"use client";

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

import { api } from "@/lib/api/client";
import type { ForeshadowView } from "@/lib/api/types";
import {
  classifyChapterForeshadow,
  type ChapterForeshadowGroups,
} from "./chapterForeshadow";

// 写作台「本章伏笔」提醒的数据层：拉本项目全量伏笔（GET /foreshadow，只读），
// 再按当前章号本地分类。项目内一次拉取，切章仅重新分类（不重复请求）。
export type ChapterForeshadowStatus = "loading" | "ready" | "error";

export interface UseChapterForeshadow {
  groups: ChapterForeshadowGroups;
  status: ChapterForeshadowStatus;
  reload: () => void;
}

const FORESHADOW_PATH = "/projects/{project_id}/foreshadow" as const;
const EMPTY_ITEMS: ForeshadowView[] = [];

export function useChapterForeshadow(
  projectId: string,
  chapterNo: number,
): UseChapterForeshadow {
  const [items, setItems] = useState<ForeshadowView[]>(EMPTY_ITEMS);
  const [status, setStatus] = useState<ChapterForeshadowStatus>("loading");
  // reload 触发器：自增即重新拉取。
  const [nonce, setNonce] = useState(0);

  useEffect(() => {
    let cancelled = false;
    setStatus("loading");
    void (async () => {
      try {
        const { data, error } = await api.GET(FORESHADOW_PATH, {
          params: { path: { project_id: projectId } },
        });
        if (cancelled) return;
        if (error || !data) {
          setItems(EMPTY_ITEMS);
          setStatus("error");
          return;
        }
        setItems(data.foreshadow ?? EMPTY_ITEMS);
        setStatus("ready");
      } catch {
        // 网络层失败（后端不可达/CORS）：openapi-fetch 直接抛而非返回 error 信封。
        if (cancelled) return;
        setItems(EMPTY_ITEMS);
        setStatus("error");
      }
    })();
    return () => {
      cancelled = true;
    };
  }, [projectId, nonce]);

  // 切章不重拉，仅重新分类（伏笔窗口相对章号变化）。
  const groups = useMemo(
    () => classifyChapterForeshadow(items, chapterNo),
    [items, chapterNo],
  );

  const reload = useCallback(() => setNonce((n) => n + 1), []);

  return { groups, status, reload };
}