# -*- coding: utf-8 -*-
#
# Copyright (C) 2007-2011 Edgewall Software
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://babel.edgewall.org/wiki/License.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://babel.edgewall.org/log/.

"""Core locale representation and locale data access."""

import os
import cPickle as pickle

from babel import localedata

__all__ = ['UnknownLocaleError', 'Locale', 'default_locale', 'negotiate_locale',
           'parse_locale']
__docformat__ = 'restructuredtext en'

_global_data = None

def get_global(key):
    """Return the dictionary for the given key in the global data.
    
    The global data is stored in the ``babel/global.dat`` file and contains
    information independent of individual locales.
    
    >>> get_global('zone_aliases')['UTC']
    'Etc/GMT'
    >>> get_global('zone_territories')['Europe/Berlin']
    'DE'
    
    :param key: the data key
    :return: the dictionary found in the global data under the given key
    :rtype: `dict`
    :since: version 0.9
    """
    global _global_data
    if _global_data is None:
        dirname = os.path.join(os.path.dirname(__file__))
        filename = os.path.join(dirname, 'global.dat')
        fileobj = open(filename, 'rb')
        try:
            _global_data = pickle.load(fileobj)
        finally:
            fileobj.close()
    return _global_data.get(key, {})


LOCALE_ALIASES = {
    'ar': 'ar_SY', 'bg': 'bg_BG', 'bs': 'bs_BA', 'ca': 'ca_ES', 'cs': 'cs_CZ', 
    'da': 'da_DK', 'de': 'de_DE', 'el': 'el_GR', 'en': 'en_US', 'es': 'es_ES', 
    'et': 'et_EE', 'fa': 'fa_IR', 'fi': 'fi_FI', 'fr': 'fr_FR', 'gl': 'gl_ES', 
    'he': 'he_IL', 'hu': 'hu_HU', 'id': 'id_ID', 'is': 'is_IS', 'it': 'it_IT', 
    'ja': 'ja_JP', 'km': 'km_KH', 'ko': 'ko_KR', 'lt': 'lt_LT', 'lv': 'lv_LV', 
    'mk': 'mk_MK', 'nl': 'nl_NL', 'nn': 'nn_NO', 'no': 'nb_NO', 'pl': 'pl_PL', 
    'pt': 'pt_PT', 'ro': 'ro_RO', 'ru': 'ru_RU', 'sk': 'sk_SK', 'sl': 'sl_SI', 
    'sv': 'sv_SE', 'th': 'th_TH', 'tr': 'tr_TR', 'uk': 'uk_UA'
}


class UnknownLocaleError(Exception):
    """Exception thrown when a locale is requested for which no locale data
    is available.
    """

    def __init__(self, identifier):
        """Create the exception.
        
        :param identifier: the identifier string of the unsupported locale
        """
        Exception.__init__(self, 'unknown locale %r' % identifier)
        self.identifier = identifier


class Locale(object):
    """Representation of a specific locale.
    
    >>> locale = Locale('en', 'US')
    >>> repr(locale)
    "Locale('en', territory='US')"
    >>> locale.display_name
    u'English (United States)'
    
    A `Locale` object can also be instantiated from a raw locale string:
    
    >>> locale = Locale.parse('en-US', sep='-')
    >>> repr(locale)
    "Locale('en', territory='US')"
    
    `Locale` objects provide access to a collection of locale data, such as
    territory and language names, number and date format patterns, and more:
    
    >>> locale.number_symbols['decimal']
    u'.'
    
    If a locale is requested for which no locale data is available, an
    `UnknownLocaleError` is raised:
    
    >>> Locale.parse('en_DE')
    Traceback (most recent call last):
        ...
    UnknownLocaleError: unknown locale 'en_DE'
    
    :see: `IETF RFC 3066 <http://www.ietf.org/rfc/rfc3066.txt>`_
    """

    def __init__(self, language, territory=None, script=None, variant=None):
        """Initialize the locale object from the given identifier components.
        
