firestore_client.py

import os
import json
import firebase_admin
from firebase_admin import credentials, firestore

COLLECTION_NAME = "CoconutAdvice"

FIREBASE_CREDENTIALS_ENV = "FIREBASE_CREDENTIALS"

def init_firestore():
    """Initializes Firestore using a service account JSON provided via an environment variable.

    The environment variable should contain the full JSON contents of the Firebase service account
    key (the same JSON that would normally be stored in a file like `serviceAccountKey.json`).
    """
    if not firebase_admin._apps:
        creds_json = os.getenv(FIREBASE_CREDENTIALS_ENV)
        if not creds_json:
            raise EnvironmentError(
                f"Environment variable {FIREBASE_CREDENTIALS_ENV} is required and must contain "
                "Firebase service account JSON."
            )
        try:
            cred_dict = json.loads(creds_json)
        except json.JSONDecodeError as e:
            raise ValueError(
                f"Failed to parse JSON from {FIREBASE_CREDENTIALS_ENV}: {e}"
            ) from e

        cred = credentials.Certificate(cred_dict)
        firebase_admin.initialize_app(cred)
    return firestore.client()

db = init_firestore()

def get_advice_by_id(doc_id: str):
    """
    Fetch one advisory record by document ID.
    """
    doc = db.collection(COLLECTION_NAME).document(str(doc_id)).get()
    return doc.to_dict() if doc.exists else None