import struct

formats = {
	'cpu': 'f',
	'mem': 'q',
	'net': 'q',
	'disk': 'q',
}

def read_stats(f):
	buf = f.read()
	stats = {}
	index = 0
	while index < len(buf):
		# read the key
		key_size = ord(buf[index])
		fmt = '%dp' % (key_size + 1)
		data = struct.unpack(fmt, buf[index:index+key_size+1])
		key = data[0]

		# get the format_code
		split = key.split('.')
		stat_group = split[0]
		format_code = formats[stat_group]

		# read the data
		fmt = '%dp 1440%s' % (key_size + 1, format_code)
		size = struct.calcsize(fmt)
		data = struct.unpack(fmt, buf[index:index+size])
		dict_insert(stats, split, data[1:])
		index += size
	return stats

def dict_insert(d, split, value):
	if len(split) > 1:
		d.setdefault(split[0], {})
		dict_insert(d[split[0]], split[1:], value)
	else:
		d[split[0]] = value

def write_datum(f, data):
	for stat_group, stats in data.items():
		if stat_group == 'client_id':
			continue
		format_code = formats[stat_group]
		for stat, datum in stats.items():
			key = '%s.%s' % (stat_group, stat)
			fmt = '%dp 1440%s' % (len(key) + 1, format_code)
			array = [-1] * 1440
			array[0] = datum
			f.write(struct.pack(fmt, key.encode('utf-8'), *array))