        >>> locale = Locale('en', 'US')
        >>> locale.language
        'en'
        >>> locale.territory
        'US'
        
        :param language: the language code
        :param territory: the territory (country or region) code
        :param script: the script code
        :param variant: the variant code
        :raise `UnknownLocaleError`: if no locale data is available for the
                                     requested locale
        """
        self.language = language
        self.territory = territory
        self.script = script
        self.variant = variant
        self.__data = None
        
        identifier = str(self)
        if not localedata.exists(identifier):
            raise UnknownLocaleError(identifier)

    @classmethod
    def default(cls, category=None, aliases=LOCALE_ALIASES):
        """Return the system default locale for the specified category.
        
        >>> for name in ['LANGUAGE', 'LC_ALL', 'LC_CTYPE']:
        ...     os.environ[name] = ''
        >>> os.environ['LANG'] = 'fr_FR.UTF-8'
        >>> Locale.default('LC_MESSAGES')
        Locale('fr', territory='FR')

        :param category: one of the ``LC_XXX`` environment variable names
        :param aliases: a dictionary of aliases for locale identifiers
        :return: the value of the variable, or any of the fallbacks
                 (``LANGUAGE``, ``LC_ALL``, ``LC_CTYPE``, and ``LANG``)
        :rtype: `Locale`
        :see: `default_locale`
        """
        locale_string = default_locale(category, aliases=aliases)
        return cls.parse(locale_string)

    @classmethod
    def negotiate(cls, preferred, available, sep='_', aliases=LOCALE_ALIASES):
        """Find the best match between available and requested locale strings.
        
        >>> Locale.negotiate(['de_DE', 'en_US'], ['de_DE', 'de_AT'])
        Locale('de', territory='DE')
        >>> Locale.negotiate(['de_DE', 'en_US'], ['en', 'de'])
        Locale('de')
        >>> Locale.negotiate(['de_DE', 'de'], ['en_US'])
        
        You can specify the character used in the locale identifiers to separate
        the differnet components. This separator is applied to both lists. Also,
        case is ignored in the comparison:
        
        >>> Locale.negotiate(['de-DE', 'de'], ['en-us', 'de-de'], sep='-')
        Locale('de', territory='DE')
        
        :param preferred: the list of locale identifers preferred by the user
        :param available: the list of locale identifiers available
        :param aliases: a dictionary of aliases for locale identifiers
        :return: the `Locale` object for the best match, or `None` if no match
                 was found
        :rtype: `Locale`
        :see: `negotiate_locale`
        """
        identifier = negotiate_locale(preferred, available, sep=sep,
                                      aliases=aliases)
        if identifier:
            return Locale.parse(identifier, sep=sep)

    @classmethod
    def parse(cls, identifier, sep='_'):
        """Create a `Locale` instance for the given locale identifier.
        
        >>> l = Locale.parse('de-DE', sep='-')
        >>> l.display_name
        u'Deutsch (Deutschland)'
        
        If the `identifier` parameter is not a string, but actually a `Locale`
        object, that object is returned:
        
        >>> Locale.parse(l)
        Locale('de', territory='DE')
        
        :param identifier: the locale identifier string
        :param sep: optional component separator
        :return: a corresponding `Locale` instance
        :rtype: `Locale`
        :raise `ValueError`: if the string does not appear to be a valid locale
                             identifier
        :raise `UnknownLocaleError`: if no locale data is available for the
                                     requested locale
        :see: `parse_locale`
        """
        if isinstance(identifier, basestring):
            return cls(*parse_locale(identifier, sep=sep))
        return identifier

    def __eq__(self, other):
        for key in ('language', 'territory', 'script', 'variant'):
            if not hasattr(other, key):
                return False
        return (self.language == other.language) and \
            (self.territory == other.territory) and \
            (self.script == other.script) and \
            (self.variant == other.variant)

    def __ne__(self, other):
        return not self.__eq__(other)

    def __repr__(self):
        parameters = ['']
        for key in ('territory', 'script', 'variant'):
            value = getattr(self, key)
            if value is not None:
                parameters.append('%s=%r' % (key, value))
        parameter_string = '%r' % self.language + ', '.join(parameters)
        return 'Locale(%s)' % parameter_string

    def __str__(self):
        return '_'.join(filter(None, [self.language, self.script,
                                      self.territory, self.variant]))

    @property
    def _data(self):
        if self.__data is None:
            self.__data = localedata.LocaleDataDict(localedata.load(str(self)))
        return self.__data

    def get_display_name(self, locale=None):
        """Return the display name of the locale using the given locale.
        
