#!/usr/bin/env python2
# vim:fileencoding=utf-8
from __future__ import (unicode_literals, division, absolute_import,
                        print_function)

__license__   = 'GPL v3'
__copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
__docformat__ = 'restructuredtext en'

import sys

is_narrow_build = sys.maxunicode < 0x10ffff

# Setup code {{{
import codecs

from calibre.constants import plugins
from calibre.utils.config_base import tweaks

_locale = _collator = _primary_collator = _sort_collator = _numeric_collator = _case_sensitive_collator = None

_none = u''
_none2 = b''
_cmap = {}

_icu, err = plugins['icu']
if _icu is None:
    raise RuntimeError('Failed to load icu with error: %s' % err)
del err
icu_unicode_version = getattr(_icu, 'unicode_version', None)
_nmodes = {m:getattr(_icu, m) for m in ('NFC', 'NFD', 'NFKC', 'NFKD')}

# Ensure that the python internal filesystem and default encodings are not ASCII


def is_ascii(name):
    try:
        return codecs.lookup(name).name == b'ascii'
    except (TypeError, LookupError):
        return True


try:
    if is_ascii(sys.getdefaultencoding()):
        _icu.set_default_encoding(b'utf-8')
except:
    import traceback
    traceback.print_exc()

try:
    if is_ascii(sys.getfilesystemencoding()):
        _icu.set_filesystem_encoding(b'utf-8')
except:
    import traceback
    traceback.print_exc()
del is_ascii


def collator():
    global _collator, _locale
    if _collator is None:
        if _locale is None:
            from calibre.utils.localization import get_lang
            if tweaks['locale_for_sorting']:
                _locale = tweaks['locale_for_sorting']
            else:
                _locale = get_lang()
        try:
            _collator = _icu.Collator(_locale)
        except Exception as e:
            print ('Failed to load collator for locale: %r with error %r, using English' % (_locale, e))
            _collator = _icu.Collator('en')
    return _collator


def change_locale(locale=None):
    global _locale, _collator, _primary_collator, _sort_collator, _numeric_collator, _case_sensitive_collator
    _collator = _primary_collator = _sort_collator = _numeric_collator = _case_sensitive_collator = None
    _locale = locale


def primary_collator():
    'Ignores case differences and accented characters'
    global _primary_collator
    if _primary_collator is None:
        _primary_collator = collator().clone()
        _primary_collator.strength = _icu.UCOL_PRIMARY
    return _primary_collator


def sort_collator():
    'Ignores case differences and recognizes numbers in strings (if the tweak is set)'
    global _sort_collator
    if _sort_collator is None:
        _sort_collator = collator().clone()
        _sort_collator.strength = _icu.UCOL_SECONDARY
        _sort_collator.numeric = tweaks['numeric_collation']
    return _sort_collator


def numeric_collator():
    'Uses natural sorting for numbers inside strings so something2 will sort before something10'
    global _numeric_collator
    if _numeric_collator is None:
        _numeric_collator = collator().clone()
        _numeric_collator.strength = _icu.UCOL_SECONDARY
        _numeric_collator.numeric = True
    return _numeric_collator


def case_sensitive_collator():
    'Always sorts upper case letter before lower case'
    global _case_sensitive_collator
    if _case_sensitive_collator is None:
        _case_sensitive_collator = collator().clone()
        _case_sensitive_collator.numeric = sort_collator().numeric
        _case_sensitive_collator.upper_first = True
    return _case_sensitive_collator

# Templates that will be used to generate various concrete
# function implementations based on different collators, to allow lazy loading
# of collators, with maximum runtime performance


_sort_key_template = '''
def {name}(obj):
    try:
        try:
            return {collator}.{func}(obj)
        except AttributeError:
            return {collator_func}().{func}(obj)
    except TypeError:
        if isinstance(obj, bytes):
            try:
                obj = obj.decode(sys.getdefaultencoding())
            except ValueError:
                return obj
            return {collator}.{func}(obj)
    return b''
'''

_strcmp_template = '''
def {name}(a, b):
    try:
        try:
            return {collator}.{func}(a, b)
        except AttributeError:
            return {collator_func}().{func}(a, b)
    except TypeError:
        if isinstance(a, bytes):
            try:
                a = a.decode(sys.getdefaultencoding())
            except ValueError:
                return cmp(a, b)
        elif a is None:
            a = u''
        if isinstance(b, bytes):
            try:
                b = b.decode(sys.getdefaultencoding())
            except ValueError:
                return cmp(a, b)
        elif b is None:
            b = u''
        return {collator}.{func}(a, b)
'''

