import { NextRequest } from "next/server";
import { getTask, getZipPathForTask } from "@/lib/testcase-backend";
import fs from "fs/promises";

export async function GET(
  _req: NextRequest,
  { params }: { params: Promise<{ taskId: string }> }
) {
  const { taskId } = await params;
  if (!taskId) {
    return Response.json({ error: "缺少 taskId" }, { status: 400 });
  }

  const task = getTask(taskId);
  if (!task) {
    return Response.json({ error: "任务未找到" }, { status: 404 });
  }

  if (task.status !== "completed") {
    return Response.json({ error: "任务尚未完成" }, { status: 400 });
  }

  const zipPath = getZipPathForTask(taskId);
  if (!zipPath) {
    return Response.json({ error: "文件未找到" }, { status: 404 });
  }

  try {
    const buffer = await fs.readFile(zipPath);
    const filename = `${task.englishName}_testcases.zip`;
    return new Response(buffer, {
      status: 200,
      headers: {
        "Content-Type": "application/zip",
        "Content-Disposition": `attachment; filename="${encodeURIComponent(filename)}"`,
      },
    });
  } catch (e) {
    console.error("[testcase] download read error:", e);
    return Response.json({ error: "文件读取失败" }, { status: 500 });
  }
}