from collections import ChainMap

from icalevents import icalevents
import sys
from httplib2 import Http
from datetime import datetime, timedelta
import SQLConnectionHandler


def crawl():
	if sys.platform == 'win32':
		http = Http(disable_ssl_certificate_validation=True)
	else:
		http = Http()

	#    ______     __                                                __
	#   / ____/__  / /_   ____  ___ _      __   ___ _   _____  ____  / /______
	#  / / __/ _ \/ __/  / __ \/ _ \ | /| / /  / _ \ | / / _ \/ __ \/ __/ ___/
	# / /_/ /  __/ /_   / / / /  __/ |/ |/ /  /  __/ |/ /  __/ / / / /_(__  )
	# \____/\___/\__/  /_/ /_/\___/|__/|__/   \___/|___/\___/_/ /_/\__/____/

	# Get events in the next year from RaPla
	try:
		events = icalevents.events(
			url='https://rapla.dhbw-karlsruhe.de/rapla?page=ical&user=eisenbiegler&file=TINF19B4',
			http=http, start=datetime.strptime('2010-01-01', '%Y-%m-%d'),
			end=datetime.strptime((datetime.now() + timedelta(days=365)).strftime('%Y-%m-%d'), '%Y-%m-%d'))
	except ValueError as error:
		# Value error sometimes happens because of a problem with dateutil and timezones
		exit(1)

	#    ______     __     __      __            __         __      __           ____                        _____ ____    __
	#   / ____/__  / /_   / /___ _/ /____  _____/ /_   ____/ /___ _/ /_____ _   / __/________  ____ ___     / ___// __ \  / /
	#  / / __/ _ \/ __/  / / __ `/ __/ _ \/ ___/ __/  / __  / __ `/ __/ __ `/  / /_/ ___/ __ \/ __ `__ \    \__ \/ / / / / /
	# / /_/ /  __/ /_   / / /_/ / /_/  __(__  ) /_   / /_/ / /_/ / /_/ /_/ /  / __/ /  / /_/ / / / / / /   ___/ / /_/ / / /___
	# \____/\___/\__/  /_/\__,_/\__/\___/____/\__/   \__,_/\__,_/\__/\__,_/  /_/ /_/   \____/_/ /_/ /_/   /____/\___\_\/_____/

	# Select existing event UIDs from RaPla
	conn = SQLConnectionHandler.getConnection()
	cur = conn.cursor()
	cur.execute("SELECT uid FROM rapla_entries")
	uids = cur.fetchall()
	uids = list(x[0] for x in uids)  # Otherwise, uids would be a list of tuples
	cur.execute("""
		WITH summary AS (
			SELECT ch.*,
				   ROW_NUMBER() OVER(PARTITION BY ch.entry_id
										 ORDER BY ch.change_id DESC) AS rk
			  FROM rapla_changes ch)
		SELECT s.*, entr.uid
		FROM summary s
		LEFT OUTER JOIN rapla_entries entr ON s.entry_id = entr.entry_id
		WHERE s.rk = 1;
	""")
	changes = cur.fetchall()

	#     ____                                         __      __
	#    / __ \________  ____  ____ _________     ____/ /___ _/ /_____ _
	#   / /_/ / ___/ _ \/ __ \/ __ `/ ___/ _ \   / __  / __ `/ __/ __ `/
	#  / ____/ /  /  __/ /_/ / /_/ / /  /  __/  / /_/ / /_/ / /_/ /_/ /
	# /_/   /_/   \___/ .___/\__,_/_/   \___/   \__,_/\__,_/\__/\__,_/
	#                /_/

	# The following function simply creates a dict with the event uid as key and all other info as value from the tuples
	# Say we have the list of tuples [(1, 'abc'), (2, 'def')] where abc and def are the uids. The the function would generate
	# a dict in the form of {'abc': (1, 'abc'), 'def': (1, 'def')}
	# The map function basically returns a list of small dicts and the ChainMap combines them to one big dict
	changeDict = dict(ChainMap(*map(lambda x: {x[15]: x}, changes)))

	# Change booleans back to boolean values as they come from SQL as integers
	for change in changeDict:
		workingList = list(changeDict[change])
		workingList[13] = changeDict[change][13] == 1
		workingList[3] = changeDict[change][3] == 1
		changeDict[change] = tuple(workingList)

	newEvents = []
	updatedEvents = []

	# Append number of recurring event to UID so we can tell them apart
	# Also removes the timezone from all the datetime objects
	evtIdx = {}
	for event in events:
		if not event.uid in evtIdx.keys():
			# Event not known yet
			uid = event.uid
			event.uid = uid + '---0'
			evtIdx[uid] = 1
		else:
			uid = event.uid
			event.uid = uid + '---' + str(evtIdx[uid])
			evtIdx[uid] += 1
		# Remove timezones
		event.start = removeTimezone(event.start)
		event.end = removeTimezone(event.end)
		event.last_modified = removeTimezone(event.last_modified)
		event.created = removeTimezone(event.created)

