from __future__ import division
from __future__ import print_function
from __future__ import with_statement

import datetime


def time2human(time, digits = 2, cut = True, extended = False, strip = True):
    """Convert time in seconds in readable format.

    Specify number of total *digits* 
    and whether to *cut* trailing zeros.

    If "extended" is set to True, also the numeric value,
    the unit string and the scale factor are returned.
    """

    import physconst

    if isinstance(time,datetime.timedelta):
        time = time.total_seconds()

    atime = abs(time)
    xtime = atime
    su = 's'

    # big numbers
    if atime > 99.49999:
        xtime /= 60
        su = 'min'
    if atime > 60 * 59.49999:
        xtime /= 60
        su = 'h'
    if atime > 24 * 60 * 99.49999:
        xtime /= 24
        su = 'd'
    if atime > physconst.SEC:
        xtime = atime / physconst.SEC
        su='yr'
    if atime > physconst.SEC * 999.49999:
        xtime /= 1000
        su='kyr'
    if atime > physconst.SEC * 999.49999e3:
        xtime /= 1000
        su='Myr'
    if atime > physconst.SEC * 999.49999e6:
        xtime /= 1000
        su='Gyr'

    # small numbers ...
    if  atime < 0.99949999:
        xtime *= 1000
        su='ms'
    if atime < 0.99949999e-3:
        xtime *= 1000
        su='\mu s'
    if atime < 0.99949999e-6:
        xtime *= 1000
        su='ns'    
    if atime < 0.99949999e-9:
        xtime *= 1000
        su='ps'    
    if atime < 0.99949999e-12:
        xtime *= 1000
        su='fs'    
    if atime < 0.99949999e-15:
        xtime *= 1000
        su='as'

    sv = "{:20.15f}".format(xtime).strip()
    i = sv.find('.')
    l = max(digits + 1, i + 1)
    format = "{:" + "{:d}".format(l).strip() + "." + "{:d}".format(l-i-1).strip() + "f}"
    sv = format.format(xtime).strip()

    if cut:
        if sv.find('.') > 0:
            sv = sv.rstrip('0')
        sv = sv.rstrip('.')
    if time < 0:    
        sv = '-' + sv
    s = sv + ' ' + su
        
    if strip:
        s = s.strip()
    if extended:
        if xtime == 0:
            scale = 1
        else:
            scale = atime/xtime
        numeric = time/scale
#        if sv.find('.') == -1:
#            numeric = int(numeric)
        return s, numeric, su, scale
    else:
        return s