"""Authentification JWT — create_access_token, verify_token, get_current_user."""
from __future__ import annotations

import os
from datetime import datetime, timedelta, timezone

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
from passlib.context import CryptContext
from sqlalchemy.orm import Session

from database import get_db
from models import User

SECRET_KEY = os.getenv("SECRET_KEY", "dev-secret-key-change-in-production")
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = int(os.getenv("ACCESS_TOKEN_EXPIRE_MINUTES", "60"))

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/auth/login")


def hash_password(password: str) -> str:
    return pwd_context.hash(password)


def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)


def create_access_token(data: dict, expires_delta: timedelta | None = None) -> str:
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + (
        expires_delta or timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    )
    to_encode["exp"] = expire
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)


def verify_token(token: str) -> dict:
    """Décode et valide un JWT. Lève HTTPException 401 si invalide."""
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        return payload
    except JWTError as exc:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Token invalide ou expiré",
            headers={"WWW-Authenticate": "Bearer"},
        ) from exc


def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: Session = Depends(get_db),
) -> User:
    """Dépendance FastAPI : retourne l'utilisateur authentifié."""
    payload = verify_token(token)
    user_id_str: str | None = payload.get("sub")
    if user_id_str is None:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Token malformé")

    user = db.get(User, int(user_id_str))
    if user is None:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Utilisateur introuvable")
    if not user.is_active:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Compte désactivé")
    return user