from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from typing import Optional
from motor.motor_asyncio import AsyncIOMotorDatabase
from bson import ObjectId
from .security import verify_token
from ..config.database import get_database
from ..models.user import UserInDB, UserRole

security = HTTPBearer()

async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: AsyncIOMotorDatabase = Depends(get_database)
) -> UserInDB:
    """Get current authenticated user"""
    token = credentials.credentials
    payload = verify_token(token)
    
    user_id = payload.get("sub")
    if user_id is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    user = await db.users.find_one({"_id": ObjectId(user_id)})
    if user is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="User not found",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    return UserInDB(**user)

async def get_current_active_user(
    current_user: UserInDB = Depends(get_current_user)
) -> UserInDB:
    """Get current active user"""
    if not current_user.is_active:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Inactive user"
        )
    return current_user

async def get_current_admin_user(
    current_user: UserInDB = Depends(get_current_active_user)
) -> UserInDB:
    """Get current admin user"""
    if current_user.role != UserRole.ADMIN:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Not enough permissions"
        )
    return current_user

async def has_index_access(
    index_id: str,
    current_user: UserInDB = Depends(get_current_active_user)
) -> bool:
    """Check if user has access to specific index"""
    # Admin users have access to all indices
    if current_user.role == UserRole.ADMIN:
        return True
    
    # Check if user has explicit access to this index
    return index_id in current_user.index_access

def require_index_access(index_id: str):
    """Dependency to require index access"""
    async def check_access(current_user: UserInDB = Depends(get_current_active_user)):
        if not await has_index_access(index_id, current_user):
            raise HTTPException(
                status_code=status.HTTP_403_FORBIDDEN,
                detail="Access denied to this index"
            )
        return current_user
    return check_access