#!/usr/bin/env python3
"""
Reminds of things.
"""
import os
import re
import time
import sqlite3
import datetime
import threading
import collections

from module import commands, example

class MonitorThread(threading.Thread):
	"""
	A custom custom thread class for monitoring the time to announce
	reminders. It allows itself to be stopped when there are no reminders
	to look for.
	"""
	def __init__(self, bot):
		threading.Thread.__init__(self)
		self._bot = bot
		self.stop = threading.Event()

	def run(self):
		# while not self._bot.channels.keys():
		while not self._bot.stillConnected():
			time.sleep(1)
			# don't try to say anything if we're not fully connected yet
		while not self.stop.is_set():
			now = int(time.time())
			unixtimes = [int(key) for key in self._bot.memory["remind"].keys()]
			oldtimes = [t for t in unixtimes if t <= now]
			if oldtimes:
				for oldtime in oldtimes:
					for reminder in self._bot.memory["remind"][oldtime]:
						channel, nick, message = reminder
						if message:
							self._bot.msg(channel, nick + ': ' + message)
						else:
							self._bot.msg(channel, nick + '!')
					del self._bot.memory["remind"][oldtime]
					delete_reminder(self._bot, oldtime)
			if not self._bot.memory["remind"] or not self._bot.stillConnected():
				self.stop.set()
			self.stop.wait(2.5)
		del self._bot.memory["remind_monitor"]


def start_monitor(bot):
	"""
	Starts the monitor thread. Does nothing if one is already running.
	"""
	if bot.memory.get("remind_monitor"):
		return
	t = MonitorThread(bot)
	t.start()
	bot.memory["remind_monitor"] = t


def load_database(bot):
	"""
	Loads all entries from the 'remind' table in the bot's database and
	stores them in memory
	"""
	data = {}
	reminds = bot.db.execute("SELECT * FROM remind").fetchall()

	for remind in reminds:
		unixtime, channel, nick, message = remind
		reminder = (channel, nick, message)
		try:
			data[unixtime].append(reminder)
		except KeyError:
			data[unixtime] = [reminder]
	return data


def insert_reminder(bot, unixtime, reminder):
	"""
	Inserts a new reminder into the 'remind' table in the bot's database.
	reminder - a tuple containing (channel, nick, message)
	"""
	bot.db.execute("INSERT INTO remind (unixtime, channel, nick, message) "
		"VALUES(?,?,?,?)", (unixtime,) + reminder)


def delete_reminder(bot, unixtime):
	"""
	Deletes a reminder from the 'remind' table in the bot's database, using
	unixtime as the key.
	"""
	bot.db.execute("DELETE FROM remind WHERE unixtime = ?", (unixtime,))


def setup(bot):
	con = bot.db.connect()
	cur = con.cursor()
	try:
		cur.execute("SELECT * FROM remind").fetchone()
	except sqlite3.OperationalError:
		cur.execute("CREATE TABLE remind("
			"unixtime INTEGER DEFAULT (STRFTIME('%s', 'now')),"
			"channel TEXT,"
			"nick TEXT,"
			"message TEXT)")
		con.commit()
	con.close()
	bot.memory["remind"] = load_database(bot)
	start_monitor(bot)


scaling = collections.OrderedDict([
	('years', 365.25 * 24 * 3600),
	('year', 365.25 * 24 * 3600),
	('yrs', 365.25 * 24 * 3600),
	('y', 365.25 * 24 * 3600),

	('months', 29.53059 * 24 * 3600),
	('month', 29.53059 * 24 * 3600),
	('mo', 29.53059 * 24 * 3600),

	('weeks', 7 * 24 * 3600),
	('week', 7 * 24 * 3600),
	('wks', 7 * 24 * 3600),
	('wk', 7 * 24 * 3600),
	('w', 7 * 24 * 3600),

