cli/timesince.py

#
# Copyright (c) 2011,2012,2013 Big Switch Networks, Inc.
#
# Licensed under the Eclipse Public License, Version 1.0 (the
# "License"); you may not use this file except in compliance with the
# License. You may obtain a copy of the License at
#
#      http://www.eclipse.org/legal/epl-v10.html
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied. See the License for the specific language governing
# permissions and limitations under the License.
#

import datetime

def ungettext(a,b,count):
    if count > 1: # plural
        return b
    return a

def ugettext(a):
    return a

def timesince_sec(since):
    chunks = (
      (60 * 60 * 24 * 365, lambda n: ungettext('year', 'years', n)),
      (60 * 60 * 24 * 30, lambda n: ungettext('month', 'months', n)),
      (60 * 60 * 24 * 7, lambda n : ungettext('week', 'weeks', n)),
      (60 * 60 * 24, lambda n : ungettext('day', 'days', n)),
      (60 * 60, lambda n: ungettext('hour', 'hours', n)),
      (60, lambda n: ungettext('minute', 'minutes', n))
    )
    for i, (seconds, name) in enumerate(chunks):
        count = since // seconds
        if count != 0:
            break
    s = ugettext('%(number)d %(type)s') % {'number': count, 'type': name(count)}
    if i + 1 < len(chunks):
        # Now get the second item
        seconds2, name2 = chunks[i + 1]
        count2 = (since - (seconds * count)) // seconds2
        if count2 != 0:
            s += ugettext(', %(number)d %(type)s') % {'number': count2, 'type': name2(count2)}
    return s
    
def timesince(d, now=None):
    
    """
    Takes two datetime objects and returns the time between d and now
    as a nicely formatted string, e.g. "10 minutes".  If d occurs after now,
    then "0 minutes" is returned.

    Units used are years, months, weeks, days, hours, and minutes.
    Seconds and microseconds are ignored.  Up to two adjacent units will be
    displayed.  For example, "2 weeks, 3 days" and "1 year, 3 months" are
    possible outputs, but "2 weeks, 3 hours" and "1 year, 5 days" are not.

    Adapted from http://blog.natbat.co.uk/archive/2003/Jun/14/time_since
    """
    # Convert datetime.date to datetime.datetime for comparison.
    if not isinstance(d, datetime.datetime):
        d = datetime.datetime(d.year, d.month, d.day)
    if now and not isinstance(now, datetime.datetime):
        now = datetime.datetime(now.year, now.month, now.day)

    if not now:
        if d.tzinfo:
            now = datetime.datetime.now(d.tzinfo)
        else:
            now = datetime.datetime.now()

    # ignore microsecond part of 'd' since we removed it from 'now'
    delta = now - (d - datetime.timedelta(0, 0, d.microsecond))
    since = delta.days * 24 * 60 * 60 + delta.seconds
    if since < 0:
        # d is in the future compared to now, stop processing.
        return 'future'
    if since == 0:
        return '0 minute' # possbibly a better string here?
    return timesince_sec(since)