import os
from pymongo import MongoClient
from dotenv import load_dotenv
from typing import List, Dict, Optional
from application.utils.logger import get_logger

logger = get_logger()

load_dotenv()

DB_NAME = "sustainability_reports_db"

def get_mongo_client():
    try:
        client = MongoClient(os.getenv("MONGODB_URI"))
        return client
    except Exception as e:
        logger.exception(f"An unexpected error occurred while connecting to MongoDB: {str(e)}")
    return None

def store_document(collection_name: str, document: Dict) -> Optional[str]:
    """
    Stores a document in MongoDB if it doesn't already exist.

    Args:
        collection_name (str): Name of the MongoDB collection.
        document (Dict): The document to be inserted.

    Returns:
        Optional[str]: Inserted document ID if successful, None otherwise.
    """
    try:
        client = get_mongo_client()
        if client is None:
            logger.error("MongoDB client is not available.")
            return None
        
        db = client.get_database(DB_NAME)
        collection = db[collection_name]

        # Check if a similar document already exists
        existing_document = collection.find_one(document)
        if existing_document:
            logger.info(f"Document already exists with ID: {existing_document['_id']}")
            return str(existing_document['_id'])

        # If no existing document, insert the new one
        result = collection.insert_one(document)
        logger.info(f"New document inserted with ID: {result.inserted_id}")
        return str(result.inserted_id)

    except Exception as e:
        logger.exception(f"An unexpected error occurred: {str(e)}")
    
    return None

def retrieve_documents(collection_name: str, query: Optional[Dict] = None) -> List[Dict]:
    """
    Retrieves documents from the specified MongoDB collection.

    Args:
        collection_name (str): Name of the MongoDB collection.
        query (Optional[Dict]): A MongoDB query filter. Defaults to {} (fetch all documents).

    Returns:
        List[Dict]: A list of documents matching the query. Empty list if none found or error occurs.
    """
    try:
        client = get_mongo_client()
        if client is None:
            logger.error("MongoDB client is not available.")
            return []

        db = client.get_database(DB_NAME)
        collection = db[collection_name]

        documents_cursor = collection.find(query or {})
        documents = list(documents_cursor)

        logger.info(f"Retrieved {len(documents)} documents from collection: {collection_name}")
        return documents

    except Exception as e:
        logger.exception(f"An error occurred while retrieving documents: {str(e)}")
        return []
    
# all_docs = retrieve_documents("Zalando")
# print(all_docs)