import { useCallback, useEffect, useRef, useState } from "react";

interface AsyncState<T> {
  data: T | null;
  loading: boolean;
  error: string | null;
  reload: () => void;
}

/** Runs an async factory on mount (and on reload), tracking loading/error so
 *  every API-backed surface has a complete state. Best-effort, no `any`. */
export function useAsyncData<T>(fn: () => Promise<T>, deps: readonly unknown[] = []): AsyncState<T> {
  const [data, setData] = useState<T | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const fnRef = useRef(fn);
  fnRef.current = fn;
  const depsKey = deps.join("\u0000");

  const run = useCallback(() => {
    let cancelled = false;
    setLoading(true);
    setError(null);
    fnRef
      .current()
      .then((res) => {
        if (!cancelled) setData(res);
      })
      .catch((err: unknown) => {
        if (!cancelled) setError(err instanceof Error ? err.message : "加载失败");
      })
      .finally(() => {
        if (!cancelled) setLoading(false);
      });
    return () => {
      cancelled = true;
    };
  }, [depsKey]);

  useEffect(() => {
    const cancel = run();
    return cancel;
  }, [run]);

  return { data, loading, error, reload: run };
}