"use client";

import { useCallback, useState } from "react";

import { api } from "@/lib/api/client";
import { useToast } from "@/components/Toast";
import { friendlyFromApiError } from "@/lib/errors/messages";
import type { OutlineChapterView } from "@/lib/api/types";

export type OutlineStatus = "idle" | "generating" | "ready" | "error";

export interface OutlineError {
  code: string;
  message: string;
}

export interface UseOutline {
  chapters: OutlineChapterView[];
  status: OutlineStatus;
  error: OutlineError | null;
  generate: (projectId: string, volume: number) => Promise<void>;
}

// 生成大纲：POST .../outline（body {volume}）。无凭据/网关失败 → 503 LLM_UNAVAILABLE
// （流前 JSON 信封），经 error 检出、引导去设置（同 draft/review 范式）。
export function useOutline(initial: OutlineChapterView[]): UseOutline {
  const [chapters, setChapters] = useState<OutlineChapterView[]>(initial);
  const [status, setStatus] = useState<OutlineStatus>(
    initial.length > 0 ? "ready" : "idle",
  );
  const [error, setError] = useState<OutlineError | null>(null);
  const toast = useToast();

  const generate = useCallback<UseOutline["generate"]>(
    async (projectId, volume) => {
      setStatus("generating");
      setError(null);
      const { data, error: apiError } = await api.POST(
        "/projects/{project_id}/outline",
        {
          params: { path: { project_id: projectId } },
          body: { volume },
        },
      );
      if (apiError || !data) {
        // surface 真实错因（如 LLM_UNAVAILABLE→去设置 provider；422→校验文案），
        // 而非永远的通用「大纲生成失败」（QA #2：原 env.error.code 漏读 422 的 detail 信封）。
        const friendly = friendlyFromApiError(apiError);
        setError({ code: "OUTLINE_FAILED", message: friendly.text });
        setStatus("error");
        toast(friendly.text, "error");
        return;
      }
      setChapters(data.chapters ?? []);
      setStatus("ready");
      toast("大纲已生成", "success");
    },
    [toast],
  );

  return { chapters, status, error, generate };
}