	#    ________              __      ____                   __
	#   / ____/ /_  ___  _____/ /__   / __/___  _____   _____/ /_  ____ _____  ____ ____  _____
	#  / /   / __ \/ _ \/ ___/ //_/  / /_/ __ \/ ___/  / ___/ __ \/ __ `/ __ \/ __ `/ _ \/ ___/
	# / /___/ / / /  __/ /__/ ,<    / __/ /_/ / /     / /__/ / / / /_/ / / / / /_/ /  __(__  )
	# \____/_/ /_/\___/\___/_/|_|  /_/  \____/_/      \___/_/ /_/\__,_/_/ /_/\__, /\___/____/
	#                                                                       /____/

	for event in events:
		if not event.uid in uids:
			# New event, create event entry and new changeset
			if not event.uid in list(x.get('uid') for x in newEvents):
				# Only add to list if this event is not in the list yet (can happen in case of recurring events)
				evt = {
					# TODO add checks for existing values
					"uid": event.uid,
					"isDeleted": False,
					"new_summary": event.summary,
					"new_description": event.description,
					"new_start": event.start,
					"new_end": event.end,
					"new_last_modified": event.last_modified,
					"new_created": event.created,
					"new_location": event.location,
					"new_organizer": event.organizer,
					"new_categories": event.categories[0] if event.categories else '',
					"new_recurring": event.recurring
				}
				newEvents.append(evt)
		else:
			# Event is known, create new changeset
			hasChanges = False
			latestKnownState = changeDict.get(event.uid)
			changeSet = latestKnownState[4:14]  # Relevant subset of latest know state data
			newEventTuple = tuple(
				[event.summary, event.description, event.start, event.end, event.last_modified, event.created,
				 event.location, event.organizer, (event.categories[0] if event.categories else ''), event.recurring,
				 event.uid])

			# Check every value by looping over both the old and new tuples
			for dataIndex in range(0, 10):
				if newEventTuple[dataIndex] != changeSet[dataIndex]:
					hasChanges = True

			if hasChanges:
				updatedEvents.append(newEventTuple)

	# Now also check for deleted events
	deletedEvents = []
	for uid in uids:
		# We have to check for every known uid if it still exists
		# The following condition my be a bit overwhelming but it basically checks three things:
		#	1. Is the uid in SQL but not in the list of fetched events? -> Has been deleted from RaPla?
		#	2. If there is already a changeset for this event, is the latest known state that it is not deleted?
		#	3. If there is no changeset for it yet, we can't check the latest known state so we just set it to deleted
		#		-> this basically can't ever happen with real data but it happened during testing and it doesn't hurt to let in in here
		if uid not in list(x.uid for x in events) and (
				uid in changeDict.keys() and not changeDict[uid][3] or uid not in changeDict.keys()):
			# Only insert if there is no 'deleted' record yet
			deletedEvents.append(tuple([uid]))

	#  _       __     _ __          __               __      __           _____ ____    __
	# | |     / /____(_) /____     / /_  ____ ______/ /__   / /_____     / ___// __ \  / /
	# | | /| / / ___/ / __/ _ \   / __ \/ __ `/ ___/ //_/  / __/ __ \    \__ \/ / / / / /
	# | |/ |/ / /  / / /_/  __/  / /_/ / /_/ / /__/ ,<    / /_/ /_/ /   ___/ / /_/ / / /___
	#  __/|__/_/  /_/\__/\___/  /_.___/\__,_/\___/_/|_|   \__/\____/   /____/\___\_\/_____/

	# Insert new events into rapla_entries table
	if newEvents:
		# Insert new events if there are any
		cur.executemany("INSERT INTO rapla_entries (uid, initialSummary) VALUES (%s, %s)",
						list((x.get('uid'), x.get('new_summary')) for x in newEvents))
		conn.commit()
		changeData = list(
			(x.get('isDeleted'), x.get('new_summary'), x.get('new_description'), x.get('new_start'), x.get('new_end'),
			 x.get('new_last_modified'),
			 x.get('new_created'), x.get('new_location'), x.get('new_organizer'), x.get('new_categories'),
			 x.get('new_recurring'), x.get('uid')
			 ) for x in newEvents)
		changeQuery = """
			INSERT INTO rapla_changes
			(isDeleted, new_summary, new_description, new_start, new_end, new_last_modified, new_created, new_location, new_organizer, new_categories, new_recurring, entry_id)
			VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, (SELECT entry_id FROM rapla_entries WHERE uid = %s))
		"""
		cur.executemany(changeQuery, changeData)
		conn.commit()

	if updatedEvents:
		# Insert changes to existing events if there are any
		changeQuery = """
			INSERT INTO rapla_changes
			(isDeleted, new_summary, new_description, new_start, new_end, new_last_modified, new_created, new_location, new_organizer, new_categories, new_recurring, entry_id)
			VALUES (False, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, (SELECT entry_id FROM rapla_entries WHERE uid = %s))
		"""
		cur.executemany(changeQuery, updatedEvents)
		conn.commit()

	if deletedEvents:
		cur.executemany(
			"INSERT INTO rapla_changes (entry_id, isDeleted) VALUES ((SELECT entry_id FROM rapla_entries WHERE uid = %s), 1)",
			deletedEvents)
		conn.commit()

	cur.close()
	conn.close()


def removeTimezone(date: datetime) -> datetime:
	"""
	Removes the timezone part of a datetime object
	:param date: The datetime object to adjust
	:return: The adjusted object
	"""
	return datetime.strptime(date.strftime('%Y-%m-%d %H:%M:%S'), '%Y-%m-%d %H:%M:%S')


if __name__ == "__main__":
	crawl()