import hashlib
import json
import time
from typing import Any

from sqlalchemy.orm import Session

from app.config import get_settings
from app.homelab.netdata import NetdataClient
from app.homelab.state import get_state, set_state

ALERT_COOLDOWN_SEC = 1800


def _alarm_key(alarm: dict[str, Any]) -> str:
    return f"{alarm.get('name')}:{alarm.get('status')}"


def check_netdata_alerts(db: Session) -> list[str]:
    settings = get_settings()
    if not settings.netdata_alerts_enabled:
        return []

    result = NetdataClient().fetch_alarms()
    if not result.get("ok"):
        return []

    alarms = result.get("alarms") or []
    significant = [
        a for a in alarms
        if (a.get("status") or "").lower() in ("warning", "critical", "raised")
    ]
    if not significant:
        return []

    prev_raw = get_state(db, "netdata_alarm_hashes") or "{}"
    try:
        prev_map: dict[str, float] = json.loads(prev_raw)
    except json.JSONDecodeError:
        prev_map = {}

    now = time.time()
    notices: list[str] = []
    new_map = dict(prev_map)

    for alarm in significant:
        key = _alarm_key(alarm)
        digest = hashlib.sha256(json.dumps(alarm, sort_keys=True).encode()).hexdigest()[:16]
        state_key = f"netdata:{key}:{digest}"
        last_sent = prev_map.get(state_key, 0)
        if now - last_sent < ALERT_COOLDOWN_SEC:
            continue

        host = alarm.get("host") or "server"
        value = alarm.get("value_string") or ""
        info = alarm.get("info") or alarm.get("name") or "алерт"
        status = alarm.get("status") or "alert"
        link = settings.netdata_public_url
        link_part = f" [Netdata]({link})" if link else ""
        notices.append(
            f"⚠️ **Netdata** · {host}: {info} — {status}"
            + (f" ({value})" if value else "")
            + link_part
        )
        new_map[state_key] = now

    if notices:
        set_state(db, "netdata_alarm_hashes", json.dumps(new_map))

    return notices