from __future__ import annotations

from collections.abc import Sequence
from re import Pattern
from typing import Union, cast

from django.conf import settings

from corsheaders.defaults import default_headers, default_methods


class Settings:
    """
    Shadow Django's settings with a little logic
    """

    @property
    def CORS_ALLOW_HEADERS(self) -> Sequence[str]:
        return getattr(settings, "CORS_ALLOW_HEADERS", default_headers)

    @property
    def CORS_ALLOW_METHODS(self) -> Sequence[str]:
        return getattr(settings, "CORS_ALLOW_METHODS", default_methods)

    @property
    def CORS_ALLOW_CREDENTIALS(self) -> bool:
        return getattr(settings, "CORS_ALLOW_CREDENTIALS", False)

    @property
    def CORS_ALLOW_PRIVATE_NETWORK(self) -> bool:
        return getattr(settings, "CORS_ALLOW_PRIVATE_NETWORK", False)

    @property
    def CORS_PREFLIGHT_MAX_AGE(self) -> int:
        return getattr(settings, "CORS_PREFLIGHT_MAX_AGE", 86400)

    @property
    def CORS_ALLOW_ALL_ORIGINS(self) -> bool:
        return getattr(
            settings,
            "CORS_ALLOW_ALL_ORIGINS",
            getattr(settings, "CORS_ORIGIN_ALLOW_ALL", False),
        )

    @property
    def CORS_ALLOWED_ORIGINS(self) -> list[str] | tuple[str]:
        value = getattr(
            settings,
            "CORS_ALLOWED_ORIGINS",
            getattr(settings, "CORS_ORIGIN_WHITELIST", ()),
        )
        return cast(Union[list[str], tuple[str]], value)

    @property
    def CORS_ALLOWED_ORIGIN_REGEXES(self) -> Sequence[str | Pattern[str]]:
        return getattr(
            settings,
            "CORS_ALLOWED_ORIGIN_REGEXES",
            getattr(settings, "CORS_ORIGIN_REGEX_WHITELIST", ()),
        )

    @property
    def CORS_EXPOSE_HEADERS(self) -> Sequence[str]:
        return getattr(settings, "CORS_EXPOSE_HEADERS", ())

    @property
    def CORS_URLS_REGEX(self) -> str | Pattern[str]:
        return getattr(settings, "CORS_URLS_REGEX", r"^.*$")


conf = Settings()
