timetable.py

from server import *

def get_monday(day):
	return day-timedelta(days=day.weekday())

def get_week_offset(value):
	if value is None:
		return 0
	day = None
	for pattern in ['%d-%m-%Y-1', '%Y-W%W-%w']:
		try:
			day = datetime.strptime(value+'-1', pattern)
		except ValueError:
			pass
		if day is not None:
			break
	if day is None:
		return 0
	return int((get_monday(day) - get_monday(datetime.now())).days/7)

def query_lectures_on_day(start, end):
	# What we want to match:
	#  lecture.time <= end AND lecture.time+lecture.duration >= start
	# But there is no SQL statement that does this and is compatible with both sqlite
	# and mysql, so we approximate the "lecture.time+lecture.duration" part
	rows = query('''SELECT lectures.*, courses.short, "course" AS sep, courses.*
		FROM lectures 
		JOIN courses ON (lectures.course_id = courses.id) 
		WHERE time <= ? AND time > ?
		ORDER BY time ASC''', end, start-timedelta(weeks=2))
	lectures = []
	for lecture in rows:
		if lecture['time']+timedelta(minutes=lecture['duration']) >= start:
			lectures.append(lecture)
	return lectures

'''Use a sweepline algorithm to find overlapping lectures

For each day the item 'maxcol' will be the number of columns required to display
the overlapping lectures. For each lecture the item 'timetable_col' will be the
index of the column the lecture is going to be rendered in.'''
def timetable_sweepline(days):
	earliest_start = time(23, 59)
	latest_end = time(0, 0)
	for day in days:
		sweeplinetupels = [(lecture['time'].time(), True, lecture) for lecture in day['lectures']]
		sweeplinetupels += [(lecture['time_end'].time(), False, lecture) for lecture in day['lectures']]
		maxcol = 0
		curcol = 0
		freecol = []
		sweeplinetupels.sort(key=lambda row: row[:2])
		for timestamp, is_start, lecture in sweeplinetupels:
			if is_start:
				curcol += 1
				maxcol = max(maxcol, curcol)
				if freecol:
					lecture['timetable_col'] = freecol.pop()
				else:
					lecture['timetable_col'] = maxcol
				earliest_start = min(earliest_start, timestamp)
			else:
				curcol -= 1
				freecol.append(lecture['timetable_col'])
				latest_end = max(latest_end, timestamp)
		day['maxcol'] = max(maxcol, 1)
	return earliest_start, latest_end

@register_navbar('personalisierter Drehplan', icon='calendar', userendpoint=True, endpoint='timetable_user')
@register_navbar('Drehplan', icon='calendar')
@app.route('/internal/timetable')
@app.route('/internal/user/<int:user>/timetable', endpoint='timetable_user')
@mod_required
def timetable(user=None):
	if 'kw' in request.args:
		week_offset = int(request.args['kw'])
	else:
		week_offset = get_week_offset(request.args.get('date', None))
	start_day = date.today() - timedelta(days=date.today().weekday() - 7*week_offset)
	days = [{'date': start_day, 'lectures': [], 'atonce': 0, 'index': 0}]
	for i in range(1, 7):
		days.append({'date': days[i-1]['date'] + timedelta(days=1), 'atonce': 0, 'index': i, 'lectures': []})
	for day in days:
		start = datetime.combine(day['date'], time(0, 0))
		end = datetime.combine(day['date'], time(23, 59))
		day['lectures'] = []
		for lecture in query_lectures_on_day(start, end):
			lecture['time_end'] = lecture['time']+timedelta(minutes=lecture['duration'])
			# "Crop" lecture's timespan to start/end of day
			lecture['time'] = max(start, lecture['time'])
			lecture['time_end'] = min(end, lecture['time_end'])
			# Ensure length > 0
			lecture['time_end'] = max(lecture['time_end'], lecture['time']+timedelta(minutes=1))
			lecture['duration'] = int((lecture['time_end'] - lecture['time']).total_seconds()/60)
			# Filter on responsible user if a user parameter was given
			lecture['responsible'] = query('''SELECT users.*
					FROM responsible
					JOIN users ON (responsible.user_id = users.id AND responsible.course_id = ?)
					ORDER BY users.realname ASC''', lecture['course_id'])
			if len(lecture['responsible']) == 0:
				lecture['responsible'] = [{"realname": "Niemand", "id": -1}]
			if not user or user in [r['id'] for r in lecture['responsible']]:
				day['lectures'].append(lecture)
	earliest_start, latest_end = timetable_sweepline(days)
	start = min(earliest_start, time(8, 0))
	end = max(latest_end, time(19, 0))
	blocks = []
	for i in range(start.hour*4, min(int((60*end.hour/15)/4)*4+5, 24*4)):
		timestamp = i*15
		blocks.append(time(int(timestamp/60), timestamp%60))
	weekofyear = '{}-W{:02d}'.format(datetime.today().year, datetime.today().isocalendar()[1])
	return render_template('timetable.html',
			days=days,
			blocks=blocks,
			kw=week_offset,
			weekofyear=weekofyear,
			user=query('SELECT * FROM users WHERE id = ?', user)[0] if user else None)