from passlib.context import CryptContext
from jose import jwt, JWTError
from datetime import datetime, timedelta, timezone
from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.config import settings
from app.database import get_db
from app.models.user import User

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
security = HTTPBearer()

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(data: dict) -> str:
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)

async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: AsyncSession = Depends(get_db)
) -> User:
    try:
        payload = jwt.decode(credentials.credentials, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
        user_id = payload.get("sub")
        if user_id is None:
            raise HTTPException(status_code=401, detail="Invalid token")
    except JWTError:
        raise HTTPException(status_code=401, detail="Invalid token")
    
    result = await db.execute(select(User).where(User.id == int(user_id)))
    user = result.scalar_one_or_none()
    if user is None:
        raise HTTPException(status_code=401, detail="User not found")
    return user