import firebase_admin
from firebase_admin import credentials, firestore
import json
import logging
from api.core.config import settings # Changed import path

logger = logging.getLogger(__name__)

db = None # Global Firestore client instance

def initialize_firebase():
    """
    Initializes the Firebase Admin SDK.
    """
    global db
    if firebase_admin._apps: # Check if app is already initialized
        logger.info("Firebase Admin SDK already initialized.")
        db = firestore.client()
        return

    try:
        firebase_json_str = settings.FIREBASE_CREDENTIALS_JSON
        if not firebase_json_str:
            raise ValueError("FIREBASE_CREDENTIALS_JSON is not set in environment variables.")

        firebase_cred_dict = json.loads(firebase_json_str)
        cred = credentials.Certificate(firebase_cred_dict)
        firebase_admin.initialize_app(cred)
        db = firestore.client()
        logger.info("Firebase Admin SDK initialized successfully from environment variable.")
    except Exception as e:
        logger.error(f"Failed to initialize Firebase Admin SDK: {e}")
        db = None


def get_firestore_db():
    """Returns the initialized Firestore client."""
    if db is None:
        logger.warning("Firestore DB client not initialized. Attempting to initialize now.")
        initialize_firebase()
        if db is None:
            raise RuntimeError("Firestore DB client could not be initialized.")
    return db