"""预警引擎：拉取实时价格，评估规则，触发即生成站内事件。"""
from __future__ import annotations

import datetime as dt

from sqlalchemy import select

import akshare_service as svc
import notifier
from db import get_session
from models import AlertRule, AlertEvent

KIND_LABEL = {
    "price_above": "价格突破",
    "price_below": "价格跌破",
    "pct_above": "涨幅达到",
    "pct_below": "跌幅达到",
}


def _hit(kind, threshold, q):
    price, pct = q["price"], q["pct"]
    if kind == "price_above":
        return price >= threshold, price
    if kind == "price_below":
        return price <= threshold, price
    if kind == "pct_above":
        return pct >= threshold, pct
    if kind == "pct_below":
        return pct <= -abs(threshold), pct
    return False, price


def check_alerts():
    with get_session() as s:
        rules = s.execute(select(AlertRule).where(AlertRule.status == "active")).scalars().all()
        if not rules:
            return {"checked": 0, "triggered": 0}
        codes = list({r.code for r in rules})
        quotes = svc.realtime_quotes(codes)
        triggered = 0
        push_msgs = []
        for r in rules:
            q = quotes.get(r.code)
            if not q:
                continue
            hit, val = _hit(r.kind, r.threshold, q)
            r.last_value = q["price"]
            if hit:
                unit = "" if r.kind.startswith("price") else "%"
                msg = (f"{q['name']} {KIND_LABEL.get(r.kind, r.kind)} {r.threshold}{unit}"
                       f"（现价 {q['price']}，{q['pct']:+.2f}%）")
                s.add(AlertEvent(rule_id=r.id, code=r.code, name=q["name"], message=msg, value=val))
                r.status = "triggered"
                r.triggered_at = dt.datetime.now()
                triggered += 1
                push_msgs.append(msg)
        s.commit()

    # 触发后向已配置渠道推送（站外）
    if push_msgs and notifier.any_enabled():
        try:
            notifier.notify("【Blackdata预警】" + (push_msgs[0] if len(push_msgs) == 1 else f"{len(push_msgs)} 条预警触发"),
                            "\n".join(push_msgs))
        except Exception:
            pass
    return {"checked": len(rules), "triggered": triggered}