"use client";

import { useEffect, useRef, useState } from "react";
import type L from "leaflet";
import { c2api } from "@/lib/c2api";
import type { Ny511Response } from "@/lib/types";

// 511NY cameras/events for the current map view (server-26#183). Unlike
// useAircraft/useVessels this is not a Firestore listener: the data is public
// and statewide, so c2-core caches it in memory and serves a bbox slice.
// Fetches only while `enabled` (the overlay is on), on pan/zoom (debounced),
// and on a poll matching the server's events TTL.
const POLL_MS = 2 * 60 * 1000;
const MOVE_DEBOUNCE_MS = 400;
const BBOX_PAD = 0.2;   // fetch a little past the edges so small pans don't blank the layer

export function use511(map: L.Map, layers: "cameras" | "events", enabled: boolean) {
  const [data, setData] = useState<Ny511Response>({});
  const [error, setError] = useState<string | null>(null);
  const seq = useRef(0);

  useEffect(() => {
    if (!enabled) { setData({}); return; }
    let debounce: ReturnType<typeof setTimeout> | undefined;

    const load = async () => {
      const b = map.getBounds().pad(BBOX_PAD);
      const mine = ++seq.current;
      try {
        const res = await c2api.get511(
          { south: b.getSouth(), west: b.getWest(), north: b.getNorth(), east: b.getEast() },
          layers,
        );
        if (mine !== seq.current) return;   // a newer pan's response wins
        setData(res);
        setError(null);
      } catch (e) {
        if (mine !== seq.current) return;
        console.error("use511:", e);
        setError(e instanceof Error ? e.message : String(e));
      }
    };
    const onMove = () => { clearTimeout(debounce); debounce = setTimeout(load, MOVE_DEBOUNCE_MS); };

    load();
    map.on("moveend", onMove);
    const poll = setInterval(load, POLL_MS);
    return () => {
      map.off("moveend", onMove);
      clearTimeout(debounce);
      clearInterval(poll);
      seq.current++;   // drop any in-flight response
    };
  }, [map, layers, enabled]);

  return { data, error };
}