import uuid
from collections.abc import AsyncGenerator

from fastapi import Depends, Request
from fastapi_users import BaseUserManager, FastAPIUsers, UUIDIDMixin
from fastapi_users.authentication import (
    AuthenticationBackend,
    BearerTransport,
    JWTStrategy,
)
from fastapi_users.db import SQLAlchemyUserDatabase
from sqlalchemy.ext.asyncio import AsyncSession

from app.auth.email import send_email
from app.config import settings
from app.db import get_async_session
from app.models.user import User

JWT_LIFETIME_SECONDS = 60 * 60 * 24 * 7  # 7 days


async def get_user_db(
    session: AsyncSession = Depends(get_async_session),
) -> AsyncGenerator[SQLAlchemyUserDatabase, None]:
    yield SQLAlchemyUserDatabase(session, User)


class UserManager(UUIDIDMixin, BaseUserManager[User, uuid.UUID]):
    reset_password_token_secret = settings.reset_password_secret
    verification_token_secret = settings.verification_token_secret

    async def on_after_forgot_password(
        self, user: User, token: str, request: Request | None = None
    ) -> None:
        reset_url = f"{settings.frontend_origin}/reset-password?token={token}"
        await send_email(
            to=user.email,
            subject="Passwort zurücksetzen — DungeonsDragons",
            body=(
                f"Hallo {user.name},\n\n"
                f"klicke auf den folgenden Link, um dein Passwort zurückzusetzen:\n{reset_url}\n\n"
                "Falls du das nicht angefordert hast, ignoriere diese E-Mail."
            ),
        )


async def get_user_manager(
    user_db: SQLAlchemyUserDatabase = Depends(get_user_db),
) -> AsyncGenerator[UserManager, None]:
    yield UserManager(user_db)


bearer_transport = BearerTransport(tokenUrl="auth/jwt/login")


def get_jwt_strategy() -> JWTStrategy:
    return JWTStrategy(secret=settings.jwt_secret, lifetime_seconds=JWT_LIFETIME_SECONDS)


auth_backend = AuthenticationBackend(
    name="jwt",
    transport=bearer_transport,
    get_strategy=get_jwt_strategy,
)

fastapi_users = FastAPIUsers[User, uuid.UUID](get_user_manager, [auth_backend])

current_active_user = fastapi_users.current_user(active=True)