import assert from "node:assert/strict";
import { spawn } from "node:child_process";
import { once } from "node:events";
import { Writable } from "node:stream";
import test from "node:test";
import { writeBusinessReport } from "./business-report.mjs";

test("large UTF-8 business report survives pipe backpressure before explicit exit", async () => {
  const script = `import {writeBusinessReport} from ${JSON.stringify(new URL("./business-report.mjs", import.meta.url).href)};
    await writeBusinessReport({schema:"freecad-web-business-cases/v1",data:"\\u4e2d".repeat(400000),results:[{capabilityId:"TechDraw:export",status:"passed"}]});
    process.exit(0);`;
  const child = spawn(process.execPath, ["--input-type=module", "-e", script], { stdio: ["ignore", "pipe", "pipe"] });
  const done = once(child, "close");
  const chunks = [];
  let error = "";
  child.stderr.on("data", value => { error += value; });
  child.stdout.pause();
  const timer = setTimeout(() => child.stdout.resume(), 50);
  child.stdout.on("data", value => chunks.push(value));
  const [code] = await done;
  clearTimeout(timer);
  assert.equal(code, 0, error);
  const bytes = Buffer.concat(chunks);
  assert.ok(bytes.length > 1000000);
  const report = JSON.parse(bytes.toString("utf8"));
  assert.equal(report.data.length, 400000);
  assert.equal(report.results[0].status, "passed");
});

test("writer waits for the final callback and rejects write failure", async () => {
  let flushed = false;
  const stream = new Writable({ write(_chunk, _encoding, callback) {
    setTimeout(() => { flushed = true; callback(); }, 5);
  } });
  const writing = writeBusinessReport({ results: [] }, stream);
  assert.equal(flushed, false);
  await writing;
  assert.equal(flushed, true);
  const broken = new Writable({ write(_chunk, _encoding, callback) { callback(new Error("pipe closed")); } });
  broken.on("error", () => {});
  await assert.rejects(writeBusinessReport({}, broken), /pipe closed/);
});