from __future__ import annotations

from django.utils import timezone
from rest_framework.authentication import BaseAuthentication, get_authorization_header
from rest_framework.exceptions import AuthenticationFailed, PermissionDenied

from apps.api.errors import api_error
from apps.api.throttles import throttle_api_auth_failure
from apps.users.models import ApiKey


class ApiKeyAuthentication(BaseAuthentication):
    keyword = "Bearer"

    def authenticate(self, request):
        raw_header = get_authorization_header(request)
        if not raw_header:
            return None

        try:
            header = raw_header.decode("utf-8")
        except UnicodeError as exc:
            raise self.authentication_failed(request) from exc

        parts = header.split()
        if len(parts) != 2 or parts[0].lower() != self.keyword.lower():
            raise self.authentication_failed(request)

        raw_key = parts[1]
        if not raw_key:
            raise self.authentication_failed(request)

        key_hash = ApiKey.hash_key(raw_key)
        try:
            api_key = ApiKey.objects.select_related("user").get(key_hash=key_hash)
        except ApiKey.DoesNotExist as exc:
            raise self.authentication_failed(request) from exc

        if not api_key.matches_key(raw_key):
            raise self.authentication_failed(request)

        if not api_key.is_active_key:
            raise PermissionDenied(
                api_error("account_disabled", "账号或 API Key 已禁用")
            )

        if not api_key.user.is_business_active:
            raise PermissionDenied(
                api_error("account_disabled", "账号或 API Key 已禁用")
            )

        now = timezone.now()
        ApiKey.objects.filter(pk=api_key.pk).update(last_used_at=now)
        api_key.last_used_at = now
        return api_key.user, api_key

    def authenticate_header(self, request) -> str:
        return self.keyword

    @staticmethod
    def authentication_failed(request) -> AuthenticationFailed:
        throttle_api_auth_failure(request)
        return AuthenticationFailed(api_error("unauthorized", "缺失或无效 API Key"))