        The display name will include the language, territory, script, and
        variant, if those are specified.
        
        >>> Locale('zh', 'CN', script='Hans').get_display_name('en')
        u'Chinese (Simplified Han, China)'
        
        :param locale: the locale to use
        :return: the display name
        """
        if locale is None:
            locale = self
        locale = Locale.parse(locale)
        retval = locale.languages.get(self.language)
        if self.territory or self.script or self.variant:
            details = []
            if self.script:
                details.append(locale.scripts.get(self.script))
            if self.territory:
                details.append(locale.territories.get(self.territory))
            if self.variant:
                details.append(locale.variants.get(self.variant))
            details = filter(None, details)
            if details:
                retval += ' (%s)' % u', '.join(details)
        return retval

    display_name = property(get_display_name, doc="""\
        The localized display name of the locale.
        
        >>> Locale('en').display_name
        u'English'
        >>> Locale('en', 'US').display_name
        u'English (United States)'
        >>> Locale('sv').display_name
        u'svenska'
        
        :type: `unicode`
        """)

    @property    
    def english_name(self):
        """The english display name of the locale.
        
        >>> Locale('de').english_name
        u'German'
        >>> Locale('de', 'DE').english_name
        u'German (Germany)'
        
        :type: `unicode`"""
        return self.get_display_name(Locale('en'))

    #{ General Locale Display Names

    @property    
    def languages(self):
        """Mapping of language codes to translated language names.
        
        >>> Locale('de', 'DE').languages['ja']
        u'Japanisch'
        
        :type: `dict`
        :see: `ISO 639 <http://www.loc.gov/standards/iso639-2/>`_"""
        return self._data['languages']

    @property    
    def scripts(self):
        """Mapping of script codes to translated script names.
        
        >>> Locale('en', 'US').scripts['Hira']
        u'Hiragana'
        
        :type: `dict`
        :see: `ISO 15924 <http://www.evertype.com/standards/iso15924/>`_"""
        return self._data['scripts']

    @property    
    def territories(self):
        """Mapping of script codes to translated script names.
        
        >>> Locale('es', 'CO').territories['DE']
        u'Alemania'
        
        :type: `dict`
        :see: `ISO 3166 <http://www.iso.org/iso/en/prods-services/iso3166ma/>`_"""
        return self._data['territories']

    @property    
    def variants(self):
        """Mapping of script codes to translated script names.
        
        >>> Locale('de', 'DE').variants['1901']
        u'Alte deutsche Rechtschreibung'
        
        :type: `dict`"""
        return self._data['variants']

    #{ Number Formatting

    @property    
    def currencies(self):
        """Mapping of currency codes to translated currency names.
        
        >>> Locale('en').currencies['COP']
        u'Colombian Peso'
        >>> Locale('de', 'DE').currencies['COP']
        u'Kolumbianischer Peso'
        
        :type: `dict`"""
        return self._data['currency_names']

    @property    
    def currency_symbols(self):
        """Mapping of currency codes to symbols.
        
        >>> Locale('en', 'US').currency_symbols['USD']
        u'$'
        >>> Locale('es', 'CO').currency_symbols['USD']
        u'US$'
        
        :type: `dict`"""
        return self._data['currency_symbols']

    @property    
    def number_symbols(self):
        """Symbols used in number formatting.
        
        >>> Locale('fr', 'FR').number_symbols['decimal']
        u','
        
        :type: `dict`"""
        return self._data['number_symbols']

    @property    
    def decimal_formats(self):
        """Locale patterns for decimal number formatting.
        
        >>> Locale('en', 'US').decimal_formats[None]
        <NumberPattern u'#,##0.###'>
        
        :type: `dict`"""
        return self._data['decimal_formats']

    @property    
    def currency_formats(self):
        """Locale patterns for currency number formatting.
        
