from __future__ import annotations

import secrets
from datetime import datetime, timezone

from fastapi import Depends, Request, Response
from sqlalchemy.orm import Session

from backend.app.db import get_db
from backend.app import models

DEVICE_COOKIE_NAME = "opc_device_token"


def _issue_new_device_user(db: Session, response: Response) -> models.User:
  token = secrets.token_hex(32)
  user = models.User(
      device_token=token,
      created_at=datetime.now(timezone.utc),
      last_seen_at=datetime.now(timezone.utc),
  )
  db.add(user)
  db.commit()
  db.refresh(user)
  response.set_cookie(
      key=DEVICE_COOKIE_NAME,
      value=token,
      httponly=True,
      secure=False,
      samesite="Lax",
      max_age=60 * 60 * 24 * 365,
  )
  return user


def get_current_user(
  request: Request,
  response: Response,
  db: Session = Depends(get_db),
) -> models.User:
  token = request.cookies.get(DEVICE_COOKIE_NAME)
  if not token:
      return _issue_new_device_user(db, response)

  user = (
      db.query(models.User)
      .filter(models.User.device_token == token)
      .first()
  )
  if not user:
      return _issue_new_device_user(db, response)

  user.last_seen_at = datetime.now(timezone.utc)
  db.commit()
  return user