from datetime import datetime, timedelta, timezone
from typing import Any
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import HTTPException, status, Depends
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import Session
from backend.core.config import settings
from backend.core.database import get_db

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


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


def verify_password(plain: str, hashed: str) -> bool:
    return pwd_context.verify(plain, hashed)


def create_access_token(subject: Any, expires_delta: timedelta | None = None) -> str:
    expire = datetime.now(timezone.utc) + (
        expires_delta or timedelta(minutes=settings.access_token_expire_minutes)
    )
    payload = {"sub": str(subject), "exp": expire}
    return jwt.encode(payload, settings.secret_key, algorithm=settings.algorithm)


def decode_token(token: str) -> dict:
    try:
        return jwt.decode(token, settings.secret_key, algorithms=[settings.algorithm])
    except JWTError:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Token invalide ou expiré",
            headers={"WWW-Authenticate": "Bearer"},
        )


def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: Session = Depends(get_db),
):
    from backend.models.user import User

    payload = decode_token(token)
    user_id: str = payload.get("sub")
    if not user_id:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Token invalide")

    user = db.get(User, int(user_id))
    if not user or not user.is_active:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Utilisateur introuvable ou inactif")
    return user