from datetime import datetime, timedelta, timezone
from typing import Optional

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

from app.config.config import settings

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


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


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


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    """Creates a signed JWT with an expiry claim."""
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + (
        expires_delta or timedelta(minutes=settings.JWT_EXPIRE_MINUTES)
    )
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, settings.JWT_SECRET_KEY, algorithm=settings.JWT_ALGORITHM)


async def get_current_user(token: str = Depends(oauth2_scheme)) -> dict:
    """FastAPI dependency — validates Bearer JWT and returns the payload sub."""
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="401 Unauthorized",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(
            token,
            settings.JWT_SECRET_KEY,
            algorithms=[settings.JWT_ALGORITHM],
        )
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception
    return {
        "username": username,
        "email": username if "@" in username else None,
        "name": payload.get("name"),
    }