Add a CSV to ICS helper tool

I wrote this to extract the schedule from the website of the EuroBSDCon:
https://2023.eurobsdcon.org/program/

Copy-paste the tables into a spreadsheet (like LibreOffice Calc), export
as CSV (, as delimiter, " as quote).

It expects:
- lines that start with the event type and day
- lines starting with an empty cell that lists the tracks,
- lines that start with start_time (eventually end), then each talk.

Lot of hardcoding and debug output to cleanup.

tools/csv2ics.py

@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+# Copyright 2023, François Revol <[email protected]>
+# MIT license
+#
+# csv2ics: convert a sensible schedule table to an icalendar program
+# Initially wrote for https://2023.eurobsdcon.org/program/
+
+import csv
+from datetime import datetime, timedelta
+import pytz
+import re
+import sys
+from icalendar import Calendar, Event
+
+
+# TODO: pass this as arguments
+cal_name = "EuroBSDCon 2023"
+timezone = "Europe/Lisbon"
+day_filter = "(?P<event_type>.*)s:.*\((?P<day_str>.*)\)"
+# You might need to run this with LC_TIME=C to parse English dates
+day_format = "%d %B %Y"
+time_filter = "(?P<start_time>\d{2}:\d{2})( *- *)?(?P<end_time>\d{2}:\d{2})?"
+
+with open(sys.argv[1], newline='') as csvfile:
+	reader = csv.reader(csvfile, delimiter=',', quotechar='"')
+	cal = Calendar()
+	cal.add('prodid', '-//csv2ics.py////')
+	cal.add('version', '2.0')
+	cal.add('name', cal_name)
+	cal.add('x-wr-name', cal_name)
+	cal.add('timezone-id', timezone)
+	cal.add('x-wr-timezone', timezone)
+	tzinfo = pytz.timezone(timezone)
+	day = None
+	event_type = None
+	locations = [] # aka Tracks for conferences
+	last_time = None
+	pending_events = []
+	for row in reader:
+		if len(row[0].strip()) == 0:
+			locations = row[1:]
+			# flush pending for previous day, assume 1h
+			for e in pending_events:
+				print("pending pending: %s" % e)
+				end_time = start_time + timedelta(hours=1)
+				e.add('dtend', datetime.combine(day, end_time.time(), tzinfo=tzinfo))
+				cal.add_component(e)
+			pending_events = []
+
+		m = re.match(day_filter, row[0])
+		#if len(row[0]) and row[0][0].isdigit():
+		if m is not None:
+			event_type = m.group('event_type')
+			day = datetime.strptime(m.group('day_str'), day_format)
+			print(day)
+			print(event_type)
+		#m = re.match("(?P<start_time>\d{2}:\d{2})")
+		m = re.match(time_filter, row[0])
+		if m:
+			start_time = m.group('start_time')
+			end_time = m.group('end_time') or None
+			start_time = datetime.strptime(start_time, "%H:%M")
+			#start_time = timedelta(start_time)
+			if end_time:
+				end_time = datetime.strptime(end_time, "%H:%M")
+				#end_time = timedelta(end_time)
+
+			# flush pending
+			for e in pending_events:
+				print("pending pending: %s" % e)
+				e.add('dtend', datetime.combine(day, start_time.time(), tzinfo=tzinfo))
+				cal.add_component(e)
+			pending_events = []
+			print("##%s" % str(m.groups()))
+			print("## %s %s" % (start_time, end_time))
+			for i, entry in enumerate(row[1:]):
+				# skip fields with just a NO-BREAK SPACE or BOM
+				if entry in ['\u00a0', '\uFEFF']:
+					entry = ""
+				entry = entry.strip()
+				print("#### %d %s" % (len(entry), entry))
+				if len(entry) < 1:
+					continue
+				print("## %d %s, %s" % (i, locations[i], entry))
+				lines = entry.split('\n')
+				e = Event()
+				e.add('summary', lines[0])
+				e.add('dtstart', datetime.combine(day, start_time.time(), tzinfo=tzinfo))
+				if len(lines) > 1:
+					desc = "(%s)\n" % event_type
+					desc += "\n".join(lines[1:]).strip('\n')
+					e.add('description', desc)
+				e.add('location', locations[i])
+				if end_time is None:
+					# we don't know the end time yet
+					print("pending += %s" % str(e))
+					pending_events.append(e)
+				else:
+					e.add('dtend', datetime.combine(day, end_time.time(), tzinfo=tzinfo))
+					cal.add_component(e)
+		print('|\n'.join(row))
+	for e in pending_events:
+		# Assume last events are an hour long
+		print("pending pending: %s" % e)
+		end_time = start_time + timedelta(hours=1)
+		e.add('dtend', datetime.combine(day, end_time.time(), tzinfo=tzinfo))
+		cal.add_component(e)
+
+	with open(sys.argv[2], 'wb') as icsfile:
+		icsfile.write(cal.to_ical())
+