# -*- coding: utf-8 -*-
##############################################################################
#
#    OpenERP, Open Source Management Solution
#    Copyright (C) 2004-2009 Tiny SPRL (<http://tiny.be>).
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################

import sys

LOG_NOTSET = 'notset'
LOG_DEBUG = 'debug'
LOG_INFO = 'info'
LOG_WARNING = 'warn'
LOG_ERROR = 'error'
LOG_CRITICAL = 'critical'

# TODO get_encodings, ustr and exception_to_unicode were originally from tools.misc.
# There are here until we refactor tools so that this module doesn't depends on tools.

def get_encodings(hint_encoding='utf-8'):
    fallbacks = {
        'latin1': 'latin9',
        'iso-8859-1': 'iso8859-15',
        'cp1252': '1252',
    }
    if hint_encoding:
        yield hint_encoding
        if hint_encoding.lower() in fallbacks:
            yield fallbacks[hint_encoding.lower()]

    # some defaults (also taking care of pure ASCII)
    for charset in ['utf8','latin1']:
        if not hint_encoding or (charset.lower() != hint_encoding.lower()):
            yield charset

    from locale import getpreferredencoding
    prefenc = getpreferredencoding()
    if prefenc and prefenc.lower() != 'utf-8':
        yield prefenc
        prefenc = fallbacks.get(prefenc.lower())
        if prefenc:
            yield prefenc

def ustr(value, hint_encoding='utf-8', errors='strict'):
    """This method is similar to the builtin `unicode`, except
    that it may try multiple encodings to find one that works
    for decoding `value`, and defaults to 'utf-8' first.

    :param: value: the value to convert
    :param: hint_encoding: an optional encoding that was detecte
        upstream and should be tried first to decode ``value``.
    :param str errors: optional `errors` flag to pass to the unicode
        built-in to indicate how illegal character values should be
        treated when converting a string: 'strict', 'ignore' or 'replace'
        (see ``unicode()`` constructor).
        Passing anything other than 'strict' means that the first
        encoding tried will be used, even if it's not the correct
        one to use, so be careful! Ignored if value is not a string/unicode.
    :raise: UnicodeError if value cannot be coerced to unicode
    :return: unicode string representing the given value
    """
    if isinstance(value, Exception):
        return exception_to_unicode(value)

    if isinstance(value, unicode):
        return value

    if not isinstance(value, basestring):
        try:
            return unicode(value)
        except Exception:
            raise UnicodeError('unable to convert %r' % (value,))

    for ln in get_encodings(hint_encoding):
        try:
            return unicode(value, ln, errors=errors)
        except Exception:
            pass
    raise UnicodeError('unable to convert %r' % (value,))


def exception_to_unicode(e):
    if (sys.version_info[:2] < (2,6)) and hasattr(e, 'message'):
        return ustr(e.message)
    if hasattr(e, 'args'):
        return "\n".join((ustr(a) for a in e.args))
    try:
        return unicode(e)
    except Exception:
        return u"Unknown message"

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