	('days', 24 * 3600),
	('day', 24 * 3600),
	('d', 24 * 3600),

	('hours', 3600),
	('hour', 3600),
	('hrs', 3600),
	('hr', 3600),
	('h', 3600),

	('minutes', 60),
	('minute', 60),
	('mins', 60),
	('min', 60),
	('m', 60),

	('seconds', 1),
	('second', 1),
	('secs', 1),
	('sec', 1),
	('s', 1),
])

periods = '|'.join(scaling.keys())


@commands('remind')
@example('.remind 3h45m Go to class')
def remind(bot, trigger):
	"""Gives you a reminder in the given amount of time."""
	if not trigger.group(2):
		return bot.msg("Missing arguments for reminder command.")
	if trigger.group(3) and not trigger.group(4):
		return bot.msg("No message given for reminder.")

	duration = 0
	message = filter(None, re.split(f"(\d+(?:\.\d+)? ?(?:(?i) {periods})) ?",
									trigger.group(2))[1:])
	reminder = ''
	stop = False
	for piece in message:
		grp = re.match('(\d+(?:\.\d+)?) ?(.*) ?', piece)
		if grp and not stop:
			length = float(grp.group(1))
			factor = scaling.get(grp.group(2).lower(), 60)
			duration += length * factor
		else:
			reminder = reminder + piece
			stop = True
	if duration == 0:
		return bot.reply("Sorry, didn't understand the input.")

	if duration % 1:
		duration = int(duration) + 1
	else:
		duration = int(duration)
	create_reminder(bot, trigger, duration, reminder)


@commands('at')
@example('.at 13:47 Do your homework!')
@example('.at 16:30UTC-5 Do cocaine')
@example('.at 14:45:45 Remove dick from oven')
def at(bot, trigger):
	"""
	Gives you a reminder at the given time. Takes hh:mm:ssUTC+/-##
	message. Timezone, if provided, must be in UTC format. 24 hour
	clock format only.
	"""
	if not trigger.group(2):
		return bot.msg("No arguments given for reminder command.")
	if trigger.group(3) and not trigger.group(4):
		return bot.msg("No message given for reminder.")

	regex = re.compile(r"(\d+):(\d+)(?::(\d+))?(?:UTC([+-]\d+))? (.*)")
	match = regex.match(trigger.group(2))
	if not match:
		return bot.reply("Sorry, but I didn't understand your input.")

	hour, minute, second, tz, message = match.groups()
	if not second:
		second = '0'

	if tz:
		try:
			tz = int(tz.replace("UTC", ""))
		except ValueError:
			bot.msg("Invalid timezone. Using the bot's current timezone.")
			tz = None

	if tz:
		timezone = datetime.timezone(datetime.timedelta(hours=tz))
	else:
		timezone = datetime.datetime.now().astimezone().tzinfo
		# current timezone the bot is in

	now = datetime.datetime.now(timezone)
	at_time = datetime.datetime(now.year, now.month, now.day,
					   int(hour), int(minute), int(second),
					   tzinfo=timezone)
	timediff = at_time - now

	duration = timediff.seconds

	if duration < 0:
		duration += 86400
	create_reminder(bot, trigger, duration, message)


def create_reminder(bot, trigger, duration, message):
	"""
	Inserts the reminder into the bot's memory and database so it can
	eventually announce for it.
	"""
	t = int(time.time()) + duration
	reminder = (trigger.channel, trigger.nick, message)
	try:
		bot.memory["remind"][t].append(reminder)
	except KeyError:
		bot.memory["remind"][t] = [reminder]
	start_monitor(bot)
	insert_reminder(bot, t, reminder)

	if duration >= 60:
		remind_at = datetime.datetime.fromtimestamp(t)
		t_format = bot.config.core.default_time_format
		timef = datetime.datetime.strftime(remind_at, t_format)

		bot.reply('Okay, will remind at %s' % timef)
	else:
		bot.reply('Okay, will remind in %s secs' % duration)