# Type stubs aren't available for regex.

# Fortunately, we're using it in a way that's API-compatible with the re

# module. We mitigate the lack of type stubs by providing type declarations

# for returned objects. This way, the only thing that isn't type checked are

# the calls to regex functions.

import regex  # type:ignore[import]

from typing import (

    Pattern,

)

    # alnum is the set of characters we always accept in entity metadata:

    # letters and digits, minus the Latin 1 supplement (i.e., Roman letters

    # with diacritics: áÁàÀâÂåÅäÄãà çÇ ðÐ ñÑ øØ ß etc.)

    # See the tests for specific cases.

    alnum = r'\p{Letter}\p{Digit}--\p{Block=Latin_1_Supplement}'

    # A regexp that would be reasonably stricter would be:

    #   f'^[{alnum}][.{alnum}]*(?:-[.{alnum}])*$'

    # However, current producers fail that regexp in a few different ways.

    # See the tests for specific cases.

    ENTITY_RE: Pattern[str] = regex.compile(f'^[{alnum}][-.{alnum}]*$', regex.VERSION1)

    del alnum

        'regex',

    # Classic entity: LastName-FirstName

    # Various people and companies have one-word names

    # Digits are allowed, as part of a name or standalone

    'Company-19',

    # No case requirements

    # No limit on the number of parts of the name

    # Names that have no ASCII are allowed, with or without dash separators

    '田中流星',

    '田中-流星',

    'スミスダコタ',

    'スミス-ダコタ',

    'Яшин-Данила',

    # The PayPal importer produces . in entity metadata

    'Du-Bois-W.-E.-B.',

    # import2ledger produces entities that end with -

    # That's probably a bug, but allow it for now.

    'foo-',

    # Starting with a - is not allowed

    # Names that can be reduced to ASCII should be

    # Producers should change this to Uberentity or Ueberentity

    # I am not wild about this rule and would like to relax it—it's mostly

    # based on an expectation that entities are typed in by a human. That's true

    # less and less and it seems like we should reduce the amount of mangling

    # producers are expected to do. But it's the rule for today.

    # Whitespace is never allowed

    '田中 流星',

    'スミス ダコタ',

    'Яшин Данила',

    # An empty string is not valid