"""Locale support module.

The module provides low-level access to the C lib's locale APIs and adds high
level number formatting APIs as well as a locale aliasing engine to complement
these.

The aliasing engine includes support for many commonly used locale names and
maps them to values suitable for passing to the C lib's setlocale() function. It
also includes default encodings for all supported locale names.

"""

import sys
import encodings
import encodings.aliases
import re
import collections
from builtins import str as _builtin_str
import functools

# Try importing the _locale module.
#
# If this fails, fall back on a basic 'C' locale emulation.

# Yuck:  LC_MESSAGES is non-standard:  can't tell whether it exists before
# trying the import.  So __all__ is also fiddled at the end of the file.
__all__ = ["getlocale", "getdefaultlocale", "getpreferredencoding", "Error",
           "setlocale", "resetlocale", "localeconv", "strcoll", "strxfrm",
           "str", "atof", "atoi", "format", "format_string", "currency",
           "normalize", "LC_CTYPE", "LC_COLLATE", "LC_TIME", "LC_MONETARY",
           "LC_NUMERIC", "LC_ALL", "CHAR_MAX"]

def _strcoll(a,b):
    """ strcoll(string,string) -> int.
        Compares two strings according to the locale.
    """
    return (a > b) - (a < b)

def _strxfrm(s):
    """ strxfrm(string) -> string.
        Returns a string that behaves for cmp locale-aware.
    """
    return s

try:

    from _locale import *

except ImportError:

    # Locale emulation

    CHAR_MAX = 127
    LC_ALL = 6
    LC_COLLATE = 3
    LC_CTYPE = 0
    LC_MESSAGES = 5
    LC_MONETARY = 4
    LC_NUMERIC = 1
    LC_TIME = 2
    Error = ValueError

    def localeconv():
        """ localeconv() -> dict.
            Returns numeric and monetary locale-specific parameters.
        """
        # 'C' locale default values
        return {'grouping': [127],
                'currency_symbol': '',
                'n_sign_posn': 127,
                'p_cs_precedes': 127,
                'n_cs_precedes': 127,
                'mon_grouping': [],
                'n_sep_by_space': 127,
                'decimal_point': '.',
                'negative_sign': '',
                'positive_sign': '',
                'p_sep_by_space': 127,
                'int_curr_symbol': '',
                'p_sign_posn': 127,
                'thousands_sep': '',
                'mon_thousands_sep': '',
                'frac_digits': 127,
                'mon_decimal_point': '',
                'int_frac_digits': 127}

    def setlocale(category, value=None):
        """ setlocale(integer,string=None) -> string.
            Activates/queries locale processing.
        """
        if value not in (None, '', 'C'):
            raise Error('_locale emulation only supports "C" locale')
        return 'C'

# These may or may not exist in _locale, so be sure to set them.
if 'strxfrm' not in globals():
    strxfrm = _strxfrm
if 'strcoll' not in globals():
    strcoll = _strcoll


_localeconv = localeconv

# With this dict, you can override some items of localeconv's return value.
# This is useful for testing purposes.
_override_localeconv = {}

@functools.wraps(_localeconv)
def localeconv():
    d = _localeconv()
    if _override_localeconv:
        d.update(_override_localeconv)
    return d


### Number formatting APIs

# Author: Martin von Loewis
# improved by Georg Brandl

# Iterate over grouping intervals
def _grouping_intervals(grouping):
    last_interval = None
    for interval in grouping:
        # if grouping is -1, we are done
        if interval == CHAR_MAX:
            return
        # 0: re-use last group ad infinitum
        if interval == 0:
            if last_interval is None:
                raise ValueError("invalid grouping")
            while True:
                yield last_interval
        yield interval
        last_interval = interval

#perform the grouping from right to left
def _group(s, monetary=False):
    conv = localeconv()
    thousands_sep = conv[monetary and 'mon_thousands_sep' or 'thousands_sep']
    grouping = conv[monetary and 'mon_grouping' or 'grouping']
    if not grouping:
        return (s, 0)
    if s[-1] == ' ':
        stripped = s.rstrip()
        right_spaces = s[len(stripped):]
        s = stripped
    else:
        right_spaces = ''
    left_spaces = ''
    groups = []
    for interval in _grouping_intervals(grouping):
        if not s or s[-1] not in "0123456789":
            # only non-digit characters remain (sign, spaces)
            left_spaces = s
            s = ''
            break
        groups.append(s[-interval:])
        s = s[:-interval]
    if s:
        groups.append(s)
    groups.reverse()
    return (
        left_spaces + thousands_sep.join(groups) + right_spaces,
        len(thousands_sep) * (len(groups) - 1)
    )

# Strip a given amount of excess padding from the given string
def _strip_padding(s, amount):
    lpos = 0
    while amount and s[lpos] == ' ':
        lpos += 1
        amount -= 1
    rpos = len(s) - 1
    while amount and s[rpos] == ' ':
        rpos -= 1
        amount -= 1
    return s[lpos:rpos+1]

