import firebase_admin
from firebase_admin import credentials, messaging
from dotenv import load_dotenv
import requests
import os

load_dotenv()

def check_can_send_notifs():
    required_env_vars = [
        "KV_REST_API_URL",
        "KV_REST_API_TOKEN",
        "FIREBASE_SERVICE_ACCOUNT_JSON_PATH"
    ]
    missing_vars = [var for var in required_env_vars if os.environ.get(var) is None]
    if missing_vars:
        return False
    else:
        return True

def get_tokens(topic):
    upstash_rest_api_url = os.environ.get("KV_REST_API_URL")
    upstash_token = os.environ.get("KV_REST_API_TOKEN")
    url = f"{upstash_rest_api_url}/smembers/fcm-{topic}"
    resp = requests.get(
        url,
        headers={"Authorization": f"Bearer {upstash_token}"}
    )
    if resp.status_code != 200:
        print("Upstash error:", resp.text)
        return []
    data = resp.json()
    return data.get("result", [])

def broadcast_to_topic(topic: str, title: str, body: str, image):
    if not firebase_admin._apps:
        cred = credentials.Certificate(os.environ.get("FIREBASE_SERVICE_ACCOUNT_JSON_PATH"))
        firebase_admin.initialize_app(cred)

    tokens = get_tokens(topic)
    if not tokens:
        print(f"No tokens found for topic '{topic}'")
        return

    multicast_message = messaging.MulticastMessage(
        notification=messaging.Notification(
            title=title,
            body=body,
            image=image
        ),
        tokens=tokens
    )
    try:
        response = messaging.send_each_for_multicast(multicast_message)
        print(f"Successfully sent {response.success_count} messages out of {len(tokens)}")
        if response.failure_count > 0:
            print(f"Failed to send {response.failure_count} messages")
            upstash_rest_api_url = os.environ.get("KV_REST_API_URL")
            upstash_token = os.environ.get("KV_REST_API_TOKEN")
            for idx, error in enumerate(response.responses):
                if not error.success:
                    failed_token = tokens[idx]
                    print(f"Error for token {failed_token}: {error.exception}")
                    url = f"{upstash_rest_api_url}/srem/fcm-{topic}"
                    resp = requests.post(
                        url,
                        headers={"Authorization": f"Bearer {upstash_token}"},
                        json={"value": failed_token}
                    )
                    if resp.status_code != 200:
                        print(f"Failed to remove token {failed_token} from topic '{topic}': {resp.text}")
                    else:
                        print(f"Removed token {failed_token} from topic '{topic}'")
    except Exception as e:
        print(f"Error sending multicast message: {e}")