %H:%M:%S]'))


@module.commands('at')
@module.example('.at 2012-12-21 18:00:00 End the world.')
def at(bot, trigger):
	"""
	Gives you a reminder at the given time and date. Datetime must be in
	YYYY-MM-DD HH:MM:SS format. Only the bot's timezone is used. If
	YYYY-MM-DD is excluded, it is assumed to be today's date.
	"""
	if len(trigger.args) < 2:
		return bot.msg("Missing arguments for reminder command.")
	if ':' in trigger.args[1]:
		at_time = datetime.now().strftime('%Y-%m-%d') + ' ' + trigger.args[1]
		reminder = ' '.join(trigger.args[2:])
	else:
		at_time = ' '.join(trigger.args[1:3])
		reminder = ' '.join(trigger.args[3:])

	try:
		dt = datetime.strptime(at_time, '%Y-%m-%d %H:%M:%S')
	except ValueError:
		return bot.msg("Datetime improperly formatted.")

	args = (trigger.channel, trigger.nick, reminder)
	bot.scheduler.add_task(announce_reminder, dt, args)
	bot.reply("Okay, will remind at " + dt.strftime('[%Y-%m-%d %H:%M:%S]'))


def announce_reminder(bot, channel, remindee, reminder):
	"""Announce the reminder."""
	if reminder:
		msg = f"{remindee}: {reminder}"
	else:
		msg = f"{remindee}!"
	bot.msg(channel, msg)