"use client";

/**
 * 拉取并缓存 /api/node-types 节点目录(每会话一次,模块级缓存)。
 * 对齐 dograh 的 useNodeSpecs:规格随后端 + 刷新生效。
 */

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

import { nodeTypesApi, type NodeTypesResponse } from "@/lib/api";
import {
  toRuntimeSpec,
  type NodeSpecMap,
  type RuntimeNodeSpec,
} from "./specs";

let _cache: NodeTypesResponse | null = null;

type State = {
  specs: RuntimeNodeSpec[];
  byType: NodeSpecMap;
  loading: boolean;
  error: string | null;
};

function build(data: NodeTypesResponse | null): {
  specs: RuntimeNodeSpec[];
  byType: NodeSpecMap;
} {
  const specs = (data?.nodeTypes ?? []).map(toRuntimeSpec);
  const byType: NodeSpecMap = {};
  for (const spec of specs) byType[spec.type] = spec;
  return { specs, byType };
}

export function useNodeSpecs(): State {
  const fetched = useRef(false);
  const [state, setState] = useState<State>(() => {
    const { specs, byType } = build(_cache);
    return { specs, byType, loading: !_cache, error: null };
  });

  useEffect(() => {
    if (_cache || fetched.current) return;
    fetched.current = true;

    nodeTypesApi
      .list()
      .then((data) => {
        _cache = data;
        const { specs, byType } = build(data);
        setState({ specs, byType, loading: false, error: null });
      })
      .catch((err: unknown) => {
        const message = err instanceof Error ? err.message : String(err);
        setState((s) => ({ ...s, loading: false, error: message }));
      });
  }, []);

  return state;
}