"""True long-polling for Telegram updates.

Uses timeout parameter to keep connection hung open.
Inbound messages process instantly, no 30s latency.

Uses TELEGRAM_BOT_TOKEN from staging config — which is the test bot
in staging environment (8469114191:...), NOT production.
"""
import asyncio
import logging

import httpx

from icarus.core.config.staging import TELEGRAM_BOT_TOKEN
from icarus.core.telegram.handler import process_update

BASE_URL = f"https://api.telegram.org/bot{TELEGRAM_BOT_TOKEN}"
OFFSET = 0


async def polling_loop():
    """Long-polling loop running alongside FastAPI."""
    global OFFSET

    # Clear any existing webhook first
    async with httpx.AsyncClient() as client:
        try:
            resp = await client.post(f"{BASE_URL}/deleteWebhook")
            result = resp.json()
            if result.get("ok"):
                logging.info("[polling] Webhook cleared, starting long-polling...")
            else:
                logging.warning("[polling] deleteWebhook: %s", result)
        except Exception as e:
            logging.warning("[polling] Failed to clear webhook: %s", e)

    logging.info("[polling] Long-polling loop started")

    while True:
        try:
            async with httpx.AsyncClient(timeout=65.0) as client:
                # timeout=60 keeps connection hung open (+5s buffer)
                resp = await client.post(
                    f"{BASE_URL}/getUpdates",
                    json={"offset": OFFSET, "limit": 100, "timeout": 60}
                )
                resp.raise_for_status()
                data = resp.json()

                if data.get("ok") and data.get("result"):
                    for update in data["result"]:
                        OFFSET = update["update_id"] + 1
                        logging.info("[polling] Processing update %s", update["update_id"])
                        try:
                            await process_update(update)
                        except Exception as e:
                            logging.exception("[polling] Error processing update: %s", e)

        except asyncio.CancelledError:
            logging.info("[polling] Loop cancelled, exiting")
            break
        except Exception as e:
            logging.error("[polling] Polling error: %s", e)
            await asyncio.sleep(5)  # Backoff on error


async def start_polling():
    """Entry point to start background task."""
    logging.info("[polling] Starting background polling task")
    asyncio.create_task(polling_loop())