        >>> print Locale('en', 'US').currency_formats[None]
        <NumberPattern u'\\xa4#,##0.00'>
        
        :type: `dict`"""
        return self._data['currency_formats']

    @property    
    def percent_formats(self):
        """Locale patterns for percent number formatting.
        
        >>> Locale('en', 'US').percent_formats[None]
        <NumberPattern u'#,##0%'>
        
        :type: `dict`"""
        return self._data['percent_formats']

    @property    
    def scientific_formats(self):
        """Locale patterns for scientific number formatting.
        
        >>> Locale('en', 'US').scientific_formats[None]
        <NumberPattern u'#E0'>
        
        :type: `dict`"""
        return self._data['scientific_formats']

    #{ Calendar Information and Date Formatting

    @property    
    def periods(self):
        """Locale display names for day periods (AM/PM).
        
        >>> Locale('en', 'US').periods['am']
        u'AM'
        
        :type: `dict`"""
        return self._data['periods']

    @property    
    def days(self):
        """Locale display names for weekdays.
        
        >>> Locale('de', 'DE').days['format']['wide'][3]
        u'Donnerstag'
        
        :type: `dict`"""
        return self._data['days']

    @property    
    def months(self):
        """Locale display names for months.
        
        >>> Locale('de', 'DE').months['format']['wide'][10]
        u'Oktober'
        
        :type: `dict`"""
        return self._data['months']

    @property    
    def quarters(self):
        """Locale display names for quarters.
        
        >>> Locale('de', 'DE').quarters['format']['wide'][1]
        u'1. Quartal'
        
        :type: `dict`"""
        return self._data['quarters']

    @property    
    def eras(self):
        """Locale display names for eras.
        
        >>> Locale('en', 'US').eras['wide'][1]
        u'Anno Domini'
        >>> Locale('en', 'US').eras['abbreviated'][0]
        u'BC'
        
        :type: `dict`"""
        return self._data['eras']

    @property    
    def time_zones(self):
        """Locale display names for time zones.
        
        >>> Locale('en', 'US').time_zones['Europe/London']['long']['daylight']
        u'British Summer Time'
        >>> Locale('en', 'US').time_zones['America/St_Johns']['city']
        u"St. John's"
        
        :type: `dict`"""
        return self._data['time_zones']

    @property    
    def meta_zones(self):
        """Locale display names for meta time zones.
        
        Meta time zones are basically groups of different Olson time zones that
        have the same GMT offset and daylight savings time.
        
        >>> Locale('en', 'US').meta_zones['Europe_Central']['long']['daylight']
        u'Central European Summer Time'
        
        :type: `dict`
        :since: version 0.9"""
        return self._data['meta_zones']

    @property    
    def zone_formats(self):
        """Patterns related to the formatting of time zones.
        
        >>> Locale('en', 'US').zone_formats['fallback']
        u'%(1)s (%(0)s)'
        >>> Locale('pt', 'BR').zone_formats['region']
        u'Hor\\xe1rio %s'
        
        :type: `dict`
        :since: version 0.9"""
        return self._data['zone_formats']

    @property    
    def first_week_day(self):
        """The first day of a week, with 0 being Monday.
        
        >>> Locale('de', 'DE').first_week_day
        0
        >>> Locale('en', 'US').first_week_day
        6
        
        :type: `int`"""
        return self._data['week_data']['first_day']

    @property    
    def weekend_start(self):
        """The day the weekend starts, with 0 being Monday.
        
        >>> Locale('de', 'DE').weekend_start
        5
        
        :type: `int`"""
        return self._data['week_data']['weekend_start']

    @property    
    def weekend_end(self):
        """The day the weekend ends, with 0 being Monday.
        
        >>> Locale('de', 'DE').weekend_end
        6
        
        :type: `int`"""
        return self._data['week_data']['weekend_end']

    @property    
    def min_week_days(self):
        """The minimum number of days in a week so that the week is counted as 
        the first week of a year or month.
        
