from __future__ import annotations

import asyncio
import logging

logger = logging.getLogger(__name__)


class PollingScheduler:
    def __init__(self, poll_func, interval: int = 30):
        self._poll_func = poll_func
        self._interval = interval
        self._task: asyncio.Task | None = None
        self._running = False

    async def start(self) -> None:
        self._running = True
        self._task = asyncio.create_task(self._run_loop())
        logger.info("Help Scout polling scheduler started: interval=%ds", self._interval)

    async def stop(self) -> None:
        self._running = False
        if self._task:
            self._task.cancel()
            try:
                await self._task
            except asyncio.CancelledError:
                pass
        logger.info("Help Scout polling scheduler stopped")

    async def _run_loop(self) -> None:
        backoff = 1
        max_backoff = 300

        while self._running:
            try:
                await self._poll_func()
                backoff = 1
            except asyncio.CancelledError:
                break
            except Exception:
                logger.exception("Help Scout polling error — backing off %ds", backoff)
                await asyncio.sleep(backoff)
                backoff = min(backoff * 2, max_backoff)
                continue

            await asyncio.sleep(self._interval)