timetracking.py

#!/usr/bin/env python
#
# Given time-tracking data in the following CSV format
#
# Date,Begin,End,Comments
# 18.01.2013,9:00,13:00,done this
# 18.01.2013,14:00,17:00,"done that, and also that other thing"
# 12.12.2012,12:00,12:12,
#
# timetracking.py reads this data from stdin and computes total times
# per month and overall. The results are presented like this
#
# 2012/12:    0:12
# 2013/01:    7:00
# total:      7:12
#
# Limitations:
#
# * Obviously begin and end of every record must be on the same day.
# * Daylight saving is not taken into account.

import sys
import csv
from datetime import datetime
from datetime import timedelta

def delta_to_hm(delta):
    days, seconds = delta.days, delta.seconds
    hours = days * 24 + seconds // 3600
    minutes = (seconds // 60) % 60
    return hours, minutes

reader = csv.reader(sys.stdin)
next(reader) # Ignore first line

delta_sums = dict()

for row in reader:
    begin = datetime.strptime(row[0] + row[1], '%d.%m.%Y%H:%M')
    end = datetime.strptime(row[0] + row[2], '%d.%m.%Y%H:%M')
    delta = end - begin

    month = begin.year, begin.month
    delta_sums[month] = delta_sums.get(month, timedelta()) + delta

total = timedelta()
for month in sorted(delta_sums.keys()):
    delta = delta_sums[month]
    total = total + delta
    hours, minutes = delta_to_hm(delta)
    print('{}/{:02}: {:4}:{:02}'.format(month[0], month[1], hours, minutes))

total_hours, total_minutes = delta_to_hm(total)
print('total:   {:4}:{:02}'.format(total_hours, total_minutes))
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