"""消息轮询引擎"""

from __future__ import annotations

import logging
import time
from collections.abc import Callable

from ..config import Config
from ..models.message import Message
from ..ui.message import MessageList
from .event import MessageEvent

logger = logging.getLogger(__name__)

# 回调签名
MessageCallback = Callable[[MessageEvent], None]


class PollingEngine:
    """以轮询方式持续从聊天面板提取新消息"""

    def __init__(self, message_list: MessageList, config: Config) -> None:
        self._message_list = message_list
        self.config = config
        self._callbacks: list[MessageCallback] = []
        self._seen_ids: set[str] = set()
        self._last_poll: float = 0
        self._running = False

    # ------------------------------------------------------------------
    # 回调注册
    # ------------------------------------------------------------------

    def on_message(self, callback: MessageCallback) -> None:
        """注册新消息回调"""
        self._callbacks.append(callback)

    # ------------------------------------------------------------------
    # 轮询控制
    # ------------------------------------------------------------------

    def poll_once(self, conversation: str = "") -> list[Message]:
        """执行一次消息提取，返回去重后的新消息"""
        try:
            messages = self._message_list.extract_messages(conversation)
        except Exception:
            logger.exception("提取消息失败")
            return []

        new_messages: list[Message] = []
        for msg in messages:
            if msg.msg_id not in self._seen_ids:
                self._seen_ids.add(msg.msg_id)
                new_messages.append(msg)

        # 清理过期的去重 ID（防止内存泄漏）
        if len(self._seen_ids) > 10_000:
            self._seen_ids = set(list(self._seen_ids)[-5_000:])

        # 触发回调
        for msg in new_messages:
            event = MessageEvent(message=msg)
            for cb in self._callbacks:
                try:
                    cb(event)
                except Exception:
                    logger.exception("消息回调执行失败")

        self._last_poll = time.time()
        return new_messages

    def start_loop(self, conversation: str = "", stop_event=None) -> None:
        """持续轮询，直到 stop_event 被 set 或调用 stop()"""
        self._running = True
        logger.info("轮询引擎启动 (间隔 %.1fs)", self.config.poll_interval)

        while self._running:
            if stop_event is not None and stop_event.is_set():
                break
            self.poll_once(conversation)
            time.sleep(self.config.poll_interval)

        logger.info("轮询引擎已停止")

    def stop(self) -> None:
        self._running = False