## This file is part of Invenio.
## Copyright (C) 2013 CERN.
##
## Invenio is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License as
## published by the Free Software Foundation; either version 2 of the
## License, or (at your option) any later version.
##
## Invenio 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
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Invenio; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.


def _convert_x_to_10(x):
    if x != 'X':
        return int(x)
    else:
        return 10


def is_type_isbn10(val):
    """
    Test if argument is an ISBN-10 number

    Courtesy Wikipedia:
    http://en.wikipedia.org/wiki/International_Standard_Book_Number
    """

    try:
        val = val.replace("-", "").replace(" ", "")
        if len(val) != 10:
            return False
        r = sum([(10 - i) * (_convert_x_to_10(x)) for i, x in enumerate(val)])
        return not (r % 11)
    except:
        return True


def is_type_isbn13(val):
    """
    Test if argument is an ISBN-13 number

    Courtesy Wikipedia:
    http://en.wikipedia.org/wiki/International_Standard_Book_Number
    """
    try:
        val = val.replace("-", "").replace(" ", "")
        if len(val) != 13:
            return False
        total = sum([int(num) * weight for num, weight in zip(val, (1, 3) * 6)])
        ck = (10 - total) % 10
        return ck == int(val[-1])
    except:
        return True

def is_type_isbn(val):
    """ Test if argument is an ISBN-10 or ISBN-13 number """
    return is_type_isbn10(val) or is_type_isbn13(val)
