Source code for stoqlib.lib.defaults

# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4

##
## Copyright (C) 2005-2012 Async Open Source
##
## This program is free software; you can redistribute it and/or
## modify it under the terms of the GNU Lesser General Public License
## as published by the Free Software Foundation; either version 2
## of the License, or (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU Lesser General Public License for more details.
##
## You should have received a copy of the GNU Lesser General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., or visit: http://www.gnu.org/.
##
##
## Author(s): Stoq Team <stoq-devel@async.com.br>
##
"""Default values for applications"""

import ctypes
from ctypes.util import find_library
import os
import platform
import re
from decimal import Decimal

from dateutil import relativedelta

from stoqlib.lib.translation import stoqlib_gettext

_ = stoqlib_gettext

#: The max int for 32bits. Should be used instead of sys.maxint since
#: it will be different depending on the cpu's architecture
#: http://en.wikipedia.org/wiki/2147483647
MAX_INT = (1 << 31) - 1

MINIMUM_PASSWORD_CHAR_LEN = 6

#
# Unicode related
#

# "Used to replace an incoming character whose value is unknown or
#  undefined in Unicode"
UNKNOWN_CHARACTER = u"\N{REPLACEMENT CHARACTER}"

# weekday constants

NL_TIME_WEEK_1STDAY = 131174
NL_TIME_FIRST_WEEKDAY = 131176

# C library

_libc = None


def get_libc():
    """Returns an accessor to C library.

    :returns: a ctypes.CDLL instance
    """
    global _libc
    if _libc is None:
        _libc = ctypes.CDLL(find_library("c"))
    return _libc


def get_weekday_start():
    """Returns the dateutil.relativedelta.weekday based on the current locale.

    :returns: a dateutil.realtivedelta.weekday instance
    """

    _system = platform.system()
    week_start = 0
    if _system == 'Darwin':
        # FIXME: Port this to use py objc
        # http://stackoverflow.com/questions/3519207/how-to-calculate-first-nsdate-of-current-week
        pass
    elif _system == 'Windows':
        # FIXME: GetLocaleInfo(LOCALE_IFIRSTDAYOFWEEK)
        pass
    elif _system == 'Linux':
        # Libc + ctypes is not working on natty and previous
        # libc = get_libc()
        # week_origin = libc.nl_langinfo(NL_TIME_WEEK_1STDAY)
        # v = libc.nl_langinfo(NL_TIME_FIRST_WEEKDAY)
        # first_weekday = ord(ctypes.cast(v, ctypes.c_char_p).value[0])

        process = os.popen("locale first_weekday week-1stday")
        first_weekday, week_origin = process.read().split('\n')[:2]
        process.close()

        # we will set week_1sday based on the dateutil.relativedelta.weekday mapping
        if week_origin == '19971130':  # Sunday
            week_1stday = 6
        elif week_origin == '19971201':  # Monday
            week_1stday = 0
        else:
            raise TypeError('Unknown NL_TIME_WEEK_1STDAY constant')

        week_start = (week_1stday + int(first_weekday) - 1) % 7

    return relativedelta.weekday(week_start)


#
# Payments
#

def payment_value_colorize(column_data):
    """A helper method for payment value columns used to set different
    colors for negative values
    """
    return column_data < 0


#
# Kiwi combobox
#

ALL_ITEMS_INDEX = -1

ALL_BRANCHES = _('All branches'), ALL_ITEMS_INDEX

#
# Common methods
#


def _split_parts(a):
    parts = re.findall(r'(\d+|\D+)', a)
    for i in range(len(parts)):
        try:
            parts[i] = int(parts[i])
        except Exception:
            pass
    return parts


def sort_sellable_code(a, b):
    return cmp(_split_parts(a), _split_parts(b))


#
# Decimal precision
#

DECIMAL_PRECISION = 2
QUANTITY_PRECISION = 3


def quantize(dec, precision=DECIMAL_PRECISION):
    """Quantities a decimal according to the current settings.
    if DECIMAL_PRECISION is set to two then everything but
    the last two decimals will be removed

    >>> quantize(Decimal("10.123"))
    Decimal('10.12')

    >>> quantize(Decimal("10.678"))
    Decimal('10.68')
    """
    _format = Decimal('10e-%d' % precision)
    return dec.quantize(_format)