from __future__ import annotations

from collections.abc import AsyncIterator
from typing import Annotated

from fastapi import Depends, Request
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
from sqlalchemy.ext.asyncio import AsyncSession

from fintracker.api.errors import Problem
from fintracker.api.security import decode_access_token
from fintracker.config import Settings, get_settings
from fintracker.db import get_sessionmaker
from fintracker.models import AppUser

_bearer = HTTPBearer(auto_error=False)


async def get_session() -> AsyncIterator[AsyncSession]:
    async with get_sessionmaker()() as session:
        yield session


SessionDep = Annotated[AsyncSession, Depends(get_session)]
SettingsDep = Annotated[Settings, Depends(get_settings)]


async def get_current_user(
    session: SessionDep,
    settings: SettingsDep,
    creds: Annotated[HTTPAuthorizationCredentials | None, Depends(_bearer)],
) -> AppUser:
    if creds is None:
        raise Problem(401, "Unauthorized", "Missing bearer token")
    user_id = decode_access_token(creds.credentials, settings)
    if user_id is None:
        raise Problem(401, "Unauthorized", "Invalid or expired token")
    user = await session.get(AppUser, user_id)
    if user is None:
        raise Problem(401, "Unauthorized", "Unknown user")
    return user


CurrentUser = Annotated[AppUser, Depends(get_current_user)]


def client_ip(request: Request) -> str:
    fwd = request.headers.get("x-forwarded-for")
    if fwd:
        return fwd.split(",")[0].strip()
    return request.client.host if request.client else "unknown"