from datetime import datetime, timedelta, timezone
import jwt
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from passlib.context import CryptContext
from config import SECRET_KEY, ALGORITHM, ACCESS_TOKEN_EXPIRE_HOURS
from models import TokenData, UserInDB, User
from database import get_users
from typing import Annotated, Optional
from jwt.exceptions import InvalidTokenError

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

# Authentication helper functions
def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)

def get_user(db, username: str):
    if username in db:
        user_dict = db[username]
        return UserInDB(**user_dict)
    return None

def authenticate_user(fake_db, username: str, password: str):
    user = get_user(fake_db, username)
    if not user:
        return None
    if not verify_password(password, user.hashed_password):
        return None
    return user  # Return the user object, not a boolean

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.now(timezone.utc) + expires_delta
    else:
        expire = datetime.now(timezone.utc) + timedelta(hours=ACCESS_TOKEN_EXPIRE_HOURS)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        print(f"Decoding token: {token[:10]}...")
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        print(f"Token payload: {payload}")
        username = payload.get("sub")
        if username is None:
            print("Username not found in token payload")
            raise credentials_exception
        token_data = TokenData(username=username)
        print(f"Token data: {token_data}")
    except InvalidTokenError as e:
        print(f"Token validation error: {str(e)}")
        raise credentials_exception
    except Exception as e:
        print(f"Unexpected error during token validation: {str(e)}")
        raise credentials_exception

    users = get_users()
    print(f"Available users: {list(users.keys())}")
    user = get_user(users, username=token_data.username)
    if user is None:
        print(f"User not found: {token_data.username}")
        raise credentials_exception
    print(f"User authenticated: {user.username}")
    return user

async def get_current_active_user(
    current_user: Annotated[User, Depends(get_current_user)],
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user