from __future__ import annotations

import asyncio
import logging
from datetime import datetime, timezone
from typing import Optional

import httpx

from backend import config, db

logger = logging.getLogger(__name__)

_TELEGRAM_API = "https://api.telegram.org/bot{token}/{method}"


async def send_message(text: str) -> None:
    url = _TELEGRAM_API.format(token=config.BOT_TOKEN, method="sendMessage")
    async with httpx.AsyncClient(timeout=10) as client:
        for attempt in range(3):
            resp = await client.post(url, json={"chat_id": config.CHAT_ID, "text": text})
            if resp.status_code == 429:
                retry_after = resp.json().get("parameters", {}).get("retry_after", 30)
                sleep = retry_after * (attempt + 1)
                logger.warning("Telegram 429, sleeping %s sec (attempt %d)", sleep, attempt + 1)
                await asyncio.sleep(sleep)
                continue
            if resp.status_code >= 500:
                logger.error("Telegram 5xx: %s", resp.text)
                await asyncio.sleep(30)
                continue
            elif resp.status_code != 200:
                logger.error("Telegram error %s: %s", resp.status_code, resp.text)
            break
        else:
            logger.error("Telegram send_message: all 3 attempts failed, message dropped")


async def set_webhook(url: str, secret: str) -> None:
    api_url = _TELEGRAM_API.format(token=config.BOT_TOKEN, method="setWebhook")
    async with httpx.AsyncClient(timeout=10) as client:
        resp = await client.post(
            api_url, json={"url": url, "secret_token": secret}
        )
    if resp.status_code != 200 or not resp.json().get("result"):
        raise RuntimeError(f"setWebhook failed: {resp.text}")
    logger.info("Webhook registered: %s", url)


# v2.0 feature
class SignalAggregator:
    def __init__(self, interval: int = 10) -> None:
        self._interval = interval
        self._buffer: list[dict] = []
        self._lock = asyncio.Lock()
        self._stopped = False

    async def add_signal(
        self,
        user_uuid: str,
        user_name: Optional[str],
        timestamp: int,
        geo: Optional[dict],
        signal_id: int,
    ) -> None:
        async with self._lock:
            self._buffer.append(
                {
                    "user_uuid": user_uuid,
                    "user_name": user_name,
                    "timestamp": timestamp,
                    "geo": geo,
                    "signal_id": signal_id,
                }
            )

    async def flush(self) -> None:
        async with self._lock:
            if not self._buffer:
                return
            items = self._buffer[:]
            self._buffer.clear()

        signal_ids = [item["signal_id"] for item in items]
        timestamps = [item["timestamp"] for item in items]
        ts_start = datetime.fromtimestamp(min(timestamps) / 1000, tz=timezone.utc)
        ts_end = datetime.fromtimestamp(max(timestamps) / 1000, tz=timezone.utc)
        t_fmt = "%H:%M:%S"

        names = []
        for item in items:
            name = item["user_name"]
            label = name if name else item["user_uuid"][:8]
            names.append(label)

        geo_count = sum(1 for item in items if item["geo"])
        n = len(items)

        text = (
            f"\U0001f6a8 Получено {n} сигнал{'ов' if n != 1 else ''} "
            f"[{ts_start.strftime(t_fmt)}—{ts_end.strftime(t_fmt)}]\n"
            f"Пользователи: {', '.join(names)}\n"
            f"\U0001f4cd С геолокацией: {geo_count} из {n}"
        )

        try:
            await send_message(text)
            await db.save_telegram_batch(text, n, signal_ids)
            # rate-limit: 1 msg/sec max (#1014)
            await asyncio.sleep(1)
        except Exception:
            logger.exception("Failed to flush aggregator batch")

    async def run(self) -> None:
        while not self._stopped:
            await asyncio.sleep(self._interval)
            if self._buffer:
                await self.flush()

    def stop(self) -> None:
        self._stopped = True