import types

import urllib

import locale

import datetime

import codecs

from django.utils.functional import Promise

try:

    from decimal import Decimal

except ImportError:

    from django.utils._decimal import Decimal # Python 2.3 fallback

class DjangoUnicodeDecodeError(UnicodeDecodeError):

    def __init__(self, obj, *args):

        self.obj = obj

        UnicodeDecodeError.__init__(self, *args)

    def __str__(self):

        original = UnicodeDecodeError.__str__(self)

        return '%s. You passed in %r (%s)' % (original, self.obj,

                type(self.obj))

class StrAndUnicode(object):

    """

    A class whose __str__ returns its __unicode__ as a UTF-8 bytestring.

    Useful as a mix-in.

    """

    def __str__(self):

        return self.__unicode__().encode('utf-8')

def smart_unicode(s, encoding='utf-8', strings_only=False, errors='strict'):

    """

    Returns a unicode object representing 's'. Treats bytestrings using the

    'encoding' codec.

    If strings_only is True, don't convert (some) non-string-like objects.

    """

    if isinstance(s, Promise):

        # The input is the result of a gettext_lazy() call.

        return s

    return force_unicode(s, encoding, strings_only, errors)

def is_protected_type(obj):

    """Determine if the object instance is of a protected type.

    Objects of protected types are preserved as-is when passed to

    force_unicode(strings_only=True).

    """

    return isinstance(obj, (

        types.NoneType,

        int, long,

        datetime.datetime, datetime.date, datetime.time,

        float, Decimal)

    )

def force_unicode(s, encoding='utf-8', strings_only=False, errors='strict'):

    """

    Similar to smart_unicode, except that lazy instances are resolved to

    strings, rather than kept as lazy objects.

    If strings_only is True, don't convert (some) non-string-like objects.

    """

    if strings_only and is_protected_type(s):

        return s

    try:

        if not isinstance(s, basestring,):

            if hasattr(s, '__unicode__'):

                s = unicode(s)

            else:

                try:

                    s = unicode(str(s), encoding, errors)

                except UnicodeEncodeError:

                    if not isinstance(s, Exception):

                        raise

                    # If we get to here, the caller has passed in an Exception

                    # subclass populated with non-ASCII data without special

                    # handling to display as a string. We need to handle this

                    # without raising a further exception. We do an

                    # approximation to what the Exception's standard str()

                    # output should be.

                    s = ' '.join([force_unicode(arg, encoding, strings_only,

                            errors) for arg in s])

        elif not isinstance(s, unicode):

            # Note: We use .decode() here, instead of unicode(s, encoding,

            # errors), so that if s is a SafeString, it ends up being a

            # SafeUnicode at the end.

            s = s.decode(encoding, errors)

    except UnicodeDecodeError, e:

        raise DjangoUnicodeDecodeError(s, *e.args)

    return s

def smart_str(s, encoding='utf-8', strings_only=False, errors='strict'):

    """

    Returns a bytestring version of 's', encoded as specified in 'encoding'.

    If strings_only is True, don't convert (some) non-string-like objects.

    """

    if strings_only and isinstance(s, (types.NoneType, int)):

        return s

    if isinstance(s, Promise):

        return unicode(s).encode(encoding, errors)

    elif not isinstance(s, basestring):

        try:

            return str(s)

        except UnicodeEncodeError:

            if isinstance(s, Exception):

                # An Exception subclass containing non-ASCII data that doesn't

                # know how to print itself properly. We shouldn't raise a

                # further exception.

                return ' '.join([smart_str(arg, encoding, strings_only,

                        errors) for arg in s])

            return unicode(s).encode(encoding, errors)

    elif isinstance(s, unicode):

        return s.encode(encoding, errors)

    elif s and encoding != 'utf-8':

        return s.decode('utf-8', errors).encode(encoding, errors)

    else:

        return s

def iri_to_uri(iri):

    """

    Convert an Internationalized Resource Identifier (IRI) portion to a URI

    portion that is suitable for inclusion in a URL.

    This is the algorithm from section 3.1 of RFC 3987.  However, since we are

    assuming input is either UTF-8 or unicode already, we can simplify things a

    little from the full method.

    Returns an ASCII string containing the encoded result.

    """

    # The list of safe characters here is constructed from the printable ASCII

    # characters that are not explicitly excluded by the list at the end of

    # section 3.1 of RFC 3987.

    if iri is None:

        return iri

    return urllib.quote(smart_str(iri), safe='/#%[]=:;$&()+,!?*')

# The encoding of the default system locale but falls back to the

# given fallback encoding if the encoding is unsupported by python or could

# not be determined.  See tickets #10335 and #5846

try:

    DEFAULT_LOCALE_ENCODING = locale.getdefaultlocale()[1] or 'ascii'

    codecs.lookup(DEFAULT_LOCALE_ENCODING)

except:

    DEFAULT_LOCALE_ENCODING = 'ascii'