#!/usr/bin/env python2

from sys import argv

# Unmodified `gittz(tz)` from git-remote-hg
def gittz(tz):
    """ Converts UTC-offset (in negated seconds) to "+HHmm" notation.

    Examples:
    >>> gittz(-1*3600)          # Paris
    '+0100'
    >>> gittz(5*3600)           # New York
    '-0500'
    >>> gittz(int(3.5*3600))    # St. John\'s (fails!)
    '-0330'
    >>> gittz(int(-3.5*3600))   # Tehran
    '+0330'
    """
    return '%+03d%02d' % (-tz / 3600, -tz % 3600 / 60)

# fixed `gittz(tz)`
def gittz_fixed(tz):
    """ Converts UTC-offset (in negated seconds) to "+HHmm" notation.

    Examples:
    >>> gittz_fixed(-1*3600)        # Paris
    '+0100'
    >>> gittz_fixed(5*3600)         # New York
    '-0500'
    >>> gittz_fixed(int(3.5*3600))  # St. John\'s
    '-0330'
    >>> gittz_fixed(int(-3.5*3600)) # Tehran
    '+0330'
    """
    sign = 1 if tz < 0 else -1
    return '%+03d%02d' % (sign * (abs(tz) / 3600), abs(tz) % 3600 / 60)


# Unmodified from `get_author(self)` in git-remote-hg"""
def pytz(tz):
    """ Converts timezone in "+HHmm" notation to UTC-offset (in negated seconds).

    Examples:
    >>> pytz('+0100')   # Paris
    -3600
    >>> pytz('-0500')   # New York
    18000
    >>> pytz('-0330')   # St. John\'s (fails!)
    12600
    >>> pytz('+0330')   # Tehran
    -12600
    """
    tz = int(tz)
    tz = ((tz / 100) * 3600) + ((tz % 100) * 60)
    return  -tz

# fixed `pytz(tz)`
def pytz_fixed(tz):
    """ Converts timezone in "+HHmm" notation to UTC-offset (in negated seconds).

    Examples:
    >>> pytz_fixed('+0100')   # Paris
    -3600
    >>> pytz_fixed('-0500')   # New York
    18000
    >>> pytz_fixed('-0330')   # St. John\'s (fails!)
    12600
    >>> pytz_fixed('+0330')   # Tehran
    -12600
    """
    tz = int(tz)
    sign = 1 if tz < 0 else -1
    tz = (( abs(tz) / 100 ) * 3600) + (( abs(tz) % 100) * 60)
    return  sign * tz


def main():
    zones = [
        ('Name'       , 'ISO TZ',    'int tz'     ),
        ('Tehran'     ,  '+0330', int(-3.5*3600), ),
        ('Berlin'     ,  '+0100',     -1*3600,    ),
        ('UTC'        ,  '+0000',      0,         ),
        ('St. John\'s',  '-0330',  int(3.5*3600), ),
        ('Halifax'    ,  '-0400',      4*3600,    ),
        ('Toronto'    ,  '-0500',      5*3600,    ),
        ('Calgary'    ,  '-0700',      7*3600,    ),
        ('Vancouver'  ,  '-0800',      8*3600,    ),
    ]
    table_fmt = "{:12s} | {:^7} {:^7} | {:^9}{:1} {:^9}{:1} | {:^9}{:1}"

    print "\nImplementation in git-remote-hg (fails for St. John's)"
    print   "------------------------------------------------------"
    for zone in zones:
        zname, isoTZ, intTZ = zone
        if zname == 'Name':
            print table_fmt.format( zname, isoTZ, intTZ,
                "gittz(tz)", "", "pytz(TZ)", "", "iso->int->iso", "" )
        else:
            flag1 = " " if gittz(intTZ)       == isoTZ else "*"
            flag2 = " " if pytz(isoTZ)        == intTZ else "*"
            flag3 = " " if gittz(pytz(isoTZ)) == isoTZ else "*"
            print table_fmt.format(
                    zname, isoTZ, intTZ,
                    gittz(intTZ), flag1, pytz(isoTZ), flag2,
                    gittz(pytz(isoTZ)), flag3)

    print "\nCorrect implementation"
    print   "----------------------"
    for zone in zones:
        zname, isoTZ, intTZ = zone
        if zname == 'Name':
            print table_fmt.format( zname, isoTZ, intTZ,
                "gittz(tz)", "", "pytz(TZ)", "", "iso->int->iso", "" )
        else:
            print table_fmt.format(
                    zname, isoTZ, intTZ,
                    gittz_fixed(intTZ), flag1,
                    pytz_fixed(isoTZ), flag2,
                    gittz_fixed(pytz_fixed(isoTZ)), flag3)


if __name__ == "__main__":
    if 'test' in argv:
        import doctest
        doctest.testmod()

    else:
        main()