"""
Authentication module for backend API.
Handles JWT-based authentication, token generation, and user context.
"""

from datetime import datetime, timedelta, timezone
from typing import Optional, Dict, Any, Tuple
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
import logging

from modules.interfaces.gatewayInterface import getGatewayInterface
from modules.shared.configuration import APP_CONFIG

# Get Config Data
SECRET_KEY = APP_CONFIG.get("APP_JWT_SECRET_SECRET")
ALGORITHM = APP_CONFIG.get("Auth_ALGORITHM")
ACCESS_TOKEN_EXPIRE_MINUTES = int(APP_CONFIG.get("APP_TOKEN_EXPIRY"))

# OAuth2 Setup
oauth2Scheme = OAuth2PasswordBearer(tokenUrl="token")

# Logger
logger = logging.getLogger(__name__)

def createAccessToken(data: dict, expiresDelta: Optional[timedelta] = None) -> str:
    """
    Creates a JWT Access Token.
    
    Args:
        data: Data to encode (usually user ID or username)
        expiresDelta: Validity duration of the token (optional)
        
    Returns:
        JWT Token as string
    """
    toEncode = data.copy()
    
    if expiresDelta:
        expire = datetime.now(timezone.utc) + expiresDelta
    else:
        expire = datetime.now(timezone.utc) + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
        
    toEncode.update({"exp": expire})
    encodedJwt = jwt.encode(toEncode, SECRET_KEY, algorithm=ALGORITHM)
    
    return encodedJwt

async def getCurrentUser(token: str = Depends(oauth2Scheme)) -> Dict[str, Any]:
    """
    Extracts and validates the current user from the JWT token.
    
    Args:
        token: JWT Token from the Authorization header
        
    Returns:
        User data
        
    Raises:
        HTTPException: For invalid token or user
    """
    credentialsException = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Invalid authentication credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    
    try:
        # Decode token
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        
        # Extract username from token
        username: str = payload.get("sub")
        if username is None:
            raise credentialsException
            
        # Extract mandate ID from token (if present)
        mandateId: int = payload.get("mandateId", 1)  # Default: Root mandate
        
    except JWTError:
        logger.warning("Invalid JWT Token")
        raise credentialsException
    
    # Initialize Gateway Interface without context
    gateway = getGatewayInterface()
    
    # Retrieve user from database
    user = gateway.getUserByUsername(username)
    
    if user is None:
        logger.warning(f"User {username} not found")
        raise credentialsException
        
    if user.get("disabled", False):
        logger.warning(f"User {username} is disabled")
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="User is disabled")
    
    return user

async def getCurrentActiveUser(currentUser: Dict[str, Any] = Depends(getCurrentUser)) -> Dict[str, Any]:
    """
    Ensures that the user is active.
    
    Args:
        currentUser: Current user data
        
    Returns:
        User data
        
    Raises:
        HTTPException: If the user is disabled
    """
    if currentUser.get("disabled", False):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="User is disabled")
        
    return currentUser

async def getUserContext(currentUser: Dict[str, Any]) -> Tuple[int, int]:
    """
    Extracts the mandate ID and user ID from the current user.
    Enhanced with better logging.
    
    Args:
        currentUser: The current user
        
    Returns:
        Tuple of (mandateId, userId)
    """
    # Default values
    defaultMandateId = 0
    defaultUserId = 0
    
    # Extract mandateId
    mandateId = currentUser.get("mandateId", None)
    if mandateId is None:
        logger.warning(f"No mandateId found in currentUser, using default: {defaultMandateId}")
        mandateId = defaultMandateId
    else:
        try:
            mandateId = int(mandateId)
        except (ValueError, TypeError):
            logger.error(f"Invalid mandateId value: {mandateId}, using default: {defaultMandateId}")
            mandateId = defaultMandateId
    
    # Extract userId
    userId = currentUser.get("id", None)
    if userId is None:
        logger.warning(f"No userId found in currentUser, using default: {defaultUserId}")
        userId = defaultUserId
    else:
        try:
            userId = int(userId)
        except (ValueError, TypeError):
            logger.error(f"Invalid userId value: {userId}, using default: {defaultUserId}")
            userId = defaultUserId
    
    return mandateId, userId