_percent_re = re.compile(r'%(?:\((?P<key>.*?)\))?'
                         r'(?P<modifiers>[-#0-9 +*.hlL]*?)[eEfFgGdiouxXcrs%]')

def format(percent, value, grouping=False, monetary=False, *additional):
    """Returns the locale-aware substitution of a %? specifier
    (percent).

    additional is for format strings which contain one or more
    '*' modifiers."""
    # this is only for one-percent-specifier strings and this should be checked
    match = _percent_re.match(percent)
    if not match or len(match.group())!= len(percent):
        raise ValueError(("format() must be given exactly one %%char "
                         "format specifier, %s not valid") % repr(percent))
    return _format(percent, value, grouping, monetary, *additional)

def _format(percent, value, grouping=False, monetary=False, *additional):
    if additional:
        formatted = percent % ((value,) + additional)
    else:
        formatted = percent % value
    # floats and decimal ints need special action!
    if percent[-1] in 'eEfFgG':
        seps = 0
        parts = formatted.split('.')
        if grouping:
            parts[0], seps = _group(parts[0], monetary=monetary)
        decimal_point = localeconv()[monetary and 'mon_decimal_point'
                                              or 'decimal_point']
        formatted = decimal_point.join(parts)
        if seps:
            formatted = _strip_padding(formatted, seps)
    elif percent[-1] in 'diu':
        seps = 0
        if grouping:
            formatted, seps = _group(formatted, monetary=monetary)
        if seps:
            formatted = _strip_padding(formatted, seps)
    return formatted

def format_string(f, val, grouping=False):
    """Formats a string in the same way that the % formatting would use,
    but takes the current locale into account.
    Grouping is applied if the third parameter is true."""
    percents = list(_percent_re.finditer(f))
    new_f = _percent_re.sub('%s', f)

    if isinstance(val, collections.Mapping):
        new_val = []
        for perc in percents:
            if perc.group()[-1]=='%':
                new_val.append('%')
            else:
                new_val.append(format(perc.group(), val, grouping))
    else:
        if not isinstance(val, tuple):
            val = (val,)
        new_val = []
        i = 0
        for perc in percents:
            if perc.group()[-1]=='%':
                new_val.append('%')
            else:
                starcount = perc.group('modifiers').count('*')
                new_val.append(_format(perc.group(),
                                      val[i],
                                      grouping,
                                      False,
                                      *val[i+1:i+1+starcount]))
                i += (1 + starcount)
    val = tuple(new_val)

    return new_f % val

def currency(val, symbol=True, grouping=False, international=False):
    """Formats val according to the currency settings
    in the current locale."""
    conv = localeconv()

    # check for illegal values
    digits = conv[international and 'int_frac_digits' or 'frac_digits']
    if digits == 127:
        raise ValueError("Currency formatting is not possible using "
                         "the 'C' locale.")

    s = format('%%.%if' % digits, abs(val), grouping, monetary=True)
    # '<' and '>' are markers if the sign must be inserted between symbol and value
    s = '<' + s + '>'

    if symbol:
        smb = conv[international and 'int_curr_symbol' or 'currency_symbol']
        precedes = conv[val<0 and 'n_cs_precedes' or 'p_cs_precedes']
        separated = conv[val<0 and 'n_sep_by_space' or 'p_sep_by_space']

        if precedes:
            s = smb + (separated and ' ' or '') + s
        else:
            s = s + (separated and ' ' or '') + smb

    sign_pos = conv[val<0 and 'n_sign_posn' or 'p_sign_posn']
    sign = conv[val<0 and 'negative_sign' or 'positive_sign']

    if sign_pos == 0:
        s = '(' + s + ')'
    elif sign_pos == 1:
        s = sign + s
    elif sign_pos == 2:
        s = s + sign
    elif sign_pos == 3:
        s = s.replace('<', sign)
    elif sign_pos == 4:
        s = s.replace('>', sign)
    else:
        # the default if nothing specified;
        # this should be the most fitting sign position
        s = sign + s

    return s.replace('<', '').replace('>', '')

def str(val):
    """Convert float to string, taking the locale into account."""
    return format("%.12g", val)

def delocalize(string):
    "Parses a string as a normalized number according to the locale settings."

    conv = localeconv()

    #First, get rid of the grouping
    ts = conv['thousands_sep']
    if ts:
        string = string.replace(ts, '')

    #next, replace the decimal point with a dot
    dd = conv['decimal_point']
    if dd:
        string = string.replace(dd, '.')
    return string

def atof(string, func=float):
    "Parses a string as a float according to the locale settings."
    return func(delocalize(string))

def atoi(string):
    "Converts a string to an integer according to the locale settings."
    return int(delocalize(string))

def _test():
    setlocale(LC_ALL, "")
    #do grouping
    s1 = format("%d", 123456789,1)
    print(s1, "is", atoi(s1))
    #standard formatting
    s1 = str(3.14)
    print(s1, "is", atof(s1))

### Locale name aliasing engine

# Author: Marc-Andre Lemburg, mal@lemburg.com
# Various tweaks by Fredrik Lundh <fredrik@pythonware.com>

# store away the low-level version of setlocale (it's
# overridden below)
_setlocale = setlocale

def _replace_encoding(code, encoding):