        >>> Locale('de', 'DE').min_week_days
        4
        
        :type: `int`"""
        return self._data['week_data']['min_days']

    @property    
    def date_formats(self):
        """Locale patterns for date formatting.
        
        >>> Locale('en', 'US').date_formats['short']
        <DateTimePattern u'M/d/yy'>
        >>> Locale('fr', 'FR').date_formats['long']
        <DateTimePattern u'd MMMM y'>
        
        :type: `dict`"""
        return self._data['date_formats']

    @property    
    def time_formats(self):
        """Locale patterns for time formatting.
        
        >>> Locale('en', 'US').time_formats['short']
        <DateTimePattern u'h:mm a'>
        >>> Locale('fr', 'FR').time_formats['long']
        <DateTimePattern u'HH:mm:ss z'>
        
        :type: `dict`"""
        return self._data['time_formats']

    @property    
    def datetime_formats(self):
        """Locale patterns for datetime formatting.
        
        >>> Locale('en').datetime_formats['full']
        u'{1} {0}'
        >>> Locale('th').datetime_formats['medium']
        u'{1}, {0}'
        
        :type: `dict`"""
        return self._data['datetime_formats']

    @property    
    def plural_form(self):
        """Plural rules for the locale.
        
        >>> Locale('en').plural_form(1)
        'one'
        >>> Locale('en').plural_form(0)
        'other'
        >>> Locale('fr').plural_form(0)
        'one'
        >>> Locale('ru').plural_form(100)
        'many'
        
        :type: `PluralRule`"""
        return self._data['plural_form']


def default_locale(category=None, aliases=LOCALE_ALIASES):
    """Returns the system default locale for a given category, based on
    environment variables.
    
    >>> for name in ['LANGUAGE', 'LC_ALL', 'LC_CTYPE']:
    ...     os.environ[name] = ''
    >>> os.environ['LANG'] = 'fr_FR.UTF-8'
    >>> default_locale('LC_MESSAGES')
    'fr_FR'

    The "C" or "POSIX" pseudo-locales are treated as aliases for the
    "en_US_POSIX" locale:

    >>> os.environ['LC_MESSAGES'] = 'POSIX'
    >>> default_locale('LC_MESSAGES')
    'en_US_POSIX'

    :param category: one of the ``LC_XXX`` environment variable names
    :param aliases: a dictionary of aliases for locale identifiers
    :return: the value of the variable, or any of the fallbacks (``LANGUAGE``,
             ``LC_ALL``, ``LC_CTYPE``, and ``LANG``)
    :rtype: `str`
    """
    varnames = (category, 'LANGUAGE', 'LC_ALL', 'LC_CTYPE', 'LANG')
    for name in filter(None, varnames):
        locale = os.getenv(name)
        if locale:
            if name == 'LANGUAGE' and ':' in locale:
                # the LANGUAGE variable may contain a colon-separated list of
                # language codes; we just pick the language on the list
                locale = locale.split(':')[0]
            if locale in ('C', 'POSIX'):
                locale = 'en_US_POSIX'
            elif aliases and locale in aliases:
                locale = aliases[locale]
            try:
                return '_'.join(filter(None, parse_locale(locale)))
            except ValueError:
                pass

def negotiate_locale(preferred, available, sep='_', aliases=LOCALE_ALIASES):
    """Find the best match between available and requested locale strings.
    
    >>> negotiate_locale(['de_DE', 'en_US'], ['de_DE', 'de_AT'])
    'de_DE'
    >>> negotiate_locale(['de_DE', 'en_US'], ['en', 'de'])
    'de'
    
    Case is ignored by the algorithm, the result uses the case of the preferred
    locale identifier:
    
    >>> negotiate_locale(['de_DE', 'en_US'], ['de_de', 'de_at'])
    'de_DE'
    
    >>> negotiate_locale(['de_DE', 'en_US'], ['de_de', 'de_at'])
    'de_DE'
    
    By default, some web browsers unfortunately do not include the territory
    in the locale identifier for many locales, and some don't even allow the
    user to easily add the territory. So while you may prefer using qualified
    locale identifiers in your web-application, they would not normally match
    the language-only locale sent by such browsers. To workaround that, this
    function uses a default mapping of commonly used langauge-only locale
    identifiers to identifiers including the territory:
    
