# dynamic_filtering implementation

import logging
from typing import Dict, List, Any

# Configure logging
logger = logging.getLogger(__name__)

class DynamicFilteringRecommender:
    def __init__(self, base_recommender: Any):
        """
        Initialize the DynamicFilteringRecommender with a base recommender.

        Parameters:
        - base_recommender (Any): An instance of a base recommender (e.g., LSA, LDA).
        """
        self.base_recommender = base_recommender
        # Keeps track of items that have been added or removed
        self.added_items: List[int] = []
        self.removed_items: List[int] = []
        logger.info("DynamicFilteringRecommender initialized with base recommender.")

    def add_item(self, item_id: int, item_features: Dict[str, Any]):
        """
        Add a new item to the recommender system.

        Parameters:
        - item_id (int): The ID of the new item.
        - item_features (Dict[str, Any]): The features of the new item.
        """
        logger.info(f"Adding item {item_id} to the base recommender.")
        if hasattr(self.base_recommender, 'add_item'):
            self.base_recommender.add_item(item_id, item_features)
            self.added_items.append(item_id)
            logger.info(f"Item {item_id} added to the base recommender successfully.")
        else:
            logger.warning("Base recommender does not support adding items dynamically.")

    def remove_item(self, item_id: int):
        """
        Remove an existing item from the recommender system.

        Parameters:
        - item_id (int): The ID of the item to remove.
        """
        logger.info(f"Removing item {item_id} from the base recommender.")
        if hasattr(self.base_recommender, 'remove_item'):
            self.base_recommender.remove_item(item_id)
            self.removed_items.append(item_id)
            logger.info(f"Item {item_id} removed from the base recommender successfully.")
        else:
            logger.warning("Base recommender does not support removing items dynamically.")

    def update_item_features(self, item_id: int, new_features: Dict[str, Any]):
        """
        Update the features of an existing item.

        Parameters:
        - item_id (int): The ID of the item to update.
        - new_features (Dict[str, Any]): The updated features of the item.
        """
        try:
            if hasattr(self.base_recommender, 'update_item_features'):
                self.base_recommender.update_item_features(item_id, new_features)
                logger.info(f"Updated features for item {item_id} in the base recommender.")
            else:
                logger.warning("Base recommender does not support updating item features dynamically.")
        except Exception as e:
            logger.error(f"Error updating features for item {item_id}: {e}")

    def handle_data_change(self, event: Dict[str, Any]):
        """
        Handle dynamic data changes such as adding or removing items.

        Parameters:
        - event (Dict[str, Any]): A dictionary containing the type of event and relevant data.
          Example:
          {
              'action': 'add',
              'item_id': 123,
              'item_features': {'genre': 'Comedy', 'duration': 120}
          }
        """
        action = event.get('action')
        if action == 'add':
            self.add_item(event['item_id'], event['item_features'])
        elif action == 'remove':
            self.remove_item(event['item_id'])
        elif action == 'update':
            self.update_item_features(event['item_id'], event['item_features'])
        else:
            logger.warning(f"Unsupported event action: {action}")

    def recommend(self, user_id: int, query: str, top_n: int = 10) -> List[int]:
        """
        Generate top-N item recommendations for a user, considering dynamic changes.

        Parameters:
        - user_id (int): The ID of the user.
        - query (str): The query text for generating recommendations.
        - top_n (int): Number of top recommendations to return.

        Returns:
        - List[int]: List of recommended item IDs.
        """
        logger.info(f"Generating recommendations for user {user_id} with query '{query}' using DynamicFilteringRecommender.")
        return self.base_recommender.recommend(query, top_n=top_n)
