import time
import logging
import requests
import jwt
from django.conf import settings

logger = logging.getLogger(__name__)


def generate_centrifugo_token(user, exp_seconds: int = 86400 * 7) -> str:
    """
    Generates an HMAC-SHA256 connection JWT for Centrifugo v5.
    Subject ('sub') is the unique user ID string.
    """
    secret = getattr(settings, 'CENTRIFUGO_SECRET', 'super_secret_centrifugo_token_key_hmac_256')
    now = int(time.time())
    payload = {
        'sub': str(user.id),
        'exp': now + exp_seconds,
        'iat': now,
        'info': {
            'id': user.id,
            'email': user.email or '',
            'fullname': user.fullname or user.email or '',
            'user_type': getattr(user, 'user_type', 'client'),
        }
    }
    return jwt.encode(payload, secret, algorithm='HS256')


def publish_to_centrifugo(channel: str, data: dict) -> bool:
    """
    Publishes real-time JSON payload to a Centrifugo v5 channel via HTTP API.
    Channel format: 'chat:{room_id}' or 'notifications:{user_id}'.
    """
    api_url = getattr(settings, 'CENTRIFUGO_API_URL', 'http://centrifugo:8000/api')
    api_key = getattr(settings, 'CENTRIFUGO_API_KEY', 'centrifugo_internal_api_access_key')

    # Centrifugo v5 API publish payload
    endpoint = f"{api_url.rstrip('/')}/publish"
    headers = {
        'Content-Type': 'application/json',
        'X-API-Key': api_key,
        'Authorization': f'apikey {api_key}',
    }
    payload = {
        'channel': channel,
        'data': data
    }

    try:
        response = requests.post(endpoint, json=payload, headers=headers, timeout=2.0)
        if response.status_code in (200, 201):
            logger.debug(f"Centrifugo published to {channel}: {data.get('type', 'message')}")
            return True
        else:
            logger.warning(f"Centrifugo API error ({response.status_code}): {response.text}")
            return False
    except Exception as exc:
        # Graceful fallback: allow persistence to succeed even if Centrifugo container is offline in dev/test
        logger.warning(f"Centrifugo publish failed (offline or unreachable): {exc}")
        return False