    >>> negotiate_locale(['ja', 'en_US'], ['ja_JP', 'en_US'])
    'ja_JP'
    
    Some browsers even use an incorrect or outdated language code, such as "no"
    for Norwegian, where the correct locale identifier would actually be "nb_NO"
    (Bokmål) or "nn_NO" (Nynorsk). The aliases are intended to take care of
    such cases, too:
    
    >>> negotiate_locale(['no', 'sv'], ['nb_NO', 'sv_SE'])
    'nb_NO'
    
    You can override this default mapping by passing a different `aliases`
    dictionary to this function, or you can bypass the behavior althogher by
    setting the `aliases` parameter to `None`.
    
    :param preferred: the list of locale strings preferred by the user
    :param available: the list of locale strings available
    :param sep: character that separates the different parts of the locale
                strings
    :param aliases: a dictionary of aliases for locale identifiers
    :return: the locale identifier for the best match, or `None` if no match
             was found
    :rtype: `str`
    """
    available = [a.lower() for a in available if a]
    for locale in preferred:
        ll = locale.lower()
        if ll in available:
            return locale
        if aliases:
            alias = aliases.get(ll)
            if alias:
                alias = alias.replace('_', sep)
                if alias.lower() in available:
                    return alias
        parts = locale.split(sep)
        if len(parts) > 1 and parts[0].lower() in available:
            return parts[0]
    return None

def parse_locale(identifier, sep='_'):
    """Parse a locale identifier into a tuple of the form::
    
      ``(language, territory, script, variant)``
    
    >>> parse_locale('zh_CN')
    ('zh', 'CN', None, None)
    >>> parse_locale('zh_Hans_CN')
    ('zh', 'CN', 'Hans', None)
    
    The default component separator is "_", but a different separator can be
    specified using the `sep` parameter:
    
    >>> parse_locale('zh-CN', sep='-')
    ('zh', 'CN', None, None)
    
    If the identifier cannot be parsed into a locale, a `ValueError` exception
    is raised:
    
    >>> parse_locale('not_a_LOCALE_String')
    Traceback (most recent call last):
      ...
    ValueError: 'not_a_LOCALE_String' is not a valid locale identifier
    
    Encoding information and locale modifiers are removed from the identifier:
    
    >>> parse_locale('it_IT@euro')
    ('it', 'IT', None, None)
    >>> parse_locale('en_US.UTF-8')
    ('en', 'US', None, None)
    >>> parse_locale('de_DE.iso885915@euro')
    ('de', 'DE', None, None)
    
    :param identifier: the locale identifier string
    :param sep: character that separates the different components of the locale
                identifier
    :return: the ``(language, territory, script, variant)`` tuple
    :rtype: `tuple`
    :raise `ValueError`: if the string does not appear to be a valid locale
                         identifier
    
    :see: `IETF RFC 4646 <http://www.ietf.org/rfc/rfc4646.txt>`_
    """
    if '.' in identifier:
        # this is probably the charset/encoding, which we don't care about
        identifier = identifier.split('.', 1)[0]
    if '@' in identifier:
        # this is a locale modifier such as @euro, which we don't care about
        # either
        identifier = identifier.split('@', 1)[0]

    parts = identifier.split(sep)
    lang = parts.pop(0).lower()
    if not lang.isalpha():
        raise ValueError('expected only letters, got %r' % lang)

    script = territory = variant = None
    if parts:
        if len(parts[0]) == 4 and parts[0].isalpha():
            script = parts.pop(0).title()

    if parts:
        if len(parts[0]) == 2 and parts[0].isalpha():
            territory = parts.pop(0).upper()
        elif len(parts[0]) == 3 and parts[0].isdigit():
            territory = parts.pop(0)

    if parts:
        if len(parts[0]) == 4 and parts[0][0].isdigit() or \
                len(parts[0]) >= 5 and parts[0][0].isalpha():
            variant = parts.pop()

    if parts:
        raise ValueError('%r is not a valid locale identifier' % identifier)

    return lang, territory, script, variant