import type { PlayerState } from "@deadhead/schema";
import { useQuery } from "@tanstack/react-query";
import { useEffect, useRef } from "react";
import { ApiError, type ApiClient } from "../api/client";
import { useApi } from "../api/context";
import { useClock } from "../clock/clock";

export const PLAYER_STATE_KEY = ["player-state"] as const;

/** Player state, or null when there is no company on this device yet ("unauthorized"). */
export async function fetchPlayerState(api: ApiClient): Promise<PlayerState | null> {
  try {
    return await api.call("getPlayerState", {});
  } catch (error) {
    if (error instanceof ApiError && error.code === "unauthorized") return null;
    throw error;
  }
}

/**
 * Server player state (Step 8.5), shared by every screen. Refetched when the app
 * regains focus; `App` also runs `useRefetchOnArrival` once for arrivals.
 */
export function usePlayerState() {
  const api = useApi();
  const query = useQuery({
    queryKey: PLAYER_STATE_KEY,
    queryFn: () => fetchPlayerState(api),
    // Screens share this query; fresh for 10 s so mounting a screen does not refetch.
    // Returning to the app, arrivals and actions always refetch.
    staleTime: 10_000,
    refetchOnWindowFocus: "always",
  });
  return query;
}

/**
 * Refetches once the server clock passes the earliest in-flight arrival, so the
 * server resolves it and the UI shows the result. Each dispatch triggers at most
 * one refetch.
 */
export function useRefetchOnArrival(state: PlayerState | null, refetch: () => unknown) {
  const now = useClock((s) => s.now);
  const triggered = useRef(new Set<string>());

  useEffect(() => {
    if (!state) return;
    const arrived = state.activeDispatches.filter(
      (d) => d.arrivalAt <= now && !triggered.current.has(d.id),
    );
    if (arrived.length === 0) return;
    for (const d of arrived) triggered.current.add(d.id);
    void refetch();
  }, [state, now, refetch]);
}