import {
  BOOKING_WINDOW_WS_EVENTS,
  BOOKING_WINDOW_WS_NAMESPACE,
  type BookingWindowPhaseEvent,
} from "@edr/types";
import { useQueryClient } from "@tanstack/react-query";
import { useEffect } from "react";
import { io } from "socket.io-client";

import { API_BASE_URL } from "@/constants/apiConfig";

function getAuthToken(): string | undefined {
  return document.cookie
    .split("; ")
    .find((row) => row.startsWith("auth-token="))
    ?.split("=")[1];
}

// The socket namespace lives at the server root, not under the `/api` REST
// prefix — strip a trailing `/api` if the base URL carries one.
const SOCKET_ORIGIN = String(API_BASE_URL ?? "").replace(/\/api\/?$/, "");

/**
 * Subscribes to live booking-window pushes. Every phase transition the window
 * engine applies (open, doc review, payment, reopen, done) invalidates the
 * cached window lists, so the home-page "Booking Windows" card flips the
 * moment the backend does — the 60s poll remains only as a fallback.
 */
export function useBookingWindowSocket(enabled: boolean) {
  const qc = useQueryClient();

  useEffect(() => {
    if (!enabled) return;
    const token = getAuthToken();
    if (!token) return;

    const socket = io(`${SOCKET_ORIGIN}/${BOOKING_WINDOW_WS_NAMESPACE}`, {
      auth: { token },
      transports: ["websocket"],
      withCredentials: true,
    });

    // Deliberate console breadcrumbs: "live updates not arriving" is only
    // diagnosable from the browser when connect/reject outcomes are visible.
    socket.on("connect", () =>
      console.debug("[booking-windows] socket connected", socket.id),
    );
    socket.on("connect_error", (err) =>
      console.warn("[booking-windows] socket connect failed:", err.message),
    );
    socket.on("disconnect", (reason) =>
      console.debug("[booking-windows] socket disconnected:", reason),
    );

    socket.on(
      BOOKING_WINDOW_WS_EVENTS.PHASE,
      (_event: BookingWindowPhaseEvent) => {
        qc.invalidateQueries({
          queryKey: ["train-scheduling", "myBookingWindows"],
        });
        qc.invalidateQueries({
          queryKey: ["train-scheduling", "contractBookingWindows"],
        });
      },
    );

    return () => {
      socket.off();
      socket.disconnect();
    };
  }, [enabled, qc]);
}