source: stamper/bin/time_sum@ 74:2290b564b51e

#!/usr/bin/env python

import sys
import time

TIME_FORMAT= "%H:%M"
HOURS_DAY = 8
SECS_DAY = HOURS_DAY * 60 * 60

def usage(name):
    msg = """
time_sum.py: Sum dates in proper hour time

Params: Worked hours
Syntax: $ ./time_sum 6:45 13:48 12:44 8:28 14:43
56:28 min. = 7 days, remaining: 0:28 (8 hours/day)
"""
    print(msg)
    exit(1)

def isTimeFormat(input):
    try:
        time.strptime(input, TIME_FORMAT)
        return True
    except ValueError:
        return False


if __name__ == '__main__':

    totalSecs = 0
    for param in sys.argv[1:]:
        if not isTimeFormat(param):
            print("Invalid hour format: %s" % param)
            help()
            exit(1)
        timeParts = [int(s) for s in param.split(':')]
        totalSecs += (timeParts[0] * 60 + timeParts[1]) * 60

    totalDays, remaining = divmod(totalSecs, SECS_DAY)
    remainingMin, remainingSec = divmod(remaining, (60))
    remainingHr, remainingMin = divmod(remainingMin, (60))

    totalSecs, sec = divmod(totalSecs, 60)
    hr, min = divmod(totalSecs, 60)
    print "%d:%02d hours. = %d days, remaining: %d:%02d (%d hours/day)" % (
        hr, min, totalDays, remainingHr, remainingMin, HOURS_DAY)