import hashlib
import secrets
from dataclasses import dataclass
from datetime import UTC, datetime, timedelta

from .database import SiteDatabase
from .crypto import TokenCipher


def hash_token(token: str) -> bytes:
    return hashlib.sha256(token.encode("utf-8")).digest()


@dataclass(frozen=True)
class BindingLink:
    url: str
    expires_at: datetime


class SiteBindingRepository:
    """Доступ сайта только к функциям выпуска токенов."""

    def __init__(self, database: SiteDatabase) -> None:
        self.database = database

    def issue(
            self,
            member_id: str,
            domain: str,
            bitrix_user_id: int,
            token_hash: bytes,
            token_expires_at: datetime,
            access_token: bytes,
            refresh_token: bytes,
            oauth_expires_at: datetime,
    ) -> None:
        """Сохраняет в БД информацию о токене, выданном пользователю."""
        query = """
                SELECT *
                FROM binding.issue_v1(%s, %s, %s, %s, %s, %s, %s, %s) \
                """
        with self.database.transaction() as connection:
            connection.execute(
                query,
                (
                    member_id,
                    domain,
                    bitrix_user_id,
                    token_hash,
                    token_expires_at,
                    access_token,
                    refresh_token,
                    oauth_expires_at,
                ),
            ).fetchone()


class BindingService:
    def __init__(
            self,
            repository: SiteBindingRepository,
            cipher: TokenCipher,
            bot_username: str,
            ttl_seconds: int,
    ) -> None:
        self.repository = repository
        self.cipher = cipher
        self.bot_username = bot_username
        self.ttl_seconds = ttl_seconds

    def issue(
            self,
            member_id: str,
            domain: str,
            bitrix_user_id: int,
            access_token: str,
            refresh_token: str,
            auth_expires_seconds: int,
    ) -> BindingLink:
        """Выдает ссылку для привязки аккаунта."""
        token = secrets.token_urlsafe(32)
        now = datetime.now(UTC)
        token_expires_at = now + timedelta(seconds=self.ttl_seconds)
        oauth_expires_at = now + timedelta(seconds=auth_expires_seconds)
        self.repository.issue(
            member_id,
            domain,
            bitrix_user_id,
            hash_token(token),
            token_expires_at,
            self.cipher.encrypt(access_token),
            self.cipher.encrypt(refresh_token),
            oauth_expires_at,
        )
        return BindingLink(
            url=f"https://t.me/{self.bot_username}?start=bind_{token}",
            expires_at=token_expires_at,
        )