"use client";

import { useEffect, useState } from "react";
import { collection, onSnapshot, query, orderBy, limit, where, FirestoreError } from "firebase/firestore";
import { onAuthStateChanged } from "firebase/auth";
import { db, auth } from "@/lib/firebase";
import type { AlertEvent } from "@/lib/types";

const toISO = (v: unknown): string =>
  (v as { toDate?: () => Date })?.toDate?.()?.toISOString?.() ??
  (typeof v === "string" ? v : new Date().toISOString());

export function useAlerts(limitCount = 50) {
  const [alerts, setAlerts] = useState<AlertEvent[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    let unsubFirestore: (() => void) | undefined;

    const unsubAuth = onAuthStateChanged(auth, (user) => {
      if (unsubFirestore) { unsubFirestore(); unsubFirestore = undefined; }

      if (!user) {
        setAlerts([]);
        setLoading(false);
        return;
      }

      const q = query(
        collection(db, "alert_events"),
        orderBy("triggered_at", "desc"),
        limit(limitCount)
      );
      unsubFirestore = onSnapshot(q, (snap) => {
        setAlerts(snap.docs.map((d) => {
          const data = d.data();
          return {
            ...data,
            triggered_at: toISO(data.triggered_at),
          } as AlertEvent;
        }));
        setLoading(false);
      }, (err: FirestoreError) => {
        console.error("useAlerts:", err);
        setError(err.message);
        setLoading(false);
      });
    });

    return () => {
      unsubAuth();
      if (unsubFirestore) unsubFirestore();
    };
  }, [limitCount]);

  return { alerts, loading, error };
}

export function useUnacknowledgedAlerts() {
  const [alerts, setAlerts] = useState<AlertEvent[]>([]);

  useEffect(() => {
    let unsubFirestore: (() => void) | undefined;

    const unsubAuth = onAuthStateChanged(auth, (user) => {
      if (unsubFirestore) { unsubFirestore(); unsubFirestore = undefined; }

      if (!user) {
        setAlerts([]);
        return;
      }

      const q = query(
        collection(db, "alert_events"),
        where("acknowledged", "==", false),
        orderBy("triggered_at", "desc"),
        limit(100)
      );
      unsubFirestore = onSnapshot(q, (snap) => {
        setAlerts(snap.docs.map((d) => {
          const data = d.data();
          return { ...data, triggered_at: toISO(data.triggered_at) } as AlertEvent;
        }));
      }, (err: FirestoreError) => { console.error("useUnacknowledgedAlerts:", err); });
    });

    return () => {
      unsubAuth();
      if (unsubFirestore) unsubFirestore();
    };
  }, []);

  return alerts;
}