_change_case_template = '''
def {name}(x):
    try:
        try:
            return _icu.change_case(x, _icu.{which}, _locale)
        except NotImplementedError:
            collator()  # sets _locale
            return _icu.change_case(x, _icu.{which}, _locale)
    except TypeError:
        if isinstance(x, bytes):
            try:
                x = x.decode(sys.getdefaultencoding())
            except ValueError:
                return x
            return _icu.change_case(x, _icu.{which}, _locale)
        raise
'''


def _make_func(template, name, **kwargs):
    l = globals()
    kwargs['name'] = name
    kwargs['func'] = kwargs.get('func', 'sort_key')
    exec(template.format(**kwargs), l)
    return l[name]


# }}}

# ################ The string functions ########################################
sort_key = _make_func(_sort_key_template, 'sort_key', collator='_sort_collator', collator_func='sort_collator')

numeric_sort_key = _make_func(_sort_key_template, 'numeric_sort_key', collator='_numeric_collator', collator_func='numeric_collator')

primary_sort_key = _make_func(_sort_key_template, 'primary_sort_key', collator='_primary_collator', collator_func='primary_collator')

case_sensitive_sort_key = _make_func(_sort_key_template, 'case_sensitive_sort_key',
                                     collator='_case_sensitive_collator', collator_func='case_sensitive_collator')

collation_order = _make_func(_sort_key_template, 'collation_order', collator='_sort_collator', collator_func='sort_collator', func='collation_order')

strcmp = _make_func(_strcmp_template, 'strcmp', collator='_sort_collator', collator_func='sort_collator', func='strcmp')

case_sensitive_strcmp = _make_func(
    _strcmp_template, 'case_sensitive_strcmp', collator='_case_sensitive_collator', collator_func='case_sensitive_collator', func='strcmp')

primary_strcmp = _make_func(_strcmp_template, 'primary_strcmp', collator='_primary_collator', collator_func='primary_collator', func='strcmp')

upper = _make_func(_change_case_template, 'upper', which='UPPER_CASE')

lower = _make_func(_change_case_template, 'lower', which='LOWER_CASE')

title_case = _make_func(_change_case_template, 'title_case', which='TITLE_CASE')


def capitalize(x):
    try:
        return upper(x[0]) + lower(x[1:])
    except (IndexError, TypeError, AttributeError):
        return x


try:
    swapcase = _icu.swap_case
except AttributeError:  # For people running from source
    swapcase = lambda x:x.swapcase()

find = _make_func(_strcmp_template, 'find', collator='_collator', collator_func='collator', func='find')

primary_find = _make_func(_strcmp_template, 'primary_find', collator='_primary_collator', collator_func='primary_collator', func='find')

contains = _make_func(_strcmp_template, 'contains', collator='_collator', collator_func='collator', func='contains')

primary_contains = _make_func(_strcmp_template, 'primary_contains', collator='_primary_collator', collator_func='primary_collator', func='contains')

startswith = _make_func(_strcmp_template, 'startswith', collator='_collator', collator_func='collator', func='startswith')

primary_startswith = _make_func(_strcmp_template, 'primary_startswith', collator='_primary_collator', collator_func='primary_collator', func='startswith')

safe_chr = _icu.chr

ord_string = _icu.ord_string


def character_name(string):
    try:
        return _icu.character_name(unicode(string)) or None
    except (TypeError, ValueError, KeyError):
        pass


def character_name_from_code(code):
    try:
        return _icu.character_name_from_code(code) or ''
    except (TypeError, ValueError, KeyError):
        return ''


def normalize(text, mode='NFC'):
    # This is very slightly slower than using unicodedata.normalize, so stick with
    # that unless you have very good reasons not too. Also, it's speed
    # decreases on wide python builds, where conversion to/from ICU's string
    # representation is slower.
    return _icu.normalize(_nmodes[mode], unicode(text))


def contractions(col=None):
    global _cmap
    col = col or _collator
    if col is None:
        col = collator()
    ans = _cmap.get(collator, None)
    if ans is None:
        ans = col.contractions()
        ans = frozenset(filter(None, ans))
        _cmap[col] = ans
    return ans


def partition_by_first_letter(items, reverse=False, key=lambda x:x):
    # Build a list of 'equal' first letters by noticing changes
    # in ICU's 'ordinal' for the first letter.
    from collections import OrderedDict
    items = sorted(items, key=lambda x:sort_key(key(x)), reverse=reverse)
    ans = OrderedDict()
    last_c, last_ordnum = ' ', 0
    for item in items:
        c = icu_upper(key(item) or ' ')
        ordnum, ordlen = collation_order(c)
        if last_ordnum != ordnum:
            if not is_narrow_build:
                ordlen = 1
            last_c = c[0:ordlen]
            last_ordnum = ordnum
        try:
            ans[last_c].append(item)
        except KeyError:
            ans[last_c] = [item]
    return ans


# Return the number of unicode codepoints in a string
string_length = _icu.string_length if is_narrow_build else len

# Return the number of UTF-16 codepoints in a string
utf16_length = len if is_narrow_build else _icu.utf16_length

################################################################################

if __name__ == '__main__':
    from calibre.utils.icu_test import run
    run(verbosity=4)
