import { useEffect } from "react";
import { supabase } from "../lib/supabase";
import { useDeviceApprovalStore } from "../stores/deviceApproval";
import type { RealtimeChannel } from "@supabase/supabase-js";

/**
 * Realtime-Subscription für Device-Approval-Requests.
 *
 * Lauscht auf INSERT/UPDATE auf rebreak.device_approval_requests gefiltert
 * nach user_id. Wenn eine pending Row hereinkommt → triggert
 * refreshIncomingFromServer() (holt die newest pending Row und zeigt das
 * Approval-Sheet auf diesem existierenden Gerät).
 *
 * Wird global im _layout.tsx aufgerufen — IMMER aktiv für eingeloggte User.
 */
export function useDeviceApprovalRealtime(enabled: boolean = true) {
  const refreshIncoming = useDeviceApprovalStore(
    (s) => s.refreshIncomingFromServer,
  );

  useEffect(() => {
    if (!enabled) return;
    let channel: RealtimeChannel | null = null;
    let cancelled = false;
    let reconnectTimer: ReturnType<typeof setTimeout> | null = null;

    async function subscribe() {
      const { data } = await supabase.auth.getSession();
      const session = data.session;
      if (!session?.access_token) return;
      if (cancelled) return;

      const myId = session.user.id;

      // Initial pull (in case we missed something while offline)
      refreshIncoming();

      channel = supabase
        .channel(`device_approvals:${myId}:${Date.now()}`)
        .on(
          "postgres_changes",
          {
            event: "INSERT",
            schema: "rebreak",
            table: "device_approval_requests",
            filter: `user_id=eq.${myId}`,
          },
          () => refreshIncoming(),
        )
        .on(
          "postgres_changes",
          {
            event: "UPDATE",
            schema: "rebreak",
            table: "device_approval_requests",
            filter: `user_id=eq.${myId}`,
          },
          () => refreshIncoming(),
        )
        .subscribe((status, err) => {
          if (status === "CHANNEL_ERROR" || status === "TIMED_OUT") {
            console.warn("[approvalRealtime] error:", status, err ?? "");
            cleanup();
            if (reconnectTimer) clearTimeout(reconnectTimer);
            reconnectTimer = setTimeout(() => {
              if (!cancelled) subscribe();
            }, 3000);
          }
        });
    }

    function cleanup() {
      if (channel) {
        supabase.removeChannel(channel).catch(() => {});
        channel = null;
      }
    }

    subscribe();

    return () => {
      cancelled = true;
      if (reconnectTimer) clearTimeout(reconnectTimer);
      cleanup();
    };
  }, [enabled, refreshIncoming]);
}