#!/usr/bin/python3

from argparse import ArgumentParser
from urllib.request import urlopen
from lxml import etree

def filter_schedule(url, ids, rooms, tracks):
    xml = urlopen(url).read()
    schedule = etree.fromstring(xml)

    for day in schedule.iter('day'):
        for room in day.iter('room'):
            for event in room.iter('event'):
                id = event.get('id')
                if ids and id not in ids:
                    continue

                room_name = room.get('name')
                if rooms and room_name not in rooms:
                    continue

                track = event.find('track').text
                if tracks and track not in tracks:
                    continue

                title = event.find('title').text

                speaker_list = None
                if event.find('persons') is not None:
                    speakers = []
                    for speaker in event.find('persons').iter('person'):
                        speakers.append(speaker.text)
                    speaker_list = ', '.join(speakers)

                yield {
                    'id': id,
                    'room': room_name,
                    'track': track,
                    'title': title,
                    'speakers': speaker_list,
                }

def main():
    parser = ArgumentParser()
    parser.add_argument('url', help='schedule url')
    parser.add_argument('--ids', nargs='+', help='select given ids')
    parser.add_argument('--rooms', nargs='+', help='select given rooms')
    parser.add_argument('--tracks', nargs='+', help='select given tracks')
    args = parser.parse_args()

    ids = args.ids or None
    rooms = args.rooms or None
    tracks = args.tracks or None
    for event in filter_schedule(args.url, ids, rooms, tracks):
        print(f"{event['id']}\t{event['title']}\t{event['speakers']}")

if __name__ == '__main__':
    main()