from datetime import datetime
from pytz import utc

# scale down coordinates to dx=1 per day to prevent SVG coordinate overflows
scale = 1/60/60/24

def get_date(dtime):
    return datetime.fromtimestamp(dtime).astimezone(utc).strftime('%Y-%m-%d %H:%M')


def make_line(event):
    evstart = event['period'][0]
    evstop = event['period'][1]
    return '<line{type} x1="{start}" x2="{stop}" y1="{height}" y2="{height}"><title>{text} ({start_date} — {stop_date})</title></line>'.format(
        type = '' if event['status'] == 'online' else ' class="error"',
        start = scale*evstart,
        stop = scale*evstop,
        start_date = get_date(evstart),
        stop_date = get_date(evstop),
        height = len(event['players']) if 'players' in event else 0,
        text = ('no one' if len(event['players']) == 0 else ', '.join(event['players'])) if event['status'] == 'online' else event['status']
    )