import { NextRequest, NextResponse } from "next/server";
import { importWords, type Grade } from "@/lib/db";
import { parseWordExcel } from "@/lib/word-excel";

export const runtime = "nodejs";
export const dynamic = "force-dynamic";

export async function POST(request: NextRequest) {
  try {
    const formData = await request.formData();
    const grade = String(formData.get("grade") ?? "") as Grade;
    const classTypeId = Number(formData.get("classTypeId"));
    const file = formData.get("file");

    if (!(file instanceof File)) {
      return NextResponse.json({ message: "请选择要导入的 Excel 表格" }, { status: 400 });
    }

    const buffer = Buffer.from(await file.arrayBuffer());
    const rows = parseWordExcel(buffer);
    const result = importWords(grade, classTypeId, rows);

    return NextResponse.json({ result });
  } catch (error) {
    return NextResponse.json({ message: getErrorMessage(error) }, { status: 400 });
  }
}

function getErrorMessage(error: unknown) {
  const message = error instanceof Error ? error.message : "导入失败";
  if (message.includes("FOREIGN KEY")) return "班级类型不存在";
  if (message.includes("Unsupported file")) return "无法读取该表格，请使用 .xlsx 文件";
  return message;
}